Water Environment Research最新文献

This study used density functional theory to study the reaction pathways and intermediates associated with the oxidation of salicylic acid (SA). The analysis was carried out for each of the three SA charge states (i.e., 0, -1, -2) that are observed in aqueous solution. SA can be oxidized to the three primary byproducts, 2,3 DHBA, 2,5 DHBA, and catechol, via cyclohexadienyl radical intermediate formation. A second mechanism consists of an initial H• radical abstraction, which produces organic radicals that react with hydroxyl radicals, but this pathway does not form a catechol. Activation energy calculations confirmed that 2,3 DHBA is the most thermodynamically favored byproduct, followed by 2,5 DHBA and catechol. Formation of uncommon byproducts was also investigated. The operational implications for water treatment processes are discussed. To the author's knowledge, this is the first study to use the electronic properties of SA to elucidate the oxidation pathways across the full range of pH values found in water.

The sustainability of sand is becoming more uncertain; therefore, a critical need exists to identify alternative materials for green infrastructure that meet desirable, site-specific functions. Technosol rain gardens (glass, shale, and shell) were tested for their ability to infiltrate and filter stormwater of chemical pollutants. Technosols had similar infiltration rates as sand, while large particle sizes of technogenic materials led to significantly higher saturated hydraulic conductivities (111-211 cm h^-1) compared to sand (37.3 cm h^-1). Technosols decreased all pollutant concentrations, except Zn, compared with the synthetic stormwater. Shale (0.0461 mg L^-1), shell (0.0544 mg L^-1), and sand (0.0306 mg L^-1) had comparable effluent NH₄-N. Compared with sand, shale removed 27.8% more Cu, while glass, shale, and shell removed 58.9%, 85.3%, and 57.7% more Pb, respectively. Glass and shell demonstrate potential for increasing long-term runoff capture under saturated conditions while removing > 50% of chemical pollutants like NH₄-N, P, Cu, and Pb.

Population growth has intensified domestic effluent generation, created environmental risks when inadequately treated. The microalga Chlorella vulgaris shows strong potential for wastewater remediation. This study combined bibliometric analysis and experimental validation to assess its application in synthetic domestic effluent treatment. Two strains, SL2C (mangrove origin) and BMAK D1 (freshwater origin), were cultivated in synthetic effluent at concentrations of 25%-100% (diluted in WC medium) for 14 days. Optimal growth occurred at 50% for SL2C, which achieved the highest specific growth rate (0.353 ± 0.003 d^-1), and for BMAK D1, optimal growth occurred at 75% (0.262 ± 0.005 d^-1). Effluent remediation was evaluated by monitoring ammoniacal nitrogen, phosphate, and chemical oxygen demand (COD). Nitrogen removal exceeded 80% across treatments, phosphate removal averaged ≈65%, and SL2C demonstrated greater COD reduction (66.9%) than BMAK D1 (54.9%). These results demonstrate the biotechnological value of C. vulgaris for wastewater treatment and its relevance to circular bioeconomy strategies, contributing to Sustainable Development Goal 6 (Clean Water and Sanitation).

Phytoplankton communities are of vital importance to the functioning of freshwater ecosystems, but the role of the metabolic capacity of the community in regulating community dynamics under natural conditions has yet to be sufficiently considered. This study investigated 26 lakes situated along the eastern section of the Hu Line, combining field surveys with metagenome-assembled analyses to ascertain the factors responsible for the divergence in Chlorophyta and Bacillariophyta communities. The results demonstrated that the diversity of Chlorophyta was markedly higher than that of Bacillariophyta whereas the abundance was significantly lower. These discrepancies in community attributes were predominantly attributable to variations in the response of the two algal groups to nutrients. The abundance and diversity of diatom metabolic genes were significantly higher than those of green algae. The greater diversity and extent of metabolic genes in Bacillariophyta confer enhanced metabolic capacity and, consequently, greater adaptive capacity. Such differences in metabolic gene composition may be attributed to the disparate evolutionary pathways that these organisms have followed.

