In this work,a novel bifunctional zirconium dioxide@zeolitic imidazolate framework-90(ZrO_(2)@ZIF-90)nanozyme was successfully developed for the catalytic degradation and electrochemical detection of methyl parathion(...In this work,a novel bifunctional zirconium dioxide@zeolitic imidazolate framework-90(ZrO_(2)@ZIF-90)nanozyme was successfully developed for the catalytic degradation and electrochemical detection of methyl parathion(MP).The ZrO_(2)@ZIF-90 nanozyme with phosphatase hydrolysis activity can convert MP into p-nitrophenol(p-NP).The addition of ZrO_(2)riched in Lewis acid Zr(IV)sites significantly enhanced the phosphatase hydrolysis activity of ZIF-90.ZrO_(2)@ZIF-90 also displayed satisfactory electrocatalytic performance on account of the high surface area,high porosity and powerful enrichment ability of the ZIF-90 and the excellent ion transfer capacity of ZrO_(2).A ZrO_(2)@ZIF-90 nanozyme modified glassy carbon electrode(ZrO_(2)@ZIF-90/GCE)was then fabricated to analyze p-NP formed through MP degradation.Under the optimized conditions,the developed sensor displayed satisfactory analytical performance with a low limit of detection of 0.53μmol/L and two wide linear ranges(3-10 and 10-200μmol/L).ZrO_(2)@ZIF-90 nanozyme accomplished to the degradation and electrochemical detection of MP in river water and spiked fruits.This study identifies a promising new strategy for the design of bifunctional nanozymes for the detection of environmental hazards.展开更多
Biodegradation of methyl parathion （MP）, a widely used organophosphorus pesticide, was investigated using a newly isolated bacterium strain Acinetobacter radioresistens USTB-04. MP at an initial concentration of 120...Biodegradation of methyl parathion （MP）, a widely used organophosphorus pesticide, was investigated using a newly isolated bacterium strain Acinetobacter radioresistens USTB-04. MP at an initial concentration of 1200 mg/L could be totally biodegraded by A. radioresistens USTB-04 as the sole carbon source less than 4 d in the presence of phosphate and urea as phosphorus and nitrogen sources, respectively. Biodegradation of MP was also achieved using cell-free extract of A. radioresistens USTB-04. MP at an initial concentration of 130 mg/L was completely biodegraded in 2 h in the presence of cell-free extract with a protein concentration of 148.0 mg/L, which was increased with the increase of pH from 5.0 to 8.0. Contrary to published reports, no intermediate or final degradation metabolites of MP could be observed. Thus we suggest that the cleavage of C-C bond on the benzene ring other than P-O bond may be the biodegradation pathway of MP by A. radioresistens USTB-04.展开更多
A new facile fluorescence probing strategy, which was based on N-doped carbon dots（NCDs） and methyl parathion hydrolase（MPH）, was developed for the determination of parathion-methyl（PM）. The fluorescence intensi...A new facile fluorescence probing strategy, which was based on N-doped carbon dots（NCDs） and methyl parathion hydrolase（MPH）, was developed for the determination of parathion-methyl（PM）. The fluorescence intensity of NCDs-MPH system was proportional to PM concentration in the range of 2.38–73.78 mmol/L, with a detection limit of 0.338 mmol/L. Moreover, the present simple and facile method could be used to determine methyl parathion in environmental and agricultural samples successfully.Furthermore, the detection mechanism of this system is inner filter effect and molecular interactions between NCDs and p-nitrophenol, which is the hydrolysis product of PM catalyzed by methyl parathion hydrolase.展开更多
Graphene nanosheets （GS） were easily prepared through liquid-phase exfoliation of graphite powder in N,N-dimethylformamide （DMF） with the assistance of sodium citrate. Then, GS was coated onto a glassy carbon elec...Graphene nanosheets （GS） were easily prepared through liquid-phase exfoliation of graphite powder in N,N-dimethylformamide （DMF） with the assistance of sodium citrate. Then, GS was coated onto a glassy carbon electrode （GCE） surface by drop to fabricate a GS]GCE nanointerface. Subsequently, by using tetraethylorthosilicate sol as precursor, nanosilica was electrochemically deposited onto the GS]GCE surface to produce a nanocomposite film electrode （nanosilicaJGSJGCE）. Electrochemical behaviors of methyl parathion （MP） on the nanosilica/GS/GCE surface were investigated thoroughly. It was found that the nanosilicaJGS nanocomposites can improve the redox peak currents of MP significantly due to the synergetic effect. The oxidation peak current was linearly related to MP concentration in the range from 0.0005 μmol/L to 5.6 μmol/L. The detection limit was calculated to be 0.07 nmol/L （SJN = 3）. The developed method was used to determine MP in real samples. The recoveries were in the range from 95.4% to 104.2%, demonstrating satisfactory results.展开更多
