Enhancement of polyethersulfone (PES) membrane doped by monodisperse Stober silica for water treatment

SiO2 nanoparticles offer promising prospects as additives for the synthesis of organic-inorganic hybrid composite membranes due to their facile synthesis procedure with low cost and toxicity to aqueous systems. This requires silica nanoparticles with good monodispersity to form a regular hydrophilic surface. In this study, monodisperse silica synthesized by the Stober method was explored as an additive in ultralow concentration for the synthesis of organic-inorganic composite membranes based on polyethersulfone, aiming at potential application in water treatment. The results indicate the polyethersulfone membrane doped with monodisperse silica has an enhanced performance. The hydrophilicity of the modified membranes was also enhanced due to the high water affinity of nano-SiO2, resulting in a higher permeability. However, in the high concentration interval of nano-SiO2, the permeability of modified membranes decreases due to pore plugging and the alteration of macrovoids in the sublayer of membranes. Simultaneously, the selectivity of the modified membranes was improved, which is an indicator for a more narrow pore size. The optimum permselectivity was obtained with the addition of 0.30% nano-silica. Additionally, the fouling resistance increased by ca. 70%. Thus, doping of nano-silica in the membranes is an alternative method to enhance permselectivity and fouling property for water treatment. (C) 2015 Elsevier B.V. All rights reserved.