Amoxicillin degradation with electro-persulfate combined with H2O2 from aqueous solution using response surface methodology

Background: Discharging wastewaters containing antibiotic into the environment causes some adverse effects on the human health and other organisms. The present study investigated the efficiency of electropersulfate combined with hydrogen peroxide (H2O2) process as a chemical oxidation in amoxicillin (AMX) degradation. Methods: Optimization of the significant operational independent variables was explored for removal of AMX. Central composite design (CCD) was employed as a statistical tool for experimental design. High-performance liquid chromatography (HPLC) was used for measuring AMX concentration. The most effective factors of the electro-persulfate and H2O2 on the removal efficiency of AMX such as initial concentration of AMX, initial pH, PS/H2O2 molar ratio, and the current density were measured. Results: The optimum conditions for electro-persulfate removal efficiency of AMX to reach the degradation efficiency of higher than 95.28 ± 2.64% at reaction time of 60 minutes were obtained at pH = 4.23, AMX concentration = 31.9 mmol/L, current density = 39 mA/cm2, and PS/H2O2 molar ratio = 0.82. AMX degradation was satisfactorily predicted by the quadratic model with high possibility and confidence level of 95%. The quadratic model had high regression coefficients (R2 = 0.9964 and R2 adj = 0.9926), which was totally acceptable. The removal efficiency of AMX reduced from 87.3 ± 6.1 to 25.9 ± 9 as pH increased from 5.5 to 7. Conclusion: According to the results, the electro-persulfate and H2O2 process can be suggested as the most effective, high efficient, and in-situ chemical oxidation for degradation of AMX.