Superior degradation of organic contaminants by the UV/CoFe2O4/PI system: Kinetics, pathways, mechanisms and DFT calculation

There is currently plenty of emphasis on measures to handle the water pollution spurred on by the misuse of antibiotics. Given its exceptional degradation accomplishment, periodate (PI), a steady solid oxidant, has promising future applications in the breakdown of antibiotics. In this research, PI was activated with UV/CoFe2O4 (CFO) for the first time in an attempt to eliminate oxytetracycline (OTC). The UV/CFO/PI system eliminated 30 mg∙L-1 OTC with a removal effectiveness of almost 100 % in 12 min (OTC 30 mg∙L-1, CFO 0.2 g∙L-1, PI 2 mM, pH 5.5). In addition, the ferromagnetism of the CFO assisted to the system's remarkable cycling achievement, with 85.9 % of the OTC still removed after ten cycles. Various organic contaminants, which include reactive blue KN-R (KN-R), ciprofloxacin (CIP), chlortetracycline (CTC), and levofloxacin (LVX), further demonstrated the UV/CFO/PI system to be useful for degrading. The primary active substances for OTC elimination were revealed and recognized through scavenging experiments and EPR analysis as h+, •IO4, •IO3, 1O2, •OH, and •O2–. Simultaneously, redox cycles of Fe(III)/Fe(II) and Co(III)/Co(II) were also observed by XPS test to hasten OTC deterioration. It appeared that this system may be a green approach for antibiotic elimination by investigating the degradation route of OTC and the influence it has on the surroundings employing FuKui functions, LC-MS, and toxicological analysis software (T.E.S.T.), respectively. Additionally, we observed that the CFO (2 2 2) crystal surface has the best adsorption impact on PI by computing Eads from DFT.