Degradation Of Fungicides Research Articles

Photocatalytic Degradation of Mancozeb Pesticide Residue using Nanoceria Doped Zinc Oxide Nanoparticles under Natural Solar Irradiation

Introduction: Excessive applications of agrochemicals to meet the high food demand from ever-increasing populations are becoming a major issue for both health practitioners and environmental managers. Chemicals such as ethylene bis-dithiocarbamate pesticide mancozeb (MCZ) are known to have deleterious effects on the ecosystem. AIM: This study, aimed at assessing the suitability of cerium-doped zinc oxide (Ce-ZnO) for efficient degradation of MCZ fungicide. Method: The photocatalysts were synthesized using the coprecipitation method with zinc nitrate hexahydrate, cerium nitrate hexahydrate, and sodium hydroxide. The synthesized nanocomposites were further characterized by Powder X-ray Diffraction (PXRD), Fourier Transform Infrared spectroscopy (FTIR), Scanning Electron Microscopy (SEM), and Energy Dispersive X-ray Spectroscopy (EDAX). The average crystallite size of the as-synthesized particles was found to be 31.42 nm, with very sharp PXRD peaks revealing the pure crystal nature of the particles. The photocatalytic degradation activity was evaluated following a series of experiments under natural environmental conditions. The optimal conditions for the degradation of MCZ fungicide using Ce-ZnO were found to be 10 ppm initial concentration of MCZ, 20 mg dose of the Ce- ZnO photocatalyst, 180 minutes irradiation time, and 10-11 atmospheric UV index. Result: At the optimum conditions, the degradation efficiency was found to be about 90% after 180 minutes. The reported photocatalytic degradation of MCZ using Ce-ZnO fits a pseudo-firstorder kinetic model with an R2 value of 0. 9677. Similarly, the reusability of the as-synthesized photocatalyst was evaluated and found to be active for five rounds with little change in the activity. Conclusion: Thus, the degradation method in the current study can be suitable for the degradation and removal of MCZ in agricultural runoff in the field.

In-vitro Isolation of Serratia marcescens and Computational Analysis of Lipase–Chitinase as a Hybrid Enzyme for the Degradation of Fungicides to Sustain the Ecosystem

The application of fungicides for commercial purposes has grown in response to increased food demand and shifting disease patterns. However, there is a scarcity of studies demonstrating their proper degradation. Due to the expanding global population, there is a heightened need for more agriculture to fulfill the growing demand for food, and this necessitates safeguarding crops from pests and diseases. Disease outbreaks in crops can result in the loss of food and the depletion of valuable resources. According to the European Union, organic fungicides constitute 60% of all fungicide sales, while synthetic fungicides make up the remaining 40% of pesticide sales. Fungicide usage is indispensable but needs to be considered within the context of potential environmental risks. Nonetheless, there is a pressing need to break down fungicides to preserve the natural environment. Our research is centered on hybrid enzymes derived from [Formula: see text] marcescens, which exhibit the capability to degrade fungicides. We employed computational techniques to assess the enzymes’ effectiveness in breaking down fungicides. S. marcescens was isolated from soil and identified through 16s rRNA analysis. Chitanase and lipase, enzymes identified in S. marcescens, can individually break down fungicides, as confirmed by auto-dock vina docking simulations. Notably, the combined action of these two enzymes surpasses the performance of individual docking, a result also corroborated by auto-dock vina. To further establish the efficacy and degradability of this approach, computational techniques were employed. In the future, it may be possible to create an in vitro antifungal agent, which could be categorized as a bioactive agent.

Unveiling highly efficient degradation mechanism of strobilurin fungicides by strain Hyphomicrobium sp. DY-1

