Search Results (710)

Secondary aluminum dross (SAD) is classified as hazardous waste (HW48) due to its content of toxic (e.g., heavy metals, fluorides) and highly reactive phases (e.g., aluminum nitride, AlN). This review systematically synthesizes the sources, heterogeneous composition, and environmental risks of SAD, and critically evaluates state-of-the-art hydrometallurgical and pyrometallurgical detoxification and resource-utilization technologies. Comparative, mechanism-oriented analyses are used to elucidate the respective advantages, limitations, and scalability of wet versus thermal routes. Particular emphasis is placed on the migration, transformation, and ultimate fate of key hazardous species (AlN, fluorides, chlorides, and heavy metals) during treatment and product valorization. An integrated hydro–pyro nexus is conceptualized as synergistic hybrid processing that transcends the trade-offs between efficiency, energy consumption, and product purity that currently limit standalone technologies. Emerging hybrid process concepts, advanced additives, and circular-economy-oriented product pathways are evaluated to address current technological bottlenecks. Finally, critical knowledge gaps and research priorities are identified to accelerate safe, low-carbon, and high-value utilization of SAD. Full article

Polyvinyl chloride (PVC) is widely used in engineering applications; however, its inherent thermal instability associated with dehydrochlorination limits its processing window and long-term performance. While blending with thermoplastic polyurethane (TPU) and plasticization are common strategies to improve flexibility, their combined influence on the thermal behavior and stability of PVC, particularly when bio-based plasticizers are employed, has not been thoroughly investigated. In this study, the thermal behavior and stability of PVC/TPU blends plasticized with glycerol diacetate monolaurate, a bio-based plasticizer derived from waste cooking oil, were investigated. Dynamic mechanical analysis (DMA) and Fourier transform infrared spectroscopy (FTIR) were used to examine segmental mobility and intermolecular interactions, while scanning electron microscopy (SEM) provided insight into microstructural organization. Thermal stability was evaluated through conductivity-based dehydrochlorination measurements, complemented by thermogravimetric and derivative thermogravimetric analyses (TGA/DTG) to assess degradation behavior. The results showed that neither TPU nor the bio-plasticizer alone improved the resistance of PVC to dehydrochlorination. In contrast, ternary PVC/TPU/bio-plasticizer blends exhibited a pronounced delay in HCl evolution, accompanied by a more homogeneous phase distribution and interaction-driven modification of the molecular environment. TGA/DTG analysis indicated that this stabilization arises from altered degradation kinetics rather than a simple shift in degradation onset. Overall, the findings clarify the thermal behavior of PVC-based blends and demonstrate a sustainable formulation approach for achieving flexible and thermally balanced PVC materials while reducing reliance on potentially toxic phthalate plasticizers. Full article

In this study, potential fungicides were prepared following the principles of green chemistry. The compounds were synthesized in deep eutectic solvents as an alternative medium and compared with syntheses in traditional solvents such as ethanol. The efficiency of the reaction was improved by ultrasonic synthesis in both eutectic solvents and ethanol, resulting in higher yields while reducing reaction energy and time. For the first time, deep eutectic solvents (DES) were used for quaternisation reactions, with choline chloride as a hydrogen bond acceptor and urea, glycerol, malic acid, malonic acid, and levulinic acid as donors. DES, composed of biodegradable, non-toxic, and renewable components, represented a greener alternative to conventional solvents. However, reactions in DES by the conventional method generally resulted in lower yields, probably due to solubility and viscosity limitations inherent in the eutectic medium. The combination of ultrasound and deep eutectic solvents proved to be a good alternative to organic solvents for the quaternisation reaction, as higher yields were achieved in a shorter time compared to conventional methods. The antifungal activity of all 18 synthesized compounds was tested. The compounds exhibited significant antifungal activity against all four pathogens, with varying levels of mycelial growth inhibition. B. cinerea was the most sensitive species (up to 70.7% inhibition), while F. culmorum was the least sensitive (≤32%). Full article

