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Search Results (1,266)

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Keywords = mechanical chemical adsorption

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24 pages, 6246 KiB  
Article
Anti-Herpes Simplex Virus Type 1 Activity of Rosa damascena Mill Essential Oil and Floral Water in Retinal Infection In Vitro and In Silico
by Neli Vilhelmova-Ilieva, Rayna Nenova, Kalin Kalinov, Ana Dobreva, Dimitar Peshev and Ivan Iliev
Int. J. Mol. Sci. 2025, 26(15), 7521; https://doi.org/10.3390/ijms26157521 - 4 Aug 2025
Abstract
Recently, essential rose oils and rose products have gained increasing importance in both the cosmetic and food industries, as well as in the composition of medicinal products. We investigated the in vitro antiviral activity of essential oil and floral water from Rosa damascena [...] Read more.
Recently, essential rose oils and rose products have gained increasing importance in both the cosmetic and food industries, as well as in the composition of medicinal products. We investigated the in vitro antiviral activity of essential oil and floral water from Rosa damascena Mill against herpes simplex virus type 1 (HSV-1) infection in rabbit retinal cells (RRCs). The composition of the main chemical components in the rose essential oil was determined by means of gas chromatographic analysis. The effect on the viral replication cycle was determined using the cytopathic effect (CPE) inhibition assay. The virucidal activity, the effect on the adsorption stage of the virus to the host cell, and the protective effect on healthy cells were evaluated using the endpoint dilution method. The effects were determined as deviation in the viral titer, Δlg, for the treated cells from the one for the untreated viral control. The identified main active components of rose oil are geraniol (28.73%), citronellol (21.50%), nonadecane (13.13%), nerol (5.51%), heneicosane (4.87%), nonadecene (3.93), heptadecane (2.29), farnesol (2.11%), tricosane (1.29%), eicosane (1.01%), and eugenol (0.85%). The results demonstrated that both rose products do not have a significant effect on the virus replication but directly affect the viral particles and reduce the viral titer by Δlg = 3.25 for floral water and by Δlg = 3.0 for essential oil. Significant inhibition of the viral adsorption stage was also observed, leading to a decrease in the viral titers by Δlg = 2.25 for floral water and by Δlg = 2.0 for essential oil. When pretreating healthy cells with rose products, both samples significantly protected them from subsequent infection with HSV-1. This protective effect was more pronounced for the oil (Δlg = 2.5) compared to the one for the floral water (Δlg = 2.0). We used the in silico molecular docking method to gain insight into the mechanism of hindrance of viral adsorption by the main rose oil compounds (geraniol, citronellol, nerol). These components targeted the HSV-1 gD interaction surface with nectin-1 and HVEM (Herpesvirus Entry Mediator) host cell receptors, at N-, C-ends, and N-end, respectively. These findings could provide a structural framework for further development of anti-HSV-1 therapeutics. Full article
(This article belongs to the Special Issue Advances in Retinal Diseases: 2nd Edition)
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14 pages, 4225 KiB  
Article
DFT Investigation into Adsorption–Desorption Properties of Mg/Ni-Doped Calcium-Based Materials
by Wei Shi, Renwei Li, Xin Bao, Haifeng Yang and Dehao Kong
Crystals 2025, 15(8), 711; https://doi.org/10.3390/cryst15080711 - 3 Aug 2025
Viewed by 124
Abstract
Although concentrated solar power (CSP) coupled with calcium looping (CaL) offers a promising avenue for efficient thermal chemical energy storage, calcium-based sorbents suffer from accelerated structural degradation and decreased CO2 capture capacity during multiple cycles. This study used Density Functional Theory (DFT) [...] Read more.
