Sustainable Chemistry doi: 10.3390/suschem7020018

Authors: Joaquín Hernández-Fernández Rafael González-Cuello Rodrigo Ortega-Toro

In this work, density functional theory (DFT) was used to comparatively investigate the thermodynamic and electronic factors governing the association of Cd(II), Hg(II), and Pd(II) with native chitosan (CTS) and functionalized derivatives (CTS–COOH, CTS–COO−, CTS–NH3+, and CTS–SH). Representative acid–base states were considered to approximate changes in site availability, and a uniform explicit microhydration scheme was adopted to enable controlled relative comparisons across metals and materials. Within this framework, the calculated free energies suggest metal-dependent affinity regimes: the carboxylic microenvironment favors Cd(II), the thiolated microenvironment provides the most favorable association for Hg(II), and native CTS affords the strongest calculated stabilization for Pd(II). Geometry optimizations show that most complexes retain the first hydration sphere of the metal, indicating that stabilization is dominated by outer-sphere association rather than by systematic first-sphere ligand substitution. ESP/MEP maps reveal that the heterogeneity and directionality of the electrostatic landscape govern selectivity. In contrast, NCI analysis supports a cooperative contribution of weak interactions and second-sphere organization. These results provide a comparative electronic framework to guide future experimental validation of selective metal capture by functionalized chitosan materials.

Sustainable Chemistry doi: 10.3390/suschem7020017

Authors: Tianyi Guo David Thielen Malik Aydin Nils Tippkötter

Wheat straw is an abundant agricultural residue with high potential for carbohydrate-based bioconversion, yet its efficient utilization is limited by lignocellulosic recalcitrance. This study systematically investigated Organosolv extraction of wheat straw (Triticum aestivum) with the goal of achieving near-complete enzymatic hydrolysis at minimized process severity and energy demand. Process severity was evaluated using the P-Factor concept. In preliminary screening, acid catalysts and liquor ratios were assessed. Strong acids clearly outperformed weak acids: at comparable severity, 5% (w/w, DM) H2SO4 or p-toluenesulfonic acid (PTSA) yielded glucose yields of 83 ± 2.4% and 81 ± 6.2%, respectively, whereas weak acids (phosphoric, lactic, acetic) and a catalyst-free control resulted in only ~20–41% glucose yield. Liquor ratio strongly affected extraction performance; a ratio of 1:19 provided the highest glucose yield (85 ± 1.4%) and robust mixing compared to 1:12–1:15 (67–68%). Two novel pretreatment strategies applied prior to Organosolv extraction, namely Hot-Water Pretreatment (HWP) and Water Pretreatment (WP), significantly increased hydrolysability compared to untreated straw (58 ± 3%), reaching 79 ± 2% for HWP and 86 ± 5% for WP. DoE-based experiments (135–170 °C; P-Factor 3.0–4.0) showed that increasing temperature from 135 to 150 °C markedly improved hydrolysability (e.g., WP: 74 ± 3% to 96 ± 3%), while further increasing to 170 °C provided no additional benefit. Response-surface modeling predicted a maximum hydrolysability of approximately 88% for HWP but complete hydrolysis for WP within 152–170 °C, indicating a broad operational window. Overall, combining simple Water-based Pretreatment with severity-optimized Organosolv extraction enables energy-efficient, near-complete hydrolysis at lower operating temperatures, reducing both energy demand and pressure requirements, and thereby offering advantages in process cost and scalability.

Sustainable Chemistry doi: 10.3390/suschem7020016

Authors: Katherine Liset Ortiz Paternina Rodrigo Ortega-Toro Joaquín Hernández Fernández

The adsorption and activation of CO2 on CuxScy nanoclusters with x + y equal to 4 were analyzed using DFT and PDOS and TDOS signatures. The geometries of Cu3Sc, Cu2Sc2, and CuSc3 were optimized in the gas phase, and the minima were verified by frequencies in ORCA using M06-2X/def2-TZVP. Multiplicities 1, 3, and 5, temperatures between 298 and 400 K, and four CO2 coordination modes R1 to R4 were evaluated. Naked and complex cluster comparison panels were constructed, and two energy windows, −18 to −10 eV and −8 to 6 eV around the Fermi level, were analyzed, complemented by frontier orbitals and charge maps. Thermodynamics indicated that mode and multiplicity control the adsorption energy, with ANOVA p-values of 0.002 and 0.008, while temperature was not significant (p = 0.682). In Cu3Sc–C2v(1), the R1 singlet at 298 K showed Eads −33.43 kcal·mol−1 with spin contamination, while alternative modes in the singlet were unfavorable. In PDOS and TDOS, the bare cluster exhibits a Cu d band at −11 to −10 eV and a valley around −5 eV. The exergonic complexes show CO2 signals near the Fermi level, superimposed on Cu and Sc states, with state filling and broadening. Transferable indicators based on CO2 intensity in the −8 to 6 eV range and metal–adsorbate overlap are proposed as predictors of exergonic adsorption.

Sustainable Chemistry doi: 10.3390/suschem7010015

Authors: Suteera Witayakran Demi T. Djajadi Helle J. Martens Jens Risbo Mogens L. Andersen Lisbeth G. Thygesen

This study investigated the effects of adding lignin nanoparticles (LNPs) to glycerol-plasticized chitosan nanocomposite films (pCS-LNP). Specifically, different LNP sizes (mean hydrodynamic diameters of about 70, 125 or 170 nm) and loadings (1, 3 or 5% of CS) were studied. The two largest LNP types aggregated mostly in the upper side of the cast films, while the smallest LNP type was found more uniformly throughout the film cross-section. The results showed a trade-off between film properties. Both UV barrier, visible light opacity and antioxidant properties increased with increasing LNP loading, while smaller LNPs resulted in higher stiffness and tensile strength than larger types. The radical scavenging activity of the films correlated with the migration of lignin-derived substances out of the films.

Sustainable Chemistry doi: 10.3390/suschem7010014

Authors: Mirza Mariela Ruiz-Ramirez Balter Trujillo-Navarrete Rosa María Félix-Navarro Jassiel Rolando Rodríguez-Barreras Luis Pérez-Cabrera Arturo Zizumbo-López Juan José Hinostroza-Mojarro

This study presents the synthesis and ball-milling modification of titanite (CaTiSiO5) powders to enhance the thermal stability and performance of polypropylene (PP) separators for lithium-ion batteries (LIBs). CaTiSiO5 was synthesized using a ceramic route, and the experimental design varied the milling cycles and sphere sizes. Characterization techniques, including scanning electron microscopy, X-ray diffraction, Fourier-transform infra-red spectroscopy, surface area analysis, thermal analysis, and electrochemical tests, confirmed the production of high-purity monoclinic CaTiSiO5. Ball milling effectively reduced the particle and crystallite sizes while increasing the specific surface area, total pore volume, double-layer capacitance, and ionic conductivity, while also reducing the cell resistance. Coating PP separators with the modified CaTiSiO5 significantly improved their thermal stability and enhanced their electrochemical properties, including the electron transfer rate and Coulombic efficiency. These findings demonstrate the potential of ball-milled CaTiSiO5 as a valuable material for developing safer and more efficient LIBs.

Sustainable Chemistry doi: 10.3390/suschem7010013

Authors: Marta Piccioni Roberta Peila Maria Laura Tummino

This paper aims to analyze the biodegradation behavior of a common synthetic fiber, well-known for its environmental recalcitrance: polyamide 6.6. In particular, polyamide 6.6 fabrics finished with chitosan to impart antibacterial properties and the natural red dye carmine were studied. Fabrics of standard polyamide 6.6 served as references. Some specimens were buried in compost-enriched soil for 1, 2 and 3 months and kept in the laboratory; simultaneously, others were placed in an outdoor house garden to simulate landfill conditions. After each sample withdrawal, various characterization techniques were employed to assess the status of the fibers. The first evidence was that, in general, there were no weight changes or significant macroscopic damage within three months, except for white stains as an index of microorganism colonization, which was confirmed by microscopic analyses, where bacteria and fungi could be clearly seen. On the one hand, some effects were revealed during the burial in the house garden that impacted the fabrics’ surface characteristics in terms of interaction with soil derivatives (susceptibility to adsorption of water and soil-derived substances). On the other hand, the samples buried under laboratory conditions showed a weak antibacterial efficacy, leading to the hypothesis that more aggressive degradation may have occurred at the expense of chitosan. Still, three months of burial led to mild surface deterioration, opening possibilities for further research.

Sustainable Chemistry doi: 10.3390/suschem7010012

Authors: Abderrahim Bouaid

In this paper, batch stirred-tank alcoholysis reactions of used and refined sunflower oils were performed with n-octyl, myristyl, cetyl, oleyl, and stearyl alcohols using immobilized lipases Novozym 435 and Lipozyme IM as catalysts. Alcohol conversions ranged from 74% to 94%, with slight differences between used frying sunflower oil and refined sunflower oil. The resulting wax esters were purified via stepwise column chromatography. The different regioselectivity of the biocatalysts led to distinct reaction pathways, and Novozym 435 proved to be the most effective enzyme, providing higher conversions and no detectable by-products. This study demonstrates the valorization of waste frying oils into high-value wax esters through enzymatic alcoholysis, comparing two industrially relevant immobilized lipases and achieving high conversion across multiple long-chain alcohols. The results highlight a sustainable alternative to conventional chemical catalysis and extend biocatalytic applications beyond traditional biodiesel production. By incorporating waste lipids into value-added products, the overall sustainability and circularity of the system are improved, contributing to green and sustainable chemistry.

Sustainable Chemistry doi: 10.3390/suschem7010011

Authors: Daniela Godina Prans Brazdausks Maris Puke

The development of sustainable biorefining processes is essential for increasing the value of lignocellulosic resources and reducing the environmental footprint of the forest-based industry. Birch wood is one of Latvia’s most abundant renewable feedstocks, yet current catalytic technologies for furfural production—primarily based on sulfuric acid (H2SO4)—cause extensive cellulose degradation and generate sulfur-containing residues that hinder further valorization. This study proposes an integrated biorefining approach in which orthophosphoric acid (H3PO4) is utilized as an alternative catalyst to selectively convert hemicellulose into furfural and acetic acid while preserving cellulose in birch veneer chips (BVC). The experimental plan was based on a full central composite circumscribed (CCC) response surface methodology (RSM) design, which consists of factorial points, axial (star) points, and centre points. In total, 26 experimental runs were performed, including 24 non-centre points (comprising both factorial and axial points (±α)) and two centre points. The optimized conditions enabled high acetic acid yields (6.29–6.48% o.d.m., corresponding to 98–100% of theoretical), furfural yields of 8.75–10.41% o.d.m. (57–68% of theoretical), and exceptional glucan preservation (38.84–40.92% o.d.m., 94–99% of theoretical). Compared with sulfuric acid pretreatment, the H3PO4-based process significantly reduced cellulose degradation and improved the suitability of the resulting lignocellulosic residue for subsequent 5-hydroxymethylfurfural (5-HMF) production and other biorefining routes. The findings demonstrate that orthophosphoric acid catalysis is a promising pathway for integrating furfural extraction with cellulose-retentive pretreatment, thereby enhancing the sustainability, efficiency, and circularity of birch veneer chips’ biomass utilization.

Sustainable Chemistry doi: 10.3390/suschem7010010

Authors: Adil Allahverdiyev Jonas Gurauskis Vanesa Gil Harald Gröger

A commercially available attapulgite sample (Red Attapulgite) was acid-pretreated to enhance its catalytic activity. It turned out to efficiently facilitate the dehydration of a range of substituted alcohols. The dehydration of the primary alcohol was conducted at 150–180 °C, which represents energy-saving conditions when taking into account the typical dehydration conditions of primary alcohols with temperatures of >300 °C. The alkene yields obtained in this study were found to be comparable to those when utilizing commercially available montmorillonite as catalysts, thereby underscoring the potential of the acid-pretreated attapulgite as a catalyst for a variety of reactions. In a parallel study, dehydration catalyzed by a range of Brønsted acids was investigated. However, only two of these acids were found to be suitable for the dehydration of primary alcohols. Nevertheless, these acids lacked both dehydration activity and recyclability. Therefore, a recyclability study was conducted in the presence of the acid-pretreated attapulgite sample. It is remarkable that no loss of activity was found over five cycles. We hypothesize that after acid-pretreatment, a synergistic effect of the Brønsted and Lewis acid sites is the cause for the high catalytic activity of the sample.

Sustainable Chemistry doi: 10.3390/suschem7010009

Authors: Viktor Husak Eliška Kováříková Olena Bobrova

Natural deep eutectic solvents (NADES) are gaining interest as environmentally friendly alternatives to conventional organic solvents in the functional food sector. Their low volatility, biodegradability, and tunable polarity, combined with high affinity for phenolics, carotenoids, and other phytochemicals, make them particularly relevant for developing antioxidant and anti-inflammatory ingredients at a time of rising diet-related chronic disease burden. This review critically analyses the role of NADES along the functional food chain. We summarize their composition, preparation, and key physicochemical properties, and then examine the NADES-based extraction of antioxidant and anti-inflammatory compounds from plants and food by-products in comparison with traditional solvent systems. The influence of NADES on the stability and biological activity of recovered compounds is discussed, together with their use in the formulation, stabilization, and delivery strategies for functional foods. Emerging data indicate that NADES often enhance extraction yields and may protect labile bioactives, leading to stronger antioxidant and anti-inflammatory responses in vitro compared with ethanol or water extracts when normalized to phenolic content. At the same time, large-scale implementation is limited by challenges related to safety assessment, regulatory acceptance, viscosity, and recovery issues, and incomplete techno-economic data. This review highlights these constraints, identifies key knowledge gaps, and outlines research priorities required to translate NADES-based processes into scalable, safe, and health-promoting functional food applications.

Sustainable Chemistry doi: 10.3390/suschem7010008

Authors: Mateusz Gocyla Lizzie Boakes Herbert Struyf Rachid Chokri Tibo Vandevenne Jo Van Caneghem Cedric Rolin Stefan De Gendt

Semiconductor manufacturing is a resource and energy-intensive industry with a substantial environmental footprint. To address the footprint, we present a methodology for quantifying the environmental impact of semiconductor unit processes using the Environmental Footprint 3.1 Life Cycle Impact Assessment (LCIA) framework, focusing on identifying improvement opportunities in process steps with less sensitivity to defects. We apply this methodology to backside wet cleaning by proposing an alternative single-wafer process that adopts ozonated chemistries. The assessment used primary data from imec’s 300 mm pilot line. Results show that the proposed process reduces the total environmental footprint by 55% compared to the baseline Spin Cleaning with Repetitive use of Ozonated water and Diluted HF process. Key reductions include 67% less electricity for cleaning, 59% less HF use, and a 31% reduction in ultrapure water consumption. When scaled to a facility producing N28 Logic wafers at 50,000 wafer starts per month, with 46 backside clean steps per processed wafer, the process achieves annual savings of approximately 4 million kWh of electricity and 28 million liters (28,000 m3) of tap water per year. A sensitivity analysis revealed that replacing fossil-based electricity with hydroelectric power further reduces total environmental impacts by up to 63%, emphasizing the benefit of combining process innovation with renewable energy sourcing.

