环境•农林最新文献

Remediation of eutrophic water is a challenging task. Modification of biochar has been demonstrated to enhance the removal ability of contamination of biochar. In this work, magnesium (Mg) and copper (Cu) were incorporated in biochar during preparation to increase the removal of phosphate (P) and inhibit algae bloom. The results showed that Mg-modification significantly (p < 0.05) improved the adsorption of phosphate, and the adsorption capacity was 138.7 mg g⁻¹, and the improvement on P removal was attributed by the formation of MgO which enhanced the sorption affinity on PO₄³⁻. In addition, Cu-modification showed significant (p < 0.05) inhibition effect on growth of cyanobacteria as compared to original biochar with biomass decrease of 62% for Cu-biochar and 85% for Cu-Mg-biochar after three week incubation. Among all modified biochar composites, Cu-Mg-biochar showed highest inhibition effect due to the removal of nutrient and directly causing cell lysis. Moreover, in the water co-existing with different ratios of oil and PO₄³⁻, Cu-Mg-biochar showed highest (p < 0.05) efficiency in inhibition on the growth of toxic cyanobacteria, biomass decreased from 2.85 mg L⁻¹ to 0.20 mg L⁻¹. Overall, Cu-Mg-biochar composite was suggested effective remediation material in treating oil-impacted eutrophic water.

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Water contamination by synthetic organic compounds is one of the major environmental issues facing the world today. Among the available methods to treat them, catalytic advanced oxidation processes using Cu(II) ions to activate peroxymonosulfate is a potential candidate at slightly alkaline conditions (pH 8). In this work, we investigated the influence of PMS concentration (0–1000 μmol L^–1), solution pH (7–10), and the effect of water matrix (ultrapure, tap, and simulated municipal wastewater—SMWW) on imidacloprid (IMD) insecticide oxidation. After optimization of the investigated variables (500 μmol L^–1 PMS and pH 8), almost complete IMD oxidation was achieved in 6 h using ultrapure and tap water. The main detected byproducts resulting from IMD oxidation in ultrapure water are due to hydroxylation reactions and rupture of the imidazolidine ring. When SMWW was used, IMD oxidation was only 10% in 6 h, probably due to the scavenging effect of inorganic and organic compounds. The main produced working oxidants were radical (mainly HO^● and SO₄^●–) and non-radical (¹O₂, Cu(I), and Cu(III)) species, based on scavenging experiments and mass spectrometry detection of produced DMPO byproducts. Among these, HO^● species seems to promptly oxidize IMD.

The present study investigates the need to improve photocatalytic processes for the treatment of textile effluents, which are traditionally reliant on ultraviolet radiation, which is impractical on an industrial scale. Therefore, enhancing efficiency in the visible spectrum is crucial. This study emphasizes the importance of the synthesis methodology in the creation of gold nanoparticles (Au-NPs) to boost their photocatalytic activity via electron transfer and surface plasmon resonance. This study explores the synthesis of modified Au-NPs on TiO₂ using precipitation deposition (PD) and modified wet impregnation (MWI) techniques. Results showed that MWI synthesis yields catalysts with greater surface area and smaller particle sizes than PD, enhancing the photocatalytic efficiency, and achieving 100% dye removal in less than 90 min, and a reduction in total organic carbon (TOC) of more than 70%. Photocatalytic degradation tests under solar and visible light reveal that MWI-derived catalysts outperform PD-derived ones in reducing RB5 dye. The analysis of active species involved in the redox reactions identified h⁺, ^{− •}O₂, e⁻, and ^•OH radicals as contributors to the degradation of the organic pollutant RB5, with photogenerated holes being the primary active species in the photocatalytic process, followed by hydroxyl radicals. Thus, it was possible to confirm the important role of gold nanoparticles in the enhancement of the photocatalytic activity.