The ligand-stabilized soluble Mn(Ⅲ) recognized as active intermediate can potentially mediate the attenuation of contaminants. In this study,the abiotic degradation behaviors of methyl parathion in the ligand stabili...The ligand-stabilized soluble Mn(Ⅲ) recognized as active intermediate can potentially mediate the attenuation of contaminants. In this study,the abiotic degradation behaviors of methyl parathion in the ligand stabilized Mn(Ⅲ)-sulfite system were investigated. The results showed that the yield of soluble Mn(Ⅲ) produced from the redox reaction of MnO2 and oxalic acid was dependent linearly on the dosage of Mn O2 and caused the decomposition of methyl parathion up to 50.1% in Mn(Ⅲ)-sulfite system after 30 minutes. The fitted pseudo-first-order reaction constants of methyl parathion degradation increased with the increasing of the amount of produced Mn(Ⅲ) but was not effected linearly by the addition of sulfite. Other ligands,including pyrophosphate and oxalic acid,acted as effective complexing agents to stabilize soluble Mn(Ⅲ),and exhibited competitive effect on methyl parathion degradation with sulfite. The formation of Mn(Ⅲ)-sulfite complexes is the critical step in the system to produce abundant reactive oxygen species identified as SO3·-to facilitate methyl parathion degradation. The hydrolysis and oxidation of methyl parathion were acknowledged as two primary transformation mechanisms in Mn(Ⅲ)-sulfite system. These findings indicate that naturally ligands-stabilized soluble Mn(Ⅲ) can be generated and could oxidatively decompose organophosphate pesticides such as methyl parathion.展开更多
Organophosphorus pesticides have attracted extensive scientific concern due to their severe threats to food safety and human health.The study investigated the potential of hydroxypropyl-β-cyclodextrin(HPCD)to modulat...Organophosphorus pesticides have attracted extensive scientific concern due to their severe threats to food safety and human health.The study investigated the potential of hydroxypropyl-β-cyclodextrin(HPCD)to modulate the binding interactions of methyl parathion(MP)and its metabolite p-nitrophenol(PNP)with human serum albumin(HSA).Fluorescence quenching studies indicated that static quenching occurred both in the absence and presence of HPCD.The molecular interactions primarily involved hydrogen bonds and van der Waals forces during the binding process.Notably,the binding constants of both MP-HSA and PNP-HSA complexes were significantly reduced when HPCD was present(decreased about 44%and 79%,respectively).3D fluorescence and CD spectral analyses demonstrated that the involvement of HPCD inhibited the microenvironmental changes of residues and restored the initial alterations in the secondary structure of HSA.Molecular docking results indicated that HPCD incorporates MP/PNP into its hydrophobic cavity,forming a ternary complex that exhibited a more favorable binding energy compared to the binary systems.The findings elucidate how food-grade HPCD modulates pesticide-HSA interactions through encapsulation,enabling targeted interventions for pesticidecontaminated food matrices and providing new insights in food safety,medical detoxification and environmental remediation.展开更多