Sustainable Chemistry doi: 10.3390/suschem7010007

Authors: Jelena Vesković Milica Lučić Andrijana Miletić Marija Vesković Antonije Onjia

Accurate prediction of the Langelier Saturation Index (LSI), an indicator of water’s scaling and corrosive potential, is vital for water treatment and infrastructure maintenance. In this study, five machine learning models (Ridge Regression, Support Vector Machine, Random Forest, Deep Neural Network, and XGBoost) were applied to predict the LSI from physicochemical characteristics of groundwater in the Morava River basin (Serbia). Rigorous data preprocessing (outlier removal, missing data handling, z-score normalization) and feature selection were performed to ensure robust model training. Models were optimized via 10-fold cross-validation on a 70/30 train–test split. All models achieved high predictive accuracy, with ensemble methods outperforming others. XGBoost yielded the best performance (R2 = 0.98; RMSE = 0.06), followed closely by Random Forest (R2 = 0.95). The linear Ridge model showed the lowest (yet still strong) performance (R2 = 0.90) and larger errors at extreme LSI values. Feature importance analysis consistently identified pH as the most influential predictor of the LSI, followed by alkalinity and calcium. Partial dependence plots confirmed that the models captured established nonlinear LSI behavior. The LSI rises steeply with increasing pH and moderately with mineral content. Overall, this comparative study demonstrates that modern machine learning models can predict the LSI accurately, providing interpretable insights through feature importance and dependence plots. These results underscore the potential of data-driven approaches to complement traditional water stability indices for proactive water quality management.

Sustainable Chemistry doi: 10.3390/suschem7010006

Authors: Tsung-Yen Tsai Basharat Hussain Naveen Bunekar

A sustainable circular pathway was developed for poly(ethylene terephthalate) (PET) nanocomposites through a catalyst-driven polymerization and depolymerization process. In this study, calcium dodecylbenzene sulfonate with n-butyl alcohol modified ZnAl layered double hydroxides (LDHs) were utilized as bifunctional catalysts to synthesize highly exfoliated PET/LDH nanocomposites via in situ polycondensation of bis(2-hydroxyethyl) terephthalate (BHET). The organic modification of LDHs expanded interlayer spacing, improved interfacial compatibility, and promoted uniform dispersion, leading to enhanced mechanical, thermal, and barrier properties. In the second stage, the pristine LDH catalyst efficiently depolymerized the prepared PET/LDH nanocomposites back into BHET through glycolysis, completing a closed-loop BHET-to-BHET cycle. This integrated strategy demonstrates the reversible catalytic functionality of LDHs in both polymerization and depolymerization, reducing metal contamination and energy demand. The proposed approach represents a sustainable route for designing recyclable high-performance PET nanocomposites aligned with the principles of green chemistry and circular material systems.

Sustainable Chemistry doi: 10.3390/suschem7010005

Authors: Marina Radenković Ana Lazić Marija Kovačević Miloš Ognjanović Dalibor Stanković Dubravka Relić Ana Kalijadis Aleksandra Dimitrijević Sanja Živković

This work used activated carbon material obtained by chemical activation of abundantly available agricultural sunflower waste residues to remove metol (4-(methylamino) phenol sulfate, MTL) from aqueous solutions. The adsorbent structure was characterized using SEM-EDS and FT-IR spectroscopy. A modified screen-printed carbon electrode (SPCE) with gold nanoparticles synthesized using the Laser Ablation Synthesis in Solution (LASIS) method was used to detect MTL. The successful LASIS formation of gold nanoparticles was confirmed by the specific dark burgundy–red color. TEM measurements showed uniform pseudo-spherical particles with an average diameter of 7.9 ± 0.2 nm. The modified electrode showed improved electrochemical activity, which was confirmed by comparing it with an unmodified electrode using cyclic voltammetry and electrochemical impedance spectroscopy. The modified electrode was subsequently used to optimize the MTL detection conditions. UV–Vis spectroscopy was used to optimize the adsorption conditions, with the optimal values for pH and contact time found to be 8 and 120 min, respectively. The electrochemical detection of MTL was performed using differential pulse voltammetry, and the linear calibration range was established for concentrations ranging from 0.73–49.35 µM. The obtained limits of detection (LOD) and quantification (LOQ) were 0.06 µM and 0.2 µM, respectively. The efficiency of MTL removal was 100% after a contact time of 1 min and remained at 100% after 120 min.

Sustainable Chemistry doi: 10.3390/suschem7010004

Authors: Luisa F. Medina-Ganem Neali Valencia-Espinoza Godwin A. Ayoko Erick Bandala Alain Salvador Conejo-Davila Alejandro Vega-Rios Ashantha Goonetilleke Oscar M. Rodriguez-Narvaez

Biogenic nanoparticles have recently emerged as promising bacterial growth inhibitors, requiring low concentrations and not producing harmful byproducts. However, knowledge gaps remain regarding how different extraction techniques affect nanoparticle synthesis, thereby influencing their replicability and scalability across various applications. To address these knowledge gaps, this study compared six extracts derived from Moringa oleifera biomass for the synthesis of iron oxide nanoparticles. Multivariate statistical analyses correlated extraction methods with biomolecule content (polyphenols, flavonoids, carbohydrates, proteins), iron percentage, and E. coli growth inhibition. All extracts showed varying concentrations of biomolecules, and different extraction methods were preferable for specific components. Flavonoids were best extracted by salting-out, while infusion methods were better for obtaining carbohydrates. Higher percentages of iron (22.77%) were linked to the presence of polyphenols and flavonoids. Nanoparticles prepared using salting-out and infusion extraction from leaf biomass displayed the highest efficiency in inhibiting E. coli growth, up to a dilution factor of 4. The outcomes of this research study provide an in-depth understanding of the role of specific biomolecules in biogenic nanoparticle synthesis, confirming that both synthesis yield and application effectiveness depend on the extract preparation method.

Sustainable Chemistry doi: 10.3390/suschem7010003

Authors: Rami Doukeh Cristian Nicolae Eparu Alina Petronela Prundurel Mihail Tudose Gheorghe Brănoiu Iuliana Veronica Ghețiu Laura Ștefania Păun Sonia Mihai Ioana Gabriela Stan Doru Bogdan Stoica

Water-based drilling fluids (WBDFs) are widely used due to their economic and environmental advantages; however, shale hydration remains a major limitation. This study evaluates Fe2O3, CuO, ZnO, and MgO nanocrystalline metal oxides synthesized via co-precipitation as inorganic shale inhibitors for WBDFs. Comprehensive characterization confirmed phase-pure nanocrystalline oxides (17–38 nm) with high thermal stability. Performance tests revealed that MgO-based WBDF exhibited the lowest plastic viscosity (17 cP), the highest pH (≈10.0), and the strongest shale inhibition (6.1% swelling), while Fe2O3 provided superior filtration control (6.0 mL). CuO showed balanced rheology, whereas ZnO displayed comparatively weaker inhibition. Compared with commercial inhibitors (Amine NF and Glycol), MgO- and Fe2O3-based systems achieved comparable or improved performance with enhanced thermal and environmental robustness. These results demonstrate the potential of nanocrystalline metal oxides as sustainable additives for improving WBDF performance under high-pressure, high-temperature (HPHT) conditions.

Sustainable Chemistry doi: 10.3390/suschem7010002

Authors: Effrosyni Mitrousi Triantafyllia Kokkinou Maria Zografaki Maria Nikopoulou Angeliki Banti Dimitra A. Lambropoulou Sotiris Sotiropoulos

This study investigates amorphous anodized porous TiO2 (a-TiO2) as a substrate for iridium-based oxygen evolution catalysts. The substrates were prepared via anodization of Ti foil in a glycerol-based solution for 15 min @ 60 V. Nickel was subsequently electrodeposited to act both as a conductive and sacrificial layer for the galvanic deposition of iridium from an Ir(IV) chloro-complex solution. Electrochemical anodization resulted in a uniform IrOx layer on the a-TiO2 substrate, featuring Ir aggregates ~250 nm in size and an Ir:Ni atomic ratio of ca. 7, as determined by EDS analysis. The quantity of Ni determined by ICP-MS bulk analysis indicated that Ni resided also within the porous matrix. Varying the Ni deposition charge density (qNi) revealed that an intermediate loading (1463 mC cm−2) provided the best balance between Ir accessibility during the galvanic replacement step and electronic continuity. The optimized IrOx/Ir-Ni/a-TiO2 electrode achieved excellent OER performance (η = 344 mV @ 10 mA cm−2; 1.68 mA μgIr−1 @ η = 300 mV) at an ultra-low Ir loading of 2.15 μgIr cm−2 and demonstrated good short-term stability, with only a 20 mV potential increase over 4 h of continuous operation at 5.5 mA cm−2. Overall, this strategy offers a scalable pathway for producing efficient OER electrodes with minimal noble metal loading.

Sustainable Chemistry doi: 10.3390/suschem7010001

Authors: Réka Dobozi Zoltán Péter Jákói Sándor Beszédes Balázs P. Szabó Szabolcs Kertész

In whey valorization, membrane separation stands out as a highly effective technique for purifying and isolating the various components of whey. The efficiency of whey ultrafiltration and diafiltration (UF/DF) largely depends on the balance between membrane selectivity, hydrodynamic conditions, and solute interactions at the membrane interface. In this study, sweet whey was fractioned using 10, 30 and 50 kDa polyether sulfone (PES) membranes under identical transmembrane pressure (TMP = 2.5 bar) with ultrafiltration and a subsequent 4-step constant volume diafiltration stages. The resulting compositional and dielectric changes were evaluated to identify optimal separation conditions and assess the applicability of dielectric parameter measurement as a rapid, non-destructive monitoring technique. Results showed that, regardless of the applied molecular weight cut-off (MWCO), using three DF cycles can wash out almost all the removable lactose from the retentates, and the dielectric assessment of both permeate and retentate fractions showed a strong, linear relationship between the change in dielectric behavior and the composition of each fraction. Analysis of the dielectric spectra confirmed that the ratio of the dielectric constant to the loss factor (ε′/ε″) exhibited a strong linear correlation (R2 > 0.98, r > 0.99) with lactose concentration in the permeate fractions of all three MWCO membranes, as well as a similarly strong correlation (R2 > 0.975, r > 0.98) with the total chemical oxygen demand (TCOD) measured in the retentate fractions.

Sustainable Chemistry doi: 10.3390/suschem6040049

Authors: Marco Russo Antonella Di Vincenzo Michele Antonio Floriano Paolo Lo Meo

The old spectral displacement method can be suitably revitalized for a didactic experimental approach to fundamental concepts of supramolecular chemistry and to the study of complex equilibria in general. In particular, the case of the β-cyclodextrin/phenolphthalein/adamantane ternary system has been taken into account as a viable and impressive example due to the remarkable color changes that can be observed when performing the experiments. A new method for data regression analysis is proposed, with a smart trick able to overcome the mathematical difficulties arising whenever multiple equilibria must be considered. Hence, some aspects of the reliability of fitting procedures are discussed.

Sustainable Chemistry doi: 10.3390/suschem6040048

Authors: Awal Adava Abdulsalam Sabina Khabdullina Zhamilya Sairan Yersain Sarbassov Madina Pirman Dilnaz Amrasheva George Z. Kyzas Tri Thanh Pham Elizabeth Arkhangelsky Stavros G. Poulopoulos

Mercury (Hg2+) contamination in water systems poses a severe environmental and health hazard due to its high toxicity and bioaccumulation potential. In this study, a novel adsorbent was developed by sequentially modifying kaolin via acid–base treatment, titanium dioxide (TiO2) incorporation, and 3-aminopropyltriethoxysilane (APTES) grafting. Batch adsorption experiments revealed that the fully modified kaolin (TiO2-loaded and APTES grafted) exhibited the highest adsorption capacity (25.6 mg/g) compared to the acid–base-treated (5.8 mg/g) and TiO2-loaded (17.7 mg/g) kaolin. Under optimal conditions (75 mg adsorbent dosage; 70 mg/L Hg2+; pH 5), the fully modified kaolin maintained its performance even in the presence of varying ionic strengths, natural organic matter, and competing metal ions. Adsorption kinetics followed a pseudo-second-order model, and the equilibrium data were well fitted by the Langmuir isotherm. Antibacterial activity assay revealed that the TiO2-loaded kaolin effectively inhibited S. aureus (minimum inhibitory concentration = 2.5 mg/mL) and showed moderate activity against E. coli (BL21) (minimum inhibitory concentration = 5 mg/mL). However, antibacterial activity decreased after amine functionalization, indicating a compromise between enhancing adsorption capacity and preserving antibacterial functionality. This study presents a promising cost-efficient approach for the simultaneous removal of Hg2+ ions from water matrices and inhibiting bacterial growth, aligning with SDG 6 (Clean Water and Sanitation).

Sustainable Chemistry doi: 10.3390/suschem6040047

Authors: Marta Jiménez-Salcedo Filipe H. B. Sosa João A. P. Coutinho María Teresa Tena

Deep eutectic solvents (DES) were selected for the extraction of anthocyanins from red grape skins as an efficient and environmentally friendly solvent alternative to traditional mixtures based on methanol. In silico studies (COSMO-RS) were employed as screening tools to identify the most suitable options, significantly reducing the chemical space of potential DES to be studied. A total of 30,132 DES combinations were assessed. The DESs selected were polyalcohols (ethyleneglycol, glycerol, 1,2-propanediol, and 1,6-hexanediol) and carboxylic acids (citric, oxalic, malic, and lactic acid) as hydrogen bond donors (HBD) and choline chloride, betaine, or salts (potassium carbonate, sodium acetate, and propionate), as hydrogen bond acceptors (HBA). Choline chloride:glycerol and choline chloride:oxaclic acic were selected as solvents to optimize time, temperature, and water content in ultrasound- and microwave-assisted extraction of anthocyanins. In both cases, around 20 wt% of water was found to be the optimum to maximize the extractions, whereas extraction time and temperature depended on the type of anthocyanin. The amount of malvidin-3-O-glucoside extracted by microwave-assisted extraction with choline chloride: oxalic acid was 172 ± 7 mg/kg and 119.5 ± 0.5 mg/kg by ultrasound-assisted extraction with choline chloride: glycerol, which means an increase in performance of, respectively, 64 and a 13% compared to the traditional method.

Sustainable Chemistry doi: 10.3390/suschem6040046

Authors: Vukašin Ugrinović Anđela Simović Marija Ćorović Katarina Mihajlovski Jelena Lađarević Jelena Bajat Aleksandra Ivanovska

This interdisciplinary study explores the potential of bioactive compounds from Aronia melanocarpa pomace, a juice industry by-product. The ethanol extract of the pomace was analyzed using HPLC, revealing key polyphenolic acids and anthocyanins. The extract exhibited outstanding antioxidant activity (100% as measured by the ABTS assay and 98.23% as measured by the DPPH assay) and >99% antibacterial efficacy against E. coli and S. aureus. This bioactive extract was utilized in a one-step process to dye and functionalize textiles (wool, silk, cellulose acetate, cotton, and viscose), with cotton and viscose suited for colored disposable bioactive textiles, particularly protective healthcare textiles, due to strong antioxidant (>97% as measured by the ABTS assay and >76% as measured by the DPPH assay) and antibacterial (>75% for E. coli and >80% for S. aureus) properties. The aronia pomace extract was also incorporated into newly synthesized starch/gelatin hydrogels with a compression modulus of 0.041–0.127 MPa and equilibrium swelling ratios of 3.33–4.26 g/g. Functionalized hydrogels demonstrated over 99% ABTS antioxidant activity, while the antibacterial efficacy against E. coli and S. aureus exceeded 70% and 97%, respectively. These properties, combined with the hydrogels’ ability to control the release of extract compounds, make them adequate for wound care applications. The extract’s effectiveness as a green inhibitor for carbon steel, with inhibition efficiency surpassing 94% at a concentration of aronia pomace extract of 100 ppm, was confirmed by electrochemical methods. Moreover, the extract predominantly retards the cathodic reaction. The current research represents the first exploration of alternative and green sustainable technologies for developing novel products based on aronia pomace extract.

