AppliedChem, Volume 6, Issue 1 (March 2026) – 19 articles

The recycling of polyamide 6 (PA) and elastane (EL) from post-consumer textiles is increasingly relevant for sustainable materials development. This study investigates blends obtained from a commercial PA fabric containing 16% EL, processed via extrusion under various conditions to evaluate the influence of temperature, screw type, and speed on phase morphology and thermo-mechanical performance. The results demonstrate that processing parameters, particularly temperature, significantly affect melt viscosity and the final mechanical properties of the blends. Enhanced ductility was observed in all recycled samples compared to pure PA, indicating that mechanical recycling is a promising strategy for PA/EL textile waste. These findings support the feasibility of this approach, while highlighting the need for further research into compatibilization techniques and industrial scalability. Full article

PrFeTiO₃ perovskite composite was synthesized, and its structural, morphological, chemical, and optical properties were comprehensively characterized. X-ray diffraction (XRD) and a selected area electron diffraction (SAED) confirm the formation of an orthorhombic distorted perovskite phase with no secondary impurities. Transmission electron microscope (TEM) observations show aggregated nanocrystalline domains, while EDS mapping reveals homogeneous cation distribution (Pr, Fe, Ti, O), confirming successful incorporation of Fe and Ti into the perovskite lattice. X-ray photoelectron spectroscopy (XPS) analysis identifies Pr³⁺, Fe³⁺, and Ti⁴⁺ as the dominant oxidation states, supporting charge-compensated B-site substitution. Optical analysis reveals a bandgap of ~2.0 eV, significantly narrower than pristine titanates, indicating enhanced visible-light absorption. This multi-modal characterization verifies the successful formation of PrFeTiO₃ and highlights its potential as a visible-light-active photocatalyst. Although PrTiO₃ showed little reactivity to visible light, PrFeTiO₃ showed excellent efficiency in visible light photocatalytic reactions. PrFeTiO₃ showed more than 20 times better performance than PrTiO₃ in the photodegradation of methylene blue in the liquid phase and formaldehyde in the gas phase. Furthermore, PrFeTiO₃ showed more than 95% superior bactericidal activity against the pathogenic bacterium Staphylococcus aureus than PrTiO₃. Its high photocatalytic efficiency can be attributed to its strong photosensitivity to visible light and small band gap energy. Full article

The Folin–Ciocalteu method remains the standard approach for quantifying total phenolics in plant extracts; however, matrix-specific optimization is essential for obtaining accurate results for chemically complex botanical materials. The Peruvian Amazon harbors extensive botanical biodiversity, including numerous medicinal species with uncharacterized phenolic profiles. This study developed and validated a Folin–Ciocalteu method specifically optimized for twelve ethnomedicinal plants representing eleven families from the Peruvian Amazon, following ICH Q2(R2) guidelines. Method optimization established optimal analytical conditions: 765 nm wavelength, 60 min reaction time, 14.05% sodium carbonate, and gallic acid as the reference standard. Comprehensive validation demonstrated excellent linearity (R² = 0.995–1.000), specificity confirmed through parallel standard addition curves (slope differences < 3%), precision with relative standard deviations below 2.63% for both repeatability and intermediate precision, and accuracy with recovery of 89.43 ± 2.76% meeting AOAC guidelines for complex matrices (80–120%). Robustness testing via response surface methodology confirmed method stability across variations in sodium carbonate concentration (7.50–14.05%), Folin–Ciocalteu reagent dilution (50–100%), and reaction time (30–90 min). Limits of detection and quantification were 4.43 and 13.44 μg/mL, respectively. Application to the twelve species revealed 10-fold variation in total phenolic content (24.6 ± 2.1 to 256.8 ± 4.3 mg gallic acid equivalents per gram dry extract), with Aspidosperma schultesii leaves exhibiting the highest concentration. This validated methodology provides a reliable analytical framework for the quality control and standardization of Amazonian medicinal plants, supporting bioprospecting efforts and therapeutic development. Full article

