Titanate nanotubes–incorporated poly(vinyl alcohol) mixed matrix membranes for pervaporation separation of water-isopropanol mixtures

Abstract

Mixed matrix membranes (MMMs) base on poly(vinyl alcohol) (PVA) incorporated with titanate nanotubes (TNTs), cross-linked with glutaraldehyde, were prepared. The hydrothermally synthesized TNTs and the membranes were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffractometer (XRD), Thermogravimetric analysis (TGA), Field emission scanning electron microscope (FESEM), and tensile strength analyses. The prepared nanocomposite membranes were used for dehydration of isopropanol by pervaporation process. The effects of the weight fraction of TNTs, feed temperature, and concentration on the performance of the membranes were investigated. The results indicated that incorporation of hydrophilic TNTs could effectively improve the separation performance of PVA membranes in terms of both permeability and separation factor. Based on the results, the separation factor of all nanocomposite membranes was increased. Moreover, the membrane containing 4 wt% of TNTs exhibited the highest separation factor value of 5520, while the maximum value of flux was about 0.126 kg/m2h for the membrane containing 10 wt% TNTs. So, there was about 794% and 741% enhancement in separation factor and flux respectively, compared to the pristine PVA membranes. Consequently, the results confirm incorporating TNTs in the PVA matrix could improve the separation of water from isopropanol aqueous solutions effectively due to the intrinsic hydrophilicity and special structure of TNTs.