Improved interfacial polymerization process in the presence of non-ionic surfactant for preparation of TFC nanofiltration membrane

A polyamide (PA) thin layer was formed on the PES support membrane by using trimesoyl chloride (TMC), piperazine (PIP) and triethylamine (TEA) as interfacial polymerization reactionreagents. Different contents of the non-ionic surfactant (Triton X-100) were used in the aqueous phase. After preparation thePES support, an aqueous phase containing PIP (0.15 wt.%), TEA (0.4 wt.%), and different concentrations of the surfactant were poured on top of the support membrane an allowed to wetthe membrane. Then, after draining off the excess solution, the organic solution (n-hexane) of trimesoyl chloride (0.1 wt.%) waspoured into the frame where the conventional interfacial polymerization reaction took place. After 5 minutes, the excessorganic solution was poured off and the frame with membrane was held in an oven for 5 minutes and at 70 oC. The water permeation performance, salt rejection, chemical structure andmembrane surface morphology were measured for characterization of obtained membranes by using ATR-IR,SEM, AFM. The ATR-IR spectrum indicates that the interfacial polymerization occurred. By increasing the amount of Triton X-100, the rejection capability of thin layer for Cd and Pb ions improved and an increasing in the rejection capability of Cd ions from 10 to near 30% observed. The rejection of Pb ions reached around 45%.