Preparation of MnFe2O4-CR and its activation performance on peroxymonosulfate for tetracycline hydrochloride degradation
Supported composite catalyst MnFe2O4-CR was prepared from loading MnFe2O4 onto biomass gasification carbon residue(CR)by hydrothermal method,characterized by SEM,XRD,XPS,BET and VSM,and then utilized to activate peroxymonosulfate(PMS)for tetracycline hydrochloride(TC)degradation.The effects of different reaction systems,mass ratio of MnFe2O4 to CR,PMS dosage,catalyst dosage,temperature,pH,anions(HCO3-,H2PO4-,Cl-,NO3-)and humic acid(HA)on degradation of TC in MnFe2O4-CR/PMS system were investigated.The stability and recyclability of MnFe2O4-CR as well as the TC degradation mechanism were further analyzed.The MnFe2O4-CR prepared with a mass ratio of MnFe2O4 to CR of 1∶2 exhibited good catalysis performance,with a degradation rate of TC in 100 mL TC solution with natural pH and with a mass concentration of 50 mg/L reaching 91.32%under the conditions of temperature 30℃,30 mg MnFe2O4-CR,40 mg PMS and 90 min.The MnFe2O4-CR could be recovered by its magnetic properties.After 5 cycles,the TC degradation rate in MnFe2O4-CR/PMS system could still reach 82.90%,demonstrating the good stability and reusability of MnFe2O4-CR.It was also found that SO4-·,·OH,singlet oxygen(1O2)and O2-·were the main reactive oxygen species for TC degradation in MnFe2O4-CR/PMS system,and the corresponding catalytic degradation mechanism was discussed.