High-flux TFN nanofiltration membranes incorporated with Camphor-Al2O3 nanoparticles for brackish water desalination

Abstract

A new approach of highly fluxes thin film nanocomposite (TFN) nanofiltration (NF) membranes is reported. The fabricated module was made by incorporation of commercial-Al2O3 (CO.TFN) and camphor-Al2O3NPs (CA.TFN) into polyamide layers throughout the interfacial polymerization method. A simple biological reduction technique was adopted in preparation of camphor-Al2O3 NPs by using CinnamomumCamphora (CC) leaf extract. The crystallography of the commercial and camphor-Al2O3 NPs was examined by XRD and FTIR analyses. The CO.TFN and CA.TFN membranes were characterized by determining their surface roughness, pore size, porosity, zeta potential and contact angle parameters. The morphology and the cross-sectional of the NF membranes were studied by atomic force microscope (AFM) and scanning electron microscope (SEM). NF performance was investigated at various Al2O3 NPs loads, applied pressure, and time. The results, of the membranes fabricated at low cost, showed the high permeable flux and elimination of multivalent cations (Mg2+, Ca2+, and water softening). Incorporating 0.98 mM of camphor-Al2O3 NPs into the TFC membrane increased the water flux up to 4 times compared to only 1.5 times for commercial-Al2O3 NPs. Moreover, the salt rejection of CO.TFN and CA.TFN NF membranes increased to 95.1% and 96.5%, respectively for the feed solution (2 g/L Na2SO4 at 25 °C). The optimized NF membrane module of 0.98 mM camphor-Al2O3-NPs (CA.TFN) shows the maximum water flux 69.0,62.2, 60.5 and 55.4 L/m2.h for the feed solutions of following salts NaCl, Na2SO4, MgCl2 and MgSO4 with high salt rejections 92.4%, 96.5%, 91.7% and 95.3%, respectively. This proves that camphor-Al2O3 NPs have a significant role in increasing the membrane hydrophilicity. Hence, the CA.TFN membrane module proved to be a promising candidate for the real brackish water desalination as that collected from Marsa Alam, Egypt.