Hydrosilylation-based UV-curable polydimethylsiloxane pervaporation membranes for n-butanol recovery

UV-cured polydimethylsiloxane (PDMS) pervaporation membranes (pristine and mixed matrix membranes (MMMs) containing silicalite-1 particles) were fabricated by using a new class of hydrosilylation-based UV-curable PDMS to facilitate the manufacturing process as well as to enhance performance for n-butanol recovery. Unlike the pristine (heat- and UV-cured) PDMS membranes which showed no discernible difference in their morphology, the UV-cured MMM exhibited a more loosely-packed structure with a rougher surface due to the protuberant features compared to the conventional heat-cured MMM. It was attributed presumably to the different curing mechanisms as well as the different compositions and chemical structures of the PDMS used. Importantly, the UV-cured MMM exhibited a higher permeate flux with a similar separation factor compared to the heat-cured counterpart. Our UV-cured MMM further enhanced separation performance at the elevated temperature with the highest flux of ∼1,520 g m² h⁻¹ and separation factor of ∼19.8 at 60 °C. This flux enhancement of the UV-cured MMM was explained by its unique morphology (higher surface roughness and loosely-packed structure) and more pronounced temperature-dependent diffusivity enhancement. Our proposed strategy could provide a more efficient and commercially viable route to fabricate highly permeable PDMS-based pervaporation membranes for efficient butanol recovery in the bio-butanol production process.