Although concentrated solar power (CSP) coupled with calcium looping (CaL) offers a promising avenue for efficient thermal chemical energy storage, calcium-based sorbents suffer from accelerated structural degradation and decreased CO2 capture capacity during multiple cycles. This study used Density Functional Theory (DFT) calculations to investigate the mechanism by which Mg and Ni doping improves the adsorption/desorption performance of CaO. The DFT results indicate that Mg and Ni doping can effectively reduce the formation energy of oxygen vacancies on the CaO surface. Mg–Ni co-doping exhibits a significant synergistic effect, with the formation energy of oxygen vacancies reduced to 5.072 eV. Meanwhile, the O2− diffusion energy barrier in the co-doped system was reduced to 2.692 eV, significantly improving the ion transport efficiency. In terms of CO2 adsorption, Mg and Ni co-doping enhances the interaction between surface O atoms and CO2, increasing the adsorption energy to −1.703 eV and forming a more stable CO32− structure. For the desorption process, Mg and Ni co-doping restructured the CaCO3 surface structure, reducing the CO2 desorption energy barrier to 3.922 eV and significantly promoting carbonate decomposition. This work reveals, at the molecular level, how Mg and Ni doping optimizes adsorption–desorption in calcium-based materials, providing theoretical guidance for designing high-performance sorbents. Full article
(This article belongs to the Special Issue Performance and Processing of Metal Materials)
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25 pages, 3387 KiB  
Article
Efficiency of Spirulina sp. in the Treatment of Model Wastewater Containing Ni(II) and Pb(II)
by Eleonora Sočo, Andżelika Domoń, Mostafa Azizi, Dariusz Pająk, Bogumił Cieniek, Magdalena M. Michel and Dorota Papciak
Materials 2025, 18(15), 3639; https://doi.org/10.3390/ma18153639 - 1 Aug 2025
Viewed by 331
Abstract
In this work, the biosorption potential of Spirulina sp. as an effective and eco-friendly biosorbent for the removal of Ni(II) and Pb(II) ions from aqueous solutions was investigated. Detailed characterization of the biosorbent was carried out, including surface morphology, chemical composition, particle size, [...] Read more.
In this work, the biosorption potential of Spirulina sp. as an effective and eco-friendly biosorbent for the removal of Ni(II) and Pb(II) ions from aqueous solutions was investigated. Detailed characterization of the biosorbent was carried out, including surface morphology, chemical composition, particle size, zeta potential, crystallinity, zero-point charge, and functional group analysis. Batch tests were performed to determine the kinetic constants and adsorption equilibrium of the studied ions. The adsorption behavior of Spirulina sp. was described using six adsorption isotherms. The best fit was obtained for the Redlich-Peterson and Langmuir isotherms, indicating that monolayer adsorption occurred. The maximum biosorption capacities for Ni(II) and Pb(II) were 20.8 mg·g−1 and 93.5 mg·g−1, respectively, using a biosorbent dose of 10 g·L−1, initial metal concentrations ranging from 50 to 5000 mg·L−1, at pH 6, 20 °C, and a contact time of 120 min. Low values of the mean free energy of adsorption (E) in the Dubinin–Radushkevich and Temkin model (0.3 and 0.1 kJ·mol−1 for Pb(II) and 0.35 and 0.23 kJ·mol−1 for Ni(II)) indicate the dominance of physical processes in the ion binding mechanism. The adsorption of Pb(II) ions was more effective than that of Ni(II) ions across the entire range of tested concentrations. At low initial concentrations, the removal of Pb(II) reached 94%, while for Ni(II) it was 80%. Full article
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14 pages, 271 KiB  
Review
Surface Functionalization of Nanoparticles for Enhanced Electrostatic Adsorption of Biomolecules
by Marks Gorohovs and Yuri Dekhtyar
Molecules 2025, 30(15), 3206; https://doi.org/10.3390/molecules30153206 - 30 Jul 2025
Viewed by 192
Abstract
Electrostatic adsorption plays a crucial role in nanoparticle-based drug delivery, enabling the targeted and reversible loading of biomolecules onto nanoparticles. This review explores the fundamental mechanisms governing nanoparticle–biomolecule interactions, with a focus on electrostatics, van der Waals forces, hydrogen bonding, and protein corona [...] Read more.
