Long-lasting antibacterial cellulose acetoacetate membrane loaded with Ag@UiO-66-NH2 nanoparticals for efficient dye/salt fractionation

Loose nanofiltration membranes (LNMs) have attracted increasing attention due to their applications in sustainable management of high salinity textile wastewater. Remained challenges include achieving efficient dye/salt fractionation and mitigating high biofouling tendencies. In this work, Ag-loaded UiO-66-NH2 (Ag@UiO-66-NH2) nanoparticles were prepared by a simple method of stirring, and subsequently used to blend with cellulose acetoacetate (CAA) to obtain antibacterial Ag@UiO-66-NH2 @CAA (MOF@CAA) LNMs. Water contact angle (WCA), scanning electron microscopy (SEM), and X-ray photoelectron spectrometer (XPS) were used to characterize the MOF@CAA membranes. In addition, the antibacterial properties, pure water flux and dye/salt fractionation properties of the membrane were studied in detail. MOF@CAA LNMs has a porous surface and a sponge-like cross-sectional structure. The membrane has a reasonable water permeability (65.3 L/m2 h), a rejection of 99.2 % for Congo red (CR) and almost zero rejection to inorganic salts (CR concentration: 100 mg/L, inorganic salts concentration: 1000 mg/L, operating pressure: 0.2 MPa). In addition, the MOF@CAA LNMs reduced 99.70 % of E. coli and 99.69 % of S. aureus in the bacterial suspensions. It is also found that the release of Ag+ ion from the MOF@CAA LNMs is stably maintained at 0.1 μg L−1 day−1 for a period of 30 days. As the Ag nanoparticals (NPs) presented in the membrane were stably wrapped in UiO-66-NH2, its release could be maintained at a very slow rate continuously to achieve the purpose of controlled release and long-term sterilization.