A comprehensive study was conducted to determine the suitability of biochar produced from agricultural waste in the form of alfalfa (BL₅₀₀) and corn (BC₅₀₀) for methylene blue (MB) adsorption. As part of the research, biochar was produced at 500 °C by pyrolysis using a CO₂ atmosphere. BL₅₀₀ and BC₅₀₀ biochar were characterised in terms of their physicochemical and structural properties using FTIR spectroscopy, Raman spectroscopy, and N₂ adsorption–desorption. The produced biochars are characterised by a significant ash content and high carbon content. They have a specific surface area of 4.12 m²/g (BL₅₀₀) and 19.84 m²/g (BC₅₀₀), a micro-mesoporous structure and are rich in functional groups (including OH, COOH, CO). BL₅₀₀ biochar showed greater effectiveness in removing methylene blue (MB) than BC500, with maximum sorption capacities of 39.94 mg/g and 19.47 mg/g, respectively. Furthermore, kinetic model fitting indicated that the adsorption process follows a pseudo-second-order model and a Langmuir monolayer model. However, the intramolecular diffusion model (IPD) and Bangham models confirmed that the adsorption process does not occur in a single stage. The produced biochar can be used as a sustainable adsorbent for MB from aqueous solutions. Full article

Imidazole dipeptides (IDPs), including carnosine, anserine, and balenine, are functional food ingredients found in meats. They have been reported to exhibit high antioxidant activity. 2-Oxo-imidazole dipeptides (2-oxo-IDPs) are present in trace amounts in various tissues and show notably higher antioxidant activity compared with IDPs. Trace amounts of 2-oxo-IDPs are also present in commercial IDP reagents, suggesting that they affect the antioxidant activity of IDPs. Trace amounts of 2-oxo-IDPs were detected in IDP reagents from various manufacturers by HPLC. Some reagents with trace amounts of 2-oxo-IDPs exhibited higher antioxidant activity in a DPPH radical-scavenging assay compared with high-purity IDP reagents devoid of 2-oxo-IDPs. Therefore, it is important to use highly purified IDP reagents to measure antioxidant activity accurately. The antioxidant activity of highly purified IDPs and 2-oxocarnosine (2-oxo-Car) was evaluated through their ability to protect protein and DNA from ROS. 2-Oxo-Car markedly inhibited the protein and DNA degradation by ClO⁻ and ONOO⁻ compared with IDPs. Moreover, 2-oxo-Car was not cytotoxic, even at high concentrations, and suppressed pyocyanin-induced ROS generation in C2C12 cells compared with IDPs and glutathione. Overall, 2-oxo-IDPs are effective antioxidants and are equivalent or superior to known water-soluble antioxidants, such as glutathione and vitamin C. Full article

The positive effects of phenolic compounds in the gastrointestinal tract are influenced by dietary fibers. The aim of this work was to study the interactions between syringic acid and soluble and insoluble dietary fibers from the β-glucan group, including laminarin from Laminaria digitata, zymosan A from Saccharomyces cerevisiae and β-glucan from Euglena gracilis. Kinetic models of the pseudo-first and pseudo-second order were applied to describe the interactions in time. The stability of the complexes between syringic acid and dietary fibers was monitored at different times by the DPPH method. The water holding capacity, water swelling capacity and water solubility of dietary fibers were determined. FTIR spectra were recorded to characterize the possible binding of syringic acid and dietary fibers. The results showed that syringic acid adsorbed onto dietary fibers with different adsorption capacities. The highest adsorption capacity was observed for zymosan A (431 mg g⁻¹), followed by laminarin (382 mg g⁻¹) and β-glucan from Euglena gracilis (336 mg g⁻¹). The parameters of the kinetic models showed good agreement with the experimental data. The highest antiradical activity was found for the complex of syringic acid—β-glucan from Euglena gracilis. The FTIR spectrum confirmed the bonding of syringic acid onto dietary fibers. The interactions of polyphenols and dietary fibers are important to understand the role of dietary fibers as carriers of polyphenols. Full article

