Modification of polyamide nanofiltration membranes with green Dragon's blood natural resin: Improvement in permselectivity and antifouling properties

In this study, dragon blood resin (DBR), which is a novel green and antibacterial bio-additive, was used to fabricate thin-film composite (TFC) nanofiltration (NF) membranes with improved antifouling and membrane performance properties. Pure water flux (PWF), different salt solution fluxes (Na₂SO₄ and NaCl), rejection, flux recovery rate (FRR), and long-term tests were carried out to assess the membrane performance and antifouling properties. Compared to bare TFC NF membranes, DBR-doped TFC NF membranes showed higher hydrophilicity, rougher surface layer, and higher negative charge. The 0.005 DBR NF membrane indicated the highest pure water, Na₂SO₄, and NaCl solution permeabilities of 67.9, 62.3 and 63.9 LMH, respectively. DBR-doped NF membranes showed the best desalination performance with NaCl, Na₂SO₄, and MgSO₄ rejections of 51.3 %, 97.3 %, and 93.2 %, respectively. In addition, long-term studies have shown that DBR-doped NF membranes exhibit an 8 % flux decrease toward the HA/Na₂SO₄ solution fouling. The DBR TFC NF membrane displayed antibacterial activity against E.coli and S. aureus and showed antifouling characteristics, resulting in a notable reduction in fouling resistance parameters and a marked improvement in the antifouling performance of the bare TFC NF membrane. As a result, the findings showed that DBR was a superior and efficient novel bio-based additive for modifying the TFC NF membrane.