Strobilurin fungicides are a type of agricultural chemical commonly used to control fungal diseases in crops. However, the abuse of strobilurin fungicides leads to heavy residue in the environment, posing serious threats to ecosystems and human health. In this regard, the strains Hyphomicrobium sp. DY-1 and Hyphomicrobium sp. B1 could hydrolyze the strobilurin fungicides effectively (trifloxystrobin, azoxystrobin, pyraclostrobin, and picoxystrobin), generating the corresponding parent acid. Therefore, the present study sought to explore the molecular degradation mechanism of strobilurin fungicides by strain DY-1. The results showed that strain DY-1 exhibited a faster degradation rate for strobilurin fungicides than strain B1. Comparative genomic analysis and functional verification of both strains revealed that strain DY-1 possesses six strobilurin hydrolases (TriH, StrH, StrH1, StrH2, StrH3, and StrH4), whereas strain B1 possesses only three strobilurin hydrolases (TriH, StrH, and StrH1). All StrHs (StrH1, StrH2, StrH3, and StrH4) shared 50%–77% identity with StrH and contained conserved catalytic motif Ser-Glu-His. Further investigation into the distribution of strobilurin fungicide hydrolases revealed that strH and strH1 were aligned together and surrounded by transposases in the strains DY-1 and B1 and a genomic island containing strH and strH1 derived from the Hyphomicrobium genus. Overall, the function, diversity, and distribution of strobilurin hydrolases will provide insights into the microbial degradation of strobilurin fungicides.

Degradation of Triazole Fungicides by Plant Growth-Promoting Bacteria from Contaminated Agricultural Soil.

The widespread application of triazole fungicides (TFs) in agricultural practices can result in the considerable accumulation of active compound residues in the soil and a subsequent negative impact on the soil microbiota and crop health. In this study, we isolated three TF-degrading bacterial strains from contaminated agricultural soils and identified them as Klebsiella sp., Pseudomonas sp., and Citrobacter sp. based on analysis of morphological characteristics and 16S rRNA gene sequences. The strains used three common TFs, namely hexaconazole, difenoconazole, and propiconazole, as their only sources of carbon and energy for growth in a liquid mineral salt medium, with high concentrations (~ 500 mg/l) of each TF. In addition to the ability to degrade fungicides, the isolates also exhibited plant growth-promoting characteristics, such as nitrogen fixation, indole acetic acid production, phosphate dissolution, and cellulose degradation. The synergistic combination of three bacterial isolates significantly improved plant growth and development with an increased survival rate (57%), and achieved TF degradation ranging from 85.83 to 96.59% at a concentration of approximately 50 mg/kg of each TF within 45 days in the soil-plant system. Based on these findings, the three strains and their microbial consortium show promise for application in biofertilizers, to improve soil health and facilitate optimal plant growth.

CoFe2O4/MoS2@Au: Multifunction Z-Scheme Heterojunction for SERS Monitoring and Photocatalytic Degradation of Fungicides

Efficient detection and degradation of fungicides are greatly concerned with aquatic food safety. Herein, a multifunction CoFe2O4/MoS2@Au (ACMS) composite was synthesized for crystal violet (CV) and malachite green (MG) photocatalytic degradation and SERS determination. As the construction of the Z-scheme heterostructure of ACMS, which enhanced the light absorption capability and the separation efficiency of photoexcited carrier significantly, ACMS possessed an excellent photocatalytic performance with a degradation rate of 94.76% for CV under simulated solar light irradiation. Furthermore, the multifunction ACMS exhibited superior SERS capability with a detection limit (LOD) of 4.309 × 10−2 μg L−1 for MG residues in water. And the ACMS substrates could be utilized to determine the MG residues in crucian carp extract, resulting in a recovery rate of 96.00~116.00%. In addition, such multifunction heterojunctions were performed for in situ monitoring of the photodegradation process. This research opened up a novel perspective on the applications of heterojunction-based multifunction materials for food safety control.

Use of cover crops in vineyards to prevent groundwater pollution by copper and organic fungicides. Soil column studies.

Several fungicides, such as copper and organic products (synthetic or natural), are currently being used in vineyards to control downy mildew (Plasmopara viticola) resulting in soil, surface water, and groundwater pollution. This study aims to assess the effectiveness of using cover crops as an agricultural practice in vineyards to protect soil and groundwater pollution. For that purpose, we performed different soil column studies to quantify soil leaching of selected fungicides (copper, dimethomorph, oxathiapiprolin, zoxamide, acibenzolar-s-methyl, and laminarin) following a rainfall event after a conventional fungicide vineyard application. Two types of vineyard soils (loam and sandy-loam soil textures) and three ground covers (bare ground, monoculture cover, and polyculture cover) were assessed. These studies were completed with hydroponic assays to check the effectiveness of cover roots in the fungicide degradation. Mass balance results show that whereas 3 fungicides (Cu, zoxamide, and dimethomorph) were leached through sandy soil columns, only copper was leached from loam soil columns. The effect of cover crops was only significant for Cu and zoxamide when fungicides were applied 24h before the rain event, reducing the fungicide leaching by 30%. Hydroponic studies showed that cover roots enhanced the kinetic rates of almost all tested fungicides by 5-467%, suggesting that they are relevant to improving the degradation of fungicides in the soil column. These results are relevant to drawing up recommendations on the use of cover crops to protect soil and groundwater pollution by fungicides.