Microplastics (MPs), though often invisible to the naked eye, pose a significant and pervasive environmental threat, subtly integrating into natural systems and disrupting ecological balance. Ingestion of MPs at different trophic levels has been widely documented, but their impacts on zooplankton have been under-studied despite their vital ecological roles in marine food webs. In this study, MPs were determined in popular seafood Acetes shrimps (Acetes chinensis and A. erythraeus) from the southeastern coast of Bangladesh. The entire body of the shrimps (500 individuals of each species) underwent comprehensive MP analysis through aquamation (alkaline hydrolysis), microscopic examination and polymer identification by Attenuated Total Reflectance-Fourier Transformed Infrared Spectroscope (ATR-FTIR). A total of 67 and 110 particles were visually identified, among which 39 and 51 particles were determined as MPs using ATR-FTIR in A. erythraeus and A. chinensis, respectively, averaging 0.078–0.102 particles per species. This study encountered various colours, shapes, and types of MPs, among which white/transparent (49–59%), filamentous (76–82%), and fiber (76–77%) were prevalent. The study observed a size range of MPs from < 500 µm to 5 mm, with a concentration of 1.33–11.15 items/g biomass. ATR-FTIR analysis identified 37, 25, 11, 9, 5, and 3 polymer particles of Polyethylene, Polypropylene, Polyethylene Terephthalate, Nylon-6 (Polyamide), Ethylene Vinyl Acetate and Polybutylene Terephthalate respectively. The findings of this study have elicited a “wake-up call” on the bioaccumulation of MPs in Acetes shrimps with potential contamination of seafood and public health concerns in the Bay of Bengal region.

The leather tanning industry generates significant environmental impacts due to the release of effluents containing high concentrations of heavy metals, particularly chromium (Cr). This study investigates the efficacy of mercerized microcrystalline cellulose particles (MCPs) as a sustainable adsorbent for Cr removal from tannery effluents. MCPs were synthesized and characterized using Raman spectroscopy and scanning electron microscopy (SEM) to assess their structural modifications post-mercerization. Adsorption assays were conducted under various experimental conditions, including agitation rate, pH, temperature, effluent concentration, and MCP concentration. The adsorption capacity was modeled using Langmuir, Freundlich, Dubinin-Radushkevich, and Temkin isotherms, with Langmuir providing a better fit (R² = 0.9884), indicating indicating a monolayer adsorption of Cr ions onto the MCPs surface. Results showed a maximum adsorption capacity of 28.17 mg/g for Cr, with optimal conditions identified as 400 rpm agitation, pH 5.0, 35 °C temperature, and 25 mg/L MCP concentration. Multiple regression analysis highlighted pH and effluent dilution as significant factors affecting adsorption efficiency. Additionally, cluster analysis and Detrended Correspondence Analysis (DCA) confirmed the complex interactions among the variables. Our findings suggest that mercerized MCPs are a promising and sustainable solution for Cr removal from tannery effluents, offering a high adsorption capacity and potential for environmental application. Future research should focus on the regeneration and reuse of MCPs, assessing other pollutants, and the economic feasibility of large-scale implementation.

This study used chicken nail hydrochar (CH) to make a matrix environment in Mrytus communis (M. communis) emulsion gel (MEg). The inhibition potential of MEg containing CH against Acinetobacter baumannii (A. baumannii) and Enterococcus faecalis (E. faecalis) pathogens and the characterization were investigated. Characteristics and surface analysis of hydrochar-based M. communis emulsion gel (H-MEg) were analysed using FT-IR and SEM. M. communis essential oil (EO) was emulsified using tween 80, gelified using collagen and then immobilized into the hydrochar using a lyophilizer. In the antibacterial activity test, inhibition zones of MEg and H-MEg against A. baumannii were 7.26, and 9.1, respectively. E. faecalis was inhibited with 47.81 and 5.82 mm by MEg, and H-MEg, respectively. The highest reduction at the final of 30 min for A. baumannii inoculated carcass skin was 1.3 CFU/cm², 95.9% for H-MEg (p < 0.05). The zeta potential, conductivity and viscosity of H-MEg were -14.5 ± 0.4 mV, 0.0012, and 0.8872, respectively. As a result, the addition of CH to MEg-containing microdroplets enabled the composite to become fully stable. The hydrochar itself did not have antimicrobial effects, while the bioactive M. communis emulsion gel enhanced the functionality of chicken nail waste-based hydrochar. H-MEg obtained from chicken nail waste can be used for treatment purposes in infections where A. baumannii ve E. faecalis bacteria are active.

