Antifouling and photocatalytic properties of 2-D Zn/Al layered double hydroxide tailored low-pressure membranes

In this study, Zinc-Aluminium layered double hydroxide (LDH) was synthesized to fabricate membranes with superior hydrophilic and photocatalytic characteristics. The prepared LDH was extensively characterized and employed for the preparation of polyetherimide mixed matrix ultrafiltration (UF) membranes, which displayed > 96 % BSA rejection and a flux recovery ratio of 88 % even after 3-cycles. M-1 (UF, 1 wt. %) displayed a 94 % degradation of organic dye (methylene blue) in 120 min when irradiated with UV-light. Further, nanofiltration (NF) membranes were prepared by incorporating Zn/Al LDH into the polyamide (PA) layer during the in-situ interfacial polymerization to prepare thin-film nanocomposite membranes. MT-2 (NF, 0.4 wt.% LDH in PA layer) displayed improved hydrophilicity (lower water contact angle), > 94.5 % rejection of cationic dye (Methylene blue), > 91 % rejection of inorganic salt (CaSO₄) with an 80 % flux recovery after long-term filtration. The LDH holds an auspicious potential to tune the properties of UF and NF membranes to be used in the treatment of industrial effluents.