Antifouling loose nanofiltration membrane for dye/salt separation by interfacial polymerization with capsaicin derivatives

Accurate dye and inorganic salt separation from wastewater is crucial to effective dye wastewater recovery. Loose nanofiltration membranes (LMNs) exhibiting high dye rejection and low salt retention are expected to be applied in dye/salt separation. However, membrane fouling still restricts the effective application of LMNs. In this work, a novel capsaicin-containing functional structural derivative, N-(6-methacrylamido-3,4 hydroxybenzyl)acrylamide (DHMAM), was used as an aqueous phase reactive monomer to prepare high-performance antifouling loose nanofiltration membranes (PSf-DHMAM LMNs) by interfacial polymerization with 1,3,5- benzenetricarbonyl trichloride (TMC). The obtained PSf-DHMAM LMNs have good hydrophilic and charge-negative properties. The optimized PSf-DHMAM 0.5 LMNs exhibited high permeability performance (61.24 ± 3.29   L   m -2 h -1 bar -1 ), excellent dye rejection (99.46 ± 0.08% for Congo Red) and ultra-low salt retention (2.49 ± 0.1% for NaCl). In addition, PSf-DHMAM 0.5 LMNs have good antibacterial properties (the antibacterial rate against Escherichia coli can reach 89.53%), antifouling properties and long-term stability, which are promising for future applications in the field of dye/salt separation.