Single-atom cobalt anchored biochar/PVDF membrane for antibiotic removal via coupling membrane filtration and sulfate-based advanced oxidation processes.

Currently, the treatment of antibiotic-contaminated wastewater remains a serious challenge. In this study, a novel catalytic membrane, PVDF-CG@5%Co, combining polyvinylidene fluoride (PVDF), coffee grounds derived biochar (CG), and single-atom cobalt was developed for the effective removal of antibiotics from wastewater. The catalytic membranes were fabricated by phase inversion method, integrating sulfate radical-based advanced oxidation processes (SR-AOPs) with membrane filtration to address the limitations of traditional treatment methods. CG acted as the "bridging structure" which provides active sites for stable loading of single-atom catalysts (SACs) and also forms a strong interfacial bond with PVDF. The PVDF-CG@5%Co membrane exhibited excellent performance in tetracycline (TC) removal. Under optimized conditions (applied pressure 1 × 10-2 MPa, 1.125 mM peroxymonosulfate (PMS)), the PVDF-CG@5%Co membrane can achieve 90% TC removal in 10 min, which is much higher than that of filtration alone, SR-AOPs alone, and their combined effects. The membrane exhibited effective fouling resistance and good stability over a long operation period, maintaining 83.7% flux retention after 60 min running with the existence of natural organic matter (humic acid) and displayed strong stability during continuous operation. This study provides an innovative solution for antibiotic wastewater treatment and offers valuable insights into the design and development of SR-AOP-based catalytic membrane.