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Membrane distillation (MD) is a thermally driven separation process in which separation is driven by phase change. A hydrophobic membrane presents a barrier for the liquid phase , allowing the vapour phase (e.g. water vapour) to pass through the membrane's pores. [ 1 ]
Selective electrodialysis uses ion selective exchange membranes to concentrate only some ions, whereas other species remain in the diluted channel. Selective electrodialysis is usually done by employing monovalent anion and/or cation exchange membranes, that only allows migration of monovalent anion or cations, respectively.
Electrodialysis reversal (EDR) is an electrodialysis reversal water desalination membrane process that has been commercially used since the early 1960s. [1] An electric current migrates dissolved salt ions, including fluorides, nitrates and sulfates, through an electrodialysis stack consisting of alternating layers of cationic and anionic ion exchange membranes.
Compared to RO membranes, ion exchange requires repetitive regeneration when inlet water is hard (has high mineral content). [citation needed] Industrial and analytical ion-exchange chromatography is another area to be mentioned. Ion-exchange chromatography is a chromatographical method that is widely used for chemical analysis and separation ...
An ion-exchange membrane is a semi-permeable membrane that transports certain dissolved ions, while blocking other ions or neutral molecules. [1] Ion-exchange membranes are therefore electrically conductive. They are often used in desalination and chemical recovery applications, moving ions from one solution to another with little passage of ...
The membrane assembly consists of a pressure vessel with a membrane that allows feedwater to be pushed against it. The membrane must be strong enough to withstand the pressure. RO membranes are made in a variety of configurations. The two most common are spiral-wound and hollow-fiber. Only part of the water pumped onto the membrane passes through.
The membrane separation of the FO process in effect results in a "trade" between the solutes of the feed solution and the draw solution. The forward osmosis process is also known as osmosis or in the case of a number of companies who have coined their own terminology 'engineered osmosis' and 'manipulated osmosis'.
Electrodeionization (EDI) is a water treatment technology that utilizes DC power, ion exchange membranes, and ion exchange resin to deionize water. EDI is typically employed as a polishing treatment following reverse osmosis (RO), and is used in the production of ultrapure water. It differs from other RO polishing methods, like chemically ...