Wastewater contamination by toxic heavy metal ions poses a huge threat to ecosystem integrity and human health. Herein, we designed a polyelectrolyte (T-PEI) with a tunable positive charge property to construct a layer-by-layer (LBL) nanofiltration membrane for efficient heavy metal ion removal. The T-PEI was obtained via a Mannich reaction between polyethyleneimine (PEI) and tetrakis (hydroxymethyl) phosphonium chloride (THPC). The introduction of THPC imparted T-PEI with a strong and tunable positive charge, attributed to the quaternary phosphonium groups in THPC. Converting the weakly charged PEI into the strongly charged T-PEI allowed regulation of both T-PEI’s deposition behavior and the electrostatic interactions with sodium polystyrenesulfonate (PSS) during LBL assembly. As a result, after depositing only one bilayer, the positively charged PSS/T-PEI membrane achieved a pore size radius of 0.35 nm, meeting the typical criteria for nanofiltration membranes. Under the optimal preparation conditions, the resultant membranes exhibited a water flux of 38.1 L m⁻² h⁻¹ and high rejections to various heavy metal ions at low operation pressure, such as Cr³⁺ (99.8%), Ni²⁺ (96.1%), Cu²⁺ (92.5%), and Mn²⁺ (90.3%). Additionally, the membrane possessed robust operation stability, along with excellent antifouling/bacterial performance. After cyclic filtration of a lysozyme solution, the flux recovery ratio reached 94.7%. The membrane also exhibited effective bactericidal activity against both Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), with no visible microbial colonies observed. This work highlights the effectiveness of tailoring polyelectrolyte characteristics in enhancing the LBL membrane performance and presents a promising LBL nanofiltration membrane for heavy metal ion removal. Full article

Waste products of zinc hydrometallurgy, such as Pb–Ag jarosite sludge, represent a significant environmental problem due to toxic properties associated with elevated lead content. At the same time, this material has economic value, making its valorization beneficial from both ecological and financial perspectives. This study investigates the chloride leaching of pretreated Pb–Ag jarosite sludge, which underwent sulphation roasting followed by water leaching. The experiments were conducted with a constant solid/liquid ratio of 1:20, a stirring rate of 150 rpm, and using a 4 mol dm³ MgCl₂ solution as the leaching agent, while temperature (40–80 °C) and leaching time (up to 120 min) were varied. The results showed that temperature significantly affects the lead leaching degree, with the highest (95%) achieved at 80 °C after 60 min. Kinetic analysis revealed a diffusion-controlled mechanism, with an activation energy of 18.40 kJ mol⁻¹. Due to the characteristics of the leaching curve, the process was divided into four segments, with corresponding activation energies determined for each segment (16.48, 11.80, 13.88, and 20.50 kJ mol⁻¹). The proposed MgCl₂ system enables efficient lead leaching with a reduced amount of leaching agent, thus representing a more sustainable approach to the valorization of Pb–Ag jarosite sludge. Full article

Copper–organic compounds are being investigated as antitumor candidates. Besides their efficacy as cytotoxic agents alone, the oxidative potential of electrochemical Cu²⁺-to-Cu¹⁺ transition emerges as an attractive approach for elimination of tumor cells otherwise resistant to chemotherapy. To minimize side effects of the potent oxidative burst upon Cu(II) reduction, the metal cations should be delivered to the tumor site. Taking advantage of the ability of bisphosphonates to accumulate in the bone, we synthesized a Cu(II) complex of zoledronic acid (ZA), an FDA-approved drug for prevention of bone destruction. The CuZA complex obtained upon precipitation of ZA and different copper salts (sulfate, chloride or perchlorate) were structurally identical, consisting of two organic moieties coordinated by three metal cations. Combined treatment with water-soluble formulations of CuZA and cysteine triggered rapid death in human cell lines. This effect was achievable with non-toxic concentrations of CuZA and cysteine alone. Importantly, the K562 chronic myelogenous leukemia cells that demonstrated an attenuated response to the 3d generation Bcr-Abl tyrosine kinase inhibitor in the medium conditioned by bone marrow-derived fibroblasts, were readily killed by CuZA–cysteine combination. Thus, oxidative burst upon metal reduction in CuZA complexes emerges as a promising method of eradication of tumor cells in the bone microenvironment. Full article

