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What is reverse osmosis (RO)?

Aug 16, 2018

Reverse osmosis means that when a pressure greater than osmotic pressure is applied on the side of a concentrated solution, the solvent in a concentrated solution will flow to a dilute solution.

This principle is used in the field of liquid separation to purify, remove impurities, and treat liquid materials.

Reverse osmosis membrane working principle: the membrane that has the selectivity to pass through the material is called semi-permeable membrane, and the membrane that can only pass through the solvent but cannot pass through the solute is called ideal semi-permeable membrane.

When a dilute solution of the same volume (such as fresh water) and a concentrated solution (such as salt water) are placed on both sides of the semi-permeable membrane, the solvent in the dilute solution will naturally flow through the semi-permeable membrane and flow spontaneously to the side of the concentrated solution, which is called infiltration.

reverse osmosis equipment .jpg

When the osmosis reaches equilibrium, the liquid surface on the side of the concentrated solution will be higher than that of the dilute solution by a certain height, that is, a pressure difference is formed, which is the osmotic pressure.

Reverse osmosis is a reverse migration movement, is a pressure driven by withholding effect on the choice of a semipermeable membrane separation of the solute in the solvent is separated from solvent method, it has been widely used in all kinds of purification and concentration of solution, one of the most common application is in the water treatment process, using reverse osmosis technology of inorganic ions, bacteria, viruses, organic matter in raw water and colloidal impurities removal, in order to obtain high quality of pure water.