Electrostatic adsorption plays a crucial role in nanoparticle-based drug delivery, enabling the targeted and reversible loading of biomolecules onto nanoparticles. This review explores the fundamental mechanisms governing nanoparticle–biomolecule interactions, with a focus on electrostatics, van der Waals forces, hydrogen bonding, and protein corona formation. Various functionalization strategies—including covalent modification, polymer coatings, and layer-by-layer assembly—have been employed to enhance electrostatic binding; however, each presents trade-offs in terms of stability, complexity, and specificity. Emerging irradiation-based techniques offer potential for direct modulation of surface charge without the addition of chemical groups, yet they remain underexplored. Accurate characterization of biomolecule adsorption is equally critical; however, the limitations of individual techniques also pose challenges to this endeavor. Spectroscopic, microscopic, and electrokinetic methods each contribute unique insights but require integration for a comprehensive understanding. Overall, a multimodal approach to both functionalization and characterization is essential for advancing nanoparticle systems toward clinical drug delivery applications. Full article
(This article belongs to the Special Issue Advances in Nanomaterials for Biomedical Applications, 2nd Edition)
24 pages, 5828 KiB  
Article
Removal of Rifampicin and Rifaximin Antibiotics on PET Fibers: Optimization, Modeling, and Mechanism Insight
by Elena Fasniuc-Pereu, Elena Niculina Drăgoi, Dumitru Bulgariu, Maria-Cristina Popescu and Laura Bulgariu
Polymers 2025, 17(15), 2089; https://doi.org/10.3390/polym17152089 - 30 Jul 2025
Viewed by 212
Abstract
The removal of antibiotics from aqueous media along with their recovery is still an open research topic, due to their practical and economical importance. Adsorption allows these two objectives to be achieved, provided that the adsorbent used is chemically and mechanically stable and [...] Read more.
The removal of antibiotics from aqueous media along with their recovery is still an open research topic, due to their practical and economical importance. Adsorption allows these two objectives to be achieved, provided that the adsorbent used is chemically and mechanically stable and has a low preparation cost. In this study, PET (polyethylene terephthalate) fibers, obtained by mechanically processing PET waste, were used for the adsorption of rifampicin (RIF) and rifaximin (RIX) antibiotics from aqueous media. The experimental adsorption capacity of PET fibers for the two antibiotics (RIF and RIX) was determined at different pH values (2.0–6.5), adsorbent dose (0.4–20.0 g/L), contact time (5–1440 min), initial antibiotic concentration (4.0–67.0 mg/L), and temperature (10, 22, and 50 °C); the experimental values of these parameters were analyzed using a neuro-evolutive technique (ANE) combining sequential deep learning (DL) models with a differential evolution algorithm. The obtained optimal ANN-DL algorithm was then used to obtain the optimal models for the adsorption of RIF and RIX on PET fibers, which should adequately describe the adsorption dynamics for both antibiotics. The adsorption processes are spontaneous and endothermic (ΔG < 0, ΔH > 0) and are described by the Langmuir model (R2 > 0.97) and the pseudo-second order kinetic model (R2 > 0.99). The retention of RIF and RIX on the surface of PET fibers occurs through physicochemical interactions, and the FTIR spectra and microscopic images support this hypothesis. The presence of inorganic anions in the aqueous solution leads to an increase in the adsorption capacities of RIF (max. 7.6 mg/g) and RIX (max. 3.6 mg/g) on PET fibers, which is mainly due to the ordering of water molecules in the solution. The experimental results presented in this study allowed for the development of the adsorption mechanism of RIF and RIX on PET fibers, highlighting the potential practical applications of these adsorption processes. Full article
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37 pages, 1767 KiB  
Review
Antibiotics and Antibiotic Resistance Genes in the Environment: Dissemination, Ecological Risks, and Remediation Approaches
by Zhaomeng Wu, Xiaohou Shao and Qilin Wang
Microorganisms 2025, 13(8), 1763; https://doi.org/10.3390/microorganisms13081763 - 29 Jul 2025
Viewed by 414
Abstract
Global antibiotic use saturates ecosystems with selective pressure, driving mobile genetic element (MGE)-mediated antibiotic resistance gene (ARG) dissemination that destabilizes ecological integrity and breaches public health defenses. This review synthesizes the sources, environmental distribution, and ecological risks of antibiotics and ARGs, emphasizing the [...] Read more.