Sustainable Chemistry doi: 10.3390/suschem6040045

Authors: Dušan V. Trajković Natalija D. Milojković Nevenka N. Mijatović Aleksandra S. Popović Đorđe N. Veljović Aleksandra A. Perić Grujić Dragana Z. Živojinović

The burning of coal in thermal power plants throughout Serbia produces significant amounts of industrial waste, primarily in the form of fly ash, boiler ash, and slag. Given their annual production, availability, and fine grain structure, it is necessary that sustainable strategies are developed for their reuse, instead of depositing them directly in landfills. In this research, the possibility of using fly ash, slag, and diatomaceous earth as raw materials for the synthesis of geopolymers at low temperatures was examined, in order to replace cement in construction materials, with the aim of reducing carbon dioxide emissions. Special emphasis was put on the effect of addition of organic macromolecules—polyvinyl alcohol (PVA), chitosan, and starch—upon the structure and mechanical properties of the obtained materials. In addition, the behavior of the materials with regard to the leaching of heavy metals in different environmental conditions was examined. Chemometric methods of multivariate analysis were used to examine the correlations between the obtained physical–chemical parameters, while the dependence of mechanical properties on the composition of the raw mixture was analyzed using the Mixture Design of Experiments method. The results obtained indicate that the examined waste materials have potential to be used as an environmentally friendly alternative to cement. The addition of PVA and chitosan had a positive effect on the mechanical properties of the geopolymers, with the highest strength achieved in formulations based solely on fly ash, containing 2.5% PVA, which reached 12.6 MPa. It was also shown that the addition of 30% diatomaceous earth increases the density and compressive strength of the material, while reducing the number of microcracks present in its structure, with a compressive strength of 13 MPa.

Sustainable Chemistry doi: 10.3390/suschem6040044

Authors: Amosi Makoye Ferenc Lónyi Hanna E. Solt Catia Cannilla Giuseppe Bonura Gyula Novodárszki Róbert Barthos József Valyon Tibor Nagy Anna Vikár

Catalytic upgrading of bioethanol via a C–C coupling reaction is a sustainable method of producing 1-butanol, a high-performance biofuel. This reaction was studied using a flow-through microreactor system with Pd/MgO-Al2O3 and bimetallic Pd-Cu/MgO-Al2O3 mixed oxide-based catalysts in a H2 carrier gas at a pressure of 21 bar and temperatures ranging from 200 to 350 °C. The effect of the metal promoter(s) on the hydrogen transfer reaction steps in the overall reaction was investigated. The palladium promoter significantly improved the activity and butanol selectivity across the entire temperature range. However, the yield of liquid products decreased significantly at temperatures higher than 250 °C, primarily because the decarbonylation side reaction of the acetaldehyde intermediate accelerated. The promoting effect of Pd was most beneficial below 250 °C because the decarbonylation reaction was inhibited by the reversible poisoning effect of CO on multiple Pd sites responsible for decarbonylation. Diluting the Pd phase with Cu increased liquid yields due to gradually decreasing decarbonylation activity. However, the dehydrogenation–hydrogenation activity decreased as well, as did the promoting effect on the corresponding reaction steps in the coupling reaction. Additionally, the product distribution changed dramatically, decreasing 1-butanol selectivity, because metallic Cu can catalyze the formation of ethyl acetate and ketone products.

Sustainable Chemistry doi: 10.3390/suschem6040043

Authors: Debora de Figueiredo Luiz Martien Koppes Marija Sarić Jurriaan Boon

Ammonia, widely regarded as the “hydrogen carrier of the future,” offers high hydrogen content, ease of production, and a well-established infrastructure for handling and transportation globally. Meanwhile, ammonia cracking requires a heat supply at high temperatures, and induction heating provides efficient, precise, and rapid heating to conductive materials of different shapes and sizes. Therefore, this work presents a proof of concept for ammonia cracking using induction heating with three different reactor configurations: (1) a 3D metal workpiece; (2) a 3D metal workpiece and Ni/Al2O3 catalyst; and (3) only Ni/Al2O3 catalyst. The performance of the inductively heated reactor is also compared to an electric furnace. The results showed that the reactor with the workpiece and the catalyst required 97 W to reach 650 °C, being the most efficient in terms of power usage when compared to the workpiece alone and the electric tube furnace, which required 39% and 132% more, respectively; the least efficient configuration is with just the catalyst, needing 138 W to reach just 116 °C. Overall, the introduction of the 3D workpiece allowed for fast and uniform conversion and heating within the reactor, enabling efficient and dynamic process control when applying induction heating to chemical reactors.

Sustainable Chemistry doi: 10.3390/suschem6040042

Authors: Morayma Muñoz Diego Flores Grace Morillo Ricardo Narváez Antonio Marcilla Marco Rosero

Mesoporous materials have attracted increasing attention due to their ordered pore systems; tunable surface chemistry; and versatile applications in catalysis, adsorption, and environmental technologies. Among them, SBA-15 stands out for its large surface area, uniform mesopores, and high hydrothermal stability, which make it a promising platform for gas adsorption and mass transport studies. This review examines the functionalization of SBA-15 through strategies such as post-synthesis grafting and co-condensation, focusing on the introduction of amines, thiols, and organometallic species that enhance selectivity, adsorption capacity, and thermal stability. The discussion integrates classical diffusion models, including Fickian and Knudsen transport, with more advanced approaches such as the Maxwell–Stefan formalism, to describe molecular transport within mesoporous networks and highlight the role of van der Waals interactions in gas capture processes. Special emphasis is placed on the relationship between structural features and diffusive behavior, supported by recent advances in computational modeling and spectroscopic validation. Applications in CO2 capture, heterogeneous catalysis, drug delivery, and environmental remediation are critically assessed to illustrate the versatility of functionalized SBA-15. This review concludes by outlining future perspectives on the rational design of hierarchical and multifunctional mesoporous materials for clean energy conversion, pollutant removal, and biomedical applications.

Sustainable Chemistry doi: 10.3390/suschem6040041

Authors: Ivana Sokol Hanja Mlinar Dajana Kučić Grgić Leentje Persoons Dirk Daelemans Moris Mihovilović Tatjana Gazivoda Kraljević

This study reports the solvent-free mechanochemical synthesis of a novel series of 2-hydrazone-bridged benzothiazole derivatives 19–52 via the reaction of 2-hydrazinylbenzothiazole derivatives 4–6 with O-alkylated benzaldehydes 7–18. The stereostructure of the E-isomers was confirmed by 2D NOESY spectroscopy. The antiproliferative potential of these newly prepared 2-hydrazone derivatives of benzothiazole 19–52 was evaluated in vitro against eight human cancer cell lines. Several compounds demonstrated low micromolar IC50 values, with some outperforming the reference drug etoposide. Among the most potent compounds, the 6-chloro-2-hydrazone(3-fluorophenyl)benzothiazole derivative 38 exhibited remarkable activity against pancreatic adenocarcinoma (Capan-1, IC50 = 0.6 µM) and non-small cell lung cancer (NCI-H460, IC50 = 0.9 µM). Structure–activity relationship analysis revealed that derivatives 45–52, featuring a methoxy group at position 6 of the benzothiazole ring and either a methoxy or fluorine substituent at position 3 of the phenyl ring, showed consistently strong antiproliferative effects across all tested cell lines (IC50 = 1.3–12.8 µM). Furthermore, compounds bearing N,N-diethylamino or N,N-dimethylamino groups at position 4 of the phenyl ring generally exhibited superior activity compared to those with morpholine or piperidine moieties. However, as this study represents an initial screening, further mechanistic investigations are required to confirm specific anticancer pathways and therapeutic relevance. In addition to their in vitro anticancer properties, the antibacterial activity of the compounds was assessed against both Gram-positive and Gram-negative bacteria. Notably, compound 37 demonstrated selective antibacterial activity against Pseudomonas aeruginosa (MIC = 4 µg/mL). Overall, this work highlights the efficiency of a green, mechanochemical approach for synthesizing E-isomer hydrazone-bridged benzothiazoles and underscores their potential as promising scaffolds for the development of potent antiproliferative agents.

Sustainable Chemistry doi: 10.3390/suschem6040040

Authors: Paraskevas Parlakidis Víctor Castro-Gutiérrez Mario Masís-Mora Zisis Vryzas Carlos E. Rodríguez-Rodríguez

Biopurification systems are designed for the treatment of pesticide-containing agricultural wastewater; their biologically active matrix, the biomixture, can be modified to enhance the pesticide removal capacity. Two approaches, fungal bioaugmentation with Trametes versicolor and amendment with biochar, were applied for the potential improvement of biomixtures’ capacity to remediate myclobutanil-contaminated wastewater. The conventional biomixture (B) and its modifications, either bioaugmented with Trametes versicolor (biomixture BT) or supplemented with pineapple biochar (5% v/v) (biomixture BB), were spiked with myclobutanil at a very high concentration (10,000 mg/kg) to simulate extreme on-farm events such as the disposal or leakage of commercial formulations. The dissipation followed a bi-phasic behavior in every case. Both modifications of the conventional biomixture increased the dissipation rates, resulting in estimated DT50 values of 61.9 (BB) and >90 days (BT) compared to biomixture B (DT50 = 474 days). The assessment of biomixtures’ detoxification was carried out with two different bioindicators: a seed germination test in Lactuca sativa and an algal growth inhibition test. Some degree of detoxification was achieved for all biomixtures in both indicators, with the exception of the biochar-containing biomixture, which, despite showing the fastest myclobutanil dissipation, was unable to maintain a steady detoxification trend towards the algae over the course of the treatment, probably due to biochar adverse effects. This approach seems promising for removing persistent myclobutanil from agricultural wastewater and demonstrates the dissipation capacity of biomixtures at extremely high pesticide concentrations likely to take place at an on-farm level.

Sustainable Chemistry doi: 10.3390/suschem6040039

Authors: Rizqan Jamal Manabu Miyamoto Yasuhisa Hasegawa Yasunori Oumi Shigeyuki Uemiya

Known for its excellent adsorption and molecular sieving properties, CHA-type zeolite is highly effective in separation technologies, including alcohol dehydration and gas separation. Despite their advantages, especially in terms of energy savings, the prolonged synthesis time of zeolite membranes limits their commercial adoption. The remarkably rapid synthesis of CHA membranes was demonstrated using an exceptionally small tubular reactor (ID: 4.0 mm, OD: 6.0 mm, L: 135 mm). The formation of membranes could be observed after 10 min of synthesis, and a membrane with a thickness of 0.65 µm, αH2O/2-PrOH of 1662, and a total flux of 2.97 kg/(m2 h), was produced after 40 min of synthesis in an oil bath. Using the synthesis time of 40 min and longer, membranes with good quality and enhanced reproducibility were produced, as the number of defects was reduced. These findings demonstrate the potential for rapid, scalable CHA membrane production, paving the way for broader industrial applications.

Sustainable Chemistry doi: 10.3390/suschem6040038

Authors: Timo Steinbrecher Jakob Albert Martin Kaltschmitt

The composite material lignocellulose makes up the majority of biomass on earth and is characterized by a high biological and chemical resistance, which is essentially caused by the phenylpropanoid polymer lignin. Thus, the removal and depolymerization of lignin to produce aromatic chemicals can significantly enhance the material usability of all lignocellulose constituents. This review summarizes the current state of knowledge on the nature of lignin, including its biosynthesis, structure, chemistry and biodegradation. Second, it attempts to derive implications regarding the technical valorization of lignin from native biomass through depolymerization. Finally, the consequences of the findings for conventional, recently developed and future processes valorizing lignocellulose are assessed, and the associated technical and economic hurdles are discussed. It becomes clear that lignin depolymerizability is restricted in established pulping processes, primarily due to repolymerization reactions. Strategies avoiding lignin repolymerization involve an increased process complexity and additional economic expenditure but might enable an increased value creation from lignocellulosic biomass.

Sustainable Chemistry doi: 10.3390/suschem6040037

Authors: Oskars Bitmets Bejan Hamawandi Raitis Grzibovskis Jose Francisco Serrano Claumarchirant Muhammet S. Toprak Kaspars Pudzs

This study explores the development of a water-based hybrid thermoelectric (TE) material composed of Sb2Te3 nanoparticles (NPs) and polyethylene oxide (PEO). Sb2Te3 NPs were synthesized via the microwave-assisted colloidal route, where X-ray diffraction confirmed the purity and quality of the Sb2Te3 NPs. Key properties, including the Seebeck coefficient (S), electrical conductivity (σ), power factor (PF), and long-term stability, were studied. X-ray photoelectron spectroscopy (XPS) analysis revealed that exposure to water and oxygen leads to NP oxidation, which can be partially mitigated by hydrochloric acid (HCl) treatment, though this does not halt ongoing oxidation. Scanning electron microscopy (SEM) images displayed a percolation network of NPs within the PEO matrix. While the initial σ was high, a decline occurred over eight weeks, resulting in similar conductivity among all samples. The effect of surface treatments, such as 1,6-hexanedithiol (HDT), was demonstrated to enhance long-term stability. The results highlight both the challenges and potential of Sb2Te3/PEO hybrids for TE applications, especially regarding oxidation and durability, and underscore the need for improved synthesis and processing techniques to optimize their performance. This study provides valuable insights for the design of next-generation hybrid TE materials and emphasizes the importance of surface chemistry control in polymer–inorganic nanocomposites.

Sustainable Chemistry doi: 10.3390/suschem6040036

Authors: Mateusz Ciszewski Szymon Orda Michał Drzazga Katarzyna Leszczyńska-Sejda Andrzej Chmielarz Patricia Córdoba

Antimony (Sb), bismuth (Bi), and arsenic (As) are common contaminants of copper (Cu) electrolyte and anodes, necessitating strict control of their concentrations. The purification of Cu electrolytes is required and demands the application of appropriate techniques. This paper presents the methodology of selective precipitation, applied for Sb, Bi, and As recovery from the acidic eluate of a Cu electrolyte purification plant. An important aspect was the change in solution type from chloride to sulfate, prior to arsenic sequestration. A facile precipitation method, preceded by a reduction in As(V) and Sb(V), was applied. The primary objectives are focused on the preparation of three distinct concentrates: antimony oxychloride, bismuth oxychloride, and iron(III) arsenate(V), emphasizing optimal recovery and purity. The processes were performed in a specially designed, cascade-lined pilot scale installation, with a daily capacity of approximately 2.5 m3. In total, 22 m3 of eluate was processed, yielding 191 kg of Sb concentrate, 97 kg of Bi concentrate, and 163 kg of scorodite. The recovery of Sb was as high as 98%, with antimony content up to 50% in the concentrate. The recovery of bismuth varied from 60 to 99%, depending on the process parameters. The elimination of arsenic from the eluate was close to 100%.

Sustainable Chemistry doi: 10.3390/suschem6040035

Authors: Guilherme de Souza Lopes Matheus Almeida Conceição Carlos Toshiyuki Hiranobe Camila da Silva Erivaldo Antônio da Silva Renivaldo José dos Santos Leandro Ferreira-Pinto

This study evaluated the extraction of oils from the seeds of bacupari (Garcinia brasiliensis Mart.) and leiteira (Tabernaemontana catharinensis), using carbon dioxide (CO2) in the supercritical state. The effects of temperature (40, 50, and 60 °C) and pressure (20, 24, and 28 MPa) on the yield and extraction kinetics were investigated. The results indicated that, within the studied limits, temperature had a negligible influence on the process, while pressure had a greater impact on the yields owing to its effect on the density of supercritical CO2 and the solubility of the extracted compounds. The maximum yields obtained were 14.8% for bacupari and 15.2% for leiteira, with most of the oil extracted within the first 30 min, indicating initial rapid extraction. Chemical composition analysis revealed relevant bioactive compounds in bacupari, including oleic acid (35%) and delta-tocopherol (19.6%). In leiteira, the main compounds identified were hexanedioic acid (29.2%) and stigmast-5-ene (7.95%). These results suggest the potential application of these oils in the pharmaceutical, cosmetic, and food sectors, while also highlighting the feasibility of using supercritical CO2 as an extraction method for these plant matrices.

