Thin film nanocomposite membranes filled with bentonite nanoparticles for brackish water desalination: A novel water uptake concept

Bentonite nanoparticles (NPs) prepared via solvothermal method were filled into thin film nanocomposite (TFN) membranes for brackish water desalination. Membranes were prepared by the interfacial polymerization (IP) between m-phenylenediamine (MPD) aqueous solution and an organic solution of trimesoyl chloride (TMC); the IP reaction occurred on a support sheet of polysulfone (PSU). The NPs (<= 50 nm) were dispersed at different percentages, from 0 to 0.15%, in MPD solution during TFN membranes preparation. Scanning electron microscopy (SEM), surface area, pore size and zeta potential techniques were used to characterize the NPs. And SEM, transmission electron microscopy (TEM), attenuated total reflection Fourier transform infrared spectroscopy (ATR FT-IR), contact angle measurement, and the membranes performance assessments were used for membrane characterization. Results showed that bentonite NPs improved the performance of all TFN membranes, as tested under the conditions of: 2000 ppm NaCl solution, 25 degrees C, and 300 psi (20.68 bar) trans-membrane pressure. With 0.1% NPs, the water flux was increased from 45.6 to 58.8 L/m(2) h in comparison with the control membrane and the salt rejection was simultaneously increased from 96.25 to 97.3%.