Global antibiotic use saturates ecosystems with selective pressure, driving mobile genetic element (MGE)-mediated antibiotic resistance gene (ARG) dissemination that destabilizes ecological integrity and breaches public health defenses. This review synthesizes the sources, environmental distribution, and ecological risks of antibiotics and ARGs, emphasizing the mechanisms of horizontal gene transfer (HGT) driven by MGEs such as plasmids, transposons, and integrons. We further conduct a comparative critical analysis of the effectiveness and limitations of antibiotics and ARGs remediation strategies for adsorption (biochar, activated carbon, carbon nanotubes), chemical degradation (advanced oxidation processes, Fenton-based systems), and biological treatment (microbial degradation, constructed wetlands). To effectively curb the spread of antimicrobial resistance and safeguard the sustainability of ecosystems, we propose an integrated “One Health” framework encompassing enhanced global surveillance (antibiotic residues and ARGs dissemination) as well as public education. Full article
(This article belongs to the Special Issue Antibiotic and Resistance Gene Pollution in the Environment)
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15 pages, 2927 KiB  
Article
Schiff Base-Functionalized Melamine Sponge with Hierarchical Porous Architecture for High-Efficiency Removal of Organic Dyes in Wastewater
by Xiaoyu Du, Hailiang Nie, Yanqing Qu, Jingyu Xu, Hongge Jia, Yong Zhang, Wenhui Ma and Boyu Du
Nanomaterials 2025, 15(15), 1157; https://doi.org/10.3390/nano15151157 - 26 Jul 2025
Viewed by 297
Abstract
Melamine sponges have demonstrated significant application potential in the field of adsorption materials due to their unique three-dimensional porous network structure, excellent chemical/mechanical stability, and abundant amino active sites on the surface. However, the development of modified melamine sponges with efficient Congo red [...] Read more.
Melamine sponges have demonstrated significant application potential in the field of adsorption materials due to their unique three-dimensional porous network structure, excellent chemical/mechanical stability, and abundant amino active sites on the surface. However, the development of modified melamine sponges with efficient Congo red dye removal capabilities remains a substantial challenge. In this study, a stable linear polymer network structure was constructed on the surface of melamine sponges via an in situ polymerization strategy based on the Schiff base reaction mechanism. Characterization analyses reveal that the modified sponge not only retained the original porous skeleton structure but also significantly enhanced the density of surface active sites. Experimental data demonstrate that the modified sponge exhibited excellent adsorption performance for Congo red dye, with the adsorption process conforming to the pseudo-second-order kinetic model and achieving a practical maximum adsorption capacity of 380.4 mg/g. Notably, the material also displayed favorable cyclic stability. This study provides an efficient adsorbent for Congo red dye-contaminated wastewater treatment through the development of a novel surface-functionalized sponge material while also offering new solutions for advancing the practical applications of melamine-based porous materials and environmental remediation technologies. Full article
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30 pages, 3715 KiB  
Article
The Inhibitory Effect and Adsorption Properties of Testagen Peptide on Copper Surfaces in Saline Environments: An Experimental and Computational Study
by Aurelian Dobriţescu, Adriana Samide, Nicoleta Cioateră, Oana Camelia Mic, Cătălina Ionescu, Irina Dăbuleanu, Cristian Tigae, Cezar Ionuţ Spînu and Bogdan Oprea
Molecules 2025, 30(15), 3141; https://doi.org/10.3390/molecules30153141 - 26 Jul 2025
Viewed by 449
Abstract
Experimental and theoretical studies were applied to investigate the adsorption properties of testagen (KEDG) peptide on copper surfaces in sodium chloride solution and, implicitly, its inhibition efficiency (IE) on metal corrosion. The tetrapeptide synthesized from the amino acids lysine (Lys), glutamic acid (Glu), [...] Read more.
Experimental and theoretical studies were applied to investigate the adsorption properties of testagen (KEDG) peptide on copper surfaces in sodium chloride solution and, implicitly, its inhibition efficiency (IE) on metal corrosion. The tetrapeptide synthesized from the amino acids lysine (Lys), glutamic acid (Glu), aspartic acid (Asp), and glycine (Gly), named as H-Lys-Glu-Asp-Gly-OH, achieved an inhibition efficiency of around 86% calculated from electrochemical measurements, making KEDG a promising new copper corrosion inhibitor. The experimental data were best fitted to the Freundlich adsorption isotherm. The standard free energy of adsorption (ΔGadso) reached the value of −30.86 kJ mol−1, which revealed a mixed action mechanism of tetrapeptide, namely, chemical and physical spontaneous adsorption. The copper surface characterization was performed using optical microscopy and SEM/EDS analysis. In the KEDG presence, post-corrosion, SEM images showed a network surface morphology including microdeposits with an acicular appearance, and EDS analysis highlighted an upper surface layer consisting of KEDG, sodium chloride, and copper corrosion compounds. The computational study based on DFT and Monte Carlo simulation confirmed the experimental results and concluded that the spontaneous adsorption equilibrium establishment was the consequence of the contribution of noncovalent (electrostatic, van der Waals) interactions and covalent bonds. Full article
(This article belongs to the Section Computational and Theoretical Chemistry)
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13 pages, 4712 KiB  
Article
Adsorptive Removal Behavior of Two Activated Carbons for Bis(2-ethylhexyl) Phosphate Dissolved in Water
by Lifeng Chen, Jing Tang, Zhuo Wang, Hongling Wang, Wannian Feng, Junjie Chen, Qingqing Yan, Shunyan Ning, Wenlong Li, Yuezhou Wei and Di Wu
Toxics 2025, 13(8), 624; https://doi.org/10.3390/toxics13080624 - 25 Jul 2025
Viewed by 292
Abstract
Bis(2-ethylhexyl) phosphate (P204) is widely used in extraction processes in the nuclear and rare earth industries. However, its high solubility in water results in high levels of total organic carbon and phosphorus in aqueous environments, and may also lead to radioactive contamination when [...] Read more.
