Thin film nanocomposite reverse osmosis membrane modified by reduced graphene oxide/TiO 2 with improved desalination performance

A novel thin film nanocomposite reverse osmosis (TFN-RO) membrane was prepared by interfacial polymerization of m-phenylenediamine (MPD) and trimesoyl chloride (TMC) monomers and embedding reduced graphene oxide (rGO)/TiO 2 nanocomposite in its polyamide layer. The rGO/TiO 2 nanocomposite was added to the MPD solution with aim of improving RO performance, enhancing antifouling property and increasing chlorine resistance. Surface scanning electron microscopy (SEM) images show that all of the membranes have a rough surface with a layer of “ridge-and-valley” structure that is typical morphology of MPD/TMC polyamide membranes. The contact angle analysis showed that hydrophilicity of the membranes was improved by increasing the concentration of rGO/TiO 2 due to the presence of various hydrophilic and negatively charged functional groups on the rGO/TiO 2 nanocomposite. The superior performance of the rGO/TiO 2 /RO membrane was observed in the case of 0.02 wt% rGO/TiO 2 with water flux of 51.3 L/m 2 h and salt rejection of 99.45%. Antifouling ability of the membranes studied by bovine serum albumin (BSA) solution filtration showed that 0.02 wt% rGO/TiO 2 /RO membrane had the best antifouling property. Also, after the chlorination tests, the salt rejection of the bare RO membrane decreased by 30%, while this value was only 3% for 0.02 wt% rGO/TiO 2 /RO membrane which confirmed its great chlorine resistance.