Chemosphere最新文献

Wastewater management has become necessary in this industrialized era to meet the water needs of the world. Wastewater is one of the major crises in depletion of the environment. Photocatalysis is considered as the best way to remove pollutants. Therefore, in this study, pure and g-C₃N₄-SnWO₄ nanocomposites were produced employing hydrothermal route. Prepared composites were studied by various techniques. SnWO₄ band gap were altered by introduction of g-C₃N₄. The morphology was uniformly developed by the addition of g-C₃N₄ to the SnWO₄. Evans Blue dye was employed as model pollutant. The photocatalytic action was improved by adding g-C₃N₄, which formed a heterojunction with SnWO₄. The calculated rate constant was 0.000878, 0.0068, 0.01 and 0.0122 min^-1 for EB, SnWO₄-EB, 0.1 g g-C₃N₄-SnWO₄-EB and 0.2 g g-C₃N₄-SnWO₄-EB. The rate constant increased for 0.2 g g-C₃N₄-SnWO₄ photocatalyst. A heterojunction appeared between g-C₃N₄ and SnWO₄ facilitated SnWO₄ for better e^-/h⁺pair's separation and a lower recombination rate, which increased photocatalytic action of product. 0.2 g of g-C₃N₄-SnWO₄ is a promising candidate for future wastewater degradation.

Benzophenone-3 (BP-3) is one of the organic ultraviolet (UV) filters widely used in personal care products, resulting in its ubiquitous occurrence in aquatic systems. This study discovered the potential risks of benzophenone-3 and its metabolites (BP-1 and BP-8) in aquatic environments. This study investigated the toxicity of three single BPs and their mixtures' effects on the survival of Daphnia magna. All three BP types were found to have toxic effects on D. magna, with median effective concentration (EC50) values of 22.55 mg/L for BP-1, 1.89 mg/L for BP-3, and 2.36 mg/L for BP-8, after 48 h of exposure. When the three BPs were binary and ternary mixtures, the EC50 values fell within 2.74-32.26 mg/L. Binary and tertiary mixtures of the three BPs indicated no strong synergistic or antagonistic effects. The mixture toxicity predictions using the classical mixture concept of concentration addition and measured toxicity data showed good predictability. The ecological risks of BPs were assessed using the maximum measured environmental concentrations of BPs collected from a river in Taiwan, divided by their respective predicted no-effect concentration (PNEC) values derived from the assessment factor (AF) method. The result showed a low ecological risk for the sum of three BPs. However, BP-3 had the highest potential risk, while BP-1 was the lowest among the three BPs. Therefore, BP-3 should pay attention to long-term environmental monitoring and management. This study provides valuable information for establishing scientifically-based water quality criteria for BPs and evaluating and managing the potential risk of BPs in the aquatic environment.

The presence of pharmaceutical pollutants in water bodies represents a significant environmental and public health concern, largely due to their inherent persistence and potential to induce antibiotic resistance. Advanced oxidation processes (AOPs) that employ peroxymonosulfate (PMS) activation have emerged as an effective means of degrading these contaminants. Bismuth oxyiodides (BiOI), which are known for their visible-light photocatalytic properties, demonstrate considerable potential for removal of pharmaceutical pollutants. This study examines the synthesis and performance of BiOI-based composites with barium ferrite (BFO) nanoparticles for enhanced PMS activation under visible light. BiOI and Bi₅O₇I were synthesized via solvothermal and electrodeposition methods, respectively, and their morphologies and crystalline structures were observed to exhibit distinctive characteristics following annealing. The formation of the composite with BFO resulted in an improvement in the catalytic properties, which in turn enhanced the surface area and availability of active sites. The objective of the photocatalytic studies was to evaluate the degradation and mineralization of tetracycline (TC) under visible light, PMS, and combined conditions. The Bi₅O₇I(ED)-BFO catalyst was identified as the optimal candidate, achieving up to 99.8% TC degradation and 99.4% mineralization within 90 min at room temperature. The synergistic effect of BFO in BiOI-based composites significantly enhanced performance across all conditions, indicating their potential for efficient remediation of pharmaceutical pollutant. The material's performance was further evaluated in tap water, where the degradation efficiency decreased to 56.4% and mineralization to 38.2%. These results reflect the challenges posed by complex water matrices. However, doubling the PMS concentration to 5 mM led to improved outcomes, with 93.8% degradation and 81.4% mineralization achieved. These findings demonstrate the material's robust potential for treating pharmaceutical pollutants in real-world conditions, advancing sustainable water treatment technologies.

