Preparation of thermally stable 3-glycidyloxypropyl-POSS-derived polysilsesquioxane RO membranes for water desalination

Reverse osmosis (RO) membranes with polysilsesquioxane (PSQ) framework having high NaCl rejection and favorable resistance to heat and chlorine were prepared by the copolymerization of 3-glycidyloxypropyl-POSS (GPOSS) and bis[3-(triethoxysilyl)propyl]amine (BTESPA). It was found that NaCl rejection and liquid permeability were significantly improved by the introduction of GPOSS-derived units to the BTESPA-based membranes, yielding NaCl rejection of approximately 99% and liquid permeability of 5.5 × 10−13 m/s·Pa. These PSQ RO membranes with GPOSS-derived units also demonstrated excellent resistance to heat treatment of up to 100 °C and favorable resistance to chlorine in that no obvious RO performance change was observed after exposure to NaOCl aqueous solution (1000 ppm) for 10 h.