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Abstract
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Membrane technology is one of the most common methods for removal of water impurities. The industrial development of membrane technology has been established in various industries such as pharmaceutical, petrochemical, food and dairy industries. The high and easy performance of membrane separation have given special credit to ultrafiltration (UF) and nanofiltration (NF) systems[1]. Deposition of foulants on the membrane surface, fouling, is an issue that reduces the efficiency of the membrane as well as energy loss.[2] Many methods have been introduced to modify the membrane surface and improve antifouling by increasing hydrophilicity. These techniques include mixing with hydrophilic polymers, coating, adsorption, chemical cross-linking, embedding of hydrophilic nanoparticles (NPs) and grafting, which have been developed to reduce membrane fouling[3]. In this work, nitrogen-rich graphitic carbon nitride (g-C3N5) was synthesized using precursors 3-amino-1,2,4-triazole (3-AT) and NH4CL by thermal modification method. Next, by adding g-C3N5, the performance and efficiency of the ultrafiltration membranes were improved. Ultrafiltration membranes with different weight percentages of nitrogen were prepared by phase inversion method. Pure water flux, protein flux and fouling tests were performed to check the performance improvement of ultrafiltration membranes. It was determined by the obtained results, the flux of Pure water and the flux of protein solution increased with the addition of g-C3N5. Pure water flux, protein flux and flux recovery ratio in unmodified membrane were 168.39 L.m-2.h-1, 46.71 L.m-2.h-1 and 45.16%, respectively. These values increased to 216.25 L.m-2.h-1, 60.55 L.m-2.h-1 and 58.29% in the optimal modified membrane with 0.50 wt% g-C3N5. This indicates the improvement of hydrophilicity and anitfouling ability of the modified membranes. The contact angle in the unmodified membrane was 57°, which decreased to 36° in the optimal modified membrane.
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