Efficient degradation of tetracycline in water by a Mn-doped FeOCl-functionalized carbon catalytic membrane

Constructing high-performance catalytic membrane materials for addressing antibiotic wastewater pollution is of great significance. In this work, a Mn-doped FeOCl functionalized carbon catalytic membrane (CM-FM) was successfully fabricated by immobilizing a Mn-doped FeOCl catalyst onto a low-cost coal-based porous carbon membrane through a straightforward co-impregnation and calcination approach. A systematic investigation was conducted on the effects of key preparation parameters, including the doping ratio and precursor concentration. Results demonstrated that the CM-FM prepared with a Mn:Fe doping ratio of 1:8 and a precursor concentration of 7 wt% exhibited optimal catalytic performance. Under these conditions, the H₂O₂ decomposition efficiency reached 83.5 %, significantly higher than that of the pristine CM (14 %) and CM-FeOCl (78 %). Moreover, the removal efficiencies of tetracycline (TC) and total organic carbon (TOC) were considerably enhanced, achieving 97 % and 48.5 %, respectively. The influence of operational parameters on the catalytic degradation of TC by CM-FM was also examined, confirming its good applicability across different water matrices. Mechanistic studies revealed that Mn doping promotes the catalytic activation of H₂O₂ by the membrane, leading to increased generation of hydroxyl radicals (·OH) and singlet oxygen ( 1 O₂). Based on HPLC-MS analysis, potential TC degradation pathways during the catalytic process were proposed. Additionally, ECOSAR software was employed to evaluate changes in the toxicity of degradation products in the permeate solution after catalytic treatment, providing an assessment of the environmental impact reduction.