Treating emerging pollutants at low concentrations presents significant challenges in terms of degradation efficiency. Anodic oxidation using active and non-active electrodes shows great potential for wastewater treatment. Thus, this study compared the efficiency of a commercial mixed metal oxide anode (MMO: Ti/Ti_0.7Ru_0.3O₂) and a boron-doped diamond anode (BDD) for the electrochemical oxidation of diuron in methanol, in chloride and sulfate media. The MMO anode achieved diuron removal rates of 94.9% and 92.8% in chloride and sulfate media, respectively, with pseudo-first-order kinetic constants of 0.0177 and 0.0143 min^-1. The BDD anode demonstrated slightly higher removal rates, achieving 96.2% in sulfate medium and 96.9% in chloride medium, with respective kinetic constants of 0.0193 min⁻¹ and 0.0177 min⁻¹. Increasing the current density enhanced diuron removal by up to 15% for both electrodes; however, excessively high current densities led to increased energy consumption due to side reactions. The present of water had antagonistic effects, resulting in removal rates of 91.1% for chloride media using the BDD anode; and 87.4% and 90.4% in sulfate media with MMO and BDD anodes, respectively. The MMO anode in chloride medium did not show significant difference in the degradation percentage, reaching 96% of diuron removals. The degradation mechanism was proposed based on the detection of various by-products. The primary reactions observed during the oxidation of diuron in methanol involved chlorine substitution in the aromatic ring and dealkylation. These processes generated several intermediates and by-products at low concentrations, ultimately leading to high diuron removal.

The aquaculture industry is under the framework of the food-water-energy nexus due to the extensive use of water and energy. Sustainable practices are required to support the tremendous growth of this sector. Currently, the aquaculture industry is challenged by its reliance on capture fisheries for feed, increased use of pharmaceuticals, infectious outbreaks, and solid/liquid waste management. This review posits microalgal technology as a comprehensive solution for the current predicaments in aquaculture in a sustainable way. Microalgae are microscopic, freshwater and marine photosynthetic organisms, capable of carbon mitigation and bioremediation. They are indispensable in aquaculture due to their key role in marine productivity and their position in the marine food chain. Microalgae are nutritious and are currently used as feed in specific sectors of aquaculture. Due to their bioremediation potential, direct application of microalgae in shellfish ponds and in recirculating systems have been adopted to improve water quality and aquatic animal health. The potential of microalgae for integration into various aspects of aquaculture processes, namely hatcheries, feed, and waste management has been critically analyzed. Seamless integration of microalgal technology in aquaculture is feasible, and this review will provide new insights into using microalgal technology for sustainable aquaculture.

Magnetite has been proved to facilitate direct interspecies electron transfer (DIET)-based syntrophys and might alleviate inhibitory effects of antibiotics in anaerobic digestion (AD), while feeding ethanol was an effective approach to enrich the DIET partners. However, most of the existing studies were conducted at fixed ethanol concentration, few attentions were paid on the effects of differential ethanol proportion on AD, the underlying roles and mechanisms of ethanol stimulation remains unclear. This study systematically investigated the impact of ethanol stimulation on anaerobic processes treating oxytetracycline (OTC)-contaminated wastewater at varying proportions (20%, 50%, and 80%, based on equivalent COD value). In the presence of magnetite, ethanol stimulation promoted the methane production from 244.9 mL/g COD to a maximum 434.2 mL/g COD, with the most pronounced enhancement observed at high ethanol proportions. In particular, the average methane production obtained at 50% and 80% ethanol was 328.5 and 297.7 mL/g COD, respectively, whereas the enhancement of 20% ethanol stimulation was relatively limited. Concurrently, more stable COD removal and OTC reduction was noted in the existence of both magnetite and high ethanol proportions. Microbial analysis revealed the pivotal roles of Methanosaeta, alongside the predominance of Methanobacterium, in regulating COD conversion and driving methanogenesis through the CO₂ reduction pathway. Notably, high ethanol proportions fostered the enrichment of exoelectrogens (Geobacter, Desulfovibrio) in the magnetite-amended system, accompanied by the up-regulation of genes involved in organic metabolism pathways. Further investigation of functional genes highlighted the prevalence of pilA enrichment in the magnetite-amended system at low ethanol proportions, whereas omcS became more abundant at high ethanol proportions.

This research aimed to assess the potential of Cu₅₀PANI@UG composite for sunlight drive photocatalytic dye degradation, targeting specifically Thymol Blue (TB) and Black NT (BNT) dyes and their mixture (DM). The Cu₅₀PANI@UG composite was successfully synthesized via electropolymerization in acetonitrile/sulfuric acid mixture under atmospheric conditions. Photocatalytic experiments were conducted by exposing aqueous dye solutions to sunlight. N,N-dimethyl-p-nitrosoaniline (RNO) served as a molecular probe for detecting hydroxyl radicals (^•OH). Additionally, experiments capturing free radicals were performed to identify active components, with a concomitant proposal of plausible degradation reaction mechanism for the Photo-Fenton-Like degradation into the Cu₅₀PANI@UG composite + H₂O₂ + hv reaction system. Various operating parameters affecting dye degradation were evaluated, including catalyst dosage (from 0.27 to 0.67 g L^-1), H₂O₂ concentration (from 16 to 64 mM), pH (from 3.0 to 9.0), and dye concentration (from 25 to 100 mg L^-1). Optimization of key parameters such as pH, catalyst dosage, and H₂O₂ concentration was conducted. The highest degradation efficiency, ca. 100% of DM dye, was achieved within 35 min under optimized conditions, using Cu₅₀PANI@UG composite as a catalytic precursor. These conditions were determined as follows: Catalyst dosage = 0.67 g L^-1, pH = 3.0-6.0, H₂O₂ = 32-64 mM, and irradiation time of 35 min. The degradation percentage under the Response Surface Methodology (RSM) was utilized as a statistical tool to correlate influential parameters. Four consecutive reusability trials were performed to assess catalyst stability.

