Fabrication of a Novel Galp/ <scp>PIP</scp> ‐Based Polyesteramide <scp>NFC</scp> Membrane for Dye Desalination

ABSTRACT In order to obtain a loose selective layer of NFC membranes for dye desalination, a novel polyesteramide composite nanofiltration membrane based on Galp/PIP was fabricated by interfacial polymerization (IP) with d ‐(+)‐galactose (Galp) and piperazine (PIP) as the alcoholic hydroxyl‐amino mixed aqueous monomer and trimesoyl chloride (TMC) as the organic monomer in this work. The influence of the Galp/PIP weight ratio on the membrane's properties and separation performance was systematically investigated. The results indicate that the water flux and dye wastewater flux, the thickness of the selective layer, surface roughness, molecular weight cutoff (MWCO), and average pore size increased; however, the surface zeta potential became less negative due to the neutral charge of Galp, and the water contact angle decreased with the increase of the Galp/PIP. The water permeance and dye rejection were strongly dependent on the Galp/PIP ratio. At the optimal ratio of 4/6, the water permeation and the dye wastewater flux were up to 19.7 and 13.8 L/m 2 h bar, respectively, and the RB5 rejection was 92%. Compared to 0/10, the water permeation and the dye wastewater flux increased 59.2% and 57.5%, respectively, and the RB5 rejection was 97.4%, while the NaCl rejection was below 5%. In addition, this outstanding fractionation performance remained stable during extended operation with simulated dye/salt wastewater.