Methyl parathion is a highly hazardous organophosphorus pesticide widely used in agriculture,and its environmental residues pose a significant threat to the ecosystem.Achieving highly efficient and selective adsorptio...Methyl parathion is a highly hazardous organophosphorus pesticide widely used in agriculture,and its environmental residues pose a significant threat to the ecosystem.Achieving highly efficient and selective adsorption removal is an important challenge.Inspired by the adsorption filtration function of the kidney by its hierarchical porous organ structure,we have fabricated a bioinspired hierarchical porous polymer(P5HPP)by introducing the intrinsic molecular cavity of pillar[5]arene to porous organic polymers using a photoclick reaction.P5HPP possesses hierarchical nanoporous structures,abundant adsorption sites,and remarkable host-vip interactions.It can achieve the highly efficient and selective adsorption of methyl parathion in various pesticide solutions by specific host-vip binding(π-πinteractions)between pillar[5]arene and methyl parathion.The adsorption efficiency of methyl parathion(10-4M)can achieve nearly 99.1%by 0.5 mg mL-1P5HPP,and the maximum adsorption capacity reaches up to 148.58 mg g^(-1),which is far superior to other reported pesticide adsorbents.In practical applications,P5HPP is used as the packing material of the adsorption columns to efficiently and rapidly remove 98.6%of methyl parathion(10-4M)from water and alleviate pesticide poison for aquatic organisms.Because of its excellent adsorption performance,good stability,easy recyclability,and low cost,P5HPP is a superb adsorbent for pesticide pollutant treatment with great potential for application in water resource protection.展开更多
Cerium dioxide was used for the first time as reactive sorbent for the degradation of the organophosphate pesticides para-thion methyl, chlorpyrifos, dichlofenthion, fenchlorphos, and prothiofos, as well as of some ch...Cerium dioxide was used for the first time as reactive sorbent for the degradation of the organophosphate pesticides para-thion methyl, chlorpyrifos, dichlofenthion, fenchlorphos, and prothiofos, as well as of some chemical warfare agents-nerve gases soman and O-ethyl S-[2-（diisopropylamino） ethyl] methylphosphonothioate （VX）. CeO2 specimens were prepared by calcination of basic cerous carbonate obtained by precipitation from an aqueous solution. The CeO2 samples containing certain amounts （1 wt.%-5 wt.%） of the neighboring lanthanides （La, Pr, Nd） were prepared in a similar way from pure lanthanide salts. It was shown that ceria accelerated markedly the decomposition of parathion methyl causing the cleavage of the P-O-aryl bond in the pesticide molecule. A similar reaction mechanism was proposed for the degradation of other organophosphate pesticides and nerve agents. The degradation times （reaction half-times） were in an order of minutes in the presence of CeO2, compared to hours or days under common environ-mental conditions. The reaction in suitable organic solvents allowed conversions of about 90%for parathion methyl loading of 20 mg pesticide/g CeO2 within 2 h with a reactant half-life in the order of 0.1 min. The key parameter governing the degradation efficiency of CeO2 was the temperature during calcination. At optimum calcination temperature （about 773.15 K）, the produced ceria retained a sufficiently high surface area, and attained an optimum degree of crystallinity （related to a number of crystal defects, and thus poten-tial reactive sites）. The presence of other lanthanides somewhat decreased the reaction rate, but this effect was not detrimental and permitted the possible use of chemically impure ceria as a reactive sorbent. A fast organophosphate degradation was demonstrated not only in non-polar solvents （such as heptane）, but also in polar aprotic solvents （acetonitrile, acetone） that are miscible with water. This opens new possibilities for designing more versatile decontamination strategies. The cleavage of phosphate ester bonds is of a great importance not only for the degradation of dangerous chemicals （chemical weapons, pesticides）, but also for interactions of ceria （es-pecially the nano-sized one） in biologically relevant systems.展开更多
The mutagenic and carcinogenic effects of parathion-methyl were examined by bacterial reverse mutation assay and a long-term experiment with wistar rats. The potential mutagenic effect of parathion-methyl in Salmonell...The mutagenic and carcinogenic effects of parathion-methyl were examined by bacterial reverse mutation assay and a long-term experiment with wistar rats. The potential mutagenic effect of parathion-methyl in Salmonella typhimurium TA100 bacterial cells was observed without rat liver S9 metabolic activation. Parathion-methyl was further investigated for pathological changes in rat pancreas and liver. The long-term rat experiments showed that parathion-methyl exposure for 3 months can cause pathological changes in rat pancreases acinar cells and pancreatic hepatocytes. Atypical acinar cell focuses （AACF） were determined in the liver and pancreas of the rats. The results from short-term Ames test and long-term rat experiments suggested that parathion-methyl would be potential carcinogenic.展开更多
