Acid and multivalent ion resistance of thin film nanocomposite RO membranes loaded with silicalite-1 nanozeolites

Abstract

The incorporation of NaA nanozeolites into thin film composite (TFC) reverse osmosis (RO) membranes has been found to elevate water permeability, but the unfavorable acid and multivalent ion sensitivity of NaA limits the application of the thin film nanocomposite (TFN) membranes for seawater desalination. To overcome these drawbacks, the chemically stable silicalite-1 nanozeolite was incorporated into the skin layer of the RO composite membrane via interfacial polymerization. In this paper, the resulting membrane was characterized with outstanding chemical stability (acid and multivalent cation tolerance) compared with the NaA mixed membrane. Additionally, silicalite-1 showed better capacity to enhance membrane permeability than NaA, which can be explained by larger channel pores and a higher water diffusion rate in silicalite-1. This investigation indicates that the silicalite-1 mixed membrane has great potential in large-scale seawater desalination because of its excellent permeability and chemical stability.