A method for purifying a liquid is described. A liquid feed is fed to a feed chamber. A carrier gas is fed through the liquid feed in the feed chamber to form a humidified carrier gas. A coolant is fed to a coolant chamber. The coolant chamber is separated from the feed chamber by a permeate gap chamber. The permeate gap chamber is separated from the feed chamber by a membrane that allows vapor to pass while blocking liquid flow across the membrane. The coolant chamber is separated from the permeate gap chamber by a thermally conductive plate. At least a portion of the vapor from the feed chamber that transported through the membrane is condensed by the coolant in the coolant chamber and the thermally conductive plate to form a first distillate. At least a portion of the humidified carrier gas is condensed to form a second distillate.

A method of making a polyimide membrane includes mixing dianhydride and phenylenediamine monomers in a first solvent to form a mixture; heating the mixture thereby polymerizing to form a polyimide polymer in a crude mixture; precipitating and separating the polyimide polymer from the crude mixture; mixing and dissolving the polyimide polymer in a second solvent to form a polyimide solution; applying the polyimide solution onto a surface of a substrate to form a polyimide liquid layer on the substrate; immersing the substrate after the applying in at least one liquid medium selected from the group consisting of water and alcohol, thereby precipitating the polyimide polymer from the polyimide solution to form the polyimide membrane disposed on the surface of the substrate. A desalination system containing the polyimide membrane, and a desalination process.

Provided are a concentration method and system for concentrating a raw material solution, and in which a raw material solution containing a solute and a solvent is concentrated to obtain a concentrate of the raw material solution, wherein the solvent contains water and an organic solvent. In the method and system for concentrating a raw material solution, the system includes a combination of: a first concentrating means for removing water in the raw material solution by means of a forward osmosis method; and a second concentrating means for evaporating and removing water and an organic solvent in the raw material solution.

A system for desalinating water using membrane distillation (MD) integrated with an ejector includes an ejector module and a membrane module. The ejector module includes a water ejector, a first water circulation pump, and a freshwater tank. Freshwater is continuously pumped from the freshwater tank, through the water ejector, and back to the freshwater tank. The membrane module includes a feed tank, a second water circulation pump, a water heater, and a membrane distillation unit. Salt water from the feed tank is pumped through the water heater to form vapor, which is then directed to the membrane distillation unit. The membrane distillation unit comprises a feed chamber, a membrane, and a vapor chamber. Vapor passes through the membrane to the vapor chamber, which has an air inlet for pressure differential and is connected to the water ejector. Desalinated water is collected in the freshwater tank.