A study on the sorption of monocrotophos and parathion methyl on Yellow River's sediments was performed. The influence of some factors, such as pH value and ionic strength, on the sorption was investigated and f...A study on the sorption of monocrotophos and parathion methyl on Yellow River's sediments was performed. The influence of some factors, such as pH value and ionic strength, on the sorption was investigated and first order kinetics mode for the sorption of monocrophos was shown. Freundlich isotherm was suggested as the most appropriate type for monocrophos and parathion methyl. But the sorption isotherms of monocrotophos and parathion methyl are also in conformity with Langmuir equation. Both partition and adsorption occur to the sorption of monocrophos to Yellow River's sediments, but partition is the predominant for that of parathion methyl.展开更多
The metal-organic framework(MOF)ZIF-8 has found extensive application in the medicinal and agricultural fields.This study aimed to immobilize the methyl parathion hydrolase(MPH)enzyme from Azohydromonas australica(Aza...The metal-organic framework(MOF)ZIF-8 has found extensive application in the medicinal and agricultural fields.This study aimed to immobilize the methyl parathion hydrolase(MPH)enzyme from Azohydromonas australica(Azau-MPH)within ZIF-8 using an in-situ synthesis method.Interestingly,the immobilized Azau-MPH(abbreviated as Azau-MPH@ZIF-8)exhibited enhanced thermostability and tolerability towards organic solvents compared to the free enzyme.Moreover,Azau-MPH@ZIF-8 retained more than 50%of its initial activity after six cycles,demonstrating its desirable reusability.To further improve the recyclability and catalytic activity of the immobilized enzyme,we introduced magnetic Fe_(3)O_(4) nanoparticles into the immobilization carrier.Notably,the resulting Azau-MPH@(Fe_(3)O_(4)@ZIF-8)biocomposite displayed superior catalytic activity and stability when compared to Azau-MPH@ZIF-8.In practical applications,we employed Azau-MPH@ZIF-8 for cyclic degradation of methyl parathion(20 mg/L)in cherries,and it exhibited exceptional degradation ability.Hence,both Azau-MPH@ZIF-8 and Azau-MPH@(Fe3 O4@ZIF-8)hold great promise as valuable biodegradation tools against MP contamination.展开更多
基金financially supported by the National Natural Science Foundation of China(No.31972149)Innovation Capability Improvement Project of Scientific and Technological Small and Medium-sized Enterprises in Shandong Province(No.2022TSGC2409)the Mac Diarmid Institute for Advanced Materials and Nanotechnology and the Dodd-Walls Centre for Photonic and Quantum Technologies。
文摘In this work,a novel bifunctional zirconium dioxide@zeolitic imidazolate framework-90(ZrO_(2)@ZIF-90)nanozyme was successfully developed for the catalytic degradation and electrochemical detection of methyl parathion(MP).The ZrO_(2)@ZIF-90 nanozyme with phosphatase hydrolysis activity can convert MP into p-nitrophenol(p-NP).The addition of ZrO_(2)riched in Lewis acid Zr(IV)sites significantly enhanced the phosphatase hydrolysis activity of ZIF-90.ZrO_(2)@ZIF-90 also displayed satisfactory electrocatalytic performance on account of the high surface area,high porosity and powerful enrichment ability of the ZIF-90 and the excellent ion transfer capacity of ZrO_(2).A ZrO_(2)@ZIF-90 nanozyme modified glassy carbon electrode(ZrO_(2)@ZIF-90/GCE)was then fabricated to analyze p-NP formed through MP degradation.Under the optimized conditions,the developed sensor displayed satisfactory analytical performance with a low limit of detection of 0.53μmol/L and two wide linear ranges(3-10 and 10-200μmol/L).ZrO_(2)@ZIF-90 nanozyme accomplished to the degradation and electrochemical detection of MP in river water and spiked fruits.This study identifies a promising new strategy for the design of bifunctional nanozymes for the detection of environmental hazards.
基金Project supported by the National Natural Science Foundation of China (No.20377047,20507002)Innovation Foundation in University of Science and Technology Beijing.
