Abstract: A forward osmosis water treatment device includes a plurality of forward osmosis separation membrane in which each forward osmosis separation membrane includes an active layer and a support layer, first spacers disposed between two active layers facing each other, and second spacers disposed between two support layers facing each other, wherein a plurality of the first spacers and the second spacers are included so as to form a stack structure together with the forward osmosis membranes, the plurality of the first spacers form a first flow path forming a flow of water to be treated, and the plurality of the second spacers form a second flow path forming a flow of a draw solution.

Abstract: A draw solute including an ionic oligomer having a repeating unit that includes at least two phosphonate moieties and counter ions thereof, and a forward osmosis device and method for water treatment using the draw solute and an aqueous solvent, are disclosed.

Abstract: A draw solute includes a water-soluble alkyl ammonium salt compound, the water-soluble alkyl ammonium salt compound including an ionic moiety and at least two ammonium cationic moieties, the ionic moiety including an anion selected from a carbonate anion (COO?), a sulfonate anion (SO3?), a sulfate anion (SO42?), a phosphonate anion (PO32?), and a phosphate anion (PO43?), and a cation selected from an alkali metal cation and an alkaline earth metal cation.