Experimental Study On Degradation Of Pyrrithione By Modified Coke Catalytic Oxidation-biochemical Method

Pyraclostrobine?Pyraclostrobine?is a pyrazole structure containing methacrylic acid ester fungicide,because of its toxicity to the human body and the environment is small,so pyrazole bacteria as a new broad-spectrum sterilization In the agricultural production in the amount of continuous increase,this will inevitably lead to environmental pollution,pyrazole bacteria ester degradation research is of great significance.In recent years,there have been many studies on the degradation of pesticide contaminants at home and abroad.The main research is biodegradation and pHotochemical degradation.At present,all kinds of catalysts are modified to catalyze the degradation of wastewater by catalytic oxidation.The catalytic activity of the modified coke was studied by catalytic oxidation of the modified pyrocarbamate with modified coke as the catalyst.The catalytic activity of the modified pyrocarbamate was studied.In the environment to provide a basis for degradation.At the same time,the biodegradation of catalyzed oxidative degradation was studied and the toxicity of the final degradation products was studied.The specific research contents and results are as follows:?1?Preparation of modified coke catalyst with HNO₃modification and coke loading metal modification and its characterization.The preparation conditions of modified coke directly affected the effect of catalytic oxidation on degradation of pyrazole.In general,the effect of modified iron and manganese on the pyrolysis of Pyrazole is more obvious than that of nitric acid.The best effect is that the catalytic oxidation of 1:9Fe-Mn-Coke at 400?reaches 82.5%,which proves the feasibility of catalytic oxidation of modified coke to degrade pyrazole.The thermogravimetric and related SEM images of Coke-0and 1:9Fe-Mn-Coke can be proved to be successful in the preparation of nitric acid and supported metal modified coke.1:9Fe-Mn-Coke sample has a BET of 21.521 m²/g and a carboxyl group of 1.60 mmol/g,which is substantially the same as the carboxyl content of 30%N-Coke,but the total number of acid groups is only 1.97 mmol/g,The total amount of acid groups after coke loading metal modification is lower,but its carboxyl content is still high,and the surface catalytic activity of supported metal modified coke is higher.?2?Catalytic Oxidation of Modified Coke.The degradation rate of pyrithione was increased with the increase of H₂O₂ concentration when the concentration of H₂O₂ was lower than 150 mg/L,and the degradation rate of the solution was increased with the increase of H₂O₂concentration.And the removal rate of pyroxazole was gradually increased with the increase of the amount of modified coke.When the amount of modified coke was less than 5.00g/L,the degradation rate of pyrazole,Thus indicating that within a certain range,modified coke promoted the degradation of pyrazole bacteria ester.?3?Response surface analysis was used to determine the optimum degradation conditions of pyrazole bacteria ester.The optimum conditions were pH4.16,H₂O₂152.49mg/L,1:9Fe-Mn-Coke dosage1.89g/L,corresponding pyrazole The degradation rate of carbendazim was 99.12%.?4?Biodegradation of Pyrrithione by Catalytic Oxidation.From the LC-MS to the ion current map and the relevant degradation product data,combined with the relevant literature research,pyrazole bacteria ester catalytic oxidation degradation process mainly for the catalytic oxidation system to produce a large number of hydroxyl radicals,hydroxyl radical attack pyrazole Ether ester structure of the methyl ester bond,ether and CN bond,resulting in aromatic ring hydroxylation,double bond position on the oxidation reaction.?5?Biochemical toxicological effects The experimental results show that the effect of modified coke on the degradation of pyrithione is the greatest effect on the biochemical system when the modified coke is catalyzed by oxidative degradation of pyrazole bacteria for 10 min Value,biochemical system on the influent COD removal rate is only about 20%,combined with the growth of aquatic plants analysis,dripping Guanyin and Eichhornia crassipes leaves short time quickly yellow,indicating that pyrazole bacteria in the catalytic The toxicity of the intermediate product at the initial stage of oxidation is more potent than that of pyrazole.?6?The degradation of pyrithione was lower than that of Eichhornia crassipes.The results showed that the adaptability of Eichhornia crassipes to pyrazole The The results showed that with the increase of the running time of the ETS biochemical system,the COD and ammonia nitrogen of the ETS biochemical system decreased gradually,and the decrease trend was related to the plant height of the aquatic plants.,The fresh weight increase trend is the same,in the reaction 24h after the ammonia nitrogen is only 5.4mg/L,48h after the reaction COD value is only 20mg/L.