Effect of chemically activated natural vermiculite nanosheets on the performance of mixed matrix polyethersulfone membranes

In this study, natural raw vermiculite (RVMT) nanosheets, as an accessible and economic mineral, were chemically activated and used to modify polyethersulfone (PES) membranes. In this way, RVMT was modified with acid (AVMT) and cetyltrimethyl ammonium bromide (CTAB, OVMT) to increase its hydrophilic functional groups and dispersion properties. Various characterization methods, such as XRD and FTIR, verified the successful preparation of AVMT and OVMT. PES polymeric membranes' properties were improved by the utilization of these additives. The fabrication of AVMT and OVMT/PES mixed matrix membranes with different quantities (0–1 wt.%) was carried out by a non-solvent-induced phase separation procedure. The asymmetric structure of the membranes was confirmed by SEM images. By modifying the matrix of the PES membranes, the porosity of the obtained membranes was improved from 60.50 to 84.92 and 85.09% in the presence of AVMT and OVMT, respectively. Furthermore, the flux of the PES mixed matrix membranes containing 0.5 wt.% AVMT and OVMT were enhanced from 201.76 to 315.89 and 272.07 L/m2 h with an improved flux recovery ratio of 51.81 and 49.15%, respectively.