Search Results (10)

The increasing prevalence of emerging pesticides in aquatic ecosystems poses significant risks to environmental and human health. This study explores the valorization of date seeds—an abundant agro-waste in arid and semi-arid regions—into functional biochar for the adsorption of emerging pesticides from contaminated wastewater. Biochar was synthesized via pyrolysis at 550 °C for 30 min under a nitrogen atmosphere and characterized using BET and FT-IR techniques. The prepared date seed biochar (DSBC) exhibited a high specific surface area of 307.45 m²/g and a well-developed microporous structure conducive to pollutant adsorption. The optimized DSBC achieved maximum adsorption capacities of 28.3 mg/g for carbendazim and 25.7 mg/g for linuron. The removal efficiency exceeded 90% for all pesticides at pH 6–8 and equilibrium was reached within 60 min. Regeneration tests demonstrated that DSBC retained its removal efficiency of 60.3% and 75.5% for carbendazim and linuron, respectively, after tenth cycles, highlighting its reusability and cost-effectiveness. Significant performance potential was demonstrated via the formed biochar regarding stability when exposed to real wastewater composition. Overall, date seed biochar presents a sustainable, low-cost, and efficient solution for mitigating pesticide pollution in wastewater treatment systems. Full article

This study presents the fabrication of a samarium-doped Ti/Sb-SnO₂/PbO₂ electrode and investigates its applications in polluted water treatment and energy conversion. Physicochemical properties were characterized by scanning electron microscopy with energy-dispersive X-ray spectroscopy, X-ray powder diffraction analysis, and Raman spectroscopy. The Ti/Sb-SnO₂/Sm-PbO₂ electrode showed 2.5 times higher oxygen evolution potential activity than the Ti/Sb-SnO₂/PbO₂ electrode. Density Functional Theory was used to conduct first-principles calculations, and the obtained results indicated that Sm doping enhances the production of reactive oxygen species. The application of the Ti/Sb-SnO₂/Sm-PbO₂ electrode in carbendazim (CBZ) removal was investigated, since CBZ is a fungicide whose presence in the environment, including food, water, and soil, poses a threat. After 60 min of the treatment under optimized working parameters, the degradation rate of CBZ reached 94.2% in the presence of 7.2 g/L Na₂SO₄ with an applied current density of 10 mA/cm² in an acidic medium (pH 4). Of the four investigated parameters, the current density had the most significant influence on the degradation process. At the same time, the initial pH value of the solution was shown to have the least impact on degradation efficiency. These results imply a potential use of the proposed treatment for CBZ removal from wastewater. Full article

Pokkah Boeng disease has been observed in nearly all countries where sugarcane is commercially cultivated. The disease was considered a minor concern in earlier times, but due to climate change, it has now become a major issue. It is caused by fungi, specifically the Fusarium fungal complex. Fusarium fujikuroi, F. sacchari, F. oxysporum, F. verticillioides, F. proliferatum, and F. subglutinans are the major species causing the disease in sugarcane. The disease spreads rapidly, and unpredictable environmental conditions, along with the overlap of crop stages with biotic factors, contributed to its increased severity and varied symptom patterns. This disease is primarily airborne, spreading through air currents. Secondary transmission occurs via infected setts, irrigation water, splashed rain, and soil. It typically emerges during hot and humid conditions, particularly when the sugarcane is experiencing rapid growth. The most effective way to control Pokkah Boeng is by cultivating resistant varieties and removing canes exhibiting ‘top rot’ or ‘knife cut’ symptoms. Apply 0.1% carbendazim, 0.2% copper oxychloride, or 0.3% mancozeb for two to three sprayings at 15-day intervals. Using biological methods to control plant pathogens presents a promising alternative to the heavy reliance on chemical fungicides in modern agriculture, which can lead to environmental pollution and the development of resistant strains. Full article

A mechanistic model was developed to simulate one-dimensional pesticide transport in two-stage vertical flow constructed wetland. The two pesticides taken under study were carbendazim and chlorothalonil. The water flow patterns within the constructed wetland were simulated using the Richards equation. Water content and vertical flux, which are the outputs of the substrate water flow model, were used to calculate the substrate moisture-related parameters and advection term in the solute transport model. The governing solute transport equation took into account a total of six processes: advection, molecular diffusion, dispersion, adsorption to the solid surface, degradation and volatilization. A total of 14 simulation cases, corresponding with available experimental data, were used to calibrate the model, followed by further simulations with standardized influent pesticide concentrations. The simulations indicated that the constructed wetland reached a steady state of pesticide removal after 7 days of operation. Two distinct water flow patterns emerged under saturated and unsaturated conditions. The patterns observed while varying the hydraulic loading rates were similar for each individual saturation condition. Two-factor ANOVA of the simulated data further revealed that the carbendazim and chlorothalonil removal was dependent on the hydraulic loading rates, but it was independent of the influent pesticide concentration. Analysis of the simulated pesticide removal showed that degradation emerged as the predominant removal process over time for both the pesticides. The model developed in this study can be an important tool for the design and construction of treatment wetlands for pesticide removal from wastewater. Full article