High tolerance and degradation of fungicides by fungal strains isolated from contaminated soils

ABSTRACT The aim of this work was to isolate fungal strains from phytotoxic agricultural soils, screen them, categorize the most tolerant fungi to three fungicides, and identify them by a molecular approach. In this study, 28 fungal strains were isolated from phytotoxic agricultural soil with intensive use of pesticides. The capacity of fungi to resist and degrade different concentrations of carbendazim, captan, and zineb was determined by an exploratory multivariate analysis. Actinomucor elegans LBM 239 was identified as the most tolerant fungus to these fungicides, degrading a 86.62% of carbendazim after 7 days of treatment. In conclusion, A. elegans LBM 239 demonstrated the highest tolerance and capacity to biodegrade carbendazim, becoming a potential candidate for bioremediation of contaminated soils with carbendazim, captan, or zineb.

Electrochemical oxidation degradation of fungicide 5-chloro-2-methyl-4-isothiazoline-3-one (CMIT) in brine of reverse osmosis by a novel Ti/CB@MXene anode

The electrochemical oxidation purification of reverse osmosis concentrated brine was sustainable water purification technology; however, anode oxidation efficiency and capacity limit its development. According to MXene’s high surface area and structure characterization, a novel Ti/ carbon black (CB) @MXene anode was prepared for the first time for electrochemical oxidation degradation of 5-chloro-2-methyl-4-isothiazoline-3-one (CMIT) in reverse osmosis brine, even though MXene was studied more widely in sulfate radical based AOP and photocatalysis. This anode showed slippy surface and high oxygen evolution potential (2.84 V), suggesting it is hard to be fouled and eliminated the side reaction effect. According to the anode fabrication parameters optimization, the best mass ratio of Ti3C2Tx and CB was 1:1, showing the highest oxygen evolution potential. The reaction parameters including current density and plate spacing were optimized as 5.625 mA/cm2 and 1.0 cm, where the best CMIT degradation efficiency was 89.86 %. This performance was better than DSA and similar with BDD anode, however its stability needs to be improved. The indirect oxidation dominated CMIT degradation as 99.69 % and •OH formation rate was 13.81 L·mol−1·s−1, which was approximately 5.04 fold higher than that of traditional Ti anode. Three possible degradation pathways of CMIT were proposed, as below: electron rich sulfur in SN bond was oxidized to form sulfoxide structure, chlorine was replaced by •OH, olefin double bond was attacked by •OH. The formed intermediates showed less ecotoxicity. The Ti/CB@MXene anode showed better potential in electrochemical oxidation treatment of reverse osmosis brine.

Glutathione Promotes Degradation and Metabolism of Residual Fungicides by Inducing UDP-Glycosyltransferase Genes in Tomato.

Reduced glutathione (GSH) is a key antioxidant, which plays a crucial role in the detoxification of xenobiotics in plants. In the present study, glutathione could reduce chlorothalonil (CHT) residues in tomatoes by inducing the expression of the UDP-glycosyltransferase (UGT) gene. In plants, UGT is an important glycosylation catalyst, which can respond to stresses in time by activating plant hormones and defense compounds. Given the importance of plant growth and development, the genome-wipe analyses of Arabidopsis and soybean samples have been carried out, though not on the tomato, which is a vital vegetable crop. In this study, we identified 143 UGT genes in the tomato that were unevenly distributed on 12 chromosomes and divided into 16 subgroups and found that a variety of plant hormones and stress response cis-elements were discovered in the promoter region of the SlUGT genes, indicating that the UGT genes were involved in several aspects of the tomato stress response. Transcriptome analysis and results of qRT-PCR showed that most SlUGT genes could be induced by CHT, and the expression of these genes was regulated by glutathione. In addition, we found that SlUGT genes could participate in plant detoxification through interaction with transcription factors. These findings further clarify the potential function of the UGT gene family in the detoxification of exogenous substances in tomatoes and provide valuable information for the future study of functional genomics of tomatoes.

