Modification of SiO2 by n-dodecyltrimethoxysilane and preparation of SiO2-filled regenerated cellulose nanocomposite membranes for dehydration of caprolactam by pervaporation

Novel organic inorganic nanocomposite pervaporation membranes were prepared by the incorporation of the unmodified and modified SiO2 nanoparticles with a silane coupling agent (WD10, C12H25Si(OCH3)(3)) into regenerated cellulose (RC) membranes. The WD10-modified SiO2 particles were characterized by FTIR. The chemical and physical properties of the membranes were characterized by attenuated total reflection-Fourier transform infrared, AFM, scanning electron microscopy, thermogravimetric analysis, XRD and degree of swelling measurements. Furthermore, the effects of nano-SiO2, WD10-modified SiO2, WD10, feed temperature and feed concentration on the pervaporation performances were investigated for caprolactam dehydration by pervaporation. Among all the prepared membranes, RC-SiO2 (5%)-WD10 nanocomposite membrane exhibited excellent pervaporation (PV) properties with a flux of 611.3 g m(-2) h(-1) and separation factor of 95,404.8 at 333 K, for 70 wt.% caprolactam. Diffusion coefficient of water and caprolactam molecules was analyzed by Fick's equation. The results show that the diffusion plays a dominant role in the transport of binary liquid molecules in PV process. The membranes developed in the present study have the ability for the separation of caprolactam water mixture.