Bis(2-ethylhexyl) phosphate (P204) is widely used in extraction processes in the nuclear and rare earth industries. However, its high solubility in water results in high levels of total organic carbon and phosphorus in aqueous environments, and may also lead to radioactive contamination when it is used to combine with radionuclides. In this paper, we characterized a coconut shell activated carbon (CSAC) and a coal-based activated carbon (CBAC) for the adsorption of P204 and then evaluated their adsorption performance through batch and column experiments. The results found that, except for the main carbon matrix, CSAC and CBAC carried rich oxygen-containing functional groups and a small amount of inorganic substances. Both adsorbents had porous structures with pore diameters less than 4 nm. CSAC and CBAC showed good removal performance for P204 under low pH conditions, with removal efficiencies significantly higher than those of commonly used adsorption resins (XAD-4 and IRA900). The adsorption kinetics of P204 conformed to the pseudo-second-order kinetic model, and the adsorption isotherms conformed to the Langmuir model, indicating a monolayer chemical reaction mechanism. Both adsorbents exhibited strong anti-interference capabilities; their adsorption performance for P204 did not change greatly with the ambient temperature or the concentrations of common interfering ions. Column experiments demonstrated that CSAC could effectively fix dissolved P204 with a removal efficiency exceeding 90%. The fixed P204 could be desorbed with acetone. The findings provide an effective method for the recovery of P204 and the regeneration of spent activated carbon, which shows promise for practical applications in the future. Full article
(This article belongs to the Section Toxicity Reduction and Environmental Remediation)
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36 pages, 7620 KiB  
Review
Hydrogen Energy Storage via Carbon-Based Materials: From Traditional Sorbents to Emerging Architecture Engineering and AI-Driven Optimization
by Han Fu, Amin Mojiri, Junli Wang and Zhe Zhao
Energies 2025, 18(15), 3958; https://doi.org/10.3390/en18153958 - 24 Jul 2025
Viewed by 491
Abstract
Hydrogen is widely recognized as a key enabler of the clean energy transition, but the lack of safe, efficient, and scalable storage technologies continues to hinder its broad deployment. Conventional hydrogen storage approaches, such as compressed hydrogen storage, cryo-compressed hydrogen storage, and liquid [...] Read more.