Bayannur City in northern China, which includes Urad Rear Banner, has a high concentration of non-ferrous metal mining activities and is a key region for the regulation of heavy-duty enterprises. There are 14 heavy-duty enterprises in Urad Rear Banner, involving a population of 48,000. The regulation of mining activities in this area necessitates effective ecological and human health risk assessments of the heavy metal(loid)s produced by the numerous lead-zinc ore and copper ore smelting operations. In this study, the pollution levels and pollution sources of toxic heavy metal(loid)s (Cr, As, Pb, Cd, and Hg) in topsoil and groundwater were analyzed using a self-organizing feature map (SOM) for the first time. So the pollution source impacts, site characteristics and geographic properties can be further evaluated. The results revealed significant Pb and Cd pollution, exceeding the standard established by China MEE, resulting from the high concentration of heavy industry in the study area. The distributions of toxic metals were linked to pollution source and site characteristics using the neural network-based SOM. Based on the optimal neurons, k-means clustering, and the Davies-Bouldin index (DBI), the SOM indicated five possible pollution sources: human factors, natural sources, natural settlement, wastewater leakage, and wind effect. Meanwhile, the ecological risk assessment showed that the ecological risk decreased in the order of Cd > Hg > As > Pb > Cr, which reflects the difference between ecotoxicological sensitivity and pollution level. That is, low-polluting metals may still have high toxicity. In the health risk assessment of heavy metal(loid)s in topsoil and groundwater, the hazard quotient (HQ) and hazard index (HI) were all below the safety limit of 1, while the carcinogenic risk (CR) and total carcinogenic risk (TCR) values were 10^-6 to 10^-4 (within the range of human tolerance). Among the heavy metal(loid)s evaluated, Pb and As had relatively high carcinogenic risks. Due to contributions from multiple sources, the southeastern part of the study area was heavily polluted. This study represents an innovative use of SOM in pollution source apportionment. This novel approach has the advantages of high precision, high efficiency, good visualization, and little human interference. SOM can be used to quantify sources while also comprehensively considering the hydrogeochemical characteristics, and it is especially suitable for case studies with large sample sizes. In this study, we applied SOM in an innovative way to evaluate the ecological and human health risks of heavy metal pollution in an area with numerous heavy industries and revealed the potential risk pathways. The findings provide a basis for the prevention, control, and remediation of pollution along with associated policymaking.

The global shortage of potable water and the rising environmental burden from industrial waste highlight the need for sustainable and low-cost desalination technologies. This study presents an enhanced passive solar still (PSS) that integrates recycled aluminum thin films and polypropylene insulation to improve thermal performance, freshwater productivity, and overall system sustainability. Material characterization confirms that waste-derived recycled aluminum plates possess high solar absorptivity and excellent thermal conductivity, enabling rapid heat absorption and extended thermal storage. Experimental evaluation under real climatic conditions shows that the PSS achieves a 35.5% increase in daily yield compared to the conventional solar still (CSS), supported by higher basin temperatures, improved evaporation-condensation dynamics, and reduced heat losses. Thermodynamic analysis reveals significant improvements in energy efficiency, exergy efficiency, gain output ratio, and productivity ratio, whereas economic assessment indicates a reduction in cost per liter and a shortened payback period. A machine-learning framework using RNN, XGBoost, Random Forest, and RVFL models accurately predicts hourly yield, and NSGA-II optimization identifies an optimal configuration of 18 recycled aluminum plates with 2 × 5 cm spacing. Environmental metrics confirm substantial reductions in material cost, energy consumption, and CO₂ emissions. The proposed system demonstrates a practical, scalable, and circular-economy-driven approach for decentralized freshwater production.