Sustainable Chemistry doi: 10.3390/suschem6040034

Authors: Ebuka Ogbuoji Odianosen Ewah Anastasia Myers Corey Roberts Anastasia Shaverina Isabel C. Escobar

The substitution of hazardous, environmentally persistent solvents (NMP and DMAc) with more sustainable alternatives (ETAc and GBL) in fabricating flat sheet polyactic acid (PLA) membranes via nonsolvent-induced phase separation for air filtration applications was the focus of this study. The polymer-solvent affinity was first evaluated using Hansen solubility parameters, confirming suitable Relative Energy Difference (RED) values (<1) for all solvent candidates. Dope solutions prepared with biodegradable solvents demonstrated higher viscosity compared to those prepared with environmentally persistent solvents. These biodegradable solvent systems also exhibited slower precipitation rates during membrane formation. This resulted in spongelike cross-sectional morphologies, contrasting with the combined fingerlike and spongelike structures observed in membranes fabricated with environmentally persistent NMP and DMAc. Thermal analysis revealed that membranes fabricated with biodegradable solvents exhibited superior thermal stability with higher glass transition temperatures (Tg = 54.39–55.34 °C) compared to those made with environmentally persistent solvents (Tg = 49.97–50.71 °C). Membranes fabricated with ethyl acetate (ETAc) showed the highest hydrophobicity (contact angle = 115.1 ± 9°), airflow rate (12.7 ± 0.28 LPM at 0.4 bar) and maintained filtration efficiency at values greater than 95% for 0.3 μm aerosols.

Sustainable Chemistry doi: 10.3390/suschem6040033

Authors: Rebecca M. Brown Ethan Struhs Amin Mirkouei David Reed

Rare earth elements (REEs) make up integral components in personal electronics, healthcare instrumentation, and modern energy technologies. REE leaching with organic acids is an environmentally friendly alternative to traditional extraction methods. Our previous study demonstrated that batch ultrasound-assisted organic acid leaching of REEs can significantly decrease environmental impacts compared to traditional bioleaching. The batch method is limited to small volumes and is unsuitable for industrial implementation. This study proposes a novel approach to increase reaction volume using a continuous ultrasound-assisted organic acid leaching method. Laboratory experiments showed that continuous ultrasound-assisted leaching increased the leaching rate (µg/h) 11.3–24.5 times compared to our previously reported batch method. Techno-economic analysis estimates the cost of the continuous approach using commercially purchased organic acids is $9465/kg of extracted REEs and $4325/kg of extracted REEs, using gluconic acid and citric acid, respectively. The sensitivity analysis reveals that substituting commercially purchased organic acids with microbially produced biolixiviant can reduce the process cost by approximately 99% while minimally increasing energy consumption. Environmental assessment shows that most of the emissions stemmed from the energy required to power the ultrasound reactor. We concluded that increased leaching capacity using a continuous ultrasound-assisted approach is feasible, but process modifications are needed to reduce the environmental impact.

Sustainable Chemistry doi: 10.3390/suschem6040032

Authors: Maiara A. P. Frigulio Angélica G. Morales Felipe A. Santos Juliane C. Forti

The confectionery industry produces effluents with diverse and complex compositions and high organic loads, which are typically not treated by conventional treatment plants. In this context, the Fenton process presents itself as an advanced chemical treatment alternative due to its ease of application, cost-effectiveness, and ability to improve the degradability of challenging effluents. This study addressed the question: How can Fenton’s reagent be applied as a pretreatment to reduce the organic load in real effluents from the food industry? The research evaluated this chemical pretreatment for effluents from a starch-based gummy candy production process, aiming to reduce the organic load and aid subsequent conventional treatments. Parameters such as COD, total dissolved solids (TDS), temperature, pH, electrical conductivity, dissolved oxygen, and degrees Brix (°Bx) were monitored before and after 2 and 4 h of pretreatment. The results showed that Fenton pretreatment reduced COD by more than 31%, with efficiency influenced by effluent composition and concentration. This removal can reduce discharge rates and operating costs, providing an economic advantage. The process proved to be a promising pretreatment option, contributing to the initial removal of pollutants and improving the performance of wastewater treatment systems, thus supporting sustainable industrial practices.

Sustainable Chemistry doi: 10.3390/suschem6040031

Authors: Fabrizio E. Viale Verónica R. Elías Tamara B. Benzaquén Gerardo F. Goya Griselda A. Eimer Gabriel O. Ferrero

Bimetallic mesoporous photocatalysts were synthesized via a wet impregnation method using SBA-15 as a support, and characterized by UV–visible diffuse reflectance spectroscopy, low-angle X-ray diffraction and N2 physisorption. Among the tested materials, the Ti/Mn combination exhibited the highest photocatalytic activity in azo dye degradation. To understand this enhanced performance, catalysts with varying Mn loads and calcination ramps were evaluated. Additionally, experiments with radical scavengers (isopropanol, chloroform) and under N2 insufflation were conducted to identify the active radical species. Catalysts prepared with low Mn content and higher calcination ramps showed the greatest activity, which significantly decreased with isopropanol, indicating hydroxyl radicals as the main reactive species. In contrast, samples with higher Mn content and quicker heating displayed reduced activity in the presence of chloroform, suggesting superoxide radical involvement. Spectroscopic analyses (XPS, UV–Vis DRS) revealed that increasing Mn load promotes the formation of Mn2+ over Mn4+ species and lowers the band gap energy. These findings highlight the direct correlation between synthesis parameters, surface composition and optical properties, providing a strategy for fine-tuning the performance of a photocatalyst.

Sustainable Chemistry doi: 10.3390/suschem6030030

Authors: Theresa Coetsee Frederik De Bruin

Aluminothermic reduction is gaining renewed interest as an alternative processing route for the circular economy. Aluminium is produced electrochemically in the Hall–Héroult process with minimal CO2 emissions if electricity is sourced from non-fossil fuel energy sources. The Al2O3 product from the aluminothermic reduction process can be recycled via hydrometallurgy, with leaching as the first step. NaAlO2 is a water-leachable compound that forms a pathway for recycling Al2O3 with hydrometallurgy. In this work, a suitable slag formulation is applied in the aluminothermic reduction of manganese ore to form a Na2O-based slag of high Al2O3 solubility to effect good alloy–slag separation. The synergistic effect of added chromium metal as a collector metal is illustrated with an increased alloy yield at 68%, from 43% without added Cr. The addition of small amounts of carbon reductant to MnO2-containing ore ensures rapid pre-reduction to MnO. This approach negates the need for a pre-roasting step. The alloy and slag chemical analyses are compared to the thermochemistry-predicted phase chemistry. The alloy consists of 57% Mn, 18% Cr, 18% Fe, 3.4% Si, 1.5% Al, and 2.2% C. The formulated slag exhibits high Al2O3 solubility, enabling effective alloy–slag separation, even at an Al2O3 content of 55%.

Sustainable Chemistry doi: 10.3390/suschem6030029

Authors: Irina Tamara Ortiz Maia Balod Pablo Edmundo Antezana Gisel Nadin Ortiz Martin Federico Desimone Carlos Gamarra-Luques Jorgelina Cecilia Altamirano María Belén Hapon

Iodine is an essential element for the synthesis of thyroid hormones. Iodine deficiency leads to a range of health consequences known as iodine deficiency disorders. To assess the iodine nutritional status of a population, urinary iodine (UI) is typically measured. This work introduces a novel and simple analytical method for determining UI using silver triangular nanoplates (AgTNPs) after interfering substances are removed via solid-phase extraction (SPE). The AgTNPs were synthesized and characterized using Transmission Electron Microscopy, UV–vis spectroscopy, and zeta potential measurements. The limit of detection of iodide of the AgTNPs assessed spectrophotometrically was 35.78 µg I−/L. However, urine samples interfered with the colorimetric reaction. Thus, an SPE methodology was developed and optimized to eliminate urine interferents that hinder AgTNP performance. A logistic regression analysis was conducted to validate the combined application of SPE and AgTNPs for the qualitative determination of UI. This work demonstrated that the developed SPE methodology eliminates these interferents and extracts iodide from the sample, allowing the accurate determination of UI using AgTNPs. This reliable sample preparation method was then used on actual human urine samples to accurately identify UI deficiency levels. The proposed methodology offers an effective and environmentally friendly approach for monitoring iodine status, without requiring highly complex equipment.

Sustainable Chemistry doi: 10.3390/suschem6030028

Authors: Anka Jevremović Maja Ranković Aleksandra Janošević Ležajić Snežana Uskoković-Marković Bojana Nedić Vasiljević Nemanja Gavrilov Danica Bajuk-Bogdanović Maja Milojević-Rakić

This review sheds some light on the emerging niche of the reuse of spent adsorbents in electrochemical devices. Reuse and repurposing extend the adsorbent’s life cycle, remove the need for long-term storage, and generate additional value, making it a highly eco-friendly process. Main adsorbent-type materials are overviewed, emphasising desired properties for initial adsorption and subsequent conversion to electroactive material step. The effects of the most frequent regeneration procedures are compared to highlight their strengths and shortcomings. The latest efforts of repurposing and reuse in supercapacitors, fuel cells, and batteries are analysed. Reuse in supercapacitors is dominated by materials that, after a regeneration step, lead to materials with high surface area and good pore structure and is mainly based on the conversion of organic adsorbents to some form of conductive carbon adlayer. Additionally, metal/metal-oxide and layered-double hydroxides are also being developed, but predominantly towards fuel cell and battery electrodes with respectable oxygen reduction characteristics and significant capacities, respectively. Repurposed adsorbents are being adopted for peroxide generation as well as direct methanol fuel cells. The work puts forward electrochemical devices as a valuable avenue for spent adsorbents and as a puzzle piece towards a greener and more sustainable future.

Sustainable Chemistry doi: 10.3390/suschem6030027

Authors: Muhammad Husnain Manzoor Islam Elsayed El Barbary Hassan

With increasing concerns about climate change and the depletion of fossil fuels, hemicellulose sugars from lignocellulosic biomass are gaining attention as sustainable feedstocks for producing biofuels and valuable chemicals. In this study, the extraction of hemicellulose sugars from corncob biomass was performed using hydrothermal pretreatment. Response Surface Methodology (RSM) with the Box–Behnken Design (BBD) was employed to optimize different parameters. The tested parameters included the corncob-to-water ratio (0.5:10, 1.5:10), time (30 to 90 min), and temperature (150 to 170 °C), to achieve the highest sugar yields (xylose, arabinose, and total sugars). The ANOVA results for the full quadratic polynomial model, which evaluates the effects of the three variables on xylose yield, indicate that the model is highly significant and provides a good fit to the data. This was evidenced by the minimal difference (0.003) between the predicted R2 and the adjusted R2. This study reports one of the highest recoveries of hemicellulosic sugars from corncobs and also evaluates degradation byproducts, offering a more efficient and comprehensive pretreatment approach that employs a lower temperature and a mild acid concentration (1%) compared with earlier research. The highest yields of xylose (103.49 mg/g), arabinose (26.75 mg/g), and total sugars (163.21 mg/g) were obtained at 160 °C and a corncob-to-water ratio of 0.5:10, after 90 min. Degradation products such as HMF and furfural in the hydrolysate were also analyzed by HPLC. The hydrolysate obtained from hydrothermal pretreatment contained oligomers that were converted into monomers through 1% H2SO4 hydrolysis. The highest yields after the acidic hydrolysis were 301.93 mg/g xylose, 46.96 mg/g arabinose, and 433.79 mg/g total sugars hydrolysis.

Sustainable Chemistry doi: 10.3390/suschem6030026

Authors: Diana Barros Ricardo Pereira-Pinto Élia Fernandes Preciosa Pires Manuela Vaz-Velho

This study investigates the potential of Pinus pinaster subsp. atlantica bark, a forestry by-product from northern Portugal, as a source of phenolic compounds with strong antioxidant properties. Microwave-assisted extraction (MAE) was used to optimize recovery, assessing the effects of solvent composition (water, ethanol, and 50:50 water–ethanol), extraction time (15 or 30 min), and temperature (90, 110, or 130 °C) using a one-variable-at-a-time approach. High-Performance Liquid Chromatography (HPLC) profiling characterized the polyphenol composition. The results showed that solvent choice strongly influenced extract composition and bioactivity, with hydroethanolic and ethanolic extracts exhibiting the highest antioxidant activities in DPPH, ABTS, and ORAC assays. Optimal conditions—50:50 water–ethanol, 130 °C, 15 min—yielded 11.13% (w/w) extract, 3.10 mg GAE/mL total phenolics, and 2.01 mg CE/mL condensed tannins, comparable to commercial extracts such as Pycnogenol®. MAE proved effective, rapid, and solvent-efficient, enhancing phenolic recovery without degrading extract quality. These findings highlight the potential of P. pinaster bark extracts for biomedical, nutraceutical, and cosmetic applications, supporting the sustainable valorization of forestry residues and aligning with circular economy principles.

Sustainable Chemistry doi: 10.3390/suschem6030025

Authors: Bárbara G. S. Guinati Rhett C. Smith

This review highlights recent advances in the use of nutshell-derived materials, including peanut, walnut, and other lignocellulosic shell wastes, as reinforcers in polymer composites. The focus is placed on evaluating how the incorporation of nutshell fillers influences the mechanical and thermal properties of various polymer matrices. Key findings across multiple studies show that nutshell reinforcement can significantly enhance tensile strength, modulus, thermal stability, and biodegradability, depending on filler concentration, particle size, and surface treatment. The review also discusses the sustainability and economic benefits of using agricultural waste as a functional additive, offering insights into the design of low-cost, eco-friendly polymer composites for packaging, construction, and environmental applications.

Sustainable Chemistry doi: 10.3390/suschem6030024

Authors: Maria Laura Tummino Francesca Deganello Vittorio Boffa

Facing energy and environmental issues is recognized globally as one of the major challenges for sustainable development, to which sustainable chemistry can make significant contributions. Strontium ferrate-based materials belong to a little-known class of perovskite-type compounds in which iron is primarily stabilized in the unusual 4+ oxidation state, although some Fe3+ is often present, depending on the synthesis and processing conditions and the type and amount of dopant. When doped with cerium at the Sr site, the SrFeO3−δ cubic structure is stabilized, more oxygen vacancies form and the Fe4+/Fe3+ redox couple plays a key role in its functional properties. Alone or combined with other materials, Ce-doped strontium ferrates can be successfully applied to wastewater treatment. Specific doping at the Fe site enhances their electronic conductivity for use as electrodes in solid oxide fuel cells and electrolyzers. Their oxygen storage capacity and oxygen mobility are also exploited in chemical looping reactions. The main limitations of these materials are SrCO3 formation, especially at the surface; their low surface area and porosity; and cation leaching at acidic pH values. However, these limitations can be partially addressed through careful selection of synthesis, processing and testing conditions. This review highlights the high versatility and efficiency of cerium-doped strontium ferrates for energy and environmental applications, both at low and high temperatures. The main literature on these compounds is reviewed to highlight the impact of their key properties and synthesis and processing parameters on their applicability as sustainable thermocatalysts, electrocatalysts, oxygen carriers and sensors.

Sustainable Chemistry doi: 10.3390/suschem6030023

Authors: Arvind Negi

Natural dyes and pigments are gaining importance as a sustainable alternative to synthetic dyes. Sourced from renewable materials, they are known for their biodegradable and non-toxic properties, offering a diverse range of color profiles and applications across industries such as textiles, cosmetics, food, and pharmaceuticals. This manuscript discusses various aspects of natural dyes and pigments (derived from plants and microbes), including anthocyanins, flavonoids, carotenoids, lactones, and chlorophyll. Furthermore, it highlights the polyphenolic nature of these compounds, which is responsible for their antioxidant activity and contributes to their anticancer, antibacterial, antifungal, antiprotozoal, and immunomodulatory effects. However, natural dyes are often categorized as pigments rather than dyes due to their limited solubility, a consequence of their molecular characteristics. Consequently, this manuscript provides a detailed discussion of key structural challenges associated with natural dyes and pigments, including thermal decomposition, photodegradation, photoisomerization, cross-reactivity, and pH sensitivity. Due to these limitations, natural dyes are currently used in relatively limited applications, primarily in the food industry, and, to lesser extent, in textiles and coatings. Nevertheless, with ongoing research and technological innovations, natural dyes present a viable alternative to synthetic dyes, promoting a more sustainable and environmentally conscious future.