Human remains detection (HRD) canines are a class of odor detection canines trained with training aids representative of distinctive stages of putrefaction. This is necessary for canines to detect the whole spectrum of decomposition products, which is encountered in operational deployments. Understanding the definition of the cadaveric profile can help better train canine detection teams and assist with technological developments. This study aimed to (1) monitor chemical odor profiles utilizing two containment vessels, and (2) monitor two preservation methods on chemical odor profile changes as a function of freezing to thawing cycles. Instrumental analysis used solid phase microextraction- gas chromatography/mass spectrometry (SPME-GC/MS) for identification of volatile organic compounds (VOCs) from tissue/bone samples of pig carcasses at various decomposition stages. Samples were analyzed weekly for six (6) weeks to monitor chemical odor profiles as a function of time. Clear vials provided slightly better storage stability for the fresh stage compared to amber vials. However, amber vials were more suitable for the advanced decay and skeletal stages, helping to preserve the chemical odor profile. Regarding the preservation methods, a continuous preservation method portrayed better reproducibility of the original odor profile throughout the 6-week period, as depicted from higher Spearman correlation values. This study is the first to explore simulated training aids under freezing conditions, uncovering the dynamic and complex nature of odor over time. The results highlight that understanding these shifting odor profiles is essential for canine handlers aiming to optimize the realism and effectiveness of maintenance training. Full article

This study explores a sustainable synthesis route for FAU-type zeolite X using acid-treated ladle slag as a silicon source and waste aluminum cans as an alternative aluminum precursor. Conventional zeolite synthesis relies on high-purity reagents, which are costly and environmentally intensive to produce. Previous research has rarely addressed the valorization of ladle slag and metallic aluminum waste for zeolite formation, leaving their potential largely unexplored. The study focuses on the effective utilization of industrial and post-consumer wastes—acid-treated ladle slag and aluminum cans—as precursors for FAU-type NaX zeolite, demonstrating their feasibility as alternative silicon and aluminum sources. Here, zeolite X was synthesized hydrothermally from treated slag combined with either dissolved aluminum cans and commercial sodium aluminate at 90 °C for 6 h. FAU-type zeolite X was successfully synthesized using both aluminum sources, with a SiO₂/Al₂O₃ ratio of approximately 1.4. The results demonstrate that waste-derived precursors can effectively replace conventional chemicals, yielding predominantly NaX zeolite with high crystallinity and minor NaA impurity (as observed by XRD), with experimental yields of 1.47 g for aluminum cans and 1.266 g for sodium aluminate. The obtained zeolite X samples were structurally and texturally characterized by XRD, FTIR, XRF, BET surface area analysis, and thermogravimetric analysis (TG). Full article

This research investigates the potential of secondary lavender biomass (Lavandula officinalis) as a raw material for paper production within the context of the circular economy and its practical applications. Lavender stems, a by-product of essential oil extraction, were processed using the nitrate–alkali pulping method. The chemical composition of the raw material was analysed according to TAPPI standards, and the resulting pulp was characterised in terms of its mechanical and physical properties, including tensile strength and air permeability. Lavender stems contained 29.43% cellulose and 24.10% lignin, indicating moderate delignification efficiency under the applied conditions. The pulp yield was 24.2% with a Kappa number of 15.9. Of the prepared sheets, the paper with a weight of 80 g·m⁻² showed the best mechanical properties, with a breaking length of 1.71 km and a tensile strength index of 16.76 N·m·g⁻¹. In addition, lavender-based paper demonstrated measurable repellent activity against Tineola bisselliella, reducing insect presence by 70% compared to control samples, as determined by controlled laboratory exposure tests. This bioactivity is attributed to residual volatile compounds such as linalool and linalyl acetate, originating from lavender biomass. Overall, lavender secondary biomass represents a promising non-wood fibre for the production of biodegradable, functional paper materials that combine structural integrity with natural repellent properties. Full article

