Synthesis of Chitosan‐Grafted Terpolymer Nanocomposite Membranes Using Neem Extract for Oil–Water Separation by Ultrafiltration

Most of the conventional separation technologies employed for the separation of oily wastewater are expensive and have low efficiency. However, ultrafiltration effectively separates oil–water emulsions over a wide droplet size. With the objective of developing a low‐cost ultrafiltration membrane, iron oxide nanoparticles (FeNPs) were generated in situ during the graft polymerization of acrylonitrile (AN), hydroxyethyl methacrylate (HEMA), and N‐vinyl‐2‐pyrrolidone (VP) in the presence of chitosan (CS). Neem extract ( Azadirachta indica ) was used as a green reducing and capping agent. The nanocomposite and membranes were characterized. Membranes fabricated from these nanocomposites exhibited improved pure water flux ( J 0 ), oil–water emulsion flux ( J 1 ), oil rejection (%), and antifouling properties with increasing molar% of HEMA+VP ( C HEMA+VP ), CS wt.% ( C CS ), and FeNPs wt.% ( C FeNPs ). The CSM 20 F 2 membrane prepared with C HEMA+VP = 20, C CS = 2.9, and C FeNPs = 1.8 showed J 0 / J 1 values of 696/461 L·m −2 h −1 bar −1 and 98.2% oil rejection from a 1000 mg/L feed. A similar CSM 20 F 3 membrane prepared with the same C HEMA+VP and C CS , but C FeNPs = 2.1 achieved J 0 / J 1 values of 691/454 L m −2 h −1 bar −1 and 99.2% oil rejection. The CSM 20 F 2 and CSM 20 F 3 membranes also achieved flux recovery ratios of 74.4% and 73.3%, respectively, after three consecutive filtration cycles, demonstrating good antifouling performance.