US Patent 9428404 Water extraction using a directional solvent

Purified water can be obtained via a continuous or semi-continuous process by mixing a liquid composition (e.g., sea water or produced frac water) including water with a directional solvent to selectively dissolve water from the liquid composition into the directional solvent. The concentrated remainder of the liquid composition (e.g., brine) is removed, and the water is precipitated from the directional solvent and removed in a purified form. The solvent is then reused as the process is repeated in a continuous or semi-continuous operation.