Thin Film Nanocomposite nanofiltration membrane incorporated with Cellulose Nanocrystal with superior anti-organic fouling affinity

Thin film nanocomposite (TFN) nanofiltration (NF) membranes were fabricated by incorporating cellulose nanocrystal (CNC) in polyamide (PA) layer. Membranes were synthesized by in-situ interfacial polymerization of piperazine (PIP) and trimesoyl chloride (TMC) containing different amounts (0.0, 0.01, 0.05, and 0.1 wt.%) of CNCs. Successful incorporation of CNCs into the polyamide layer was confirmed by ATR-FTIR analyses. The morphology of membranes was investigated using SEM. Water contact angle measurements showed improved hydrophilicity of the TFN membranes. Performance of prepared membranes for nanofiltration of different saline solutions (Na2SO4, NaCl, MgCl2, and CaCl2) with 1 g/L concentration, at 6, 8 and 10 bar pressures, 25 oC temperature and constant feed solution flow rate of 2.25 L/min was investigated. By increasing CNC loading in the PA layer and operating pressure water flux increased, significantly. By increasing CNC loading to 0.05 wt.% in the PA layer the Na2SO4 rejection increased at all pressures. Increment of CNC concentration to 0.1 wt.% resulted in reduction of Na2SO4 rejection. The TFN membrane fabricated using 0.05 wt.% CNC (TFN 0.05) showed water flux of 22.47 Lm-2h-1 and Na2SO4 rejection of 93.44%. The trend of salt rejection form aqueous solutions for TFN 0.05 membrane was as follows: Na2SO4 (93.44 ٪) > MgCl2 (79.52٪) > CaCl2 (71.03٪) > NaCl (62.68٪). TFN 0.05 membrane could significantly improved Bovine Serum Albumin (BSA) fouling compared to the TFC membrane during NF process. In addition, about 22.5% of the water flux of TFN 0.05 was able to recover by a simple water rinse, which indicates that organic fouling in NF0.05 is highly revocable.