Enhancing membrane hydrophobicity using silica end-capped with organosilicon for CO2 absorption in membrane contactor

Silica nanoparticles (SiNPs) modified with hexamethyldisilazane (HMDS), dimethyldichlorosilane (DMDCS) and polydimethylsiloxane (PDMS) were used to fabricate mixed matrix membranes (MMMs) for carbon dioxide (CO2) absorption. It is vital for membrane contactors to be hydrophobic in order to avoid membrane wetting. Of the three functionalised SiNPs, the one treated with HMDS, dubbed TS-530, was well-dispersed within the polyvinylidene fluoride (PVDF) polymer matrix, producing a membrane with high porosity and liquid entry pressure of 77.57% and 7.51 bar, respectively. In addition to higher resistance to membrane wetting, the PVDF/TS-530 MMM also demonstrated superior thermal and mechanical stability. Although the CO2 absorption flux of the MMMs could not rival the 2.84 × 10−4 mol/m2s flux of the neat PVDF membrane, all three SiNPs/PVDF MMMs had demonstrated better selectivity. The MMM with TS-530 SiNPs had reported a CO2 absorption flux of 1.91 × 10−4 mol/m2s as well as the best selectivity of 22.5; over three times higher selectivity than the neat membrane.