Sustainable Chemistry doi: 10.3390/suschem6030022

Authors: Juan Zelin Hernán Antonio Duarte Alberto Julio Marchi Camilo Ignacio Meyer

2,5-bis(hydroxymethy)lfuran (BHMF), a renewable compound with extensive industrial applications, can be obtained by selective hydrogenation of the C=O group of 5-hydroxymethylfurfural (HMF), a platform molecule derived from lignocellulosic biomass. In this work, we perform kinetic modeling of the selective liquid-phase hydrogenation of HMF to BHMF over a Cu/SiO2 catalyst prepared by precipitation–deposition (PD) at a constant pH. Physicochemical characterization, using different techniques, confirms that the Cu/SiO2–PD catalyst is formed by copper metallic nanoparticles of 3–5 nm in size highly dispersed on the SiO2 surface. Before the kinetic study, the Cu/SiO2-PD catalyst was evaluated in three solvents: tetrahydrofuran (THF), 2-propanol (2-POH), and water. The pattern of catalytic activity and BHMF yield for the different solvents was THF > 2-POH > H2O. In addition, selectivity to BHF was the highest in THF. Thus, THF was chosen for further kinetic study. Several experiments were carried out by varying the initial HMF concentration (C0HMF) between 0.02 and 0.26 M and the hydrogen pressure (PH2) between 200 and 1500 kPa. In all experiments, BHMF selectivity was 97–99%. By pseudo-homogeneous modeling, an apparent reaction order with respect to HFM close to 1 was estimated for a C0HMF between 0.02 M and 0.065 M, while when higher than 0.065 M, the apparent reaction order changed to 0. The apparent reaction order with respect to H2 was nearly 0 when C0HMF = 0.13 M, while for C0HMF = 0.04 M, it was close to 1. The reaction orders estimated suggest that HMF is strongly absorbed on the catalyst surface, and thus total active site coverage is reached when the C0HMF is higher than 0.065 M. Several Langmuir–Hinshelwood–Hougen–Watson (LHHW) kinetic models were proposed, tested against experimental data, and statistically compared. The best fitting of the experimental data was obtained with an LHHW model that considered non-competitive H2 and HMF chemisorption and strong chemisorption of reactant and product molecules on copper metallic active sites. This model predicts both the catalytic performance of Cu/SiO2-PD and its deactivation during liquid-phase HMF hydrogenation.

Sustainable Chemistry doi: 10.3390/suschem6030021

Authors: Gordana Stevanović Jovan Parlić Marija Ajduković Nataša Jović-Jovičić Vojkan Radonjić Zorica Mojović

Dry Turkish oak (Quercus cerris) sawdust, untreated and treated with three activators, (H3PO4, NaOH and H2O2) was pyrolyzed under limited-oxygen conditions to obtain biochar samples. The electrochemical properties of these samples were tested and compared to the properties of several commercial carbon blacks. The electrochemical characterization was performed via cyclic voltammetry, analyzing the response toward two commonly used redox probes, [Fe(CN)6]3−/−4− and [Ru(NH3)6]2+/3+. The influence of the scan rate on this response was investigated, and the resulting data were used to obtain the values of the heterogenous charge transfer constant, k0. Higher k0 values were observed for carbon blacks than for investigated biochar samples. The detection of 4-nitrophenol and heavy metal ions was used to assess the applicability of biochars for electroanalytical purposes. The response of untreated biochar was comparable with the response of Vulcan carbon black, which showed the best response of all analyzed carbon blacks.

Sustainable Chemistry doi: 10.3390/suschem6030020

Authors: Nicolás Sacco Ezequiel Banús Juan P. Bortolozzi Sabrina Leonardi Eduardo Miró Viviana Milt

Biomorphic mineralization was employed to synthesize novel Mn–Ce and Mn–Co–Ce oxide fibers using commercial cotton as a biotemplate, aiming to assess their catalytic performance in diesel soot combustion and CO oxidation. Two synthesis protocols—one with and one without citric acid—were investigated. The inclusion of citric acid led to fibers with more uniform morphology, attributed to improved precursor distribution, although synthesis yields decreased for Co-containing systems. In soot combustion tests, Mn–Ce catalysts synthesized with citric acid outperformed their monometallic counterparts. While cobalt incorporation enhanced the mechanical robustness of the fibers, it did not significantly boost catalytic activity. Selected formulations were also evaluated for CO oxidation, with Mn–Co–Ce fibers achieving T50 values in the 240–290 °C range, comparable to Co–Ce nanofibers reported in the literature. These results demonstrate that biomorphic fibers produced through a simple and sustainable route can offer competitive performance in soot and CO oxidation applications.

Sustainable Chemistry doi: 10.3390/suschem6030019

Authors: Veronika Jančíková Michal Jablonský

The thermal modification of wood has emerged as a sustainable and effective method for enhancing the physical, chemical, and mechanical properties of wood without the use of harmful chemicals. This review summarizes the current state-of-the-art in thermal wood modification, focusing on the mechanisms of wood degradation during treatment and the resulting changes in the properties of the material. The benefits of thermal modification of wood include improved dimensional stability, increased resistance to biological decay, and improved durability, while potential risks such as reduced mechanical strength, color change, and higher costs of wood under certain conditions are also discussed. The review highlights recent advances in process optimization and evaluates the trade-offs between improved performance and possible structural drawbacks. Finally, future perspectives are outlined for sustainable applications of thermally modified wood in various industries. Emerging trends and future research directions in the field are identified, aiming to improve the performance and sustainability of thermally modified wood products in construction, furniture, and other industries.

Sustainable Chemistry doi: 10.3390/suschem6030018

Authors: Imren Basar David Torrens-Martín Lucía Fernández-Carrasco Cristhian Caiza Joan Martínez-Bofill Marcel Hürlimann

Volcanic ashes (VA) ejected by the Tajogaite Volcano were studied to determine their potential as pozzolanic materials for construction applications. A representative number of VA samples (15 in total) were collected from different geolocations and altitudes during and immediately after the volcanic eruption, in order to assess their reactivity as a function of position and environmental exposure. Various analytical techniques—XRD, FTIR, and SEM/EDX—were used to determine the initial microstructural composition of the VA samples. Additionally, saturated lime testing and the Frattini test were performed to evaluate their pozzolanic reactivity for use in historical mortars. The microstructural analyses revealed that the dominant mineral phases are aluminosilicates. The reactivity tests confirmed a good pozzolanic response, with the formation of C-A-S-H gels identified as the main hydration products at the studied curing times.

Sustainable Chemistry doi: 10.3390/suschem6020017

Authors: Mallory E. Thomas Alistair J. Lees

A primary challenge in the further development of anion sensors in real water samples of environmental concern is the need for highly water-soluble compounds that are able to detect low concentrations of analytes. Small-molecule sensors can mitigate solubility constraints and highly aromatic or conjugated systems may provide a new way to recognize target analytes with high sensitivity and/or selectivity. Organic aggregates that have the ability to form large frameworks can exhibit aggregated-induced emissions to detect target analytes, and their coagulation can provide enhanced detection via colorimetric or fluorescent measurements. This review aims to draw attention to the emerging area of small-molecule organic chemosensors that utilize aggregation to detect environmentally detrimental anions in an aqueous solution. A number of mechanisms of interaction for anion recognition are recognized and discussed here, including electrostatic interactions, covalent bond formation, hydrophobic interactions, and even complexation.

Sustainable Chemistry doi: 10.3390/suschem6020016

Authors: Klaus Günter Steinhäuser Markus Große Ophoff

The chemical industry faces major challenges worldwide. Since 1950, production has increased 50-fold and is projected to continue growing, particularly in Asia. It is one of the most energy- and resource-intensive industries, contributing significantly to greenhouse gas emissions and the depletion of finite resources. This development exceeds planetary boundaries and calls for a sustainable transformation of the industry. The key transformation areas are as follows: (1) Non-Fossil Energy Supply: The industry must transition away from fossil fuels. Renewable electricity can replace natural gas, while green hydrogen can be used for high-temperature processes. (2) Circularity: Chemical production remains largely linear, with most products ending up as waste. Sustainable product design and improved recycling processes are crucial. (3) Non-Fossil Feedstock: To achieve greenhouse gas neutrality, oil, gas, and coal must be replaced by recycling plastics, renewable biomaterials, or CO2-based processes. (4) Sustainable Chemical Production: Energy and resource savings can be achieved through advancements like catalysis, biotechnology, microreactors, and new separation techniques. (5) Sustainable Chemical Products: Chemicals should be designed to be “Safe and Sustainable by Design” (SSbD), meaning they should not have hazardous properties unless essential to their function. (6) Sufficiency: Beyond efficiency and circularity, reducing overall material flows is essential to stay within planetary boundaries. This shift requires political, economic, and societal efforts. Achieving greenhouse gas neutrality in Europe by 2050 demands swift and decisive action from industry, governments, and society. The speed of transformation is currently too slow to reach this goal. Science can drive innovation, but international agreements are necessary to establish a binding framework for action.

Sustainable Chemistry doi: 10.3390/suschem6020015

Authors: Juan Peña-Martínez Jessica Beltrán-Martínez Ana Cano-Ortiz Noelia Rosales-Conrado

This work reviews the use of biodiesel synthesis experiments in science education, emphasising their potential for explicit nature of science (NOS) teaching. Through a literature review and experimental insights, it highlights how transesterification of waste cooking oil (WCO) with a basic catalyst can serve as an educational tool. While biodiesel reaction conditions are well-documented, this study presents them in a pedagogical context. Simple viscosity and density measurements illustrate empirical analysis, while a design of experiments (DoE) approach using a Hadamard matrix introduces systematic optimisation and scientific reasoning. By integrating biodiesel synthesis with explicit NOS instruction, this work provides educators with a framework to foster critical thinking and a deeper understanding of scientific inquiry. Additionally, this approach aligns with green chemistry principles and resource efficiency, reinforcing the broader relevance of sustainable chemistry.

Sustainable Chemistry doi: 10.3390/suschem6020014

Authors: Christian Hernández-Hernández Luis E. Estrada-Gil Sonia A. Lozano-Sepúlveda Ana M. Rivas-Estilla Mayela Govea-Salas Jesús Morlett-Chávez Cristóbal N. Aguilar Juan A. Ascacio-Valdés

Rambutan peel is a great source of bioactive compounds, the same that, over the years, has been extracted using conventional technologies which have been proven to be harmful to the environment and potentially toxic to human beings. This study aimed to extract the same compounds using a hybridization of ultrasound/microwave extraction. The results were promising, as a total of 378.48 ± 9.19 mg/g of polyphenols were recovered from this procedure, and the most important molecules (geraniin, corilagin, and ellagic acid) were identified, giving this much more relevance. Furthermore, treatment with rambutan peel extract recovered with green technologies significantly reduced cell viability in HCV-infected liver cells. Notably, higher concentrations (4000 and 5000 ppm) led to more pronounced cell death in huh7 cells. The treatment also led to a significant reduction in viral protein and RNA expression in HCV-infected cells. These findings suggest that rambutan peel extract obtained from the combination of ultrasound and microwave extraction, particularly the ellagitannins present, have potential antiviral properties. Further research is needed to explore its mechanism of action and its potential as a therapeutic agent for Hepatitis C.

Sustainable Chemistry doi: 10.3390/suschem6020013

Authors: Damázio Borba Sant’Ana Júnior Maikon Kelbert Pedro Henrique Hermes de Araújo Cristiano José de Andrade

Physical pretreatments play a crucial role in reducing the recalcitrance of lignocellulosic biomass, facilitating its conversion into fermentable sugars for bioenergy and chemical applications. This study critically reviews physical pretreatment approaches, including mechanical comminution, irradiation (ultrasound, microwave, gamma rays, and electron beam), extrusion, and pulsed electric field. The discussion covers the mechanisms of action, operational parameters, energy efficiency, scalability challenges, and associated costs. Methods such as ultrasound and microwave induce structural changes that enhance enzymatic accessibility, while extrusion combines thermal and mechanical forces to optimize hydrolysis. Mechanical comminution is most effective during short periods and when combined with other techniques to overcome limitations such as high energy consumption. Innovative approaches, such as pulsed electric fields, show significant potential but face challenges in large-scale implementation. This study provides technical and strategic insights into developing more effective physical pretreatments aligned with economic feasibility and industrial sustainability.

Sustainable Chemistry doi: 10.3390/suschem6020012

Authors: Isaac de Carvalho Guimarães Mirele Santana de Sá Tarcísio Martins Alberto Wisniewski

Sustainable hydrocarbons are one of the main methods of decreasing the use of fossil fuels and derivatives, contributing to the mitigation of environmental impacts and greenhouse gas emissions. Circular economic concepts focus on reusing waste by converting it into new products, which are then input again into industrial production lines, thus decreasing the necessity of fossils. Polypropylene-based plastic waste can be depolymerized into smaller chemical chains, producing a liquid phase rich in hydrocarbons. In the same way, triacylglycerol-based waste biomasses can also be converted into renewable hydrocarbons. Our research studied the co-processing of polypropylene (PP) and cottonseed oil dreg (BASOs) waste from the biodiesel industry using a micropyrolysis system at 550 °C, previously validated to predict the scale-up of the process. PP showed the production of alkanes and alkenes, while BASOs also produced carboxylic acids in addition to the PP products. The main impacts were observed in the conversion yields, reaching the highest values of pyrolytic liquid (64%), gas (14%), and solid product (13%) compared to the co-processing mixture of BASO:PP (1:2). Also, in this mixture, the production of carboxylic acids decreased to the lowest value (~10%), improving the conversion to sustainable hydrocarbons.

Sustainable Chemistry doi: 10.3390/suschem6020011

Authors: Thiago J. T. Cruz Guilherme Q. Calixto Fabiana R. de A. Câmara Dárlio I. A. Teixeira Renata M. Braga Sibele B. C. Pergher

Chlorella sp. was cultivated in a closed system using PET bottles (5 L) and with the continuous injection of air and commercial gas (98% CO2) and in simulated conditions (15% CO2, 73% N2, and 12% O2). The culture medium was prepared using well water and mining wastewater, the cultivation period occurred in a 10-day cycle, and the cell growth curves were evaluated through cell counting using a Neubauer chamber. The cultivation was carried out under the following conditions: temperature at 22 °C to 25 °C; aeration rate with commercial and simulated CO2 gas at 0.01 vvm; and synthetic air containing 0.042% CO2. The dry biomass productivity was 0.81 g·L−1·day−1 and the maximum CO2 fixation rate was 0.90 g·L−1·day−1 when the microalgae were cultivated with a continuous flow of simulated waste gas and a culture medium composed of wastewater. The percentages of macromolecules obtained in the biomass cultivated in wastewater reached 20.95%, 26.48%, and 9.3% for lipids, proteins, and carbohydrates, respectively.

