Thin-film nanocomposite membranes incorporated with UiO-66-NH2 nanoparticles for brackish water and seawater desalination

In this work, UiO-66-NH2 nanoparticles, a type of metal-organic frameworks (MOFs) with an average size of ~100 nm, were incorporated into the polyamide-based thin-film nanocomposite (TFN) RO membranes. Their inherent porous structure, suitable triangular aperture size, hydrophilic nature, and high chemical and water stability endow the TFN membranes with greater surface hydrophilicity, lower degree of cross-linking and preferential pathways for water molecules across the selective layers. Herein, we introduce UiO-66-NH2 nanoparticles in the TFN layer via spray assisted pre-disposition. The UiO-66-NH2 TFN membranes with a spray duration of 3 min show a ~50% increase in pure water permeance while maintaining a similar rejection compared with the thin-film composite (TFC) membranes in brackish water desalination tests. The former also displays higher chlorine resistance than the latter. In the stimulated seawater desalination tests, TFN membranes also exhibit a higher water flux and salt rejection than the benchmark membranes.