Fabrication of Highly Permeable and Thermally-Stable Reverse Osmosis Thin Film Composite Polyamide Membranes.

Abstract

Developing thermally-stable polymer membranes for high-temperature water treatment is in high demand, as the recommended usage temperatures of most commercial membranes are lower than 50 °C. In this study, we synthesized novel thin film composite polyamide membranes by modifying the chemical structure of their selective layers. Triaminopyrimidine was used to synthesize a polyamide selective layer with high cross-linking density over a microporous polyethersulfone support. The addition of triamiopyrimidine to the classic m-phenylenediamine/trimesoyl chloride combination remarkably improved the permeation of the membranes. All synthesized thin-film composite membranes showed consistent permeate flux for 9 hours of operation at 75 °C with only a slight reduction in salt rejection. This study provides a promising and reproducible methodology to develop thermally-stable high-flux thin film composite membranes, opening up a new paradigm for high-temperature water treatment processes.