Millisecond-scale removal of ciprofloxacin hydrochloride using self-assembled nanolayered CoFe catalytic membrane

Advanced oxidation processes are promising strategies for treating antibiotic-containing wastewater. However, poor anti-interference ability, inherent catalyst limitations, and “low-concentration barrier” (at concentrations of <20 mg L −1 ) restrict their applications. This study developed a CoFe layered double hydroxide (CoFe-LDH) membrane (CoFe-LDHm) for removing low-concentration ciprofloxacin hydrochloride (CIP·HCl·H 2 O). A CoFe-LDHm/peroxymonosulfate (PMS) system was developed, which exhibited exceptional catalytic performance with high stability for 100 h, achieving a maximum CIP·HCl·H 2 O removal efficiency (RE) of 96 % with an ultrashort retention time of 3.6 ms and a first-order rate constant of 1.61 ms −1 . The CoFe-LDHm/PMS system demonstrated strong anti-interference capability, maintaining a CIP·HCl·H 2 O RE of ≥88 % across a pH range of 4–8 and in complex water matrices. The CoFe-LDHm/PMS system also efficiently removed other recalcitrant micropollutants, including enrofloxacin, ranitidine, sulfamethoxazole, methyl orange, and bisphenol A, with RE values of ≥92 %. Mechanistic studies revealed that sulfate and hydroxyl radicals dominated CIP·HCl·H 2 O degradation, which was facilitated by the redox cycling of Co 2+ /Co 3+ and Fe 2+ /Fe 3+ . Density functional theory calculations further elucidated PMS adsorption and activation pathways on the CoFe-LDH surface. Toxicity assessments confirmed reduced ecological risks of associated intermediates. Life cycle assessment revealed that the CoFe-LDHm/PMS system represents an environmentally favorable wastewater treatment technology. This study advances the design of nanocatalytic membranes for the sustainable treatment of recalcitrant pharmaceutical contaminants.