环境•农林最新文献

Excessive pesticide residues in natural waters are closely associated with agricultural drainage, and organophosphorus pesticides (OPPs) account for more than 80% of pesticides used in China. Although semiconductor photocatalysis for pesticide removal has been widely studied, adsorption-assisted strategies to reduce photocatalytic treatment loads remain underexplored. In this study, a TiO₂/g-C₃N₄ (CP1:1) heterojunction with adsorption–photocatalytic capability was synthesized via a pyrolysis-calcination method. Diazinon (DAZ) was selected as a representative OPP, and DAZ and its transformation product diethyl thiophosphate (DETP) were defined as pesticide-derived organic phosphorus. A sequential adsorption–photocatalysis system was established, where CP1:1 first removed pesticide-derived organic phosphorus through adsorption, followed by photocatalytic degradation of residual species. CP1:1 exhibited rapid adsorption performance, with a maximum adsorption capacity of 297.82 mg/g (as TP) at pH 7, an initial DAZ concentration of 60 mg/L (as TP), and an adsorbent dosage of 0.1 g/L. The adsorption process was likely associated with electrostatic attraction, π–π interactions, and hydrogen bonding. Under photocatalytic conditions (0.4 g/L catalyst dosage, 5 mg/L DAZ as TP), 93.4% removal of pesticide-derived organic phosphorus was achieved after 6 h of irradiation with 365 nm UV light. The optimized sequential system achieved over 95% overall removal, with adsorption contributing approximately 60%. This study provides a strategy to reduce photocatalytic treatment loads and enhance pesticide-derived organic phosphorus removal through a sequential adsorption–photocatalysis process.

Cadmium (Cd) contamination in soil poses significant risks to environmental and crop safety. One of the most important parameters controlling Cd uptake by plants from soil is pH. The role of soil pH in regulating Cd availability and its uptake by plants has been studied; however, no study has yet compared how pH changes in the rhizosphere and bulk soil differentially influence these processes. This study examined how nitrification inhibitor (3,4-Dimethylpyrazole phosphate (DMPP)) and lime affect Cd availability and concentration in wheat via modulating pH and calcium (Ca) availability in rhizosphere and bulk soil. Wheat was grown in acidic sandy soil under three lime application rates and two DMPP levels to investigate Cd accumulation. Our results indicated that DMPP application was associated with decreased rhizosphere pH, exchangeable Ca and Cd accumulation in wheat shoots. The impact of lime on shoot Cd varied depending on the presence of DMPP. Liming generally increased soil pH and exchangeable Ca and was associated with decreased plant-available Cd (CaCl₂-extractable Cd) in both bulk soil and the rhizosphere. In the absence of DMPP, liming was associated with a greater increase in exchangeable Ca in the rhizosphere and reduction in plant-available Cd (CaCl₂-extractable Cd) in the rhizosphere and bulk soil. Despite the decline in soil Cd availability, these changes were associated with higher Cd concentration and content in wheat shoots. In contrast, under DMPP application, liming decreased shoot Cd concentration but did not affect shoot Cd content, suggesting that DMPP may influence the response of shoot Cd concentration to liming. The results provide useful insights into Cd management in agricultural systems and may contribute to strategies for reducing Cd-related risks in crop production.

This study investigates the photocatalytic degradation of propylparaben (PP), a widely used preservative associated with environmental and health risks, in wastewater using various metal oxides (TiO₂, ZnO, α-Bi₂O3-CP, and β-Bi₂O₃-SG). It also provides a comparative evaluation of metal oxide photocatalysts and synthesis methods under different light sources, highlighting the strong influence of catalyst preparation and irradiation conditions on photocatalytic efficiency. All catalysts were synthesized using simple preparation techniques. Their structural, morphological, and optical properties were characterized using Brunauer–Emmett–Teller (BET), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), diffuse reflectance spectroscopy (DRS), scanning electron microscopy (SEM), and photoluminescence spectroscopy (PL). Identification of PP and its reaction intermediates was performed using liquid chromatography–tandem mass spectrometry (LC–MS/MS). Bi₂O₃-CP and Bi₂O₃-SG, synthesized via co-precipitation and sol–gel methods, respectively, exhibited superior photocatalytic activity. The Bi₂O₃-CP catalyst achieved complete removal of PP under UV-B irradiation within 90 min, while 94.55% removal was obtained under natural sunlight within 45 min. Bi₂O₃-SG achieved 100% PP removal within 60 min of UV-B irradiation, with the highest reaction rate constant (0.088 min⁻¹). These results elucidate the roles of Bi₂O₃ phase composition, band gap energy, and crystallite size in enhanced photocatalytic activity under both UV-B and natural sunlight irradiation, highlighting the potential of Bi₂O₃-based photocatalysts for removing pharmaceutical contaminants from wastewater.

Graphical Abstract

Microplastic-associated biofilms represent emerging interfaces for microbial attachment, persistence, and transport in aquatic environments, yet the mechanisms governing bacterial sorption onto microplastics and their implications for water treatment remain insufficiently resolved. This study investigated bacterial colonization, sorption behavior, plastisphere assembly, and disinfection interference associated with microplastics in water using high-throughput 16S rRNA sequencing, scanning electron microscopy, Fourier-transform infrared spectroscopy, Brunauer–Emmett–Teller surface analysis, confocal laser scanning microscopy, flow cytometry, and chlorine disinfection assays. Microplastics recovered from raw surface water showed pronounced surface modification and altered functional groups. Biofilm formation and extracellular polymeric substances were clearly observed on microplastic surfaces after exposure to water. The maximum thickness of the bottom biofilm layer in contact with the microplastics reached 43.4 μm, whereas the upper biofilm layer reached 19.53 μm. Sequencing analysis indicated that microplastics altered bacterial community structure and supported distinct plastisphere assemblages compared with the surrounding water phase. Adsorption and desorption assays demonstrated that bacteria could attach and detach from microplastics. The maximum numbers of Escherichia-Shigella attached to and detached from microplastics were approximately 4 × 10⁵ CFU/mL and 2 × 10⁶ CFU/mL, respectively. Notably, the presence of microplastics reduced the effectiveness of chlorine disinfection against Escherichia-Shigella, suggesting that microplastic-associated bacteria may be partially protected from oxidative inactivation. These findings demonstrate that microplastics are not merely passive particles in water but dynamic microbial carriers that can influence bacterial persistence, community assembly, and treatment efficiency. The results highlight the need to incorporate microplastic-biofilm interactions into water-quality assessment and disinfection-risk frameworks.