Degradation of Tricyclazole fungicide using combined oxidation strategies based on ultrasound, ultraviolet irradiation and microwave

The present study investigates the effect of using ultrasound (US), ultraviolet irradiation (UV), and microwave (MW) in different approaches also including the use of intensifying additives as H2O2 on the degradation of tricyclazole (TC). The performance of US (20 kHz) and MW have been maximized by the optimization of operating parameters. The maximum degradation of tricyclazole was observed at initial tricyclazole concentration as 10 mg/L, pH of 3, and optimum power dissipation for US as 100 W and that for MW as 490 W. The study into the effect of loading of H2O2 on the degradation of tricyclazole in US/H2O2 and UV/H2O2 confirmed the existence of optimal loading of H2O2 (TC:H2O2 as 1:5) yielding degradation of 83.93% and 40.27% respectively after 120 min whereas the optimum ratio for the approach of MW was TC:H2O2 as 1:7.5 yielding 90.23% degradation only after 60 min of operation. The approaches of US/UV/H2O2 and MW/UV/H2O2 resulted in the extent of degradation as 99.09% and 99.90% with the COD reduction as 89.06% and 92.7% respectively. The combined processes US/UV/ccc and MW/UV/H2O2 lead to the synergistic index of 3.27, and 4.88 respectively. The degradation of TC using different types of oxidation processes followed first-order rate kinetics. In summary, the combination of MW/UV/H2O2 is established as the best approach for the degradation of tricyclazole with significant benefits.

Safety evaluation of the use of one- and two-component fungicides to protect grapes

Viticulture and winemaking are traditional industry of agriculture in the southern regions of the Russian Federation, which playing an important role in their economy. A rich and undamaged crop is almost impossible to grow without plant protection measures. Preparations used to spray plants are by no means harmless, and do not always completely disintegrate before harvesting. The objective of the work was to study the dynamics of degradation of fungicides of systemic action, belonging to different classes, in grapes. The two-component preparation was a combination of 120 g/l difenoconazole + 60 g/l tetraconazole (MEC). The one-component preparation contained 250 g/l of cyprodinil (EC). The work was done in the Krasnodar region for 2 years. The half-lives of difenoconazole and tetraconazole were about 5 days, cyprodinil 2.7 and 4 days, 1 and 2 years, respectively. The concentration of difenoconazole and tetraconazole went down to below the MRL in the first year of the study, two weeks after the last spraying, and in the second – after three weeks, which was most likely caused by the prevailing weather conditions – “dangerous phenomenon – intense heat”. At the time of harvest, no residual amounts of difenoconazole, tetraconazole and cyprodinil were found, which indicates the safety of the products obtained for consumers.

Removal and degradation of triazole fungicides using Ag/PEG-CuO: an efficient adsorbent-catalyst coupling process

ABSTRACT In this work, an effective adsorbent-catalyst coupling (ACC) process is proposed and investigated to treat the wastewater polluted with triazole fungicides. In this regard, PEG-CuO as well as Ag particles were prepared and used as the adsorbent and catalyst in the ACC process, respectively. For comparison purposes, Fe3O4 was also utilised as a catalyst. The experiments were conducted to remove penconazole, hexaconazole, and diniconazole (as representative fungicides which were analysed by HPLC-UV). The results show that sole catalysts could not completely remove the triazole fungicides. However, it was found that complete removal and degradation of all fungicides can be obtained using the ACC approach. In the next step, the effects of important operating parameters of the ACC process, i.e. adsorbent load, catalyst load, ratio of catalyst to adsorbent, salt concentration, pH, and operation time were studied. It was found that the optimum condition for all the fungicides was 50/50 ratio of Ag/PEG-CuO, pH of 7, and operating time of 85 min. Finally, the ACC process capability was evaluated for the treatment of five real wastewaters containing triazole fungicides, and the excellent performance of this process was confirmed by observing the complete removal and degradation.