Carbendazim (CBZ), a widely used fungicide in agriculture, is frequently detected in aquatic environment and causes significant concerns because of its endocrine-disrupting activity. This study investigated the degradation kinetics of CBZ in ferrate (Fe(VI)) oxidation, the influence of water matrices, and the transformation pathways of CBZ. The second-order rate constant for the reaction between CBZ and Fe(VI) decreased from 88.0 M⁻¹·s⁻¹ to 1.6 M⁻¹·s⁻¹ as the solution pH increased from 6.2 to 10.0. The optimum reaction conditions were obtained through response surface methodology, which were pH = 7.8 and [Fe(VI)]/[CBZ] = 14.2 (in molarity), and 96.9% of CBZ could be removed under such conditions. Cu²⁺ and Fe³⁺ accelerated the degradation of CBZ by Fe(VI) oxidation; common cations and anions found in natural water had no significant effect, while the presence of humic acid also accelerated the degradation of CBZ. Based on the degradation products identified, degradation of CBZ in Fe(VI) oxidation proceeded via three pathways: namely, hydroxylation, removal of the methoxyl group, and cleavage of the C–N/C=N bond. The initial reaction site of CBZ oxidation by Fe(VI) was also supported by the atomic partial charge distribution on the CBZ molecule obtained from density functional theory (DFT) calculations. CBZ in natural water matrices was efficiently removed by Fe(VI) oxidation under near-neutral conditions, indicating that Fe(VI) oxidation could be a promising treatment option for benzimidazole fungicides. Full article

The extremely high levels of water pollution caused by various industrial activities represent one of the most important environmental problems. Efficient techniques and advanced materials have been extensively developed for the removal of highly toxic organic pollutants, including pesticides. This study investigated the photocatalytic degradation of the fungicide carbendazim (Czm) using composite track-etched membranes (TeMs) in an aqueous solution. Copper(I) oxide (Cu₂O) and zinc oxide (ZnO) microtubes (MTs) were prepared using an electroless template deposition technique in porous poly(ethylene terephthalate) (PET) TeMs with nanochannels with a density of 4 × 10⁷ pores/cm⁻² and diameter of 385 ± 9 nm to yield Cu₂O@PET and ZnO@PET composite membranes, respectively. A mixed Cu₂O/ZnO@PET composite was prepared via a two-step deposition process, containing ZnO (87%) and CuZ (13%) as crystalline phases. The structure and composition of all composite membranes were elucidated using scanning electron microscopy (SEM), atomic force microscopy (AFM), energy-dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) techniques. Under UV–visible light irradiation, the Cu₂O/ZnO@PET composite displayed enhanced photocatalytic activity, reaching 98% Czm degradation, higher than Cu₂O@PET and ZnO@PET composites. The maximum Czm degradation efficiency from aqueous solution was obtained at an optimal pH of 6 and contact time of 140 min. The effects of various parameters such as temperature, catalyst dosage and sample exposure time on the photocatalytic degradation process were studied. The degradation reaction of Czm was found to follow the Langmuir–Hinshelwood mechanism and a pseudo-first order kinetic model. The degradation kinetics of Czm accelerated with increasing temperature, and the activation energy (E_a) levels were calculated as 11.9 kJ/mol, 14.22 kJ/mol and 15.82 kJ/mol for Cu₂O/ZnO@PET, ZnO@PET and Cu₂O@PET composite membranes, respectively. The reusability of the Cu₂O/ZnO@PET catalyst was also investigated at different temperatures for 10 consecutive runs, without any activation or regeneration processes. The Cu₂O/ZnO@PET composite exhibited degradation efficiency levels of over 50% at 14 °C and over 30% at 52 °C after 5 consecutive uses. Full article

Although molecular hydrogen can alleviate herbicide paraquat and Fusarium mycotoxins toxicity in plants and animals, whether or how molecular hydrogen influences pesticide residues in plants is not clear. Here, pot experiments in greenhouse revealed that degradation of carbendazim (a benzimidazole pesticide) in leaves could be positively stimulated by molecular hydrogen, either exogenously applied or with genetic manipulation. Pharmacological and genetic increased hydrogen gas could increase glutathione metabolism and thereafter carbendazim degradation, both of which were abolished by the removal of endogenous glutathione with its synthetic inhibitor, in both tomato and in transgenic Arabidopsis when overexpressing the hydrogenase 1 gene from Chlamydomonas reinhardtii. Importantly, the antifungal effect of carbendazim in tomato plants was not obviously altered regardless of molecular hydrogen addition. The contribution of glutathione-related detoxification mechanism achieved by molecular hydrogen was confirmed. Our results might not only illustrate a previously undescribed function of molecular hydrogen in plants, but also provide an environmental-friendly approach for the effective elimination or reduction of pesticides residues in crops when grown in pesticides-overused environmental conditions. Full article