Transforming low-value pyrite into pesticide-detoxification catalysts while retaining the mineral scaffold and introducing bio-derived Fe/Zn interfaces remains underexplored. A green pyrite-based Fe/Zn composite (G-PyFeZn) was prepared by nitric-acid activation of framboidal pyrite followed by marjoram-assisted precipitation without removing the residual pyrite solids. X-ray diffraction confirmed retained cubic FeS₂ as the dominant crystalline phase, whereas infrared spectroscopy, electron microscopy, and N₂ sorption evidenced a poorly crystalline, phytochemical-functionalized Fe/Zn surface fraction and mesoporosity (surface area, 30 m² g⁻¹; mean pore diameter, 4.3 nm). G-PyFeZn was evaluated for methyl parathion (MPn) removal in photocatalytic, Fenton-like, and photo-Fenton systems under metal-halide irradiation. At the optimum pH of 4, photo-Fenton treatment removed 97.8% of MPn within 120 min, exceeding photocatalysis and Fenton-like oxidation by 88.2 and 61.6 percentage points, respectively. With 5 mg L⁻¹ MPn, 0.20 g L⁻¹ catalyst, and 0.02 mL of 30% H₂O₂ per 50 mL, MPn was completely degraded within 60 min and total organic carbon (TOC) was apparently completely removed within 180 min; the pseudo-first-order constants (0.1050 and 0.03060 min⁻¹) show that transformation was 3.4 times faster than mineralization. Scavenger tests (76.4, 42.7, and 16.6% inhibition) indicated the reactive-species order •OH > O₂•⁻ > h⁺, supporting a surface-mediated mechanism involving Fe²⁺/Fe³⁺ cycling, H₂O₂ activation, and photoinduced charge transfer, together with a literature-based pathway of desulfuration, P–O cleavage, hydroxylation, and ring opening. Ecotoxicity rose by 8–9 percentage points at 20 min but finally declined by 93.2–95.1% for bacterial, daphnid, and algal endpoints. G-PyFeZn retained 77.1% efficiency in the sixth cycle, demonstrating a promising pyrite-valorization strategy coupling degradation, mineralization, and detoxification.

The utilization of algal biomass as a precursor for developing functional adsorbents offers an attractive and environmentally sustainable approach to mitigating dye-contaminated wastewater. This research investigates biomass obtained from Cladophora sp. (CLA) was subjected to hydrothermal carbonization (HTC) to generate hydrochar (HCCLA), which was subsequently assessed for its selective adsorption capacity for anionic dyes. The characterization results indicated that the HTC procedure significantly increased carbon content, diminished mineral impurities, and substantially improved surface area (from 8.52 to 15.8 m²/g) and pore volume (from 0.013 to 0.058 cm³/g). Compared to untreated CLA, the synthesized HCCLA demonstrated markedly improved adsorption selectivity, with DY showing the highest removal effectiveness. The kinetic evaluation indicated that the adsorption behavior adhered to a pseudo-second-order (PSO) model, whereas the isotherm analysis revealed that the Freundlich model provided a more accurate representation, signifying multilayer adsorption on heterogeneous surfaces. Thermodynamic assessments further confirmed that the adsorption process was spontaneous (ΔG < 0) and endothermic (ΔH > 0), with enhanced favorability observed for HCCLA. Moreover, regeneration studies demonstrated that HCCLA shown improved stability and reusability during multiple adsorption–desorption cycles. These findings highlight HTC as an effective method for transforming algal biomass into superior hydrochar adsorbents, indicating considerable promise for the sustainable elimination of anionic dyes from water.

Oil spills represent a major environmental threat to marine ecosystems, coastal resources, and oil transportation infrastructure, particularly in regions with intensive petroleum activities. Ras Tanura Port, Saudi Arabia, is one of the world's largest oil export terminals and remains vulnerable to accidental oil spill incidents. In this study, a coupled mathematical model based on ordinary differential equations (ODEs) was developed in MATLAB to simulate oil spill evolution under the environmental conditions of the Ras Tanura Port. The model integrates established formulations for oil spreading, evaporation, emulsification, viscosity, volume reduction, and biodegradation into a unified ODE-based framework. The results showed that wind speed significantly influenced oil spill behavior, with increasing wind speed reducing the predicted spreading area and enhancing oil redistribution processes. Oil thickness decreased from 94.62 mm to 7.54 mm during the simulation period. Sensitivity analysis indicated that Ras Tanura crude oil (API = 33.5) exhibited the highest tendency for evaporation and emulsification among the investigated crude oils, resulting in increased viscosity and density due to the progressive removal of lighter hydrocarbon fractions. Furthermore, spill location was identified as a major controlling factor, with offshore release scenarios producing the highest spreading rates and the greatest potential for large-scale contamination. The findings demonstrate that oil properties, environmental conditions, and spill location collectively govern oil spill evolution. The developed model provides a practical tool for environmental risk assessment, emergency response planning, resource allocation, and crisis management in oil-producing coastal regions.