Degradation Of Sulfadiazine By Activation Of Sodium Persulfate With Hollow Spheres Of Iron-copper Composite Oxides

In recent years,the abuse of antibiotics has led to the widespread presence of organic pollutants represented by sulfa antibiotics in natural water bodies.Based on sulfate radicals?·SO₄^-?persulfate advanced oxidation technologies because of the high has good antioxidant stability,REDOX potential,good water solubility,the advantages of wide scope of application,widely used in organic wastewater treatment,and senior persulfate oxidation process is the key to finding efficient activation of persulfate catalyst or method.The transition metal activation method has attracted much attention due to its excellent activation performance and easy recovery characteristics.In this paper,the surface characteristics of Fe@Cu hollow sphere?FCHS?and the performance of activated PS degradation of sulfadiazine?SD?were investigated.The optimal reaction conditions of FCHS/PS system were determined by condition optimization experiments.The reaction mechanism of FCHS activated PS and the degradation pathway of SD are presumed.The main research contents are as follows:?1?Cu₂O was prepared as a precursor by low temperature liquid phase method.FCHS was prepared by adding Fe²⁺to the surface of Cu₂O.The effect of degrading SD by FCHS/PS system was investigated.Under the condition of initial pH value of 7.0,FCHS dosage of 0.2g·L^-1 and PS dosage of 2mmol·L^-1,the degradation rate of SD of5mg·L^-1 reached 93.54%at 210min,higher than 80.79%,24.95%,and 13.90%of CHS/PS,FHS/PS,and CFHS/PS systems.The surface characteristics of the catalyst were analyzed by means of SEM-EDS-Maping,TEM,XPS,XRD,FTIR and other means for FCHS.?2?The effect of different influencing factors on SD degradation in FCHS/PS system was studied.It was found that the SD degradation rate increased with the increase of FCHS dosage.When PS dosage increased,SD degradation first increased and then decreased.When the initial pH value was weakly alkaline,it was beneficial to the degradation of SD.while CO₃^2-and PO₄^3-ions all inhibited the degradation rate of SD.The degradation rate of SD decreased with the increase of CO₃^2-and PO₄^3-concentration;the degradation kinetics of SD by FCHS/PS accorded with the second-order kinetics.?3?According to the free radical quenching experiment and epr analysis,the free radical that plays a leading role in the degradation of SD in FCHS/PS system is·SO₄^-.and FCHS in the process of activating PS to produce·SO₄^-,part·SO₄^-conversion produces·OH with higher redox potential,·SO₄^-and·OH react with SD to achieve degradation of SD.Four cycles of FCHS were used to study its stability,and it was found that the SD degradation rate could reach 89.54%after the fourth cycle,indicating that FCHS has good cycle performance and is a highly efficient and reliable catalyst for SD degradation.?4?Through the SD degradation spectrum obtained by LCMS-IT-TOF analysis,10intermediate products in the degradation process were analyzed,and four pathways of SD degradation were speculated.