文摘Biodegradation of methyl parathion （MP）, a widely used organophosphorus pesticide, was investigated using a newly isolated bacterium strain Acinetobacter radioresistens USTB-04. MP at an initial concentration of 1200 mg/L could be totally biodegraded by A. radioresistens USTB-04 as the sole carbon source less than 4 d in the presence of phosphate and urea as phosphorus and nitrogen sources, respectively. Biodegradation of MP was also achieved using cell-free extract of A. radioresistens USTB-04. MP at an initial concentration of 130 mg/L was completely biodegraded in 2 h in the presence of cell-free extract with a protein concentration of 148.0 mg/L, which was increased with the increase of pH from 5.0 to 8.0. Contrary to published reports, no intermediate or final degradation metabolites of MP could be observed. Thus we suggest that the cleavage of C-C bond on the benzene ring other than P-O bond may be the biodegradation pathway of MP by A. radioresistens USTB-04.
基金supported by the National Natural Science Foundation of China(No.21207057)the Fundamental Research Funds for the Central Universities(No.lzujbky-201643)
文摘A new facile fluorescence probing strategy, which was based on N-doped carbon dots（NCDs） and methyl parathion hydrolase（MPH）, was developed for the determination of parathion-methyl（PM）. The fluorescence intensity of NCDs-MPH system was proportional to PM concentration in the range of 2.38–73.78 mmol/L, with a detection limit of 0.338 mmol/L. Moreover, the present simple and facile method could be used to determine methyl parathion in environmental and agricultural samples successfully.Furthermore, the detection mechanism of this system is inner filter effect and molecular interactions between NCDs and p-nitrophenol, which is the hydrolysis product of PM catalyzed by methyl parathion hydrolase.
基金supported by the National Natural Science Foundation of China (No. 21561011)Scientific and Technological Innovation Team Project of Hubei University for Nationalities (No. MY2014T004)the Open Foundation of Key Laboratory of Biologic Resources Protection and Utilization of Hubei Province (No. PKLHB1506)
文摘Graphene nanosheets （GS） were easily prepared through liquid-phase exfoliation of graphite powder in N,N-dimethylformamide （DMF） with the assistance of sodium citrate. Then, GS was coated onto a glassy carbon electrode （GCE） surface by drop to fabricate a GS]GCE nanointerface. Subsequently, by using tetraethylorthosilicate sol as precursor, nanosilica was electrochemically deposited onto the GS]GCE surface to produce a nanocomposite film electrode （nanosilicaJGSJGCE）. Electrochemical behaviors of methyl parathion （MP） on the nanosilica/GS/GCE surface were investigated thoroughly. It was found that the nanosilicaJGS nanocomposites can improve the redox peak currents of MP significantly due to the synergetic effect. The oxidation peak current was linearly related to MP concentration in the range from 0.0005 μmol/L to 5.6 μmol/L. The detection limit was calculated to be 0.07 nmol/L （SJN = 3）. The developed method was used to determine MP in real samples. The recoveries were in the range from 95.4% to 104.2%, demonstrating satisfactory results.
基金supported by the National Natural Science Foundation of China (Nos. 41772251, 41702267 and 41521001)the State Key Laboratory of Coal Combustion, Huazhong University of Science and Technology (No. FSKLCCA1511)+1 种基金China Postdoctoral Science Foundation (No. 2017M612536)the “111” Project of the Ministry of Education of China
文摘The ligand-stabilized soluble Mn(Ⅲ) recognized as active intermediate can potentially mediate the attenuation of contaminants. In this study,the abiotic degradation behaviors of methyl parathion in the ligand stabilized Mn(Ⅲ)-sulfite system were investigated. The results showed that the yield of soluble Mn(Ⅲ) produced from the redox reaction of MnO2 and oxalic acid was dependent linearly on the dosage of Mn O2 and caused the decomposition of methyl parathion up to 50.1% in Mn(Ⅲ)-sulfite system after 30 minutes. The fitted pseudo-first-order reaction constants of methyl parathion degradation increased with the increasing of the amount of produced Mn(Ⅲ) but was not effected linearly by the addition of sulfite. Other ligands,including pyrophosphate and oxalic acid,acted as effective complexing agents to stabilize soluble Mn(Ⅲ),and exhibited competitive effect on methyl parathion degradation with sulfite. The formation of Mn(Ⅲ)-sulfite complexes is the critical step in the system to produce abundant reactive oxygen species identified as SO3·-to facilitate methyl parathion degradation. The hydrolysis and oxidation of methyl parathion were acknowledged as two primary transformation mechanisms in Mn(Ⅲ)-sulfite system. These findings indicate that naturally ligands-stabilized soluble Mn(Ⅲ) can be generated and could oxidatively decompose organophosphate pesticides such as methyl parathion.
