Fractionation and Concentration of High-Salinity Textile Wastewater using an Ultra-Permeable Sulfonated Thin-film Composite

A sulfonated thin-film composite (TFC) nanofiltration membrane was fabricated using 2,2′-benzidinedisulfonic acid (BDSA) and trimesoyl chloride (TMC) on a polyether sulfone substrate by conventional interfacial polymerization. Due to a nascent barrier layer with a loose architecture, the obtained TFC-BDSA-0.2 membrane showed an ultrahigh pure water permeability of 48.1 ± 2.1 L–1 m–2 h–1 bar–1, and a considerably low NaCl retention ability of <1.8% over a concentration range of 10–100 g L–1. The membrane, which possesses a negatively charged surface, displayed an excellent rejection of over 99% toward Congo red (CR) and allowed the fast fractionation of high-salinity textile wastewater. The prepared membrane required only 3-fold water addition to accomplish the separation of multiple components, whereas the commercial NF270 (Dow) membrane required 4-fold water addition and almost double the length of time. Furthermore, the TFC-BDSA-0.2 membrane was subsequently tested for the dye concentration process. It ...