Growing demand for sustainable materials has intensified research into eco-friendly alternatives to conventional and synthetic leathers. Traditional bovine leather and its chromium-tanning process heavily contribute to water pollution, toxic waste generation, and carbon emissions, while synthetic leather derived from Polyvinyl Chloride (PVC) and polyurethane (PU) presents challenges related to fossil fuel dependence and non-biodegradability. This review explores bio-based and sustainable leather substitutes that are made of plants, microbial cellulose, and mycelium fungi. Plant-based leather substitutes such as Vegea^®, Desserto^®, and Piñatex^® use agricultural waste products to create durable, partially biodegradable composites. Microbial cellulose from kombucha fermentation offers material with good physical and aesthetic properties. Mycelium leather, derived from fungal biomass, demonstrates potential for scalable and low-impact production. Comparative analyses of mechanical and physical properties show that mycelium composites are approaching industrial standards, though challenges remain regarding tensile strength, water resistance, and process standardization. Despite current limitations, bio-based leathers, particularly mycelium composites, offer a promising way toward circular material innovation and carbon-neutral manufacturing in fashion, automotive, design and other industries. Full article

Over the past few decades, ionic liquids (ILs) have gained attention as electrolytes, although concerns about their environmental persistence and toxicity challenge their status as green solvents. In this framework, choline chloride (ChCl) offers a more sustainable alternative due to its low toxicity, biodegradability, and cost-effectiveness. Although ChCl has a high melting point, its combination with hydrogen bond donor compounds (HBDs) can result in liquid mixtures at much lower temperatures, known as deep eutectic solvents (DESs). This study presents a comparative evaluation of three ChCl-based DESs, glyceline, ethaline, and reline (obtained from mixtures of ChCl and glycerol, ethylene glycol, and urea), with a focus specifically on their potential as electrolyte candidates for supercapacitors. Using differential scanning calorimetry (DSC), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and nuclear magnetic resonance (NMR), we assess their thermal, electrochemical, and structural properties. All DESs displayed amorphous behavior and a strong tendency to remain liquid even at very low temperatures. Among them, ethaline showed the most promising electrochemical performance, exhibiting the lowest resistivity and the highest capacity. Full article

Textile wastewater contains recalcitrant azo dyes and auxiliary chemicals that are resistant to conventional biological treatment, resulting in persistent organic pollution in aquatic ecosystems. While supercritical water oxidation (SCWO) achieves superior chromophore mineralization, its high energy requirements limit industrial scalability. Conversely, biomass-derived activated carbon (BAC) offers a low-cost adsorption solution, but it rapidly becomes saturated with toxic oxidation intermediates. Notably, the literature lacks systematic analyses of hybrid SCWO-BAC systems with integrated thermal energy, which represents a crucial gap in assessing their economic feasibility. This review employed a systematic methodology, selecting studies relevant to the topic from peer-reviewed publications and databases, including Scopus, SciELO, ScienceDirect, and Google Scholar, for critical synthesis. Using SCWO as a pretreatment (which significantly reduces COD load), followed by BAC polishing, results in superior detoxification compared to individual processes. However, three barriers hinder scale-up: (i) chloride ion corrosion in real effluents; (ii) irreversible collapse of BAC pores after multiple regeneration cycles; and (iii) absence of standardized ecotoxicity data for hybrid-treated streams. This work outlines a technological roadmap for integrated supercritical water oxidation and biological activated carbon (SCWO-BAC) systems, targeting economically viable operational parameters for industrial-scale implementation. Full article

