Persulfate Catalytic Degradation Of Oilfield Pollutants At Low Temperature

In this paper,in order to solve the problems of easy loss of metal ions in the traditional Fenton system,stricter reaction conditions and poor stability,different types of metal catalysts are prepared,and the heterogeneous Fenton system is constructed by using the prepared catalysts and sodium persulfate to make it both With the functions of strong oxidation and high efficiency of Fenton method,it can improve the main defects of the above-mentioned traditional Fenton technology.1.In the experiment,the nanometer zero-valent metal catalyst was prepared by reduction,and the nanometer zero-valent metal copper catalyst with high catalytic activity was selected to catalyze the degradation of oilfield pollutants.By comparing SEM,XRD,physical adsorption analysis and viscosity degradation chart,it was confirmed that the prepared heterogeneous catalyst had good catalytic performance.At a temperature of 45 ° C,a pH of 11,an oxidant sodium persulfate dosage of 10%,a catalyst dosage of 10%,after 4 hours of reaction,the COD removal rate of hydroxypropyl guar gum and other oilfield polymers can be 85%.2.In the experiment,using the good ion exchange performance of bentonite,bentonite supported zero-valent metal catalyst and bentonite supported divalent metal catalyst were prepared by reduction and impregnation methods.After screening,supported catalysts with high catalytic activity,bentonite supported zero-valent metal copper catalyst and bentonite supported divalent metal copper catalyst,were obtained.This series of catalysts is used to catalyze and degrade several common polymers in oil fields.By comparing SEM,XRD,XPS,physical adsorption analysis and viscosity degradation chart,it was confirmed that the prepared heterogeneous catalyst had good catalytic performance.At a temperature of 45 ° C,a pH of 10,an oxidant sodium persulfate dosage of 10%,a catalyst dosage of 10%,after 4 hours of reaction,the COD removal rate of hydroxypropyl guar gum and other oilfield polymers can be achieved 90%.3.In the experiment,the regular layered structure of Mg-Al hydrotalcite was used as a carrier to support different metals,so as to prepare a catalyst with high dispersibility and achieve the immobilization of metal ions.After successfully preparing Mg-Al hydrotalcite by co-precipitation method,a hydrotalcite supported metal catalyst was prepared by impregnation method.Screening to obtain hydrotalcite supported metal copper catalyst with high catalytic activity.This series of catalysts is used to catalyze and degrade several common polymers in oil fields.By comparing SEM,XRD,physical adsorption analysis and viscosity degradation chart,it was confirmed that the prepared heterogeneous catalyst had good catalytic performance.At 45 ° C,pH 12,the oxidant sodium persulfate dosage is 20%,the catalyst dosage is 2%,after 4 hours of reaction,the COD removal rate of hydroxypropyl guar gum and other oilfield polymers can reach 88%.4.In the experiment,by preparing MgAlCu ternary hydrotalcite compound and using it as a precursor,a composite metal hydroxide catalyst with large specific surface area,uniform distribution of rare earth elements,and good coordination between various metal ions can be obtained after roasting.Screening to obtain a composite metal hydroxide catalyst with a high catalytic activity and a calcination temperature of 500 ° C.This series of catalysts is used to catalyze and degrade several common polymers in oil fields.By comparing SEM,XRD and viscosity degradation chart,it was confirmed that the prepared heterogeneous catalyst had good catalytic performance.At a temperature of 45 ° C,a pH of 12,an oxidant sodium persulfate dosage of 20%,and a catalyst dosage of 10%,the COD removal rate of hydroxypropyl guar gum and other oilfield polymers can be reached after 4 hours of reaction 90%.Based on the traditional Fenton system,this article prepared heterogeneous catalysts to catalyze the degradation of oilfield pollutants,which can be carried out under slightly alkaline conditions and improved the traditional Fenton system.And through repeated experiments,it is determined that the prepared catalyst can be used repeatedly and has certain chemical stability.