基金the National Natural Science Foundation of China(No.21665017)the Open Funds of the State Key Laboratory of Chemo/Biosensing and Chemometrics of Hunan University(2019014).
文摘Organophosphorus pesticides have attracted extensive scientific concern due to their severe threats to food safety and human health.The study investigated the potential of hydroxypropyl-β-cyclodextrin(HPCD)to modulate the binding interactions of methyl parathion(MP)and its metabolite p-nitrophenol(PNP)with human serum albumin(HSA).Fluorescence quenching studies indicated that static quenching occurred both in the absence and presence of HPCD.The molecular interactions primarily involved hydrogen bonds and van der Waals forces during the binding process.Notably,the binding constants of both MP-HSA and PNP-HSA complexes were significantly reduced when HPCD was present(decreased about 44%and 79%,respectively).3D fluorescence and CD spectral analyses demonstrated that the involvement of HPCD inhibited the microenvironmental changes of residues and restored the initial alterations in the secondary structure of HSA.Molecular docking results indicated that HPCD incorporates MP/PNP into its hydrophobic cavity,forming a ternary complex that exhibited a more favorable binding energy compared to the binary systems.The findings elucidate how food-grade HPCD modulates pesticide-HSA interactions through encapsulation,enabling targeted interventions for pesticidecontaminated food matrices and providing new insights in food safety,medical detoxification and environmental remediation.
基金financially supported by the National Key Research and Development Program of China(2021YFA0716702,2023YFF0717100)the National Natural Science Foundation of China(22371086,22071074)+1 种基金Self-Determined Research Funds of CCNU from the colleges'basic research and operation of MOEsupported by Researchers Supporting Project number(RSPD2025R675),King Saud University,Riyadh,Saudi Arabia。
文摘Methyl parathion is a highly hazardous organophosphorus pesticide widely used in agriculture,and its environmental residues pose a significant threat to the ecosystem.Achieving highly efficient and selective adsorption removal is an important challenge.Inspired by the adsorption filtration function of the kidney by its hierarchical porous organ structure,we have fabricated a bioinspired hierarchical porous polymer(P5HPP)by introducing the intrinsic molecular cavity of pillar[5]arene to porous organic polymers using a photoclick reaction.P5HPP possesses hierarchical nanoporous structures,abundant adsorption sites,and remarkable host-vip interactions.It can achieve the highly efficient and selective adsorption of methyl parathion in various pesticide solutions by specific host-vip binding(π-πinteractions)between pillar[5]arene and methyl parathion.The adsorption efficiency of methyl parathion(10-4M)can achieve nearly 99.1%by 0.5 mg mL-1P5HPP,and the maximum adsorption capacity reaches up to 148.58 mg g^(-1),which is far superior to other reported pesticide adsorbents.In practical applications,P5HPP is used as the packing material of the adsorption columns to efficiently and rapidly remove 98.6%of methyl parathion(10-4M)from water and alleviate pesticide poison for aquatic organisms.Because of its excellent adsorption performance,good stability,easy recyclability,and low cost,P5HPP is a superb adsorbent for pesticide pollutant treatment with great potential for application in water resource protection.
