Leaf-like ZIF-L as self-sacrificed template via acid induced removal for stronger negatively charged PES membranes based on RTIPS method

In this paper, ZIF-L was blended with citric acid (CA) and polyethersulfone (PES) to prepare a casting solution. Anovel negatively charged ultrafiltration (UF) membrane (ZIF-L/CA/PES) was obtained using the reverse thermallyinduced phase separation (RTIPS) method. The hydrophilic carboxyl groups present in CA not onlyimparted high hydrophilicity and negative charge to the membrane surface, enhancing the membrane’s selectivityand contamination resistance, but also created an acidic environment to attack the Zn atoms in ZIF-L by theionized H+ from CA, resulting in the generation of micro-defective pores and an improvement in permeability. Additionally, the results showed that membranes generated through the RTIPS process exhibit uniform poroussurfaces and spongy cross-sections, enhancing membrane performance. The optimized membranes demonstratedthe capability to achieve a pure water flux of up to 2267 L/m2h with 93.1 % humic acid (HA) retention, and aremarkable membrane flux recovery rate of 75.8 %, suggesting the crucial roles played by CA and ZIF-L in theseparation process. In conclusion, hydrophilic anti-fouling UF membranes with a high negative charge andexcellent permeation selectivity were fabricated by establishing micro-defective channels through the incorporationof carboxylic acid and ZIF-L, combined with the RTIPS process. KCI Citation Count: 0