Study On Degradation Of Trace Organochlorine Pesticides In Water By Three-dimensional Electrode Reactor

Organic micro-pollutants in water source water threaten the safety of human drinking water.Organochlorine pesticides are an important class of organic micro-pollutants in surface waters.They are characterized by ecological hazards,difficult biodegradation,long half-life,and easy bioconcentration.Conventional water treatment The process is difficult to remove effectively.The three-dimensional electrode method is an advanced oxidation technology with strong ability to oxidize and degrade organic matter,no secondary pollution and low energy consumption.It is a technology suitable for degrading organic micro-pollutants and removing their toxicity,and has a wide range of treatments for organic pollutants.The prospect of use.In this paper,Triazolone and butachlor were used as the target pollutants,and the target pollutants were degraded by self-made three-dimensional electrode reactor.The experimental study on the removal of triazolone and butachlor by three-dimensional electrode electrochemical oxidation method was carried out.The results are as follows:?1?Three-dimensional electrode reactor was constructed by using the base electrode as anode,stainless steel as cathode and granular activated carbon as particle electrode.The target pollutant removal rate and energy consumption were used as indicators to compare the three-dimensional electrode method,two-dimensional electrode method and adsorption method to triazole.The treatment effect of ketone and butachlor showed that the removal effect and energy consumption of the two pollutants were better than the two-dimensional electrode method;the three-dimensional electrode method and the two-dimensional electrode method were far away from the target pollutants.Far higher than the adsorption method,the electrochemical oxidation method can efficiently degrade the target pollutants;the activated carbon particles are in the adsorption-desorption-adsorption cycle when running in the three-dimensional electrode,and it is difficult to reach the saturated state,and the three-dimensional electrode system can realize the cleaning of the activated carbon.The three-dimensional electrode method is an advanced oxidation technology capable of effectively degrading trace organochlorine pesticide triadimefon and butachlor in water.?2?In the system of electrochemical oxidation of triazolone and butachlor in three-dimensional electrodes,different electrolytes have a great influence on the removal of pollutants.In different electrolyte systems,the change of pH before and after the reaction is indirectly presumed to occur in the sodium chloride electrolyte system.Chlorine reaction produces active chlorine such as hypochlorous acid.Active chlorine can degrade triadimefon,but active chlorine can not degrade butachlor.Anodic chlorine is a beneficial reaction for three-dimensional electrode treatment of triazolone.In the case of amines,it is a side reaction,resulting in a large difference in the degradation of contaminants in two different electrolyte systems.?3?Electrochemical oxidation of triazolone and butachlor was optimized by three-dimensional electrode.The single factor method was used to optimize the effects of electrolytes,current density,initial concentration of pollutants,initial pH and other factors on the degradation of pollutants in the three-dimensional electrode system.The optimal experimental conditions were obtained.The optimum degradation conditions for the 200?g/L triadimefon were:support electrolyte Sodium chloride injection?addition amount is 1g/L?,current density is 8mA·cm^-2,activated carbon dosage 4g/L,initial pH value of 11,after10min reaction,triazolone removal rate is as high as 99.95%;200?g The optimal degradation conditions of/L butachlor are:support electrolyte is sodium sulfate?addition amount is 3.55g/L?,current density is 50mA·cm^-2,activated carbon dosage is 4g/L,initial pH is 8,initial temperature is 25,The removal rate of butachlor was 85%after 25 minutes of reaction.?4?The mechanism of reaction is explored.The presence of hydroxyl radicals was indirectly determined by the addition of a hydroxyl radical quencher,tert-butanol,and the pH of the reaction solution changed.It is speculated that active chlorine such as hypochlorite exists.The three-dimensional electrode system supports three mechanisms of direct electrochemical oxidation,hydroxyl radical oxidation,and active chlorine oxidation of triazolone in the process of degrading triazolone.The three-dimensional electrode electricity is supported by sodium sulfate as supporting electrolyte.Chemical oxidation of butachlor is accomplished by a combination of direct oxidation of the anode and indirect electrochemical oxidation based on hydroxyl radicals.?5?Intermediate product analysis.With the aid of LC-MS,it is speculated that there may be 3,3-dimethyl-2-butanone formation during the degradation of triazolone,p-chlorophenol?m/z=129?,triazole?m/?z=70),the degradation of butachlor may be thorough,and no intermediates were detected.