Cellulose nanofiber and halloysite nanotubes embedded polyvinyl alcohol membranes for pervaporation dehydration of epichlorohydrin-isopropanol-water ternary feed mixture

The dehydration of epichlorohydrin (ECH)-isopropanol (IPA)-water mixtures was conducted by using pervaporation separation process. Two types of crosslinked polyvinyl alcohol (PVA) membranes, PVA-Glu and PVA-TEOS, were prepared using glutaraldehyde (Glu) and tetraethyl ortho silicate (TEOS), then mixed with cellulose nanofiber (CNF) and halloysite nanotube (HNT) fillers, respectively. They characterized using field emission scanning electron microscopy to observe surface morphology, Fourier-transform infrared spectroscopy to study the filler-polymer interactions and chemistries of membranes, and X-ray diffraction experiment for the analysis of membrane crystallinity. Finally, a pervaporation test was carried out to dehydrate the ECH-IPA-water feed solution at the azeotropic feed composition. From the result, the membrane of PVA-Glu, including 4% w/w CNF filler, showed a flux of 0.17 kg (m(2)h)(-1) and a separation factor of 456. However, the membrane of PVA-TEOS with 5% w/w HNTs filler indicated a flux of 0.15 kg (m(2)h)(-1) and a separation factor of 4158. The higher pervaporation performance of the HNTs-added PVA-TEOS membrane is attributed to the smaller size and more porous nature of HNTs than CNFs.