Sustainable Chemistry doi: 10.3390/suschem6010010

Authors: Caterina Trotta Ana Laura Alves Mariana Cardoso Carolina da Silva Patrícia Léo Leandro de Castro Yoannis Domínguez Marta Filipa Simões Cristiane Angélica Ottoni

Twelve marine-derived fungal strains were evaluated for their ability to synthesize silver nanoparticles (AgNPs). Mycogenic AgNPs were preliminarily characterized using different techniques, and their antimicrobial activities were assessed. Penicillium citrinum IBCLP11 and Aspergillus niger IBCLP20 were selected for AgNPs’ synthesis optimization by varying parameters such as AgNO3 concentration, biomass, agitation, temperature, and pH. AgNPIBCLP11 and AgNPIBCLP20 were able to inhibit the growth of Pseudomonas aeruginosa IPT322, Staphylococcus aureus IPT246, and Klebsiella pneumoniae IPT412 at concentrations of 25 μg/mL or higher. Aspergillus niger IPT295 and Aspergillus parasiticus IPT729 were the most sensitive to AgNPIBCLP20. Further studies are needed to fully elucidate the effects of all parameters influencing mycogenic AgNPs synthesis. However, it is evident that maintaining optimal conditions, such as temperature and pH during agitation, is crucial for preventing undesirable reactions and ensuring nanoparticle stability.

Sustainable Chemistry doi: 10.3390/suschem6010009

Authors: Maura Mancinelli Annalisa Martucci

Zeolites are amongst the most extensively explored crystalline microporous materials because of their variable chemical composition, framework geometry, pore dimensions, and tunability. Due to their high surface area, adsorption selectivity, mechanical, biological, chemical, and thermal stability, these molecular sieves are widely used in adsorption, catalysis, ion exchange, and separation technologies. This short review highlights the notable progress achieved in leveraging the properties of zeolite materials for multiple applications, including gas separation and storage, adsorption, catalysis, chemical sensing, and biomedical applications. The aim is to emphasize their capabilities by showcasing important achievements that have driven research in this field toward new and unforeseen areas of material chemistry.

Sustainable Chemistry doi: 10.3390/suschem6010008

Authors: Meseret Dawit Teweldebrihan Megersa Olumana Dinka

Heavy metal contamination of water sources has emerged as a major global environmental concern, affecting both aquatic ecosystems and human health. Therefore, this study aims to remove hexavalent chromium from an aqueous solution utilizing activated carbon developed from Spathodea campanulata. Chemical treatment with H3PO4 followed by thermal activation was employed to enhance the adsorption capability of the precursor material. On the other hand, a full factorial design of 24 including pH (3 and 9), contact time (30 and 60 min), initial chromium concentration (40 and 100 mg/L), and adsorbent dosage of 0.2 and 0.6 g/100 mL was used to optimize the batch-wise adsorption of hexavalent chromium. The characterization results showed that the prepared activated carbon is composed of various functional groups (FTIR), a high specific surface area of 1054 m2/g (BET), morphological cracks (Scanning Electron Microscopy), and a pH point of zero charge of 5.8. The maximum removal efficiency of 96.5% was recorded at optimum working conditions of pH 3, contact time of 60 min, adsorbent dosage of 0.6 g/100 mL, and initial chromium concentration of 40 mg/L. Additionally, kinetics and isotherm studies revealed that the pseudo-second-order model with R2 of 0.98 and the Sips model with R2 of 0.99 were found to fit the adsorption data better, suggesting homogenous surface and chemisorption. Overall, this research suggests that Spathodea campanulata could be a promising natural source for the development of adsorbents with potential applications in remediating chromium-saturated wastewater at an industrial scale.

Sustainable Chemistry doi: 10.3390/suschem6010007

Authors: Guangyao Jin Wanwei Zhao Jianing Zhang Wenyu Liang Mingyang Chen Rui Xu

Lithium-ion batteries that use lithium iron phosphate (LiFePO4) as the cathode material and carbon (graphite or MCMB) as the anode have gained significant attention due to their cost-effectiveness, low environmental impact, and strong safety profile. These advantages make them suitable for a wide range of applications including electric vehicles, stationary energy storage, and backup power systems. However, their adoption is hindered by a critical challenge: capacity degradation at elevated temperatures. This review systematically summarizes the corresponding modification strategies including surface modification of the anode and cathode as well as modification of the electrolyte, separator, binder, and collector. We further discuss the control of the charge state, early warning prevention, control of thermal runaway, and the rational application of ML and DFT to enhance the LFP/C high temperature cycling stability. Finally, in light of the current research challenges, promising research directions are presented, aiming at enhancing their performance and stability in such harsh thermal environments.

Sustainable Chemistry doi: 10.3390/suschem6010006

Authors: Thaiara Ramires dos Reis Donizeti Leonardo Mancini Tolari Ana Claudia Pedrozo da Silva Elton Guntendorfer Bonafé Rafael Block Samulewski André Luiz Tessaro

This study addresses the environmental challenge of surfactant removal from wastewater, focusing on the increased surfactant use during the COVID-19 pandemic. Polymeric waste, specifically polyurethane (PU) and polyamide (PA), was repurposed for surfactant adsorption to mitigate these environmental impacts. Methods included preparing surfactant solutions of sodium linear alkylbenzene sulfonate (LAS) and dodecyl pyridinium chloride (DPC) and the mechanical processing of polymeric residues. PU and PA were characterized by FTIR-ATR and by the pH at the point of zero charge, which yielded pH = 8.0 for both polymers. The adsorption efficiency was optimized using a central composite face-centered design, varying pH, temperature, and time. The results indicated that PU and PA effectively adsorbed anionic and cationic surfactants, with specific conditions enhancing performance. From the optimized experimental conditions, four assays were carried out to evaluate the adsorption isotherms and kinetics. Among the fitted models, the SIPS model was the most representative, indicating a heterogeneous surface. Regarding LAS, the maximum adsorption capacity values were ~90 and 15 mg g−1, respectively, for PU and PA. Considering the DPC surfactant, lower values were obtained (~36 mg g−1 for PU and 16 mg g−1 for PA). The results are satisfactory because the adsorbents used in this study were second-generation waste and were used without treatment or complex modifications. The study concluded that using polymeric waste for surfactant removal offers a sustainable solution, transforming waste management while addressing environmental contamination. This approach provides a method for reducing surfactant levels in wastewater and adds value to otherwise discarded materials, promoting a circular economy and sustainable waste reuse.

Sustainable Chemistry doi: 10.3390/suschem6010005

Authors: Gabriela Elizabeth Tapia-Quiroz Selene Anaid Valencia-Leal Adriana Vázquez-Guerrero Ruth Alfaro-Cuevas-Villanueva Ramiro Escudero-García Raúl Cortés-Martínez

Heavy metal pollution in water resources, particularly cadmium and lead, poses a significant environmental and public health challenge, requiring the development of sustainable, efficient, and cost-effective water treatment methods. Therefore, this study investigates the biosorption capabilities of natural (SN) and surfactant-modified (SM) guava seed biosorbents to remove Cd and Pb from aqueous solutions. Guava seeds, an agricultural waste material, were treated with hexadecyltrimethylammonium bromide (HDTMA-Br) to enhance their adsorption efficiency. The biosorbents were characterized by FTIR, SEM-EDS, and zeta potential analysis to explain the surface modifications and their influence on the adsorption mechanisms. Batch experiments were performed to evaluate the effects of pH, contact time, temperature, biosorbent dosage, and concentration on Cd and Pb removal efficiencies. Adsorption isotherm and kinetic data were analyzed using mathematical models to obtain the basic parameters of the systems under study. The results showed that SM exhibited superior adsorption capacities of 328 mg/g for Cd and 594 mg/g for Pb at 25 °C, significantly outperforming SN. The study analyzed the thermodynamic parameters of adsorption systems, revealing endothermic and exothermic properties for SN and SM. Functional groups like hydroxyl and carbonyl were crucial for metal ion binding. HDTMA-Br introduced active sites and enhanced surface charge interactions. Regeneration tests showed reusability, maintaining over 85% efficiency after four cycles. Guava seeds could be cost-effective and sustainable biosorbents for heavy metal removal.

Sustainable Chemistry doi: 10.3390/suschem6010004

Authors: Eva Naughton Emerson C. Kohlrausch Jesum Alves Fernandes James A. Sullivan

The incorporation of Ag nanoparticles onto BiVO4 (a known H2O oxidising photocatalyst) through magnetron sputtering to form a composite was studied. ICP-OES results showed that the loading of Ag on BiVO4 was below 1% in all cases. UV-Vis DRS and CO2-TPD analyses demonstrated that upon incorporation of Ag onto BiVO4, an increase in the extent of visible light absorption and CO2 adsorption was seen. TEM imaging showed the presence of Ag particles on the surface of larger BiVO4 particles, while XRD analysis provided evidence for some doping of Ag into BiVO4 lattices. The effect of the composite formation on the activity of the materials in the artificial photosynthesis reaction was significant. BiVO4 alone produces negligible amounts of gaseous products. However, the Ag-sputtered composites produce both CO and CH4, with a higher loading of Ag leading to higher levels of product formation. This reactivity is ascribed to the generation of a heterojunction in the composite material. It is suggested that the generation of holes in BiVO4 following photon absorption is used to provide protons (from H2O oxidation), and the decay of an SPR response on the Ag NPs provides hot electrons, which together with the protons reduce CO2 to produce CH4, CO, and adsorbed hydrocarbonaceous species.

Sustainable Chemistry doi: 10.3390/suschem6010003

Authors: Amara Martinson Mandy Guinn Peter Mortensen Ram Krishna Hona

The perovskite oxides CaMnO3-δ, Ca0.5Sr0.5MnO3-δ, and SrMnO3-δ were synthesized in air using a solid-state method, and their structural, electrical, and electrocatalytic properties were studied in relation to their oxygen evolution reaction (OER) performance. Iodometric titration showed δ values of 0.05, 0.05, and 0.0, respectively, indicating that Mn is predominantly in the 4+ oxidation state across all materials, consistent with prior reports. Detailed characterization was performed using X-ray diffraction (XRD), scanning electron microscopy (SEM), iodometric titration, and variable-temperature conductivity measurements. Four-point probe DC measurements revealed that CaMnO3-δ (δ = 0.05) has a semiconductive behavior over a temperature range from 25 °C to 300 °C, with its highest conductivity attributed to polaron activity. Cyclic voltammetry (CV) in 0.1 M KOH was employed to assess OER catalytic performance, which correlated with room-temperature conductivity. CaMnO3-δ exhibited superior catalytic activity, followed by Ca0.5Sr0.5MnO3-δ and SrMnO3-δ, demonstrating that increased conductivity enhances OER performance. The conductivity trend, CaMnO3-δ > Ca0.5Sr0.5MnO3-δ > SrMnO3-δ, aligns with OER activity, underscoring a direct link between electronic transport properties and catalytic efficiency within this series.

Sustainable Chemistry doi: 10.3390/suschem6010002

Authors: Alcione S. de Carvalho Iva S. de Jesus Patrícia G. Ferreira Acácio S. de Souza Rafael P. R. F. de Oliveira Debora O. Futuro Vitor Francisco Ferreira

This review explores both the positive and negative impacts of chemistry on society, focusing on the intersection between pharmaceutical, natural, and synthetic chemicals. On the one hand, drugs developed through medicinal chemistry have saved lives, improved people’s quality of life, and increased longevity. However, they also pose risks, including fatalities and environmental damage. Pharmaceutical chemistry has revolutionized medical practice by enabling the treatment and cure of fatal or debilitating diseases, significantly contributing to the rise in global life expectancy through the research and development of new bioactive substances. This article also highlights the harmful effects of toxic synthetic substances, which negatively impact human health and the environment, affecting plants, animals, air, water, soil, and food.

Sustainable Chemistry doi: 10.3390/suschem6010001

Authors: Mitsuhiro Honda Yusaku Yoshii Nobuchika Okayama Yo Ichikawa

The titanium dioxide (TiO2) photocatalyst is an important semiconducting material that exhibits environmental purification functions when exposed to light. Elemental doping of TiO2 is considered an important strategy to improve its photocatalytic activity. Herein, we have achieved the low-temperature, atmospheric-pressure synthesis of anatase TiO2 particles with doping of 3d metals (Fe, Co, Ni and Cu) based on the liquid phase deposition technique. All products prepared by adding 3d metals were found to consist of TiO2 crystals in the anatase phase with a fine protruding structure of about 40 nm on the surface, as was the case without the addition of metal ions. Iron and copper were observed to be incorporated at higher concentrations than cobalt and nickel, with an elemental addition of up to 4 at% and 1 at%, respectively, when 10 mM iron and copper nitrate were applied. Such doping efficiency could be explained by the difference in ionic radius and chemical stability. A narrowing of the optical band gap with doping elements was also observed, and it was found that optical sensitivity could be imparted down to the visible-light region of 2.4 eV (Fe: 4 at% addition). Furthermore, the 3d metal-doped TiO2 demonstrated in this study was shown to exhibit photocatalytic methane degradation activity. The amount of methane degradation per unit area of the microparticles was twice as great when iron and copper were added, compared to the undoped counterpart. It has been demonstrated that the strategy of doping TiO2 with 3d metal ions by low-temperature synthesis methods is effective in enhancing carrier dynamics and introducing surface active sites, thus increasing methane degradation activity.

Sustainable Chemistry doi: 10.3390/suschem5040024

Authors: Marco Russo Maria Luisa Testa

Biofuels have long been firmly established in the energy landscape in order to meet a considerable portion of the world’s energy demand and to contribute to the reduction in CO2 emissions [...]

Sustainable Chemistry doi: 10.3390/suschem5040023

Authors: Chiara Aliotta Francesca Deganello

The well-being of the Earth and its inhabitants is compromised by the energy and climate crisis that has arisen from the prolonged and uncontrolled utilization of fossil fuels, which has caused a tremendous increase in anthropogenic CO2 and a consistent depletion of natural energy resources [...]

Sustainable Chemistry doi: 10.3390/suschem5040022

Authors: Emilia Paone Francesco Mauriello

We stand at the crossroads of innovation and crisis [...]

Sustainable Chemistry doi: 10.3390/suschem5040021

Authors: Lucielle Ferreira Nunes Gustavo Andrade Ugalde Kéllen Francine Anschau Edson Irineu Müller Marcus Vinícius Tres Giovani Leone Zabot Raquel Cristine Kuhn

Brewer’s spent grains (BSG) are a by-product of the beer industry and can be used to produce biofuels. In this case, the objective of this study was to obtain reducing sugars from this biomass by subcritical water hydrolysis in a semi-continuous mode after steam explosion. Temperatures of 120–180 °C, reaction times of 1–5 min, and pressures of 15–25 MPa were used for the steam explosion without CO2. Moistures of 10–50% (w/v), temperatures of 120–180 °C, reaction times of 1–5 min, and pressures of 15–25 MPa were used for the steam explosion with CO2. Subcritical water hydrolysis of solid-exploded material was developed at 210 °C, 15 MPa, a solid/feed ratio of 16 g/g, and a flow rate of 20 mL/min. The characterization of BSG, reducing sugar yields, kinetic profiles, the composition of monosaccharides and furanic moieties, and the characterization of remaining solid by Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) were performed. For steam explosion with CO2, the significant variables were the temperature and moisture, and the optimized conditions were moisture of 50% (w/v), 120 °C, pretreatment for 1 min, and 15 MPa, with a reducing sugars yield of 18.41 ± 1.02 g/100 g BSG. For steam explosion without CO2, the significant variables were the time and temperature, and the optimized conditions were 120 °C, pretreatment for 1 min, and 15 MPa, with a reducing sugars yield of 17.05 ± 0.48 g/100 g BSG. The process was successful because the steam explosion ruptured the lignocellulosic matrix, and the subsequent process of subcritical water hydrolysis could dissociate the polymers into low-chain saccharides.

Sustainable Chemistry doi: 10.3390/suschem5040020

Authors: Karam Abu El Haija Rafael M. Santos

Biochar, produced through the pyrolysis of biomass and green waste, offers significant potential as a soil amendment to enhance soil health and sustainability in agriculture. However, the current Measurement, Reporting, and Verification (MRV) systems for biochar predominantly focus on carbon credits/offsets, neglecting crucial aspects related to its usability and suitability as a soil amendment on agricultural fields. Through an examination of recent findings, this perspective explores the integration of geochemical tracers, functional group (hydroxyl, carboxyl, phenolic, lactonic, etc.) analysis, and nutrient dynamics into MRV procedures/systems to create a more comprehensive framework. By examining the applicability of these indicators, this paper identifies key gaps and proposes a more robust MRV approach. Such a system would not only facilitate better assessment of biochar’s agronomic benefits but also guide its optimal use in various soil types and agricultural practices.

