Preparation Of Oyster Shell Carrier Ozone Catalyst And Catalytic Oxidation Of Ciprofloxacin

In recent years,with the fast development of aquaculture industry and animal husbandry,the usage range and amount of antibiotics which is used for animal medicines has been growing,even existing the abuse of antibiotics.Catalytic ozonation is an advanced oxidation technology which has the advantages of strong oxidation,rapidly reaction and simple devices that has been widely used in the treatment of antibiotics wastewater.In this paper,a kind of cheap biocomposites,oyster shell,is chosen as the support of catalytic ozonation catalyst,using impregnation method to prepare the catalyst successfully.And this catalyst is used for the degradation of ciprofloxacin?CIP?.In this study,we optimize different catalyst preparation methods,such as the concentration of immersion solution,calcination temperature and calcination time,to get the best catalytic performance.As for the results,when the concentration of immersion solution is 0.3 mol·L^-1,calcination temperature is 500?,and calcination time is 3 h,the degradation of CIP achieves the best catalytic performance.In order to get the morphology,structure,elementary composition of the catalyst,we adopt SEM,EDX,XRD,BET and XPS methods to characterize it and get the characteristics of the catalyst's morphology,structure and elementary compositon successfully.In the degradation process,we optimize different reaction conditions to get the best degradation efficiency.According to the results,initial concentration of the solution,dosage of catalyst and the reaction time will influence the removal efficiency of CIP.When the initial concentration of CIP is 10 mg·L^-1,catalyst dosage is 2.0 g,and reaction time is 50 min,the degradation efficiency of CIP reaches maximum.The removal efficiency is 98.84%and mineralization efficiency is 62.33%,these results are much better than the sole ozonation process.In order to clear the reaction mechanism,compare the differences between direct ozonation and indirect ozonation by radical scavenger,the radical scavenger,NaHSO₃,is adopted to the reaction system,results show that,the degradation efficiency of CIP in catalytic ozonation process is inhibited severely.So it can be concluded that the indirect oxidaiton of hydroxyl radical plays an important role in the degradation of CIP.We use the HPLC-MS/MS to detect degradation products of CIP,7 kinds of product were detected,and we propose the possible degradation pathway preliminarily.The oxidation of piperazine is the main reaction process in this study.In order to test the stability of the catalyst,we use the catalyst for four times and measure the degradatoion efficiency of CIP,which shows that,the catalyst can always remain high catalytic performance and the structure don't change significantly,after using it for four times.The results show that the catalyst has good stability.The low-cost catalyst we prepared in this experiment shows stable and efficient catalytic performance for the degradation of CIP.Therefore,it has a good practical value in the removal of refractory organic pollutants.