Reverse Osmosis Reverse Osmosis is the process of water flowing through a semipermeable membrane that does not allow penetration of salts or other dissolved materials this is when two channels of water are separated by the semipermeable membrane. Water will flow from the side of Low concentration to the side of higher concentration. If there are molecules only on one side of the system the pressure that stops the flow is called osmotic pressure. The solute molecules generate osmotic pressure on all the solution boundaries including the membrane, but when water flows between the two sides, it is the pressure on the moving free surface of the solution which is pushing it upward and is responsible for water pumping from the other side.
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