A method of treating an aqueous liquid. The method comprises providing an aqueous feed liquid comprising water and at least one solute to a first side of a membrane. A draw solution comprising water and a draw solute comprising at least one of a phosphazene compound and a triazine compound is provided to a second side of the membrane. At least a portion of the water of the aqueous feed liquid is osmosed across the membrane and into the draw solution to form a diluted draw solution comprising water and the draw solute. The water of the diluted draw solution is separated from the draw solute of the diluted draw solution to form a purified water product. Draw solutes comprising phosphazene compounds and draw solutes comprising triazine compounds are also disclosed, as are methods of forming the draw solutes.