Surface‐functionalized silica nanoparticles as fillers in polydimethylsiloxane membrane for the pervaporative recovery of 1‐butanol from aqueous solution

BACKGROUND Hybrid materials are being developed with improved separation properties as pervaporation ( PV ) membranes. Mixed matrix membranes ( MMMs ) containing surface‐functionalized fumed silica ( SiO 2 ) nanoparticles in polydimethylsiloxane ( PDMS ) were investigated for PV recovery of 1‐butanol. The MMMs were characterized through water contact angle, pure 1‐butanol sorption, degree of swelling and 1‐butanol partition coefficients . Results Most MMMs outperformed pure PDMS for the PV of 1.5% (w/v) 1‐butanol at ≤40°C. Functionalized SiO 2 fillers enhanced the affinity of 1‐butanol to the MMMs ( K BuOH G ) which consequently improved 1‐butanol permeability more than that of water. Thus the MMMs exhibited better separation efficiencies, but those with octyl‐functionalized (Si‐ DMOS ) and phenyl‐functionalized SiO 2 (Si‐ DMPS ) exhibited the best PV performance. Filler loading of 10 wt% Si‐ DMOS and Si‐ DMPS were found optimal for the PV performance of both MMMs . With temperature, component fluxes of both MMMs increased whereas permeability decreased. Based on PV separation index, both MMMs performed better than PDMS at ≤60°C, Si‐ DMPS / PDMS MMM outperformed PDMS even at 70 °C . CONCLUSION Improved performance of PV membranes was achieved when nonporous functionalized SiO 2 nanoparticles, especially when Si‐ DMPS is used as the filler. The MMMs developed may also be useful for organic compounds recovery from dilute aqueous solutions. © 2013 Society of Chemical Industry