Separation and Purification Technology | 2021
Ion-promoting-penetration phenomenon in the polyethyleneimine/trimesic acid nanofiltration membrane
Abstract
Abstract The preparation methods of nanofiltration (NF) membranes are various. Designing composite layer structures can obtain NF membranes with special properties. In our work, the polyethyleneimine/trimesic acid NF membrane exhibited high permeability. Based on this, the NaCl solution caused the permeate flux improving (ion-promoting-penetration phenomenon), and the flux was responsive to the solution concentration within a certain range. The detailed analysis of cross-linked structure, membrane pores, and solutions were made. The ion-promoting-penetration effect level, the highest growth rate Rg, could achieve about 70% (from 40 to 68 L m-2 h-1). This feature was still significant in mixed salt solutions, which had the potential to be applied to deep water treatment. After long-term treatment with the NaCl solution, the PEI/TMA membrane still maintain the excellent desalination performance (rejection of MgCl2, >90%). The discussion of these contents was beneficial to deepen the understanding of the NF process.