Magnetic core-hydrophilic shell nanosphere as stability-enhanced draw solute for forward osmosis (FO) application

We have developed magnetic core-hydrophilic shell nanospheres as a draw solute with enhanced stability for use in forward osmosis (FO) processes, which were prepared via a ligand exchange reaction. The combined results of TEM, DLS, FT-IR, and TGA analysis indicated that spherical magnetic nanospheres with 10nm in diameter were successfully prepared via a thermal decomposition method. Hydrophilic shell layers were prepared using a ligand exchange reaction, and the hydrophilic siloxane agents were robustly bound to the surfaces of the magnetic nanosphere without inducing morphological changes. The number of hydrophilic agents presented in the magnetic nanospheres increased dramatically as a result of the covalently attached hydrophilic siloxane agents. The magnetic core-hydrophilic shell nanosphere draw solutes generated reasonable osmotic pressures due to their hydrophilic shell layer, rendering them useful for purifying mildly brackish water. As we intended, the osmotic pressure of the magnetic core-hydrophilic shell nanosphere was well maintained during repetitive magnetic recovery processes because the robustly bound the hydrophilic shell layer prevented particle aggregation. [Display omitted] •Preparation of magnetic core-hydrophilic shell nanosphere•Core-shell magnetic nanosphere applies to durable draw solute in FO.•Magnetic draw solutes generate reasonable osmotic pressures.•Robustly capped hydrophilic siloxane prevents particle aggregation.•Osmotic power is maintained during repeated magnetic recovery process.