Sodium bicarbonate as novel additive for fabrication of composite nanofiltration membranes with enhanced permeability

Thin film composite nanofiltration membranes are frequently used to remove the residual salts from industrial wastewater. However, these nanofiltration membranes often have relatively low fluxes that limit their practical applications. To solve the problem, sodium bicarbonate was introduced into the composite nanofiltration membranes via interfacial polymerization of piperazine (PIP) and 1,3,5-benzenetricarbonyl trichloride (TMC). The membrane surfaces were characterized by scanning electronic microscopy, attenuated total reflection Fourier transform infrared spectroscopy, electro kinetic analyzer, and contact angle goniometer. The results showed that the addition of sodium bicarbonate generated more tiny cracks on membrane surface and decreased the zeta potential of the membrane, which improved the permeation properties of the membrane without significantly decreasing the rejection against four kinds of salts (Na 2 SO 4 , MgSO 4 , NaCl, MgCl 2 ). The addition of sodium bicarbonate provided a new possibility to improve the permeation properties of thin film composite nanofiltration membranes. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135 , 46363.