Sustainable Chemistry doi: 10.3390/suschem5040019

Authors: Marion Martienssen Ramona Riedel Tom Kühne

In this study, several professional cleaning products were analyzed for their impact on local air and sewage contamination. The products were first analyzed for their content of potentially harmful ingredients, their biodegradability, and the potential for the mobilization of hazardous substances from the floorings that were cleaned. The contribution of the cleaning products to sewage pollution with environmentally hazardous substances was studied at full scale. All commercially available cleaning products studied were declared to be environmentally friendly (labeled with the EU Ecolabel). However, despite being labeled as “green” products, between 16 and 24 volatile harmful ingredients were identified. An optimized experimental product, produced completely from natural raw materials, also contained several harmful substances originating from the herbal raw materials themselves. During the field study, we identified a range of trace substances in the sewage. Eight of these substances (e.g., p-cymene, butanone, eucalyptol) significantly originated from the cleaning products. Several others may have originated from the cleaning products, but other sources were also possible. The flooring materials that were cleaned contained several harmful substances themselves. The release of some substances (e.g., toluene) into the sewage significantly increased during the cleaning process.

Sustainable Chemistry doi: 10.3390/suschem5040018

Authors: Matthew D. Jones

When we watch the news and events around the world, it is almost impossible not to find items related to climate change, energy security or issues around plastic waste in the environment [...]

Sustainable Chemistry doi: 10.3390/suschem5040017

Authors: Enhui Ji Minglong Fang Haixia Wu

Phosphorus mainly exists in the form of phosphate in water. Excessive phosphorus can cause eutrophication, leading to algae reproduction and the depletion of oxygen in water, destroying aquatic ecology. This study prepared quaternized polyaniline (PN) and quaternized polyaniline with lanthanum hydrate (HLO-PN), and a new nanocomposite for removing phosphate from wastewater was proposed. The results of adsorption experiments show that HLO-PN can effectively remove phosphate in the range of pH 3~7; the maximum adsorption capacity is 92.57 mg/g, and it has excellent anti-interference ability against some common coexisting anions (F−, Cl−, NO3−, SO42−) other than CO32−. After five adsorption–desorption cycles, the phosphate adsorption capacity (60 mg/g) was still 74.28% of the initial adsorption capacity (80.85 mg/g), indicating that the HLO-PN nanocomposites had good reusability and recovery of phosphorus. The characterization results show that phosphate adsorption is realized by electrostatic adsorption and ligand exchange.

Sustainable Chemistry doi: 10.3390/suschem5030016

Authors: Omar Salmi Alessandro Molinelli Simone Gelosa Alessandro Sacchetti Filippo Rossi Maurizio Masi

For a long time, the leather industry has considered the chromium tanning process to be the easiest and fastest way to treat raw hides and transform them into valuable products. In the last few decades, increasing attention has been paid to the potential oxidation of the trivalent chromium in tanned leather. This happens for many reasons, such as the quality of the tanning agent or the adoption of good manufacturing practices. Anyway, the main problem, which is difficult to solve, is the sensibility of the free residual chromium tanned leather, which is high enough for possible harmful activity. Given this scenario, this work proposes a solution to decrease hexavalent chromium formation by using antioxidants during the leather tanning process. In this regard, a screening work was started, to find the worst-case scenario for trivalent chromium oxidation. To do this, commercial tanning products were employed, especially fatliquoring agents, which, in some cases, are the main source that could easily react with ROS (Reactive Oxygen Species) to drive chromium oxidation. After the determination of conditions, different groups of common antioxidants were tested to analyse the antioxidation performances and their possible use in the chromium-based tanning process. The results underline the efficient action of the antioxidants studied, paving the way for some interesting perspectives to limit the drawbacks of chromium tanned leather.

Sustainable Chemistry doi: 10.3390/suschem5030015

Authors: Ana S. Farioli María V. Martinez Cesar A. Barbero Diego F. Acevedo Edith I. Yslas

Cross-linked polymers synthesized through inverse vulcanization of unsaturated vegetable oils (biopolymers) were used as matrices for incorporating gentamicin (GEN) to form a biocomposite that can amplify GEN antimicrobial activity against Pseudomonas aeruginosa. Two different biopolymers were synthesized using soybean (PSB) and sunflower (PSF) oils by inverse vulcanization cross-linked with sulfur in a 1:1 weight ratio. The study involves the synthesis and characterization of these biopolymers using FTIR and SEM as well as measurements of density and hydrophobicity. The results reveal the formation of biopolymers, wherein triglyceride molecules undergo cross-linking with sulfur chains through a reaction with the unsaturated groups present in the oil. Additionally, both polymers exhibit a porous structure and display hydrophobic behavior (contact angle higher than 120°). The biopolymers swell more in GEN solution (PSB 127.7% and PSF 174.4%) than in pure water (PSB 88.7% and PSF 109.1%), likely due to hydrophobic interactions. The kinetics of GEN sorption and release within the biopolymer matrices were investigated. The antibacterial efficacy of the resulting biocomposite was observed through the analysis of inhibition growth halos and the assessment of P. aeruginosa viability. A notable enhancement of the growth inhibition halo of GEN (13.1 ± 1.1 mm) compared to encapsulated GEN (PSF-GEN 21.1 ± 1.3 and PSB-GEN 21.45 ± 1.0 mm) is observed. Also, significant bactericidal activity is observed in PSF-GEN and PSB-GEN as a reduction in the number of colonies (CFU/mL), more than 2 log10 compared to control, PSF, and PSB, highlighting the potential of these biopolymers as effective carriers for gentamicin in combating bacterial infections.

Sustainable Chemistry doi: 10.3390/suschem5030014

Authors: Anca Giorgiana Grigoras Vasile Cristian Grigoras

The plant-mediated synthesis of therapeutic metal nanoparticles is an intensively exploited field in the last decade. In particular, Salvia officinalis, considered one of these plants, was used in this work to synthesize silver particles. Here, we have used harmless substances to obtain silver particles and common characterization methods for quickly estimating sizes and shapes. Thus, UV–Visible spectroscopy helped us online-monitor and optimize the synthesis of silver particles and estimate the size of metallic particles in the stock solutions. The resulting eco-friendly synthesized silver particles were then separated and re-dispersed in water, to be analyzed by laser light scattering, transmission electron microscopy (TEM), and scanning electron microscopy (SEM) to prove their nanometric size and shape polydispersity. Furthermore, the role of citric acid in stabilizing colloidal solutions of silver nanoparticles was studied.

Sustainable Chemistry doi: 10.3390/suschem5030013

Authors: Hylse Aurora Ruiz-Velducea María de Jesús Moreno-Vásquez Héctor Guzmán Javier Esquer Francisco Rodríguez-Félix Abril Zoraida Graciano-Verdugo Irela Santos-Sauceda Idania Emedith Quintero-Reyes Carlos Gregorio Barreras-Urbina Claudia Vásquez-López Silvia Elena Burruel-Ibarra Karla Hazel Ozuna-Valencia José Agustín Tapia-Hernández

The aim of this research was to separate the over-the-counter nonsteroidal anti-inflammatory drug (NSAID), ibuprofen, from an aqueous solution using the adsorption method, as this NSAID is one of the most globally consumed. An adsorbent was crafted from the Agave angustifolia bagasse, a byproduct of the bacanora industry (a representative alcoholic beverage of the state of Sonora, in northwestern Mexico). Three bioadsorbents (BCT1, BCT2, and BCT3) were produced via pyrolysis at a temperature of 550 °C, with slight variations in each process for every bioadsorbent. The bioadsorbents achieved material yields of 25.65%, 31.20%, and 38.28% on dry basis respectively. Characterization of the bagasse and adsorbents involved scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). The biomass morphology exhibited a cracked surface with holes induced via the bacanora production process, while the surface of the bioadsorbents before ibuprofen adsorption was highly porous, with a substantial surface area. After adsorption, the surface of the bioadsorbents was transformed into a smoother grayish layer. The macromolecules of cellulose, hemicellulose, and lignin were present in the biomass. According to functional groups, cellulose and hemicellulose degraded to form the resulting bioadsorbents, although traces of lignin persisted after the pyrolysis process was applied to the biomass. In an adsorption study, BCT1 and BCT2 bioadsorbents successfully removed 100% of ibuprofen from aqueous solutions with an initial concentration of 62.6 mg/L. In conclusion, the biocarbon derived from Agave angustifolia bagasse exhibited significant potential for removing ibuprofen via adsorption from aqueous solutions.

Sustainable Chemistry doi: 10.3390/suschem5020012

Authors: Rubén González Xiomar Gómez

Ammonia can be considered a relevant compound in the future energy sector, playing a significant role as an energy carrier, storage, or carbon-free fuel. However, the production of this molecule has a high energy demand, and the use of natural gas, which is not free of controversy due to the accidental leakage into the atmosphere produced during extraction and the fact that it is a nonrenewable source, contributes to increasing greenhouse gas emissions. Reducing the process’s energy demand and carbon footprint will be essential to making ammonia a clear alternative for a carbon-free economy. Given the vast research in ammonia production and handling, this gas seems to be the logical step forward in the evolution of the energy sector. However, the current uncertainty in the global market requires cautiousness in decision making. Several factors may impact economic growth and human welfare, thus needing a careful assessment before making any transcendental decisions that could affect worldwide energy prices and raw material availability.

Sustainable Chemistry doi: 10.3390/suschem5020011

Authors: Shikha Jyoti Borah Abhijeet Kumar Gupta Vinod Kumar Priyanka Jhajharia Praduman Prasad Singh Pramod Kumar Ravinder Kumar Kashyap Kumar Dubey Akanksha Gupta

The increasing commercial, industrial, and medical applications of plastics cannot be halted during the coming years. Microplastics are a new class of plastic pollutants which have emerged as escalating environmental threats. The persistence, effects, and removal of MPs present in soil, water, and numerous organisms have become an important research field. However, atmospheric microplastics (AMPs), which are subcategorized into deposited and suspended, remain largely unexplored. This review presents the recent developments and challenges involved in fully understanding suspended and deposited AMPs. The evaluation of indoor suspended MP fibers needs to be critically investigated to understand their implications for human health. Furthermore, the transportation of AMPs to isolated locations, such as cryospheric regions, requires immediate attention. The major challenges associated with AMPs, which have hindered advancement in this field, are inconsistency in the available data, limited knowledge, and the lack of standardized methodologies for the sampling and characterization techniques of AMPs.

Sustainable Chemistry doi: 10.3390/suschem5020010

Authors: Alexander S. Shkuratov Reshma Panackal Shibu Obste Therasme Paula Berton Julia L. Shamshina

Nanochitin, especially in the form of chitin nanowhiskers (ChNWs), represents a significant advance in biopolymer technology due to its high specific surface area, superior tensile strength, and excellent thermal stability. Derived from crustacean waste, which contains 15–40% of chitin, these materials provide a sustainable option that diverts waste from landfills and contributes to environmental conservation. Traditional methods of isolating nanochitin are energy-intensive and generate substantial waste. This study introduces a more sustainable method using inexpensive ionic liquids (ILs) such as [Hmim][HSO4] and [HN222][HSO4], which bypass the costly and destructive steps of traditional procedures. This study also identified the byproduct in IL-mediated chitin hydrolysis reaction as calcium sulfate dihydrate and presented a solution to circumvent the byproduct formation. The effectiveness of the [HN222][HSO4] IL in producing ChNWs from both purified chitin and crustacean biomass was assessed, showing a high yield and maintaining the purity and structural integrity of chitin, thereby demonstrating a significant reduction in the environmental footprint of ChNW production.

Sustainable Chemistry doi: 10.3390/suschem5020009

Authors: Kinjal Moradiya Matheus M. Pereira Kamalesh Prasad

Three ionic liquids (ILs) and three deep eutectic solvents (DESs) with identical counterparts, as well as their aqueous solutions, were prepared for the selective extraction of alginate from Sargassum tenerrimum, a brown seaweed. It was found that the ILs and their hydrated systems were only able to extract alginate from the seaweed directly, while the DESs were not, as confirmed by molecular docking studies. When the quality of the polysaccharide was compared to that produced using the hydrated IL system with the widely used conventional method, it was discovered that the physicochemical and rheological characteristics of the alginate produced using the ILs as solvents were on par with those produced using the conventional method. The ILs can be seen as acceptable alternative solvents for the simple extraction of the polysaccharide straight from the seaweed given the consistency of the extraction procedure used in conventional extraction processes. The hydrated ILs were discovered to be more effective than their non-hydrated counterparts. The yield was also maximized up to 54%, which is much more than that obtained using a traditional approach. Moreover, the ionic liquids can also be recovered and reused for the extraction process. Additionally, any residual material remaining after the extraction process was converted into cellulose, making the process environmentally friendly and sustainable.

Sustainable Chemistry doi: 10.3390/suschem5020008

Authors: Isabel Albelo Rachel Raineri Sonja Salmon

Additive manufacturing, commonly referred to as 3D printing, is an exciting and versatile manufacturing technology that has gained traction and interest in both academic and industrial settings. Polymeric materials are essential components in a majority of the feedstocks used across the various 3D printing technologies. As the environmental ramifications of sole or primary reliance on petrochemicals as a resource for industrial polymers continue to manifest themselves on a global scale, a transition to more sustainable bioderived alternatives could offer solutions. In particular, cellulose is promising due to its global abundance, biodegradability, excellent thermal and mechanical properties, and ability to be chemically modified to suit various applications. Traditionally, native cellulose was incorporated in additive manufacturing applications only as a substrate, filler, or reinforcement for other materials because it does not melt or easily dissolve. Now, the exploration of all-cellulose 3D printed materials is invigorated by new liquid processing strategies involving liquid-like slurries, nanocolloids, and advances in direct cellulose solvents that highlight the versatility and desirable properties of this abundant biorenewable photosynthetic feedstock. This review discusses the progress of all-cellulose 3D printing approaches and the associated challenges, with the purpose of promoting future research and development of this important technology for a more sustainable industrial future.

Sustainable Chemistry doi: 10.3390/suschem5020007

Authors: Martinho Freitas Luís Pinto da Silva Pedro M. S. M. Rodrigues Joaquim Esteves da Silva

Green carbon-based materials (GCM), i.e., carbon materials produced using renewable biomass or recycled waste, ought to be used to make processes sustainable and carbon-neutral. Carbon nanomaterials, like carbon dots and the nanobichar families, and carbon materials, like activated carbon and biochar substances, are sustainable materials with great potential to be used in different technological applications. In this review, the following four applications were selected, and the works published in the last two years (since 2022) were critically reviewed: agriculture, water treatment, energy management, and carbon dioxide reduction and sequestration. GCM improved the performance of the technological applications under revision and played an important role in the sustainability of the processes, contributing to the mitigation of climate change, by reducing emissions and increasing the sequestration of CO2eq.