Effects of combined treatment of plasma activated liquid and ultrasound for degradation of chlorothalonil fungicide residues in tomato

The effects of combined treatment (PAL-U) of plasma-activated liquid (PAL) including plasma-activated water (PAW) and plasma-activated buffer solution (PABS) and ultrasound (U) for the degradation of chlorothalonil fungicide on tomato fruit was investigated. Distilled water and buffer solution were activated by radiofrequency plasma jet for durations of 1, 3, 5, and 10 min to obtain PAL1 to PAL10. Fruits were immersed in PAL for 15 min and also in distilled water with sonication for 15 min for individual treatments, and in PAL with sonication for 15 min for combined treatments. The maximum chlorothalonil fungicide residues were reduced by 89.28 and 80.23% for PAW10-U and PABS10-U, respectively. HPLC-MS characterization revealed chlorothalonil degradation pathway and formation of 2,4,5-trichloroisophthalonitrile, 2,4-dichloroisophthalonitrile, 4-chloroisophthalonitrile, isophthalonitrile and phenylacetonitrile as degradation products. Treatments also showed no negative effects on tomato quality. Therefore, PAL and PAL-U treatments could serve as effective methods for degrading pesticides on tomatoes.

The Impact of Disturbed Soil Structure on the Degradation of 2 Fungicides Under Constant and Variable Moisture

Degradation of agrochemicals in soil is frequently faster under field conditions than in laboratory studies. Field studies are carried out on relatively undisturbed soil, whereas laboratory studies typically use sieved soil, which can have a significant impact on the physical and microbial nature of the soil and may contribute to differences in degradation between laboratory and field studies. A laboratory study was therefore conducted to determine the importance of soil structure and variable soil moisture on the degradation of 2 fungicides (azoxystrobin and paclobutrazol) that show significant differences between laboratory and field degradation rates in regulatory studies. Degradation rates were measured in undisturbed cores of a sandy clay loam soil (under constant or variable moisture contents) and in sieved soil. For azoxystrobin, degradation rates under all conditions were similar (median degradation time [DegT50] 34-37 d). However, for paclobutrazol, degradation was significantly faster in undisturbed cores (DegT50 255 d in sieved soil and 63 d in undisturbed cores). Varying the moisture content did not further enhance degradation of either fungicide. Further examination into the impact of soil structure on paclobutrazol degradation, comparing undisturbed and sieved/repacked cores, revealed that the impact of sieving could not be mitigated by repacking the soil to a realistic bulk density. Examination of fungal and bacterial community structure using automated ribosomal spacer analysis showed significant initial differences between sieved/repacked and intact soil cores, although such differences were reduced at the end of the study (70 d). The present study demonstrates that disruption of soil structure significantly impacts microbial community structure, and for some compounds this may explain the differences between laboratory and field degradation rates. Environ Toxicol Chem 2021;40:2715-2725. © 2021 SETAC.

Degradation of the O-phenylphenol Fungicide in Water by Unconventional CeO2-WO3 Photocatalysts

Background: Water pollution due to emerging contaminants such as pesticides, pharmaceutics and/or plasticizers, is a serious environmental problem strictly connected to the safety of human and ecosystem life. For this reason, the development of high-performing (photo)catalysts for water purification is crucial. Objective: In recent years, the synergistic effects in Advanced Oxidation Processes (AOPs) can perform better strategies to remove recalcitrant contaminants from water. In this contest, the (photo)catalytic activity of CeO2-WO2materials for the degradation of the orto-phenylphenol fungicide comparing the photocatalytic, the Fenton and the photo-Fenton-like processes, has been examined. Methods: The samples were synthetized through deposition-precipitation mediated with the hexamethylenetetramine (HMTA) surfactant. The chemico-physical properties of the materials were examined by Raman, UV-Vis Diffuse Reflectance (Uv-vis DRS) and X-Ray photoelectron (XPS) spectroscopies, N2 adsorption-desorption measurements and transmission electron microscopy (TEM). The (photo)catalytic measurements were made through a home-made photoreactor irradiated by a solar lamp. The degradation of the fungicide was measured by UV-vis spectroscopy. Results : An efficient heterojunction was formed between the CeO2 and the WO2 oxides, which provided a good degradation percentage of the pesticide (65%) employing the solar photo-Fenton-like reaction that was the best performing process among the three investigated AOPs. The addition of WO3on CeO2 facilitated the ionic exchange between the Ce and the W ions, boosting the redox properties of cerium oxide. Conclusions: The strong interaction between CeO2 and WO3 and the peculiar properties of this unconventional composite pave the way to its use as a promising material for water depollution.

