Cross-linked mixed matrix membranes made up of amine-functionalized silica and chloromethylated polysulfone for organic solvent nanofiltration applications

In this study, mixed matrix membranes (MMMs) were fabricated by the incorporation of 3-aminopropyl triethoxysilane (APTES)-functionalized fumed silica nanoparticles (NPs) into a chloromethylated polysulfone membrane. Next, the prepared MMMs were cross-linked through immersing the as-fabricated membranes in an HDA aqueous solution. Various amounts of amino-functionalized fumed silica were fabricated so that optimal loading of NPs could be achieved. Furthermore, the annealing process was also conducted on the membranes for enhancing the dye rejection performance. Finally, the effects of NH2-SiO2 loading and annealing process were investigated not only on physicochemical properties of the prepared membranes but also on their separation performance for OSN applications. It was found that the prepared mixed matrix membrane with 2 mg loading of amino-functionalized fumed silica could provide the outstanding results (99.9% reactive red, 98.9% direct yellow, 91.4% methyl green, 85.5% rhodamine B, 81.6% crystal violet; and permeance of 1.26 L/m2.h.bar for ethanol). It was also observed that the rejection performance and permeance of this membrane were enhanced after 40 min annealing (99.99% reactive red, 99.94% direct yellow, 99.80% methyl green, 99.79% rhodamine B, 98.69% crystal violet and 0.46 L/m2.h.bar for ethanol, respectively).