Sustainable Chemistry doi: 10.3390/suschem5020006

Authors: Bhavika Bhatia Nagarjuna Amarnath Sumit K. Rastogi Bimlesh Lochab

Exploring sustainable approaches to replace petroleum-based chemicals is an ongoing challenge in reducing the carbon footprint. Due to the complexity and percentage variation in nature-generated molecules, which further varies based on geographical origin and the purification protocol adopted, a better isolation strategy for individual components is required. Agrowaste from the cashew industry generates phenolic lipid (cardanol)-rich cashew nutshell liquid (CNSL) and has recently shown extensive commercial utility. Cardanol naturally exists as a mixture of three structurally different components with C15-alkylene chains: monoene, diene, and triene. The separation of these three fractions has been a bottleneck and is crucial for certain structural designs and reproducibility. Herein, we describe the gram-scale purification of cardanol into each component using flash column chromatography within the sustainability framework. The solvent used for elution is recovered and reused after each stage (up to 82%), making it a cost-effective and sustainable purification strategy. This simple purification technique replaces the alternative high-temperature vacuum distillation, which requires substantial energy consumption and poses vacuum fluctuation and maintenance challenges. Three components (monoene 42%, diene 22%, and triene 36%) were isolated with good purity and were fully characterized by 1H and 13C NMR, GC-MS, HPLC, and FTIR spectroscopy. The present work demonstrates that greener and simpler strategies pave the way for the isolation of constituents from nature-sourced biochemicals and unleash the potential of CNSL-derived fractions for high-end applications.

Sustainable Chemistry doi: 10.3390/suschem5020005

Authors: Prisco Prete

An overview of the latest advances in the design of active catalysts with the ability to promote (photo) Fenton processes in water from a Green Chemistry perspective is discussed herein. A critical evaluation of the most relevant advances has been disclosed, and a brief perspective is presented about what is needed to fill the gap of knowledge in this field.

Sustainable Chemistry doi: 10.3390/suschem5020004

Authors: Manish Kumar Sah Biraj Shah Thakuri Jyoti Pant Ramesh L. Gardas Ajaya Bhattarai

The current economic development paradigm, which is based on steadily rising resource consumption and pollution emissions, is no longer viable in a world with limited resources and ecological capacity. The “green economy” idea has presented this context with a chance to alter how society handles the interplay between the environmental and economic spheres. The related concept of “green nanotechnology” aims to use nano-innovations within the fields of materials science and engineering to generate products and processes that are economically and ecologically sustainable, enabling society to establish and preserve a green economy. Many different economic sectors are anticipated to be impacted by these applications, including those related to corrosion inhibitor nanofertilizers, nanoremediation, biodegradation, heavy metal detection, biofuel, insecticides and pesticides, and catalytic CO2 reduction. These innovations might make it possible to use non-traditional water sources safely and to create construction materials that are enabled by nanotechnology, improving living and ecological conditions. Therefore, our aim is to highlight how nanotechnology is being used in the green economy and to present promises for nano-applications in this domain. In the end, it emphasizes how critical it is to attain a truly sustainable advancement in nanotechnology.

Sustainable Chemistry doi: 10.3390/suschem5010003

Authors: Konstantin Wink Ingo Hartmann

The recycling of catalysts has emerged as a key solution to address environmental pollution and the scarcity of natural resources. This dynamic is further reinforced by the growing industrial demand for catalysts and the urgent need to transition to more sustainable production methods. In the context of chemical transformations, the direct reuse of recycled catalysts for chemical applications in particular represents an elegant route towards greener syntheses. In this article, we review recent advancements in the recycling of homogeneous and heterogeneous catalysts since 2020, emphasizing the utilization of waste-derived catalysts for chemical reactions. In particular, we consider three primary sources of waste: electronic waste, spent lithium-ion batteries, and industrial wastewater. For each of these waste streams, different extraction methods are explored for their effectiveness in obtaining catalysts suitable for a broad spectrum of chemical reactions. These presented studies emphasize the potential of recycled catalysts to contribute to a sustainable and waste-efficient future.

Sustainable Chemistry doi: 10.3390/suschem5010002

Authors: Aaditya Pendse Aditya Prajapati

The transition towards sustainable and renewable energy sources is imperative in mitigating the environmental impacts of escalating global energy consumption. Methanol, with its versatile applications and potential as a clean energy carrier, a precursor chemical, and a valuable commodity, emerges as a promising solution within the realm of renewable energy technologies. This work explores the integration of electrochemistry with solar power to drive efficient methanol production processes, focusing on electrochemical reduction (ECR) of CO2 and methane oxidation reaction (MOR) as pathways for methanol synthesis. Through detailed analysis and calculations, we evaluate the thermodynamic limits and realistic solar-to-fuel (STF) efficiencies of ECR and MOR. Our investigation encompasses the characterization of multijunction light absorbers, determination of thermoneutral potentials, and assessment of STF efficiencies under varying conditions. We identify the challenges and opportunities inherent in both ECR and MOR pathways, shedding light on catalyst stability, reaction kinetics, and system optimization, thereby providing insights into the prospects and challenges of solar-driven methanol synthesis, offering a pathway towards a cleaner and more sustainable energy future.

Sustainable Chemistry doi: 10.3390/suschem5010001

Authors: Klemen Rola Sven Gruber Darko Goričanec Danijela Urbancl

Synthetically produced biofuels play a critical role in the energy transition away from fossil fuels. Biofuels could effectively lower greenhouse gas (GHG) emissions and contribute to better air quality. One of these biofuels is bioethanol, which could act as a gasoline replacement. For this purpose, a simulation of bioethanol production through lignocellulosic biomass fermentation, focused on distillation, was carried out in simulation software Aspen Plus. Since the possibility of absolute ethanol production through distillation is limited by the ethanol–water azeotrope, pressure swing distillation (PSD) was used to obtain fuel-grade ethanol (EtOH) with a fraction of 99.60 wt.%. The flowsheet was optimised with NQ analysis, which is a simple optimisation method for distillation columns. We found that the PSD has the potential to concentrate the EtOH to a desired value, while simultaneously removing other unwanted impurities whose presence is a consequence of pretreatment and fermentation processes.

Sustainable Chemistry doi: 10.3390/suschem4040025

Authors: Clarissa C. Westover Timothy E. Long

Poly(ethylene terephthalate), the fifth most produced polymer, generates significant waste annually. This increased waste production has spurred interest in chemical and mechanical pathways for recycling. The shift from laboratory settings to larger-scale implementation creates opportunities to explore the value and recovery of recycling products. Derived from the glycolysis of PET, bis(2-hydroxyethyl) terephthalate (BHET) exhibits versatility as a depolymerization product and valuable monomer. BHET exhibits versatility and finds application across diverse industries such as resins, coatings, foams, and tissue scaffolds. Incorporating BHET, which is a chemical recycling product, supports higher recycling rates and contributes to a more sustainable approach to generating materials. This review illuminates the opportunities for BHET as a valuable feedstock for a more circular polymer materials economy.

Sustainable Chemistry doi: 10.3390/suschem4040024

Authors: Ricardo M. S. Sendão Joaquim C. G. Esteves da Silva Luís Pinto da Silva

PFASs are a class of highly persistent chemicals that are slowly infiltrating soils and waterways. Thus, there is a great need for fast, sensitive, and reliable techniques to detect PFASs. Conventional methods, such as LC-MS/SPE, allow high sensitivities. However, such methods can be complex and expensive. Considering this, it is not surprising that the scientific community has turned their attention to the search for alternatives. New types of PFAS sensors have been reported over the years, being generally part of three classes: optical, electrochemical, or hybrid sensors. Carbon dots (CDs) are new alternative fluorescent sensors that can present great affinity towards PFASs, while allowing for a fast response and promising sensitivity and selectivity. Furthermore, CDs have more attractive properties than traditional fluorophores and even metal-based nanomaterials that make them better candidates for sensing applications. Thus, CDs display great potential for permitting a fast and accurate quantification of PFASs. This review aims to serve as a basis for the future development and optimization of CD-based fluorescent sensors for PFASs.

Sustainable Chemistry doi: 10.3390/suschem4040023

Authors: Kazi Afroza Sultana Javier Hernandez Ortega Md Tariqul Islam Zayra N. Dorado Bonifacio Alvarado-Tenorio Ignacio Rene Galindo-Esquivel Juan C. Noveron

Zinc oxide nanoparticles (ZnO NPs) with a high photocatalytic performance were prepared by using the aerobic combustion of saccharides such as glucose, fructose, dextrin, and starch with zinc nitrate. The ZnO NPs were characterized by using transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy-dispersive X-ray scattering spectroscopy (EDX), X-ray powder diffraction (XRPD), and UV-vis spectroscopy. The TEM images revealed that the ZnO NPs have sizes ranging from ~20 to 35 nm with a bandgap of ~3.32 eV. The XRPD pattern revealed the hexagonal wurtzite crystalline structure of the ZnO NPs. The photocatalytic properties of the ZnO NPs were studied by the photocatalytic degradation of methyl orange (MO) in deionized water (DIW) and simulated fresh drinking water (FDW) under ultraviolet light (UV-B) and sunlight illumination. The terephthalic acid photoluminescence technique was also used to study the generation of a hydroxyl radical (•OH) by ZnO NPs. The saccharide-derived ZnO NPs exhibited higher photocatalytic activity than the nonsaccharide-derived ZnO NPs. Varying the type of saccharides used during the calcination had some effect on the degree of the catalytic enhancement.

Sustainable Chemistry doi: 10.3390/suschem4030022

Authors: Teresa Celestino

In this paper, a distinction is first made between environmental, sustainable, and green chemistry; the last two are then examined in relation to the more general problem of environmental education. A brief historical digression on the Science, Technology, and Society movement attempts to dissect reasons why chemistry is seen by the general public as a problem, not as a decisive resource for the realization of the ecological transition. Although sustainable and green chemistry can be decisive in overcoming the insularity of chemical disciplines in high school, it is not well-embedded in educational practices. This situation is slowly changing thanks to the implementations of systems thinking in teaching practice, showing interconnections between the molecular world and sustainability. Historical and epistemological studies provide an all-encompassing framework for the relationship between chemistry and the environment in a broad sense, giving a solid foundation for educational projects. Specific operational goals can help chemical educators in supporting real learning, as well as an examination of the fundamental axes of sustainable and green chemistry, according to the criteria of Scientific and Technological Literacy. Finally, the results of some research carried out in secondary school are presented. These results demonstrate the effectiveness of the interdisciplinary-systemic approach in teaching chemistry as well as in guiding future green careers and reducing the gender gap, preparing high school students in the best possible way to face the challenges of an increasingly interconnected and complex world.

Sustainable Chemistry doi: 10.3390/suschem4030021

Authors: Noelia Rosales-Conrado Juan Peña-Martínez

This paper introduces a captivating topic for upper-level analytical chemistry capstone projects, focusing on aquarium water analysis. This provides a more comprehensive understanding of the role of analytical chemistry towards sustainability and its environmental, economic, societal and education dimensions. Regarding the crucial role of maintaining optimal aquarium water quality for the welfare of aquatic life, students are tasked with envisioning and executing the measurement of key parameters, including pH, ammonium, nitrite, and nitrate contents. This hands-on experience not only engages students in real-world applications, but also allows them to delve into essential analytical chemistry principles. They carefully select measurement methods, considering factors such as instrument availability, ease of use, precision and sensitivity requirements, sample size, and matrix effects. Besides fostering the acquisition of technical and soft skills, one notable aspect of this type of project is the exceptionally high student satisfaction. Furthermore, the project’s outcomes have proven to be significant predictors of learning achievements. Additionally, it lays the foundation for exploring potential designs of aquaponics systems and fosters interdisciplinary projects, expanding the practical applications in the field of chemistry education. Overall, these projects exemplify enriching and engaging educational experiences that empower students with valuable skills and knowledge while encouraging them to explore novel avenues in analytical chemistry.

Sustainable Chemistry doi: 10.3390/suschem4030020

Authors: Caroindes J. C. Gomes Vânia G. Zuin Zeidler

Green and sustainable chemistry education provides opportunities to comprehend and base chemistry knowledge on relevant social and historical contexts, reflecting on fairer and sustainable realities. For this purpose, this work discusses the possibilities and challenges observed during a chemistry teacher training course at a Brazilian university, analyzing how the undergraduates utilized the formative experiences provided by the discipline and how they reinterpreted them when developing didactic sequences based on socio-scientific issues. Using discursive textual analysis, we studied the self-assessments and the didactic sequences produced. The activities developed were positively evaluated by the students and provided the opportunity to create didactic sequences with potential application in schools, founded on cooperative and democratic dynamics and topics that were locally important. On the other hand, the students had some difficulties including chemistry content, mainly considering their relationship with the topics addressed. However, the process proved to be fundamental for the students to perceive themselves as teachers, in addition to provoking them toward (re)constructions and other possibilities.

Sustainable Chemistry doi: 10.3390/suschem4030019

Authors: Sumalatha Bonthula Srinivasa Rao Bonthula Ramyakrishna Pothu Rajesh K. Srivastava Rajender Boddula Ahmed Bahgat Radwan Noora Al-Qahtani

In recent years, copper-based nanomaterials have gained significant attention for their practical applications due to their cost-effectiveness, thermal stability, selectivity, high activity, and wide availability. This review focuses on the synthesis and extensive applications of copper nanomaterials in environmental catalysis, addressing knowledge gaps in pollution management. It highlights recent advancements in using copper-based nanomaterials for the remediation of heavy metals, organic pollutants, pharmaceuticals, and other contaminants. Also, it will be helpful to young researchers in improving the suitability of implementing copper-based nanomaterials correctly to establish and achieve sustainable goals for environmental remediation.

Sustainable Chemistry doi: 10.3390/suschem4030018

Authors: Yuliya Logvina Sónia Fernandes Luís Pinto da Silva Joaquim Esteves da Silva

A sustainable matrix based on eucalyptol essential oil/sawdust was developed and applied on laminated plywood. This finish aims to serve as a eucalyptol odor slow release. Eucalyptol odor release was monitored with gas chromatography coupled with a flame ionization detector (GC-FID: Limits of Detection and Quantification of 0.70 g/m3 and 2.11 g/m3, respectively, and with linearity up to 18.6 g/m3). Measurement of the eucalyptol odor released was performed during a six-month period, and it was found that the release followed a first-order exponential decay with a decay rate constant of 0.0169 per day. The half-life was determined to be of 48 days. The granulometry and particle size porosity of sawdust were analyzed by Scanning Electron Microscopy. A sawdust size fraction of 112–200 μm showed the best eucalyptol absorption capacity, with 1:3 masses ratio (sawdust:eucalyptol). The release duration of eucalyptol is influenced by the quantity of the eucalyptol–sawdust composite and the aperture size for release. Through the determination of this relationship, it was found that applying 15.0 g of the composite through a 0.8 mm diameter aperture resulted in a 6-month eucalyptol release period. This outcome is regarded as highly favorable, considering the inherent high volatility of eucalyptol and the relatively small amount of composite required for future product applications. The new product is characterized by a carbon footprint (considering the industry frontiers) of 5.94 kg CO2eq/m2 of plywood floor.

Sustainable Chemistry doi: 10.3390/suschem4020017

Authors: Renuka Singh Seema Gupta Manoj Kumar Bharty Chandra Shekhar Pati Tripathi Debanjan Guin

In this paper, we illustrate the synthesis, characterization, and application of a Bovine Serum Albumin-stabilized copper nanocluster (BSA@CuNCs)-based photoluminescence (PL) bifunctional sensor for the selective and rapid sensing of picric acid (PA) and hydrogen peroxide (H2O2). Blue-emitting copper nanoclusters were synthesized using one-pot synthesis at room temperature. The PL intensity of BSA@CuNCs was shown to be quenched (“Turn-off”) with an increase in the concentration of PA and intensified (“Turn-on”) with the addition of H2O2. The quenching of PL intensity of BSA@CuNCs was shown to be extremely selective and rapid towards PA. A linear decrease in the PL emission intensity of BSA@CuNCs was observed with a PA concentration in the range of 0–15 μM. An extremely low detection limit of 60 nM (3σ/k) was calculated. The as-prepared BSA@CuNCs also exhibited superior selectivity for PA detection in aqueous medium. The developed sensor was also utilized for the sensing of PA in natural water samples. The probe was found to be extremely sensitive towards the detection of H2O2. An increase in the PL intensity of BSA@CuNCs was seen with the addition of H2O2, with a detection limit of 0.11 μM.