Environmental Science and Pollution Research最新文献

The rapid growth of electronic waste has intensified the need for sustainable approaches for metal recovery from waste printed circuit boards (WPCBs). In this study, betaine-based natural deep eutectic solvents (NADES) were developed as lixiviants for metal extraction from WPCBs. Betaine (BET) was used as the hydrogen bond acceptor, while ethane-1,2-diol (ETD), propane-1,2-diol (PPD), and butane-1,2-diol (BTD) served as hydrogen bond donors (HBDs) to investigate the influence of HBD structure on the physicochemical properties and leaching performance of the resulting NADES. Fourier transform infrared spectroscopy (FTIR) indicated intermolecular interactions between BET and the diol-based HBDs, while thermogravimetric analysis/derivative thermogravimetry (TGA/DTG) showed pronounced mass-loss-rate maxima above 240 °C for all three NADES. Rheological measurements revealed Newtonian flow behaviour, with viscosity increasing with increasing diol chain length; BET:ETD exhibited the lowest viscosity (50.1 mPa·s) at 20 °C. Under the experimental conditions of 75 °C, 6 h, 1.0 M H₂O₂, 500 rpm, and a solid-to-liquid ratio of 1:20, BET:ETD achieved leaching efficiencies of 99.3% for Cu, 99.5% for Pb, 97.8% for Fe, 95.4% for Al, 90.5% for Sn, and 73.9% for Ti. Kinetic analysis based on the shrinking core model and activation energy evaluation indicated a mixed-control mechanism involving interfacial reaction and diffusion processes. SEM, XRD, and FTIR analyses further indicated substantial dissolution of metallic phases while the polymeric and glass-fibre matrix was largely preserved. Overall, the results demonstrate that betaine-based NADES, most especially BET:ETD, offer tunable physicochemical properties and effective metal-leaching performance for WPCB recycling.

We investigate the spatiotemporal dynamics of aerosol pollution in the Indo-Gangetic Plain (IGP) and the North China Plain (NCP), two of the world's most populated regions, against their anthropogenic emissions. Utilizing CAMS EAC4 reanalysis, CAMS-GLOB-ANT emission inventories, and ERA5 meteorological data for the year 2019, we analyze the seasonally changing relationship between PM-forming emissions and ambient PM_2.5 concentrations. We find a significant disparity: despite the NCP emitting 65% more total anthropogenic particulates and precursors annually (28,860 KT vs. 17,464 KT), the IGP suffers higher annual average PM_2.5 concentrations (123.6 vs. 113.2 µg/m3). Temporal and episode analyses reveal that large swathes of both regions are engulfed in polluted air during much of the year, with some respite during the summer and monsoon seasons. The NCP, with lower annual average PM_2.5, records more total "bad air quality" days (251 vs. 238), while the IGP is characterized by fewer but more prolonged episodes, with extreme stagnation events in the Delhi region lasting up to 170 consecutive days. To quantify the regional contrast in atmospheric response, we introduce the "Pollution Forming Efficiency" (PFE) metric. Our results show that during winter, the IGP's PFE is nearly double that of the NCP, meaning that the IGP atmosphere converts unit emissions into ambient concentrations far more effectively. We identify regional meteorology as the primary driver; the IGP is characterized by stagnant winds (< 6 km/h) and a shallow planetary boundary layer (< 300 m) leading to a consistently lower ventilation coefficient that inhibits vertical mixing and dispersion of pollution. Ultimately, our findings reveal that there is an inherent meteorological vulnerability to the IGP, and therefore, any economic growth strategy in this region must account for its limited carrying capacity. Recognizing that the IGP atmosphere uniquely amplifies the health impact of every kilogram emitted is the first step toward securing a breathable future for the more than one billion people who call these plains home.

Endocrine-disrupting chemicals (EDCs) can destabilize the hypothalamic-pituitary-thyroid (HPT) axis, a fundamental regulator of vertebrate development and metabolism. Pyriproxyfen (PPF), a juvenile hormone analog widely utilized in vector control, is recommended by the World Health Organization (WHO) for application at concentrations of up to 10 µg/L in drinking water; however, its safety profile for vertebrates remains a matter of concern. In this study, we investigated the endocrine and systemic impacts of PPF in adult female zebrafish exposed for 14 days to 1, 10, or 100 µg/L. Histological, hormonal, and transcriptional analyses across the thyroid, brain, liver, and kidney revealed a non-monotonic response centered on the WHO reference application concentration. The 10 µg/L group exhibited the most significant molecular impairment in the thyroid, characterized by the upregulation of slc5a5 (nis), nkx2.1, pax2a, and tshr, while repressing thyroglobulin (tg) expression. Consistent with these molecular alterations, thyroid epithelial disruption was observed at 1 and 10 µg/L. In contrast, exposure to 100 µg/L increased plasma TSH levels and the expression of pituitary tshb and hepatic dio1, suggesting a compensatory response of the HPT axis. Renal morphometry additionally revealed tubular alterations across all exposure groups. Overall, these findings demonstrate a non-monotonic concentration-response centered on 10 µg/L as a key mechanistic feature of PPF toxicity and support further evaluation of thyroid and renal endpoints in ecotoxicological risk assessment.