Hydrogen is widely recognized as a key enabler of the clean energy transition, but the lack of safe, efficient, and scalable storage technologies continues to hinder its broad deployment. Conventional hydrogen storage approaches, such as compressed hydrogen storage, cryo-compressed hydrogen storage, and liquid hydrogen storage, face limitations, including high energy consumption, elevated cost, weight, and safety concerns. In contrast, solid-state hydrogen storage using carbon-based adsorbents has gained growing attention due to their chemical tunability, low cost, and potential for modular integration into energy systems. This review provides a comprehensive evaluation of hydrogen storage using carbon-based materials, covering fundamental adsorption mechanisms, classical materials, emerging architectures, and recent advances in computationally AI-guided material design. We first discuss the physicochemical principles driving hydrogen physisorption, chemisorption, Kubas interaction, and spillover effects on carbon surfaces. Classical adsorbents, such as activated carbon, carbon nanotubes, graphene, carbon dots, and biochar, are evaluated in terms of pore structure, dopant effects, and uptake capacity. The review then highlights recent progress in advanced carbon architectures, such as MXenes, three-dimensional architectures, and 3D-printed carbon platforms, with emphasis on their gravimetric and volumetric performance under practical conditions. Importantly, this review introduces a forward-looking perspective on the application of artificial intelligence and machine learning tools for data-driven sorbent design. These methods enable high-throughput screening of materials, prediction of performance metrics, and identification of structure–property relationships. By combining experimental insights with computational advances, carbon-based hydrogen storage platforms are expected to play a pivotal role in the next generation of energy storage systems. The paper concludes with a discussion on remaining challenges, utilization scenarios, and the need for interdisciplinary efforts to realize practical applications. Full article
(This article belongs to the Section A5: Hydrogen Energy)
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20 pages, 2411 KiB  
Article
Influencing Factors of Hexavalent Chromium Speciation Transformation in Soil from a Northern China Chromium Slag Site
by Shuai Zhu, Junru Chen, Yun Zhu, Baoke Zhang, Jing Jia, Meng Pan, Zhipeng Yang, Jianhua Cao and Yating Shen
Molecules 2025, 30(15), 3076; https://doi.org/10.3390/molecules30153076 - 23 Jul 2025
Viewed by 275
Abstract
Chromium slag sites pose severe environmental risks due to hexavalent chromium (Cr(VI)) contamination, characterized by high mobility and toxicity. This study focused on chromium-contaminated soil from a historical chromium slag site in North China, where long-term accumulation of chromate production residues has led [...] Read more.
Chromium slag sites pose severe environmental risks due to hexavalent chromium (Cr(VI)) contamination, characterized by high mobility and toxicity. This study focused on chromium-contaminated soil from a historical chromium slag site in North China, where long-term accumulation of chromate production residues has led to serious Cr(VI) pollution, with Cr(VI) accounting for 13–22% of total chromium and far exceeding national soil risk control standards. To elucidate Cr(VI) transformation mechanisms and elemental linkages, a combined approach of macro-scale condition experiments and micro-scale analysis was employed. Results showed that acidic conditions (pH < 7) significantly enhanced Cr(VI) reduction efficiency by promoting the conversion of CrO42− to HCrO4/Cr2O72−. Among reducing agents, FeSO4 exhibited the strongest effect (reduction efficiency >30%), followed by citric acid and fulvic acid. Temperature variations (−20 °C to 30 °C) had minimal impact on Cr(VI) transformation in the 45-day experiment, while soil moisture (20–25%) indirectly facilitated Cr(VI) reduction by enhancing the reduction of agent diffusion and microbial activity, though its effect was weaker than chemical interventions. Soil grain-size composition influenced Cr(VI) distribution unevenly: larger particles (>0.2 mm) in BC-35 and BC-36-4 acted as main Cr(VI) reservoirs due to accumulated Fe-Mn oxides, whereas BC-36-3 showed increased Cr(VI) in smaller particles (<0.074 mm). μ-XRF and correlation analysis revealed strong positive correlations between Cr and Ca, Fe, Mn, Ni (Pearson coefficient > 0.7, p < 0.01), attributed to adsorption–reduction coupling on iron-manganese oxide surfaces. In contrast, Cr showed weak correlations with Mg, Al, Si, and K. This study clarifies the complex factors governing Cr(VI) behavior in chromium slag soils, providing a scientific basis for remediation strategies such as pH adjustment (4–6) combined with FeSO4 addition to enhance Cr(VI) reduction efficiency. Full article
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15 pages, 2406 KiB  
Article
Adsorption Performance and Mechanism of Gallium from Sulfuric Acid Leach Liquor of High-Alumina Fly Ash
by Wenfen Wu, Chaolu Wen, Shaopeng Li, Zhenhua Sun, Xinjuan Hou, Huiquan Li and Zhibin Ma
Separations 2025, 12(8), 190; https://doi.org/10.3390/separations12080190 - 23 Jul 2025
Viewed by 217
Abstract
High-alumina fly ash may potentially be a valuable source of Ga with a concentration of Ga at 80 mg/kg. Direct adsorption and enrichment of Ga from sulfuric acid leach liquor of high-alumina fly ash is developed in this study. The H-type chelating resin [...] Read more.
