FeC2O4•2H2O enables sustainable conversion of hydrogen peroxide to hydroxyl radical for promoted mineralization and detoxification of sulfadimidine

Safe treatment of antibiotics requires efficient removal of both antibiotics and their degraded intermediates. In this study, we demonstrate that FeC 2 O 4 •2H 2 O enables the more sustainable conversion of H 2 O 2 to • OH than commonly used FeSO 4 •7H 2 O, promoting the detoxification of a typical antibiotic sulfadimidine. It was found that the FeC 2 O 4 /H 2 O 2 system could completely degrade 250 mg L −1 of sulfadimidine within 40 min at pH 3.0, along with decreasing the contents of chemical oxygen demand and total organic carbon by 295.0 and 33.5 mg L −1 , respectively, more efficient than those in a classical Fenton system (FeSO 4 /H 2 O 2 ). Analysis of sulfadimidine degraded intermediates and toxicity evaluation suggested that the FeC 2 O 4 /H 2 O 2 treatment could more effectively decrease the overall toxicity of the sulfadimidine solution than the FeSO 4 /H 2 O 2 counterpart. The sustainability of FeC 2 O 4 •2H 2 O in H 2 O 2 conversion to • OH was attributed to its controlled release of Fe 2+ into the solution to prevent the quenching of • OH by excessive Fe 2+ , as well as the simultaneous release of C 2 O 4 2− to complex with Fe 2+ and Fe 3+ , which could inhibit iron sludge formation and accelerate Fe 3+ /Fe 2+ redox cycle. This study provides a promising Fenton system for the safe treatment of antibiotics and sheds light on the potential of FeC 2 O 4 •2H 2 O in environmental remediation.