Tailoring interfacially polymerized thin-film composite polyesteramide nanofiltration membranes based on carboxylated chitosan and trimesoyl chloride for salt separation

Thin-film composite polyesteramide nanofiltration membrane prepared from carboxylated chitosan and trimesoyl chloride was carefully tailored during its fabrication process of interfacial polymerization. The effects of post-curing, mid-drying and the addition of phase transfer catalysts on the membrane properties were studied using single-factor experiment. Post-curing was found to be effective in improving the separation performance of the membrane containing high concentrations of carboxylated chitosan, and the optimal post-curing effect was achieved at a temperature of 40 °C and curing time range of 15−20 min. Mid-drying enhanced the permeation flux and salt rejection of the membrane containing low concentrations of carboxylated chitosan, and the optimum temperature range for the mid-drying process was obtained at 30−40 °C. Furthermore, the membrane properties were susceptible to the addition of phase transfer catalysts, and a uniformly distributed phase transfer catalyst is vital to its influence on membrane properties. The addition of 0.025 wt% benzyltriethylammonium chloride to the aqueous solution exhibited the best effect towards the improvement of the separation performance of the produced membrane.