Detoxification Esterase StrH Initiates Strobilurin Fungicide Degradation in Hyphomicrobium sp. Strain DY-1.

Strobilurin fungicides are widely used in agricultural production due to their broad-spectrum and fungal mitochondrial inhibitory activities. However, their massive application has restrained the growth of eukaryotic algae and increased collateral damage in freshwater systems, notably harmful cyanobacterial blooms (HCBs). In this study, a strobilurin fungicide-degrading strain, Hyphomicrobium sp. strain DY-1, was isolated and characterized successfully. Moreover, a novel esterase gene, strH, responsible for the de-esterification of strobilurin fungicides, was cloned, and the enzymatic properties of StrH were studied. For trifloxystrobin, StrH displayed maximum activity at 50°C and pH 7.0. The catalytic efficiencies (kcat/Km ) of StrH for different strobilurin fungicides were 196.32 ± 2.30 μM-1 · s-1 (trifloxystrobin), 4.64 ± 0.05 μM-1 · s-1 (picoxystrobin), 2.94 ± 0.02 μM-1 · s-1 (pyraclostrobin), and (2.41 ± 0.19)×10-2 μM-1 · s-1 (azoxystrobin). StrH catalyzed the de-esterification of a variety of strobilurin fungicides, generating the corresponding parent acid to achieve the detoxification of strobilurin fungicides and relieve strobilurin fungicide growth inhibition of Chlorella This research will provide insight into the microbial remediation of strobilurin fungicide-contaminated environments.IMPORTANCE Strobilurin fungicides have been widely acknowledged as an essential group of pesticides worldwide. So far, their residues and toxic effects on aquatic organisms have been reported in different parts of the world. Microbial degradation can eliminate xenobiotics from the environment. Therefore, the degradation of strobilurin fungicides by microorganisms has also been reported. However, little is known about the involvement of enzymes or genes in strobilurin fungicide degradation. In this study, a novel esterase gene responsible for the detoxification of strobilurin fungicides, strH, was cloned in the newly isolated strain Hyphomicrobium sp. DY-1. This degradation process detoxifies the strobilurin fungicides and relieves their growth inhibition of Chlorella.

Conazole fungicides epoxiconazole and tebuconazole in biochar amended soils: Degradation and bioaccumulation in earthworms

Biochar usage in agriculture becomes increasingly important for the improvement of soil properties. However, from the perspective of pesticides, biochar can influence exposure to pesticides of both target and non-target organisms and also pesticides’ fate in soil. Our study investigated degradation and bioaccumulation (in the Eisenia andrei earthworm) of two conazole fungicides, epoxiconazole and tebuconazole, added to high- and low-sorbing soils (by means of fungicides’ sorption measured beforehand) amended with low-, moderate- and high-sorbing biochars at 0.2% and 2% doses. We aimed to investigate the effects of contrasting soil and biochar properties, different doses of biochar in soil-biochar mixtures, and different compounds on the degradation and bioaccumulation. We also wanted to explore if the beforehand determined sorption of fungicides on individual soils and biochars is manifested somehow in their degradation and/or bioaccumulation in soil-biochar mixtures. The biochars’ presence in the soils promoted the degradation of fungicides with a clear effect of dose and soil, but less clear effect of biochar or compound. The bioaccumulation factors were higher in low-sorbing soil variants and also decreased with increasing biochar dose. For low-sorbing soil variants, the bioaccumulation was also influenced by the type of biochar corresponding to its sorbing potential and the possible effect on the bioavailability of the fungicides. Our results show that mixing of biochars with soils changes the fate and bioaccumulation of the conazole fungicides. However, the sorption results from original materials are not straightforwardly manifested in the more complex soil-biota system.

