Enhanced degradation of chloramphenicol wastewater in a submerged rotating packed bed reactor: O3/PDS synergistic oxidation

Abstract

The large molecular weight and high hydrophilicity of chloramphenicol (CAP) residuals in wastewater led to severe degradation difficulty, which propelled the development of new wastewater degradation processes and reactors based on process intensification. This study enhanced the CAP degradation by ozone/peroxydisulfate (PDS) advanced oxidation process in a submerged rotating packed bed (SRPB) reactor. Compared the usage of different oxidants, it was indicated that the combination of O₃ and PDS exhibited a higher degradation efficiency than ozone and PDS alone. The more desired degradation efficiency could be achieved at the operating conditions of ascending PDS concentration, SRPB rotational speed, ozone concentration, reduced initial CAP concentration, and the water qualities of ascended pH, lower Cl⁻ and initial CO₃^2–concentrations. Under the optimized conditions of C_CAP = 20 mg·L⁻¹, C_O3 = 30 mg·L⁻¹, C_PDS = 100 mg·L⁻¹, and N = 400 r·min⁻¹, and water qualities of pH = 10, the maximum chloramphenicol degradation efficiency of 97% and kinetic constant of 0.23 min⁻¹ were achieved after treating 16 min. A comparison of the results with previously reported advanced oxidation processes of CAP indicated that the enhanced O₃/PDS advanced oxidation system using the SRPB can significantly improve the degradation efficiency of CAP.