This study presents the synthesis and characterization of oleic acid (OA)-modified silica/polyamide (PA) nanocomposite membranes. The thin film composite (TFC) polyamide was prepared with M-phenylendiamine (MPD) and trimesoyl chloride (TMC) via interfacial polymerization over porous polysulfone. Five different thin film nanocomposite (TFN) membranes were fabricated by dispersing OA-modified silica nanoparticles in TMC solution. Chemical and thermal properties, surface morphology, roughness, film thickness and hydrophilicity of synthesized membranes were characterized by ATR-IR, TGA, FESEM, AFM, TEM and contact angle analysis. The results showed that incorporating OA-modified silica into thin film layer improved chemical and physical properties of nanocomposite membranes. The effects of modification of nano silica on pure water flux and MgSO4 rejection were investigated. OAmodified silica/PA membranes showed higher pure water flux in comparison with neat polyamide TFC membrane but lower than unmodified silica/PA membrane; while significant increase in salt rejection was exhibited for OA-modified silica/PA membranes. The maximum rejection for OA-modified and unmodified nanocomposite membrane was obtained about 98.7% and 95.2%, respectively.

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