S-doped TiO2 photocatalyst for visible LED mediated oxone activation: Kinetics and mechanism study for the photocatalytic degradation of pyrimethanil fungicide

The degradation of pyrimethanil (PYR) was investigated through the activation of oxone by the S-TiO2 (ST) photocatalyst under visible LED irradiation. The catalyst characterization revealed that the sulfur doping mechanism was based on the cation (S6+) substitution of Ti4+ in TiO2 lattice. The optimal molar ratio of S/Ti at 0.25 was proven efficient in the PYR degradation. Influences of various reaction parameters including ST loading, oxone dosage, PYR concentration, and initial solution pH were examined. SO4•-, •OH, 1O2, O2•-, and h+ were found to be the reactive species generated in the ST/Oxone/Vis LED process. Different natural water constituents exerted dissimilar effects because of the generation of additional reactive species or their radical scavenging capabilities. Moreover, the reusability test indicates the ST photocatalyst is reusable and stable. A series of degradation intermediates was detected via four major degradation pathways. Overall, the ST/Oxone/Vis LED process was demonstrated to be a promising approach for the removal of organic pollutants.

Fast and efficient degradation of water pollutant dyes and fungicide by novel sulfur-doped graphene oxide-modified Ag3PO4 nanocomposite.

The sulfur-doped graphene oxide (sGO)-integrated Ag3PO4 composite displayed very high catalytic activity toward prominent water pollutants like textile dyes and fungicide under sunlight. The optimum amount of sGO doping was found as 5% for degradation. The novel composite degraded 99% of methylene blue (MB) in only 5min of sunlight exposure, which is 16 and 8 times faster than Ag3PO4 and 5% GO-Ag3PO4. High mineralization was observed for MB with a total organic carbon (TOC) removal of 98% in 30min. The composite mineralized rhodamine B, methyl orange, and acid red 18 dyes with a TOC removal above 95%. Moreover, a toxic dithiocarbamate fungicide thiram was degraded in 1h with a TOC removal of 82% leaving less toxic thiourea. The formation of sGO-Ag3PO4 n-n heterojunction increases charge transport and photocatalytic activity of the composite to incredible extent along with hollow morphology and in situ formed Ag nanoparticles (AgNPs).

Green synthesis of ZnO nanoparticle using Trema orientalis (L) leaf: an efficient photocatalyst for degradation of zoxamide fungicide in aqueous organic media under UV light irradiation

ABSTRACT This article reports the green synthesis of zinc oxide nanoparticles (ZnO NPs) by using the aqueous leaf extract of Trema orientalis (L). The ZnO NPs were synthesised by using zinc nitrate hexahydrate acts as the precursor and leaf extract acts as the reducing and capping agent. The synthesis of ZnO NPs was confirmed by the powder X-ray diffraction (XRD) analysis and the average crystalline size was calculated by Scherrer’s formula (24 nm) and as well as Williamson-Hall (W-H) equation (26 nm). The Dynamic Light Scattering (DLS) analysis showed the stability and particle size of approximately 65–67 nm of the synthesised ZnO NPs. The Fourier Transform Infrared Spectroscopy (FTIR) analysis confirmed the presence of various functional groups in the synthesised NPs. The UV absorption wavelength is observed at 370 nm, and the calculated direct band gap was found to be 3.13 eV. The surface morphology, the crystalline shape of the synthesised ZnO NPs was determined by using Scanning Electron Microscopy (SEM). The effectiveness of the ZnO NPs on photocatalytic degradation of zoxamide, a benzamide class of fungicide was tested under UV irradiation (λ max ≥ 250 nm). The calculated half-lives of photodegradation of zoxamide in acetonitrile/water solvent system were found to be in the range of 4.09 − 10.46 h. Moreover, the effect of pH, the initial concentration of zoxamide and photocatalyst ZnO NPs dosage were investigated. The experimental kinetic data followed the pseudo-first-order model. The reaction rate constant (kobs) was decreased from 0.1695 to 0.1511 h−1 with increasing initial zoxamide concentration from 120 to 260 mg/L, respectively. Langmuir–Hinshelwood (L–H) kinetic model was proposed for the rate equation of the zoxamide degradation in presence of ZnO NPs under UV irradiation.