Synthesis and characterization of graphitic carbon nitride nanosheet modified RO membranes

Polyamide thin film composite (PA-TFC) reverse osmosis (RO) membranes have been used for desalination method. There are lots of advantages of using PA-TFC membranes such as stable structure and high separation properties. Various modification materials use both surface active layer and sublayers to improve their permeations, antifouling properties and permeability. A novel kind of two-dimensional soft nanomaterial, graphitic carbon nitride (g-C3N4) has been investigated in various fields. In this study, nanocomposite membranes with varying g-C3N4nanosheets concentration added to Polyamide layer by interfacial polymerization. Structure and production of graphitic carbon nitride nanosheets was confirmed by FT-IR, SEM and XRD.Range of concentration was between 0.002% and 0.03%. By comparing blank membrane with novel membranes, we found that an increase in flux operation condition from 44 to 59 (L/M2h) in d.m.water and 35 to 45 (L/M2h) in 2000 ppm NaCl solution. After that, flux decreased, so results showed that the amount 0.005 wt% of g-C3N4 had the best performance. Also salt rejection test confirmed optimum concentration of g-C3N4.