Synthesis of PMHS–PDMS composite membranes embedded with silica nanoparticles and their application to separate of DMSO from aqueous solutions

Abstract

The study focused on the performance enhancement of a PDMS membrane using PMHS as the curing agent, and by incorporation of silica nanoparticles with four different silica contents of 2.5, 5, 7.5 and 10 wt%. The membranes were synthesized and applied as the separation elements to improve the separation of DMSO from their aqueous solutions. The properties of the membranes were studied by attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), field emission scanning electronic microscopy and thermal gravimetric analysis (TGA). ATR-FTIR results indicated the integration of silica nanoparticles into the nanocomposite membranes and also confirmed the cross-linking reaction between the PMHS and the PDMS. The TGA curve of hybrid membranes displayed that the proper incorporation of SiO2 nanoparticles could clearly improve the thermal stability of the unfilled membrane. Moreover, swelling of prepared membranes was attained for different feed solutions. Results showed that the separation factor and flux of the PDMS/PMHS membrane were enhanced by the incorporation of hydrophobic silica particles into the composite. The maximum separation factor of 830.33 was achieved for the feed mixture with an initial DMSO concentration of 25 vol%, using the membrane with 5 wt% silica content.