Polysulfone-based mixed matrix membranes loaded with a multifunctional hierarchical porous Ag-Cu dendrites@SiO2 core-shell nanostructure for wastewater treatment

Eliminating pollutants from wastewater is a crucial approach to securing the global water supply. It is well known that membrane purification technologies are remarkably attractive due to their high efficacy and low energy consumption. The neat polysulfone (PSF) polymer membranes, though, are prone to be fouled by organic pollutants, causing pore blockage and waned separation performance. We herein report and describe the rational design of a hierarchical porous Ag-Cu dendrites@SiO2 core-shell nanostructure/PSF mixed matrix membranes (MMMs) by coupling heterogeneous dendritic Ag-Cu@SiO2 core-shell nanostructure with PSF polymer matrix using facile phase inversion method for efficient separation of the protein (Bovine Serum Albumin; BSA) and Rose Bengal (RB) dye removal. Besides, for the first time, a theoretical mapping of molecular electrostatic potential (MESP) maps for chemical structure has been used for studying the interaction between the compounds (membrane moieties and pollutants). Practically, the SiO2 nanoparticles provide excellent hydrophilicity causing a sequential efficient, antifouling protein and dye separation with an outstanding rejection rate of over 96 % for both BSA and RB. In addition, the porous hierarchical scaffold formed from the hydrophilic Ag-Cu nanosheets embedded with SiO2 nanoparticles greatly assists the rapid permeation of water with a high flux rate of up to 50 L m−2 h−1 bar−1 for pure water. Furthermore, the hydrophilic nature of Ag and Cu nanoparticles also renders this membrane with a high removal capability for dye blocking enabling it to remove soluble pollutants in molecular dimensions as well. This design strategy not only provides an outstanding membrane for water purification but also sheds light on the design of multi-purpose functional membranes for a variety of energy and environment-related applications.