This article presents detailed research findings on the production of bio-oils and biochars from the catalytic co-pyrolysis of high-nitrogen-content biomass (e.g., barley spent grains, spent coffee grounds, and waste cooking oil). Waste shrimp shell powder was selected as a natural AAME-based catalyst to promote the production of low-oxygen bio-oil and biochar. The optimum co-pyrolysis conditions using shrimp shell powder rendered 37.1 ± 1.6 wt% and 22.6 ± 1.8 wt% for bio-oil and biochar, respectively. The natural catalyst increased the bio-oil yield by 66.6%. The optimum bio-oil and biochar display nitrogen concentrations of 5.3 ± 0.1 wt% and 3.2 ± 0.02 wt%, respectively. High nitrogen concentrations are desirable in bio-binders to enable them to function as anti-stripping agents. The oxygen contents of the bio-oils and biochars range from 7.1 ± 0.2 to 10.1 ± 0.63 wt%, respectively. These oxygen concentrations are relatively low for bio-oils and biochars compared to the typical concentrations reported in the literature. Low oxygen contents are essential in bio-binders to prevent premature ageing of the bio-binder/aggregate composite. Contact angles of the optimum bio-oil on different rock surfaces indicated the formation of uniform films wetting the rock surfaces, implying its potential functionality as an anti-stripping agent by improving binder-aggregate adhesion. Likewise, the contact angles of the water-biochar system demonstrated the biochar's hydrophobicity, suggesting compatibility with asphalt binders. This study promotes biomass waste valorization and advances the field by tailoring feedstock selection and optimizing catalytic co-pyrolysis conditions to produce tailored bio-oils and biochars with adequate physicochemical properties for prospective application in the development of bio-binders. Furthermore, fine powder biochars have the potential to partially replace binders in conventional asphalt formulations. At the asphalt bio-binder/aggregate level, we are currently evaluating the performance of several blends using these customized bio-oils and biochars.

The removal of antibiotics from water under environmentally complex laboratory systems remains insufficiently understood, particularly in the presence of coexisting contaminants such as formulation additives and microplastics. This study evaluates the performance of clay-carbon hybrid materials for the removal of oxytetracycline from aqueous solutions under both controlled and complex conditions. Natural montmorillonite and two montmorillonite-carbon hybrids were investigated through batch adsorption experiments, including kinetic and equilibrium analyses at different pH values. One of these (MDac3-210-500) exhibited a high adsorption capacity at neutral pH, reaching a maximum value of ~ 0.6 mmol/g. Mechanistic analysis suggests that chemisorption plays a key role in montmorillonite, whereas intraparticle diffusion and surface heterogeneity appear to dominate in the hybrids. To approximate realistic scenarios, adsorption experiments were conducted using a veterinary commercial oxytetracycline formulation and in the presence of polyethylene terephthalate (PET) microplastics (particles < 112 μm at 0.5 g/L). The commercial formulation led to a marked decrease in adsorption capacity for hybrids (0.05-0.08 mmol/g), highlighting matrix effects and competition for active sites, whereas, under the tested experimental conditions, PET microplastics did not substantially modify oxytetracycline adsorption by the hybrid materials. These findings highlight the sensitivity of oxytetracycline adsorption to coexisting compounds and provide a basis for understanding the performance of clay-carbon hybrids under more complex water treatment conditions. In particular, the contrasting effects of formulation additives and PET microplastics emphasize the importance of considering matrix composition when evaluating adsorbent performance.

Rubber industries process liquid latex into solid slabs in acid coagulation tanks, and the resulting waste is released into the environment, potentially harming it and living organisms. In the present study, the physicochemical properties and elemental composition of wastewater discharged from small-scale rubber industries in the Dakshina Kannada district of Karnataka, India, were evaluated, along with the biochemical, phytotoxic, and genotoxic effects on onion and mung bean plants. The study showed the presence of micronutrients, inorganic salts, viz., iron (0.5 mg/L), nitrate (25 mg/L), total hardness (625 ± 3.60 mg/L), high BOD (547.10 ± 10 mg/L) and COD (866 ± 11 mg/L), and heavy metals such as zinc (5297.50 ± 167.50 ppb) and nickel (56.00 ± 2.12 ppb) in the wastewater which is above the permissible limit of drinking water or general standards for the discharge of environmental pollutants. The studies also showed dose-dependent phytotoxicity of wastewater, with reduced root and shoot lengths, biomass, antioxidant property, and altered protein and sugar contents when onion bulbs and mung bean seeds were grown in wastewater at different concentrations. The genotoxicity of the wastewater was confirmed by increased chromosomal aberrations and a decreased mitotic index in onion root tips grown in wastewater at higher concentrations. The pollutants in the wastewater might have contributed to these changes in the plants, suggesting the need for pre-treatment of rubber wastewater before its release into the environment.