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This study evaluates the performance of artificial neural networks (ANNs) in predicting Fe (II) adsorption using activated carbon derived from Phumdi biomass (PAC) in batch and continuous fixed-bed setups. Phumdi, a unique biomass from the Loktak Lake ecosystem, serves as a sustainable and cost-effective precursor for activated carbon production due to its rich organic composition and functional groups. Large accumulations of Phumdi are commonly found along the periphery of Loktak Lake, where they are often regarded as waste. To account for variations in biomass properties, samples were collected from three different sites: a national park, an agricultural area, and a residential area. BET surface area analysis confirmed the porous nature of the activated carbons, with values ranging from 2.722 to 5.940 m²/g across different biomass sources. FTIR characterization identified key functional groups, including hydroxyl, alkyl, and carbon–carbon bonds, which play a crucial role in Fe (II) adsorption. Amongst the batch analysis parameters, the agitation speed was found to be optimum at 250 rpm, and the temperature at 298 K, with an equilibrium time of 120 min. Kinetic studies followed a pseudo-second-order model, indicating chemisorption, while isotherm analysis confirmed Langmuir model conformity, with a maximum adsorption capacity ranging from 1.12 to 6.50 mg/g. Thermodynamic studies confirmed that the adsorption process is exothermic and spontaneous, driven by energy release and a decrease in free energy. Fixed-bed experiments using activated carbon from phumdi biomass from an agricultural area were conducted at varying flow rates (2 mL/min and 4 mL/min), bed depths (20 cm, 40 cm, and 60 cm), and influent concentrations. The maximum throughput of 12 L was achieved before significant breakthrough at 5 mg/L, 4 mL/min, and 60 cm, indicating optimal adsorption performance under these conditions. ANNs demonstrated high predictive accuracy, with R² values of 1.00 for training, 0.99 for testing, and 0.95 for validation in the batch system, and 0.99 for training, 0.98 for testing, and 0.95 for validation in the fixed-bed system. The optimal ANN architectures were 6–6-1 for batch adsorption and 4–12-1 for fixed-bed adsorption, with mean squared errors (MSE) of 0.004645 and 0.000856, respectively. This study highlights the potential of Phumdi-derived PAC as a sustainable adsorbent and showcases the effectiveness of ANN modeling in optimizing adsorption efficiency and predictive accuracy, offering an environmentally friendly solution for water treatment.

In recent years, soil heavy metal pollution and the accumulation of tailings and food waste cannot be ignored. Currently, soil remediation agents are expensive or have poor remediation effects. In this experiment, alkali-modified tailings biochar composite (MTB) was prepared by low-temperature pyrolysis using tailings and food waste as raw materials for the remediation of soil heavy metal Cd. MTB has a large number of oxygen-containing functional groups on its surface (Si–O, Fe–O, -OH, C-O, -COOH), which is favorable for the adsorption of the heavy metal Cd. The adsorption behavior is consistent with the Langmuir model and the proposed second-order kinetic equation, and the adsorption mechanism is mainly complexation and precipitation. 650 °C pyrolysis preparation of MTB3 reduced bioavailable cadmium by 83% in 35 days, and the active Cd was transformed into inactive Cd. Potting experiments showed that ryegrass biomass significantly increased.Adding 8% MTB3 to ryegrass significantly reduced Cd accumulation, lowering available cadmium by 86.4% in 35 days compared to the control (CK). Tailings biochar improved soil properties, boosting plant germination and height by 26.94% to 106%. The study showed that tailings biochar composites have good prospects for remediation of soil heavy metal Cd pollution.

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