The presence of herbicides, including simazine (SIM), in aquatic environments pose significant threats to these ecosystems, necessitating a method for their removal. In this study, a hemin-doped rice husk-derived biochar (RBC@Hemin_20%) was synthesized using a simple, one-step pyrolysis, and its degradation efficiency towards SIM via peroxymonosulfate (PMS) was assessed. Under optimized conditions (hemin loading = 20 wt%, SIM = 0.5 ppm, RBC@Hemin_20% catalyst = 0.2 g L^-1, PMS = 2.0 mM, and pH = 5.84 [unadjusted]), RBC@Hemin_20%, as an Fe/N-C catalyst, could activate PMS to achieve >99% degradation of SIM. Based on radical scavenger and electron spin resonance spectroscopy (ESR) experiments, both radical (^•OH and SO₄^•-) and non-radical (such as singlet oxygen, ¹O₂) mechanisms and electron transfer were involved in the degradation system. Significant mineralization (97.3%) and reusability efficiency (∼74.1% SIM degradation after 4 applications) were exhibited by the RBC@Hemin_20%/PMS system, which also maintained a remarkable degradation efficiency in tap-, river-, and ground-water. Additionally, the RBC@Hemin_20%/PMS system exhibited rapid degradation of tetracycline (TC) and diclofenac (DCF), indicating its prospects in the degradation of other organic pollutants of aquatic environments. The plausible degradation mechanism pathways of SIM are proposed based on identified intermediates. Finally, the toxicity of these intermediate products is analysed using the Ecological Structure Activity Relationship (ECOSAR) software. It is expected that this study will expand the current knowledge on the synthesis of efficient biomass-based Fe/N-C composites for the removal of organic pollutants in water.

Contamination of water sources is a major environmental problem with far-reaching consequences for humanity. Organic substances are among the most widespread and persistent pollutants. Advanced oxidation processes, especially photocatalysis, have been considered as one of the most promising technologies for organic pollution control. In this study, hybrid photocatalysts based on N-doped TiO₂, which exhibits activity in the visible region of the spectrum, and different content of octahedral Mo₆ bromide and iodide cluster complexes were synthesized to achieve the highest efficiency of the formed S-scheme photocatalytic system under white light irradiation. According to the data obtained, the resulting materials are nanoparticles with a diameter of ∼10 nm exhibiting absorption up to ∼550 nm. Photocatalytic studies were performed using model organic molecules - the more colored rhodamine B (RhB) and the less colored antibiotic tetracycline (TET). The most active samples showed high efficiencies against both pollutants with k_eff ∼0.3-0.4 and 0.4-0.5 min^-1, respectively, while the activity of iodide complexes was ∼1.3 times higher than that of bromide complexes. The stability of the catalysts is preserved for up to 5 cycles of TET photodegradation.

Herein, effort was made to construct innovative adsorbent for the removal of polar organic micropollutants (OMPs) from water. Tetra-meso resorcinol-functionalized calix[4]pyrrole (CP) featured with endo-functionalized attribute and polyphenol hydroxyl structure was crosslinked by π-electron-rich 4,4'-bis(chloromethyl)biphenyl (BCMBP) through Friedel-Crafts reaction to generate porous calix[4]pyrrole-based polymers (PCPPs) with high surface area. The porosity of the PCPPs could be tuned by adjusting the molar ratio of hydrophilic CP to hydrophobic BCMBP, and diversified binding sites were integrated together. Based on adsorption kinetics and isotherm studies, PCPP(1-16) showed rapid adsorption rate and high removal efficiency (RE) as well as advanced adsorption capacity. The REs towards the tested polar OMPs by PCPP(1-16) were all above 95% in 30 min. Compared with granular activated carbon (GAC), the rate constant of pseudo-second-order model (k₂) and adsorption capacity upon PCPP(1-16) were 8-230 times and 1.3-3.1 times greater than those by GAC. Adsorption mechanism studies confirmed the presence of multiple interactions and thermodynamic investigation revealed the spontaneous and physical adsorption nature. Besides, PCPP(1-16) showed excellent adsorption performance in real water samples at environmental levels and exhibited advanced absorption ability in flow-through mode. Accompanied by facile regeneration under eluting with methanol and cost-effective preparation, PCPP(1-16) demonstrated great potential as promising adsorbent for water treatment.