Study On Degradation Of Bisphenol A In Water By CuO Activated Peroxydisulfate

Bisphenol A（BPA）,as a typical endocrine disruptor（EDCs）,could result in endocrine disrupting effects,developmental disorders,and malignant tumors.As an important chemical raw material,BPA is widely used.A large amount of BPA exists in industrial wastewater and is also frequently detected in the natural environment.Therefore,the treatment of wastewater containing BPA has attracted extensive attention.Advanced oxidation technology（AOPs）based on peroxydisulfate（PDS）is high efficiency,energy saving and green.It is suitable for the treatment of toxic and harmful refractory organics.In this paper,a system of CuO activated PDS was constructed to degrade BPA in water.In order to establish an efficient degradation system,three kinds of CuO with different morphologies were prepared.Their catalytic activities were tested respectively.Finally,the CuO with the best catalytic performance was selected as CuO-S.The optimal experimental conditions of CuO-S/PDS system were as follow:BPA=10 mg/L,PDS=0.5 mmol/L,CuO-S=0.06 g/L,T=25℃.Under this condition,96%BPA was degrade.The mineralization of BPA was 82%.Only 14.5%of PDS was consumed in the process.Combined with the physical and chemical characterization of the CuO.Larger specific surface area and more surface hydroxyl groups contribute to better catalytic activity of CuO-S.In order to clarify the mechanism of BPA degradation in CuO-S/PDS system,the generation process of active species in the system was analyzed.Two differtent kinds of Cu²⁺on the surface of CuO-S connected with PDS formed a complex Cu₂SO₅.Cu₂SO₅contained an electron-deficient center([Cu（Ⅲ）]_EDC),which showed the properties of Cu（Ⅲ）.It was the active species in the CuO-S/PDS system.It could either oxidize the contaminant BPA directly,or capture electrons from water to form·OH as an oxidant.It was a typical non-free radical reaction path.The process did not rely on the decomposition of PDS to produce free radicals.The special structure of Cu₂SO₅anchors PDS,which was the reason for the low consumption of PDS in the reaction.After receiving electrons,an electron-rich center([Cu（Ⅱ）]_ERC)was generated.·OH is a powerful oxidant,which can reduce the electron-rich center into the electron-deficient center by accepting electrons.Thus,the reaction could keet going.In order to fully understand the environmental application scope of the system,the effects of HA,Cl^-,HCO₃^-and CO₃^2-in water on the degradation of BPA and the reasons were investigated.The adsorption complexation and reduction of HA on CuO-S affected the formation of active substances and inhibit the degradation of BPA.Low concentration of Cl^-inhibited the degradation,while the high concentration promoted the degradation significantly.Low concentration of Cl^-consumed part of·OH in the system.High concentration of Cl^-reacted with Cu²⁺on CuO-S surface to form Cu（Ⅱ）-chlorine complex.Cu（Ⅱ）-chlorine complex was more active than Cu（Ⅱ）.After reacted with PDS,more active substance Cu（Ⅲ）-chlorine complex produced in the system.Low concentration of HCO₃^-and CO₃^2-in the system slightly promote the degradation,while high concentration inhibited the degradation.At low concentration,new active substance O₂^·-was formed,showing a slight promotion effect.At high concentration,HCO₃^-and CO₃^2-complexed with Cu²⁺on the surface of CuO-S.The process reduced the generation of active species and significantly inhibited the degradation of BPA.