High-alumina fly ash may potentially be a valuable source of Ga with a concentration of Ga at 80 mg/kg. Direct adsorption and enrichment of Ga from sulfuric acid leach liquor of high-alumina fly ash is developed in this study. The H-type chelating resin with two carboxy groups exhibited the best adsorption capacity for Ga. The maximum adsorption capacity for Ga was 55 mg/g resin with an adsorption time of 24 h, an initial Ga concentration of 500 mg/L, an adsorption temperature of 55 °C, and an initial acid concentration of 0.1 mol/L. The adsorption process of Ga was in good fit with the Langmuir isotherm and pseudo-second-order reaction kinetics model. The chemical adsorption rate was controlled by an internal diffusion mechanism. The resin had a high selectivity for Ga3+ with a Kd over 3600 compared with Fe2+, Al3+, K+, Ca2+, and Mg2+. The adsorption mechanism was found to be the ion exchange reaction between Ga and H of carboxy and hydroxyl groups. The concentration of Ga in sulfuric acid leach liquor from high-alumina fly ash achieved enrichment from 200 mg/L to 2 g/L. It is an attractive medium for large-scale Ga extraction from high-alumina fly ash. Full article
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18 pages, 2652 KiB  
Article
The Use of a Composite of Modified Construction Aggregate and Activated Carbon for the Treatment of Groundwater Contaminated with Heavy Metals and Chlorides
by Katarzyna Pawluk, Marzena Lendo-Siwicka, Grzegorz Wrzesiński, Sylwia Szymanek and Osazuwa Young Osawaru
Materials 2025, 18(15), 3437; https://doi.org/10.3390/ma18153437 - 22 Jul 2025
Viewed by 225
Abstract
The treatment of contaminants from road infrastructure poses significant challenges due to their variable composition and the high concentrations of chloride ions, heavy metals, and oil-derived substances. Traditional methods for protecting groundwater environments are often insufficient. A promising alternative is permeable reactive barrier [...] Read more.
The treatment of contaminants from road infrastructure poses significant challenges due to their variable composition and the high concentrations of chloride ions, heavy metals, and oil-derived substances. Traditional methods for protecting groundwater environments are often insufficient. A promising alternative is permeable reactive barrier (PRB) technology, which utilizes recycled materials and construction waste as reactive components within the treatment zone of the ground. This paper delves into the potential of employing a composite (MIX) consisting of modified construction aggregate (as recycled material) and activated carbon (example of reactive material) to address environmental contamination from a mixture of heavy metals and chloride. The research involved chemical modifications of the road aggregate, activated carbon, and their composite, followed by laboratory tests in glass reactors and non-flow batch tests to evaluate the kinetics and chemical equilibrium of the reactions. The adsorption process was stable and conformed to the pseudo-second-order kinetics and Langmuir, Toth, and Redlich–Peterson isotherm models. Studies using MIX from a heavy metal model solution showed that monolayer adsorption was a key mechanism for removing heavy metals, with strong fits to the Langmuir (R2 > 0.80) and Freundlich models, and optimal efficiencies for Cd and Ni (R2 > 0.90). The best fit, at Cd, Cu, Ni = 0.96, however, was with the Redlich–Peterson isotherm, indicating a mix of physical and chemical adsorption on heterogeneous surfaces. The Toth model was significant for all analytes, fitting Cl and Cd well and Pb and Zn moderately. The modifications made to the composite significantly enhanced its effectiveness in removing the contaminant mixture. The test results demonstrated an average reduction of chloride by 85%, along with substantial removals of heavy metals: lead (Pb) by 90%, cadmium (Cd) by 86%, nickel (Ni) by 85%, copper (Cu) by 81%, and zinc (Zn) by 79%. Further research should focus on the removal of other contaminants and the optimization of magnesium oxide (MgO) dosage. Full article
(This article belongs to the Special Issue Recovered or Recycled Materials for Composites and Other Materials)
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28 pages, 4509 KiB  
Article
Activated Biocarbons Based on Salvia officinalis L. Processing Residue as Adsorbents of Pollutants from Drinking Water
by Joanna Koczenasz, Piotr Nowicki, Karina Tokarska and Małgorzata Wiśniewska
Molecules 2025, 30(14), 3037; https://doi.org/10.3390/molecules30143037 - 19 Jul 2025
Viewed by 326
Abstract
This study presents research on the production of activated biocarbons derived from herbal waste. Sage stems were chemically activated with two activating agents of different chemical natures—H3PO4 and K2CO3—and subjected to two thermal treatment methods: conventional [...] Read more.