Acid violet 19 (AV19) dye is used in many fields, including photographic film, inks, leather, and textiles. Potassium ferrate (VI) (Fe(VI)) represents a novel oxidant, notable for its strong oxidative capabilities, stability, and environmental sustainability. This research investigates the decolorization and mineralization of AV19 through the application of Fe(VI), with a particular emphasis on essential parameters, including pH, molar ratios, and temperature variations. The study ascertained that the optimal conditions for AV19 oxidation are a pH of 7.0, a molar ratio of AV19: Fe(VI) of 1:5, and a temperature of 45 °C with a reaction time of 12 min. The decolorization efficiency achieved was approximately 98%, and the mineralization was 31%. The degradation process yielded intermediates, such as sulfonic acid derivatives, benzoic acid, benzene, and cyclohexane compounds, which were further oxidized into acetic acid, carbon dioxide, and water. Comprehensive computational toxicity evaluations confirmed that both the intermediates and the final products are non-toxic. Full article

Geosmin contamination in water is a worldwide concern, owing to its strong odor at trace levels and limited removal by typical water treatment methods. In this study, bentonite–alginate–magnetic (Bent-alg-mag) beads were prepared using the ionic gelation method for the removal of geosmin from aqueous solutions. The adsorbent’s physicochemical properties were characterized by scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) analysis. The influence of factors such as contact time, solution pH, initial geosmin concentration, and adsorbent dosage on adsorption performance was systematically investigated. Under optimal conditions, over 96% of geosmin was removed within 480 min. The adsorption kinetics were best described by the pseudo-first-order model (R² = 0.9918), indicating that the process is primarily controlled by surface adsorption. Adsorption equilibrium data were well fitted by the Langmuir isotherm model (R² = 0.9705) and a maximum monolayer capacity of 16.064 ng/g. The adsorbent exhibited 70% removal efficiency after three adsorption–desorption cycles, showing good regeneration potential, though long-term stability may be limited. Overall, the Bent-alg-mag beads proved to be an effective and promising material for the removal of geosmin from water. Full article

This study investigated the influence of drying techniques such as convection hot-air drying, vacuum drying, and freeze drying with slow and flash pre-freezing on the total phenolic content and the profile of dominant phenolic compounds in cultivated blueberry (Vaccinium corymbosum L.). Although fresh blueberries exhibited higher total phenolic content (1350.85 mg GAE/100 g), total flavonol glycosides (66.20 mg/100 g), and total anthocyanins (218.23 mg/100 g) compared with dried samples, freeze-dried samples, particularly those subjected to flash pre-freezing, retained higher contents of these components in the dried material compared to other drying techniques. This could be attributed to the microstructural preservation of plant tissue during freeze drying. Furthermore, the study demonstrated that subsequent milling of freeze-dried samples, whether using a knife mill or a ball mill, also affects the availability of bioactive compounds in freeze-dried blueberry powders. The combination of flash pre-freezing followed by ball milling yielded the highest availability of bioactive components in the processed blueberry powder. Full article

The increasing presence of pharmaceutical residues such as ibuprofen in aquatic environments represents a growing concern due to their persistence and limited biodegradability. In this study, selenium-doped tin oxide (SnO₂:Se) nanoparticles covered with glycerol were synthesized via a microwave-assisted method to evaluate their photocatalytic performance in the degradation of ibuprofen under ultraviolet (UV) and visible light. Optimal synthesis parameters were determined at pH 7.5–8.0 and 130 °C, yielding stable, dark-brown colloidal suspensions. HRTEM analysis revealed a coexistence of one-dimensional (1D) nanowires and zero-dimensional (0D) quantum dots, confirming nanoscale morphology with crystallite sizes between 8 and 100 nm. EDS analysis confirmed the presence of Sn, O, and trace Se (0.1 wt%), indicating Se incorporation as a dopant. UV–Vis spectroscopy showed strong absorption near 324 nm and slight band-gap narrowing in the Se-doped samples, suggesting enhanced visible-light responsiveness. Photocatalytic experiments demonstrated an ibuprofen degradation efficiency of ~60% under visible light and 80% under UV irradiation with aeration, compared to only 5% removal using commercial SnO₂. The enhanced performance was attributed to Se-induced band-gap modulation, effective charge-carrier separation, and singlet oxygen generation. Full article