Per- and polyfluoroalkyl substances (PFASs) have raised considerable concern due to their ubiquity, persistence, bioaccumulation, and toxicity. However, cost-effective, high-performance adsorbents for PFAS removal from aquatic environments remain limited. Here, we synthesized a porous graphitic biochar adsorbent (Zn-BBC) from banana peel waste via zinc chloride (ZnCl₂) activation and applied it to removing ten legacy and alternative PFASs from water. Zn-BBC achieved removal efficiencies > 95% for all target PFASs. The adsorption of PFASs onto Zn-BBC followed pseudo-second-order (PSO) kinetics, suggesting chemisorption. Additionally, the adsorption isotherms were well described by the Sips model, indicating surface heterogeneity. Zn-BBC exhibited robust performance over a broad pH range (3–9). Coexisting ions (CO₃²⁻, SO₄²⁻, Zn²⁺, Ca²⁺, and Mg²⁺), tested individually at 10 mM each, had negligible effects on the adsorption of the PFASs examined, except for perfluorobutanoic acid (PFBA). In contrast, humic acid (10 mM) significantly reduced the removal rates of PFBA, perfluorohexanoic acid (PFHxA), and hexafluoropropylene oxide dimer acid (GenX). Nevertheless, in river and lake waters, Zn-BBC achieved >85.0% removal of all PFASs except PFBA. In regeneration experiments, Zn-BBC exhibited excellent reusability. Experimental characterization and density functional theory (DFT) calculations jointly revealed that PFAS adsorption involves electrostatic interactions, hydrophobic interactions, π-CF interactions, surface complexation, and hydrogen bonding. These results suggest that Zn-BBC is a promising sorbent for PFAS removal in water. Full article

Humic substances (HSs) pose a significant challenge to safe drinking-water production due to their ubiquity, limited removal by conventional methods, and their role in forming toxic disinfection by-products, reinforcing the need for more efficient, energy-favorable, and scalable treatment technologies. This study developed and evaluated a compact hydrodynamic cavitation (HC) system that simultaneously induces coagulation and generates microbubbles for flotation-based HS removal. For the first time, HC is explored as a multifunctional unit capable of integrating rapid mixing, coagulant destabilization, and flotation within a single device. Optimal coagulation conditions were established at pH 5.0 and 9.5 mg L⁻¹ of ferric chloride. Process optimization using a Rotated Central Composite Design demonstrated that inlet pressure, flotation time, and initial HS concentration were the dominant operational factors, enabling the HC system to achieve a maximum removal efficiency of 81.9%. Five Venturi geometries with divergent angles of 4°, 8°, 11°, 14°, and 90° were investigated, with the 8° Venturi exhibiting superior performance due to stable microbubble formation and effective coagulant dispersion, as confirmed by CFD analyses. Comparative tests with a conventional Flotest unit showed that achieving similar efficiencies required at least 30% saturated water. In contrast, the HC system delivered equivalent removal in continuous flow without external air saturation. These findings demonstrate the potential of HC as an integrated coagulation–flotation core and highlight its promise as a compact, energy-efficient, and scalable technology for natural organic matter removal in water treatment. Full article

Demand for cosmetics based on green production and the circular economy is growing. The inflorescences and apical leaves of Nicotiana tabacum (tobacco) after blunting, deflowering, or topping are considered pre-harvest waste biomass. Using green and ecofriendly solvents such as natural deep eutectic solvents (NaDESs) offers a sustainable way to make use of this biomass for incorporation in cosmetic formulations. The inflorescence and apical leaves of tobacco var Virginia were therefore dried, powdered, and extracted using a NaDES composed of choline-chloride, urea, and distilled water (NaDES CU). The resulting inflorescence and apical leaves extracts showed high concentrations of phenolic compounds and flavonoids. Both extracts demonstrated significant biological activity and effectively inhibited tyrosinase, the enzyme responsible for melanin regulation and skin aging (IC₅₀ = 50 μg GAE/mL), as well as showing antioxidant capacity (ABTS^•+; SC₅₀ =1.7–7 μg GAE/mL). Ten nanoemulsions containing tobacco leaf- and inflorescence extract-based NaDES CU, formulated using different polysorbates, deionized water and glycerin, were produced. A low-energy emulsification technique at a constant temperature was applied. Considering the droplet size and polydispersity index, only the nanoemulsions containing inflorescence and leaf extracts based on NaDES CU and containing 5% or 10% polysorbate 85 were selected for further stability assessment and characterization. This study highlights the potential of NaDES combined with tobacco waste extracts as a sustainable and non-toxic ingredient in anti-aging and antioxidant cosmetics. Full article