The area planted with avocado crops in Colombia has been growing rapidly in recent years, especially for export varieties such as Hass. The increase in planted area coincided with increased phytosanitary problems, where pathogens such as fungi of the genus Verticillium spp. are becoming of economic importance. The objective of this study was to evaluate different control strategies for avocado wilt disease caused by Verticillium spp., under in vitro, net house, and field conditions. Strategies tested included fungicides (benomyl, azoxystrobin, captan, and carbendazim), beneficial and antagonistic microorganisms (Trichoderma sp., and Rhizoglomus fasciculatum), and physical and cultural practices such as solarization, drainage and removal of diseased tissues. Treatments T7fi (pruning-solarization-Trichoderma-mycorrhiza-sucrose-organic matter-drainage) and T8fi (fungicide-pruning-solarization-Trichoderma-mycorrhiza-sucrose-organic matter-drainage), showed the greatest reduction in the area under disease progress curve and Verticillium dahliae inoculum in soil and plant tissues under field conditions. Fruit with extra quality increased 120.8% with T7fi and 108% with T8fi, compared to the control with diseased trees. The highest costs were identified for T7fi and T8fi; however, these treatments also showed the best cost/benefit relationship. Integrated approaches as in T7fi and T8fi showed the best results for Verticillium wilt control. As no fungicides of chemical synthesis are included in T7fi (pruning-solarisation-Trichoderma-mycorrhiza-sucrose-organic matter-drainage), it should be preferred to T8fi, which does include them, to avoid their negative impacts on avocado production. Full article

This study systematically investigated the oxidative treatment of five selected pesticides, alachlor (ALA), carbendazim (CAR), diuron (DIU), pyrimethanil (PYR), and tebuconazole (TEB), by comparing their relative reactivities as a function of three different oxidative treatment processes (i.e., chlorine (HOCl), ozone (O₃), and ozone/hydrogen peroxide (O₃/H₂O₂)) under various oxidant dosages, reaction times, and pH conditions. For oxidative treatment, pesticide standards were spiked into rainwater. The removal efficiency of the selected pesticides varied considerably depending on the oxidative treatment processes. HOCl, O₃, and O₃/H₂O₂ treatments were highly effective at eliminating CAR (>80%) and PYR (>99%), while they were not significantly effective in removing TEB (<20%). In the case of DIU, HOCl (81%) was shown to be more effective than O₃ (24%) and O₃/H₂O₂ (49%). The removal efficiency of ALA was in the order of O₃/H₂O₂ (49%) > O₃ (20%) > HOCl (8.5%). The effect of increasing the solution pH from 5.0 to 9.0 on pesticide degradation varied between the oxidative treatment processes. Additionally, NH₄⁺, NO₂⁻, and humic acid in rainwater significantly inhibited pesticide degradation. Full article

This study explored the effects of peanut shell biochar (PSB) on the adsorption capacities of fungicides with and without successive chemical modifications, using KMnO₄ and KOH (PSB_OX-A), in order to provide a valuable understanding of their adsorption mechanisms and behaviors. To this end, the physicochemical properties of PSB and PSB_OX-A were examined by using the Brunauer–Emmett–Teller method, Fourier transform infrared spectroscopy, and scanning electron microscopy with an energy dispersive X-ray spectrometer. The effects of temperature, ionic strength, and humic acids on the adsorption of fungicides, using PSB and PSB_OX-A, were estimated through batch experiments. Furthermore, adsorption kinetics, isotherms, and thermodynamics were studied. The maximum adsorption capacities of fungicides by PSB_OX-A were estimated to be more notable (Q_max of carbendazim = 531.2 μmol g⁻¹, Q_max of pyrimethanil = 467.7 μmol g⁻¹, and Q_max of tebuconazole = 495.1 μmol g⁻¹) than PSB (Q_max of carbendazim = 92.6 μmol g⁻¹, Q_max of pyrimethanil = 61.7 μmol g⁻¹, and Q_max of tebuconazole = 66.7 μmol g⁻¹). These findings suggest that successive chemical modification using KMnO₄ and KOH could potentially be used to effectively fabricate PSB to remove fungicides in water-treatment processes. Full article