This study examined the influence of short-term olive fruit storage on the quality of virgin olive oil (VOO) from three cultivars (‘Kalinjot’, ‘Leccino’, and ‘Frantoio’) grown in southwest Albania. Olive fruits were processed immediately after harvest, or after 10 days of storage under ambient conditions (20–22 °C) and refrigeration (5 °C). Oils were evaluated for physicochemical quality parameters (free acidity, peroxide value, and UV absorption indices), as well as bioactive and sensory-related compounds (bitterness index, chlorophylls, carotenoids, and total phenolic content). Results showed that immediate processing yielded the highest quality oils, with low free acidity (0.28–0.35%) and preserved bioactive compounds. Ambient storage led to marked deterioration, including significant increases in free acidity and peroxide values, loss of pigments, and 20–70% reduction in phenolic content, accompanied by decreased bitterness. In contrast, cold storage mitigated these effects, maintaining values closer to baseline and preserving sensory and functional attributes. ANOVA confirmed significant effects of storage duration, temperature, and cultivar on most parameters, with ‘Kalinjot’ exhibiting greater stability compared to ‘Frantoio’ and ‘Lecino’. These findings highlight that minimizing the interval between harvest and milling is critical for ensuring oil quality, while refrigerated storage offers a practical strategy to safeguard chemical and sensory characteristics when immediate processing is not feasible. Full article

In this paper we provide the Group Contribution parameters for acetylenes and aromatic nitro compounds fitting with a recently developed Group Contribution method with chemical accuracy (1 kcal/mol) for the heat of formation of organics. These additional parameters widen the applicability of the Group Contribution method. We also provide further G4 quantum calculated values as reference when no experimental data are available and compare to previously reported G4 data. Full article

Seeds from four landraces of dry beans (Phaseolus vulgaris L. and Phaseolus coccineus L.) from the National Collection of Bulgaria were analyzed for their chemical and lipid composition. The chemical analysis revealed that protein ranged from 24.4% to 31.5%, carbohydrates from 53.1% to 56.1%, fat from 0.9% to 1.4%, fiber from 2.6% to 2.8%, and ash from 3.9% to 4.7%, indicating their high nutritional and caloric value. The seed oils contained significant levels of bioactive compounds, including tocopherols (3483–3809 mg/kg), carotenoids (1664–2049 mg/kg), and phospholipids (24.6–62.2%), which contribute to their health-promoting properties. In the Phaseolus vulgaris accessions, the oil was primarily composed of linolenic (n-3) and linoleic acids (n-6), followed by palmitic and oleic acids, whereas in the Phaseolus coccineus accession, linoleic acid (n-6) predominated, followed by linolenic (n-3) acid. β-Sitosterol was the major sterol, followed by stigmasterol, while the tocopherol fraction was mainly composed of γ-tocopherol (88.2–95.0%), with δ-tocopherol as a secondary component. Phosphatidylcholine was the predominant phospholipid, accounting for 33.1–51.7%. These findings underscore the potential of Bulgarian bean landraces as functional ingredients in health-oriented food products due to their balanced nutritional profile and presence of bioactive lipids. Full article