This study presents research on the production of activated biocarbons derived from herbal waste. Sage stems were chemically activated with two activating agents of different chemical natures—H3PO4 and K2CO3—and subjected to two thermal treatment methods: conventional and microwave heating. The effect of the activating agent type and heating method on the basic physicochemical properties of the resulting activated biocarbons was investigated. These properties included surface morphology, elemental composition, ash content, pH of aqueous extracts, the content and nature of surface functional groups, points of zero charge, and isoelectric points, as well as the type of porous structure formed. In addition, the potential of the prepared carbonaceous materials as adsorbents of model organic (represented by Triton X-100 and methylene blue) and inorganic (represented by iodine) pollutants was assessed. The influence of the initial adsorbate concentration (5–150 (dye) and 10–800 mg/dm3 (surfactant)), temperature (20–40 °C), and pH (2–10) of the system on the efficiency of contaminant removal from aqueous solutions was evaluated. The adsorption kinetics were also investigated to better understand the rate and mechanism of contaminant uptake by the prepared activated biocarbons. The results showed that materials activated with orthophosphoric acid exhibited a significantly higher sorption capacity for all tested adsorbates compared to their potassium carbonate-activated counterparts. Microwave heating was found to be more effective in promoting the formation of a well-developed specific surface area (471–1151 m2/g) and porous structure (mean pore size 2.17–3.84 nm), which directly enhanced the sorption capacity of both organic and inorganic contaminants. The maximum adsorption capacities for iodine, methylene blue, and Triton X-100 reached the levels of 927.0, 298.4, and 644.3 mg/g, respectively, on the surface of the H3PO4-activated sample obtained by microwave heating. It was confirmed that the heating method used during the activation step plays a key role in determining the physicochemical properties and sorption efficiency of activated biocarbons. Full article
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43 pages, 1241 KiB  
Review
A Comprehensive Review of Agricultural Residue-Derived Bioadsorbents for Emerging Contaminant Removal
by Janaína Oliveira Gonçalves, André Rodríguez Leones, Bruna Silva de Farias, Mariele Dalmolin da Silva, Débora Pez Jaeschke, Sibele Santos Fernandes, Anelise Christ Ribeiro, Tito Roberto Santanna Cadaval and Luiz Antonio de Almeida Pinto
Water 2025, 17(14), 2141; https://doi.org/10.3390/w17142141 - 18 Jul 2025
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Abstract
The increasing presence of ECs in aquatic environments has drawn significant attention to the need for innovative, accessible, and sustainable solutions in wastewater treatment. This review provides a comprehensive overview of the use of agricultural residues—often discarded and undervalued—as raw materials for the [...] Read more.
The increasing presence of ECs in aquatic environments has drawn significant attention to the need for innovative, accessible, and sustainable solutions in wastewater treatment. This review provides a comprehensive overview of the use of agricultural residues—often discarded and undervalued—as raw materials for the development of efficient bioadsorbents. Based on a wide range of recent studies, this work presents various types of materials, such as rice husks, sugarcane bagasse, and açaí seeds, that can be transformed through thermal and chemical treatments into advanced bioadsorbents capable of removing pharmaceuticals, pesticides, dyes, and in some cases, even addressing highly persistent pollutants such as PFASs. The main objectives of this review are to (1) assess agricultural-residue-derived bioadsorbents for the removal of ECs; (2) examine physical and chemical modification techniques that enhance adsorption performance; (3) evaluate their scalability and applicability in real-world treatment systems. The review also highlights key adsorption mechanisms—such as π–π interactions, hydrogen bonding, and ion exchange—alongside the influence of parameters like pH and ionic strength. The review also explores the kinetic, isothermal, and thermodynamic aspects of the adsorption processes, highlighting both the efficiency and reusability potential of these materials. This work uniquely integrates microwave-assisted pyrolysis, magnetic functionalization, and hybrid systems, offering a roadmap for sustainable water remediation. Finally, comparative performance analyses, applications using real wastewater, regeneration strategies, and the integration of these bioadsorbents into continuous treatment systems are presented, reinforcing their promising role in advancing sustainable water remediation technologies. Full article
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