Organic−Inorganic Hybrid Membranes: Solving the Trade-off Phenomenon Between Permeation Flux and Selectivity in Pervaporation

To solve the trade-off phenomenon existing between permeation flux and selectivity of membranes in pervaporation, organic−inorganic hybrid membranes composed of chitosan and TiO2 were prepared using a solution technique. The resulting hybrid membranes were characterized by Fourier transform infrared spectroscopy (FTIR), wide-angle X-ray diffraction (WAXD), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). Compared to pure chitosan membrane, the hybrid membranes exhibited high thermal stability and low crystallinity. These membranes were tested for their ability to separate water−isopropanol mixtures by pervaporation in the temperature range of 30−50 °C. The experimental results demonstrated that both flux and selectivity increased simultaneously with increasing TiO2 content in the membrane. The permeation flux of pure chitosan membrane increased dramatically from 3.06 to 12.17 × 10−2 kg/(m2 h) when 40 mass % of TiO2 was incorporated, and correspondingly its separation factor increa...