This study assessed the phenolic content, antioxidant capacity, and phytochemical composition of methanolic extracts from Portuguese Mentha pulegium L. and Lavandula stoechas L. Through spectrophotometric methods (TPC, FRAP, and DPPH), high-resolution techniques (HPLC-ESI(-)-HRMS/MS), along with multivariate techniques (PCA and cluster analysis). A total of 24 to 26 metabolites were identified across the analyzed plant species, including flavonoids, phenolic acids, terpenoids, jasmonates, and fatty acids. M. pulegium was primarily composed of diosmin and hesperidin, whereas L. stoechas exhibited amounts of rosmarinic acid and associated phenolic compounds. Multivariate and correlation analyses demonstrated variability within species and emphasized connections among metabolite categories, biosynthetic routes and environmental influences like altitude. Inland accessions of M. pulegium from Beja, Portalegre and Évora showed elevated TPC and FRAP levels while DPPH activity fluctuated according to distinct metabolite profiles. Despite these variations, phytochemical diversity did not adhere to a geographic trend, indicating that genetic and biosynthetic elements are more influential. The interplay between flavonoids and phenolic acids seemed crucial in determining antioxidant activity. Overall, the Portuguese germplasm of both species demonstrates substantial bioactive potential and chemical diversity, underscoring its value for food, nutraceutical, and pharmaceutical applications. These findings provide a scientific basis for selecting promising accessions and developing future biotechnological strategies. Full article

Considering the high demand for efficient chemical recycling and reusability of polyurethane foams (PUFs), combined microwave-assisted solvolysis routes have been applied to a widely used commercial PUF for pipe pre-insulation, and the reusability of as-received recycled products in the original formulation was studied. The influence of the type and amount of recyclate on the main foaming parameters, shrinkage behavior, density, compression properties, morphology, thermal stability, and humidity uptake was determined. Based on shrinkage as the main exclusion criterion, recycling products of two routes have been evaluated as suitable for reuse in the original formulation without any purification or fractionation. However, a maximum of 5 wt.% of the original polyol compound could be replaced by these recycled products to fulfill the requirement of ≤5% shrinkage, which also resulted in foam performance that is well acceptable for use in pre-insulated pipes. The most beneficial property profiles were achieved by replacing 3 wt.% of the original polyol component. Full article

This study introduces an optimized and selective extraction methodology using dichloromethane/methanol (DCM/MeOH, 95:5, v/v) in combination with accelerated solvent extraction (ASE) for the targeted stilbenoid and phenanthrene derivatives from five orchid species: Cattleya nobilior (root), Cymbidium defoliatum (root and bulb), Dendrobium phalaenopsis (stem), Encyclia linearifolioides (leaf), and Phalaenopsis aphrodite (root). Sequential extraction was performed with hexane, followed by DCM/MeOH (95:5 and 1:1, v/v) under controlled temperatures (70 °C for hexane, 100 °C for DCM/MeOH), using three static cycles per stage. Chemical profiling by high-performance liquid chromatography with a diode-array-detector and tandem mass spectrometry (HPLC-DAD-MS/MS) enabled the identification of twenty specialized metabolites—seven stilbenoids and thirteen phenanthrenes—several reported here for the first time, including crepidatuol B, dendrosinen D, and coeloginanthridin. The analytical method showed excellent separation of structurally related phenolic compounds, demonstrating the efficiency of the extraction protocol and the selectivity of the solvent system. Many of the identification metabolites are known for cytotoxic, antioxidant, anti-inflammatory, and metabolic regulatory properties, while newly detected compounds remain unexplored and present promising candidates for future biological evaluation. The broad distribution of these metabolites across the studied orchids enhances the current understanding of their phytochemical diversity and suggests chemotaxonomic relevance within the Orchidaceae family. Importantly, the extraction strategy requires minimal plant material, offering ecological advantages when working with rare or endangered species. Overall, this environmentally conscious extraction approach provides a robust platform for metabolic discovery and supports future research in natural products chemistry, plant ecology, drug discovery, structure–activity relationships studies and biotechnological applications. Full article