In situ synthesis of ultrathin MOF-808 membranes exhibiting superior antibiotic desalination

Abstract

Multi-scale structural optimization has been proven to significantly enhance separation performance of metal–organic framework (MOF) membranes. Aiming at high-efficiency antibiotic desalination, in this work, we developed an in situ modulation strategy to synthesize defect-rich ultrathin MOF-808 membrane on tubular substrate. Among various synthetic parameters, addition of trifluoroacetic acid (TFA) as competitive modulator not only enhanced missing-linker number within the framework but also facilitated heterogeneous nucleation, thus enabling precise control over the multi-scale structure of MOF-808 membrane. Obtained membrane achieved not only rejection rate as low as 8.9 % for NaCl but also near-complete rejection of diverse antibiotics (e.g., 100 % for Rifampicin and Bacitracin, 99.8 % for Berberine chloride, and 99.6 % for Tetracycline). Of particular note, our membrane exhibited excellent NaCl/antibiotic separation factor (SF) of 787 with high water flux of 11.95 L m⁻² h⁻¹, which far surpassed state-of-the-art MOF membranes as reported in the literature. Moreover, our membrane displayed excellent operation stability over 10-cycle continuous operation, demonstrating great promise for practical antibiotic desalination in pharmaceutical industry.