In response to the growing demand for lower-impact building insulation materials, this study investigates composites combining Juncus Acutus (JA) fibers with recycled expanded polystyrene (EPS) as a strategy for valorizing biomass and polymeric waste. Three JA/EPS formulations (70/30, 60/40, and 50/50) were experimentally characterized in terms of density, thermal properties, and compressive strength, followed by life-cycle assessment and transient numerical analysis. Increasing the JA content from 50 to 70% reduced the bulk density from 371.6 to 289.9 kg·m⁻³ and thermal conductivity from 0.117 to 0.096 W·m⁻¹·K⁻¹, while thermal diffusivity decreased by approximately 15% and specific heat capacity increased by about 10%. Despite the reduction in compressive strength with increasing fiber content, the JA70 formulation reached 0.16 MPa, indicating adequate mechanical integrity for handling and use in non-structural insulation applications. Among the investigated formulations, JA70 provided the most favorable balance between thermal and mechanical properties. Its cradle-to-gate global warming potential was estimated at 1.1 kg CO₂-eq·kg⁻¹, while transient numerical simulations demonstrated improved thermal inertia and indoor temperature regulation under representative climatic conditions. Overall, the results demonstrate the potential of JA fiber-recycled EPS composites as promising lower-impact insulation materials, while also highlighting the need to further address solvent-related impacts, moisture resistance, fire performance, and long-term durability before practical building application.

Polyhydroxyalkanoates (PHAs), eco-friendly microbial bioplastics, have the potential to replace synthetic plastics, reducing pollution. The novelty of this study lies in the integration of cost‑effective substrate utilization, systematic optimization, and preliminary evaluation of multifunctional properties of PHA. Therefore, this study assessed 29 bacterial isolates for PHA production utilizing sugar beet molasses (SBM) as an inexpensive carbon source. Among the tested isolates, the strain SNS1 exhibited the highest PHA production and was genetically identified as Priestia megaterium. An optimization process and a Plackett-Burman design were applied to determine the conditions for maximum PHA production in shaking flasks. As a result, PHA concentration reached 4.79 g/L on 6% SBM, 0.50 g/L ammonium oxalate, pH 8.50, 37 °C, 200 rpm, and a 24 h incubation period. The biosynthesized PHAs were identified as Poly(3-hydroxybutyrate) (P3HB) using 1H-NMR, 13C-NMR, FTIR spectroscopy, and GC-MS. Thermal properties, evaluated by DSC and TGA analyses, indicated the presence of pure P3HB. The purified PHA sheet was tested for ultraviolet (UV) protection, showing potential as a sun protectant with an UV-shielding factor of 15.23, providing 35% UV light absorption. This work demonstrates the potential of Priestia megaterium for cost-effective and efficient PHA production with desirable polymer properties.

Microplastic (MP) contamination in tropical river systems is increasingly reported, yet the reliability and comparability of available evidence remain uncertain. This review critically appraises MP contamination in the Karnaphuli River system, Bangladesh, using a PRISMA-guided systematic literature review and an expanded Source-Pathway-Receptor framework. Fifteen peer-reviewed studies were synthesized to evaluate environmental occurrence, methodological quality, reporting comparability, source-attribution certainty, physicochemical characteristics, ecological receptors, and human exposure plausibility. Because studies differed in sampling design, particle-size thresholds, analytical methods, QA/QC reporting, and measurement units, statistical meta-analysis was not appropriate. Available evidence reports MPs in water, sediment, fish, and fishery products, with fibres, fragments, and films frequently dominant. Industrial effluents, municipal wastewater, textile discharge, urban runoff, port activities, and unmanaged plastic waste are plausible contributors, but source attribution remains mainly inferential. Fish-ingestion evidence supports biological uptake and possible trophic transfer, although Karnaphuli-specific freshwater fish data remain limited. Aquatic plants, biofilms, plankton, and benthic organisms are important but understudied receptors. Human dietary exposure through fish and dried fish is plausible but locally unquantified. Overall, the Karnaphuli River should be treated as a high-concern MP system requiring standardized monitoring, source-specific sampling, polymer confirmation, QA/QC transparency, and receptor-based studies.

The fluorite structured CeO₂ is a well-known material for catalysis, sensors, fuel cells, and environmental remediation application due to rapid Ce⁴⁺/Ce³⁺ cycling. Similarly, the recently reported high entropy oxides (HEOs) have tailorable bandgaps, improved charge separation, and multiple redox-active sites, which make them an efficient catalyst for pollutant degradation. Herein, we report the catalytic property of in-situ nanocomposite of fluorite MO₂ and spinel structured high entropy oxide of M₃O₄ (where M = Mn, Fe_, Co, Ni and Ce). The composite was able to degrade around 92% of the methylene blue (MB) dye in 60 min during the photo-Fenton reaction. Further, the mass spectroscopy (MS) study of the solution obtained after complete degradation (in 90 min) of MB justified its total mineralisation. The magnetization value of ~ 25 emu/g of the composite endorses its ability for easy recovery and recycling. The structural and morphological studies via x-ray diffraction and transmission electron microscopy indicate the existence of both CeO₂ and M₃O₄ (spinel structure) phases. The valences of the respective cations were confirmed from x-ray photoelectron spectroscopy.