基金Project supported by Czech Science Foundation(P106/12/1116)
文摘Cerium dioxide was used for the first time as reactive sorbent for the degradation of the organophosphate pesticides para-thion methyl, chlorpyrifos, dichlofenthion, fenchlorphos, and prothiofos, as well as of some chemical warfare agents-nerve gases soman and O-ethyl S-[2-（diisopropylamino） ethyl] methylphosphonothioate （VX）. CeO2 specimens were prepared by calcination of basic cerous carbonate obtained by precipitation from an aqueous solution. The CeO2 samples containing certain amounts （1 wt.%-5 wt.%） of the neighboring lanthanides （La, Pr, Nd） were prepared in a similar way from pure lanthanide salts. It was shown that ceria accelerated markedly the decomposition of parathion methyl causing the cleavage of the P-O-aryl bond in the pesticide molecule. A similar reaction mechanism was proposed for the degradation of other organophosphate pesticides and nerve agents. The degradation times （reaction half-times） were in an order of minutes in the presence of CeO2, compared to hours or days under common environ-mental conditions. The reaction in suitable organic solvents allowed conversions of about 90%for parathion methyl loading of 20 mg pesticide/g CeO2 within 2 h with a reactant half-life in the order of 0.1 min. The key parameter governing the degradation efficiency of CeO2 was the temperature during calcination. At optimum calcination temperature （about 773.15 K）, the produced ceria retained a sufficiently high surface area, and attained an optimum degree of crystallinity （related to a number of crystal defects, and thus poten-tial reactive sites）. The presence of other lanthanides somewhat decreased the reaction rate, but this effect was not detrimental and permitted the possible use of chemically impure ceria as a reactive sorbent. A fast organophosphate degradation was demonstrated not only in non-polar solvents （such as heptane）, but also in polar aprotic solvents （acetonitrile, acetone） that are miscible with water. This opens new possibilities for designing more versatile decontamination strategies. The cleavage of phosphate ester bonds is of a great importance not only for the degradation of dangerous chemicals （chemical weapons, pesticides）, but also for interactions of ceria （es-pecially the nano-sized one） in biologically relevant systems.
文摘The mutagenic and carcinogenic effects of parathion-methyl were examined by bacterial reverse mutation assay and a long-term experiment with wistar rats. The potential mutagenic effect of parathion-methyl in Salmonella typhimurium TA100 bacterial cells was observed without rat liver S9 metabolic activation. Parathion-methyl was further investigated for pathological changes in rat pancreas and liver. The long-term rat experiments showed that parathion-methyl exposure for 3 months can cause pathological changes in rat pancreases acinar cells and pancreatic hepatocytes. Atypical acinar cell focuses （AACF） were determined in the liver and pancreas of the rats. The results from short-term Ames test and long-term rat experiments suggested that parathion-methyl would be potential carcinogenic.
文摘A study on the sorption of monocrotophos and parathion methyl on Yellow River's sediments was performed. The influence of some factors, such as pH value and ionic strength, on the sorption was investigated and first order kinetics mode for the sorption of monocrophos was shown. Freundlich isotherm was suggested as the most appropriate type for monocrophos and parathion methyl. But the sorption isotherms of monocrotophos and parathion methyl are also in conformity with Langmuir equation. Both partition and adsorption occur to the sorption of monocrophos to Yellow River's sediments, but partition is the predominant for that of parathion methyl.
基金supported the Fundamental Research Funds for the Central Universities(JUSRP622008).
文摘The metal-organic framework(MOF)ZIF-8 has found extensive application in the medicinal and agricultural fields.This study aimed to immobilize the methyl parathion hydrolase(MPH)enzyme from Azohydromonas australica(Azau-MPH)within ZIF-8 using an in-situ synthesis method.Interestingly,the immobilized Azau-MPH(abbreviated as Azau-MPH@ZIF-8)exhibited enhanced thermostability and tolerability towards organic solvents compared to the free enzyme.Moreover,Azau-MPH@ZIF-8 retained more than 50%of its initial activity after six cycles,demonstrating its desirable reusability.To further improve the recyclability and catalytic activity of the immobilized enzyme,we introduced magnetic Fe_(3)O_(4) nanoparticles into the immobilization carrier.Notably,the resulting Azau-MPH@(Fe_(3)O_(4)@ZIF-8)biocomposite displayed superior catalytic activity and stability when compared to Azau-MPH@ZIF-8.In practical applications,we employed Azau-MPH@ZIF-8 for cyclic degradation of methyl parathion(20 mg/L)in cherries,and it exhibited exceptional degradation ability.Hence,both Azau-MPH@ZIF-8 and Azau-MPH@(Fe3 O4@ZIF-8)hold great promise as valuable biodegradation tools against MP contamination.