Aluminum chloride (AlCl₃), a widely used inorganic polymeric coagulant in everyday products and industrial materials, has been associated with male reproductive toxicity, though its molecular mechanisms remain poorly understood. To investigate the complex molecular mechanisms underlying GC-1spg cells’ responses to AlCl₃ exposure, transcriptome and small RNA (sRNA) sequencing analyses were performed. Transcriptome sequencing identified 1168 differentially expressed genes (DEGs), while sRNA sequencing detected 65 differentially expressed microRNAs (DEMs). An mRNA–miRNA regulatory network was established, and functional enrichment analysis showed that its target genes were significantly associated with multiple signaling pathways, particularly the p53 pathway. Further validation via Western blot and Hoechst 33342 staining assays confirmed that GC-1spg cells underwent apoptosis upon AlCl₃ exposure via the p53 signaling pathway. Among the identified DEMs, mmu-miR-503-5p was found to enhance GC-1spg cells’ tolerance to AlCl₃-induced stress. Moreover, dual-luciferase reporter assays and RT-qPCR confirmed that mmu-miR-503-5p directly binds to the Islr gene, which plays a role in modulating GC-1spg cell tolerance to AlCl₃-induced stress. These findings provide critical insights into the molecular mechanisms governing GC-1spg cells’ responses to AlCl₃ exposure. Full article

Environmental contamination caused by various types of heavy metals and chlorinated organic compounds poses a significant threat to global ecosystems. While bioremediation offers a sustainable solution, identifying microbial strains that possess the metabolic versatility to withstand metal toxicity and degrade persistent organic pollutants remains a major challenge. In this study, we characterized strain TW-R-39-2, a novel bacterium isolated from a wastewater treatment plant. Phylogenomic analysis based on complete genome sequencing revealed that strain TW-R-39-2 represents a novel species within the genus Dechloromonas, showing Average Nucleotide Identity (ANI) and digital DNA–DNA hybridization (dDDH) values of 80.17% and 23.4%, respectively, with its closest relative, Dechloromonas denitrificans. Genomic insights revealed a 3.46 Mb circular chromosome containing a diverse array of genes associated with heavy metal resistance (e.g., predicted czc and cadA clusters) and chlorinated compound degradation (e.g., dehalogenases). Phenotypic assays validated these genomic predictions, demonstrating the strain’s dual functionality: it exhibited high adsorption efficiencies for cadmium (Cd²⁺, 78.0%) and zinc (Zn²⁺, 75.1%), alongside significant degradative capacity for trichloroethylene (TCE, 83.6%) and chlorophenol (81.0%) within a 7-day incubation period, corresponding to the strain’s active growth and early stationary phases. The stoichiometric release of chloride ions confirmed the complete dechlorination of the organic pollutants. These findings demonstrate that strain TW-R-39-2 possesses versatile capacities for both the sequestration of toxic metals and the biodegradation of persistent organic compounds. This study highlights the potential of strain TW-R-39-2 as a promising candidate for the efficient bioremediation of diverse industrial wastewaters. Full article

This research designed a high-performance superabsorbent gel aligned on the integration of lignite humic residue (LHR) with a polymeric organic network in order to address ecological restoration challenges in the arid mining area in Xinjiang. This water-retaining agent was synthesized by employing solution polymerization techniques using acrylic acid (AA) and acrylamide (AM) as monomers, lignite hydrothermal residue (LHR) as a functional additive, and ammonium persulphate (APS) as the initiator. The resulting lignite hydrothermal residue–polyacrylic gel composite material was obtained by using N,N′-methylene-bisacrylamide (MBA) as the primary crosslinking agent. The water absorption capacity and mechanical strength of the acrylic gel were further enhanced by specifically incorporating low-cost, safe, and non-toxic lignite humic residue (LHR). The performance test indicated that this gel achieved a maximum water absorption of 522 g·g⁻¹ in distilled water and 65.5 g·g⁻¹ in 0.9% sodium chloride solution. Its reusability and water absorption capacity remained above 81.8% even after five cycles of natural dehydration and reabsorption. The method for synthesizing this superabsorbent gel effectively constructs a soil water retention network structure, improving the soil microenvironment, and enhancing plant salt tolerance. The field trial results showed that the application of this LHR-AA-AM superabsorbent gel considerably improved vegetation coverage in mining areas. Hence, this study provides an efficient and economical superabsorbent material for ecological restoration of saline–alkali land in arid regions without soil replacement, demonstrating promising application prospects. Full article