Contaminated groundwater must be treated to protect drinking water supplies. This study investigated the degradation of MTBE and TBA with UV/persulfate (PS) and UV/hydrogen peroxide (H₂O₂) advanced oxidation processes. Experiments were conducted at initial concentrations of MTBE and TBA of 7.4 and 6.2 mg/L respectively over a range of conditions and computational analysis was carried out to elucidate reaction mechanisms and pathways. Pseudo first-order rate constants were retrieved from temporal degradation profiles. MTBE degradation was faster than that of TBA, and UV/PS-driven oxidation of both chemicals was faster than that of UV/H₂O₂. Relative absorptivity measurements showed that PS absorbed a higher proportion of light than H₂O₂ did, which in turn created greater potential to generate radicals. Density Functional Theory (DFT) results provided additional new insights. UV/PS is a promising groundwater remediation technology for the removal of MTBE and TBA.

Green corrosion inhibitors have gained attention as natural and eco-friendly solutions for microbiologically induced corrosion in various industries. This study investigates the potential of Agave sisalana saponins (ASS) combined with glycerol, a green solvent, to control biofilm-induced corrosion on copper surfaces. Bacterial strains with strong biofilm-forming abilities were isolated from Koel River water and identified through 16S rRNA gene amplification. Phylogenetic analysis confirmed the presence of Acinetobacter spp., Exiguobacterium sp. BFR12y, and Solibacillus sp. BFR13. Structural characterization of ASS using FTIR spectroscopy, NMR, and high-resolution mass spectroscopy confirmed the surfactant properties of extracted saponins. The Agave sisalana saponins-glycerol combination (ASSG) exhibited no antibacterial activity at the tested concentrations. However, colony-forming unit (CFU/biofilm) counts, CLSM, and SEM revealed a significant biofilm inhibition efficacy of 80.14%. Corrosion rate and electrochemical impedance spectroscopy study demonstrated 76.42% corrosion inhibition. The inhibitory effect of ASSG was attributed to its adsorption onto metal surfaces, resulting in a reduction in bacterial motility and adhesion, and Cu₂O formation, as confirmed by motility assay, contact angle measurement, and Raman spectroscopy analysis. The findings suggest the potential use of the Agave sisalana saponins-glycerol combination as a green, prospective corrosion inhibitor, with promising applications in cooling water systems across various industries.

Polyethersulfone (PES) membranes, while widely used in ultrafiltration, are hindered by their inherent hydrophobicity and susceptibility to fouling. This study investigates the incorporation of aluminum oxide hydroxide-tannic acid (AlOOH-TA) hybrid nanoparticles into PES membranes via phase inversion to enhance hydrophilicity and antifouling behavior. The AlOOH-TA hybrid introduces abundant hydroxyl and phenolic groups that promote hydration layer formation and reduce foulant adhesion, while alumina contributes structural reinforcement. The modified membranes were characterized using SEM, FTIR, contact angle, and porosity analyses to correlate surface and structural changes with filtration performance. The optimized membrane (M4) achieved a pure water flux of 37.71 L·m^-2·h^-1 and a contact angle of 56.7°, representing a 38.95% flux improvement and enhanced surface wettability compared to pristine PES. In humic acid filtration, M4 exhibited a rejection efficiency of 61.4% and a flux recovery ratio (FRR) of 99.72%, confirming its excellent antifouling and reusability performance. These findings demonstrate that AlOOH-TA hybrid incorporation effectively improves membrane hydrophilicity and antifouling resistance through synergistic chemical and structural modification.

This review explores the links, challenges, and gaps among six key elements of water management: watershed models, optimization algorithms, artificial intelligence, surrogate models, monitoring, and decision support systems. The main goals of this review are twofold: (1) to examine the established interrelationships among these key elements and analyze how these connections contribute to improved management effectiveness and (2) to identify and explore potential, yet unexplored, synergies among these elements that could lead to enhanced management practices. This study adheres to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, following steps for identification, screening, eligibility assessment, and selection while applying exclusion criteria and cross-referencing. The findings highlight that while advanced watershed models leveraging high-resolution datasets offer valuable insights, they face scalability challenges in capturing spatial and temporal variations. Additionally, the adaptability and performance of machine learning approaches are constrained by data limitations, including insufficiencies and inconsistencies across diverse sources. Overall, this synthesis provides actionable insights for advancing water quality protection and resource recovery by integrating emerging technologies with established management frameworks.