TiO₂ nanofiltration membranes prepared by molecular layer deposition for water purification

In this study, molecular layer deposition (MLD) was used as a novel and highly controllable method to prepare TiO₂ nanofiltration membranes with approximately 1 nm pores for water purification. Number of deposition cycles and precursors (TiCl₄ and ethylene glycol) were used to control membrane quality and final pore sizes, respectively. Optimized TiO₂ nanofiltration membranes had a pure water permeability as high as ~48 L/(m² h bar). Salt and dye rejection measurements showed moderate rejection of Na₂SO₄ (43%) and MgSO₄ (35%) and high rejection of methylene blue (~96%). In addition, natural organic matter (NOM) removal testing showed high rejection (~99%) as well as significantly improved antifouling performance and recovery capability. MLD, as a new TiO₂ nanofiltration membrane preparation technique, has great potential to realize excellent control of membrane composition, thickness, and potentially pore sizes in a scalable way.