Outstanding anti-bacterial thin-film composite membrane prepared by incorporating silver-based metal–organic framework (Ag-MOF) for water treatment

Highlight • Hydrophilic, electronegative and porous Ag-MOF was successfully synthesized. • Ag-MOF doped membranes improved the flux and separation property for dye and salt. • Modified membranes exhibited a strong anti-bacterial property for bacteria. Biofouling was a considerable issue in the water treatment by membrane technology. In this study, high anti-bacterial property Ag-MOF was synthesized followed by embedding into polyamide layer with vacuum-assisted interfacial polymerization process to prepare an Ag-MOF incorporated membrane. The successful preparation of Ag-MOF and membranes was verified by FT-IR, FESEM, XPS, XRD, BET, zeta potential and contact angle test. On account to the strong hydrophility, porous structure, electronegativity and antibacterial property of Ag-MOF, modified membranes showed excellent performance for dyes, salts and bacteria. The water permeability of modified membranes was increased from 9.2 to 14.3 L m-2h−1 bar−1 and the rejection rate of MO, MB and RB of the optimum membranes were 95.4%, 87.8% and 99.3%, respectively. The rejection rate of Na2SO4 and MgSO4 were increased from 54.0% and 36.6% to 84.1% and 73.1%. The sterilization rate of modified membranes to E. coli and S. aureus both exceeded 99%. The leaching test of Ag+ evaluated the potential mechanism of anti-bacterial property. Moreover, dynamic bio-fouling test were used to detect the actual status in the filtration process. Those results suggested that modified membranes showed a strong resistance to bio-foulants thus enlarged the scope of application of membranes for water treatment.