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Environment Water and WastewaterReverse Osmosis
Osmosis is the natural flow of water through a semipermeable membrane from a low solute concentration solution into a solution with a higher solute concentration, in order to equate the concentrations.
Reverse osmosis (RO) is achieved by applying pressure greater than the osmotic pressure to the concentrated solution in order to induce a flow towards the dilute solution.
The RO module utilizes this principle of reverse osmosis with its separation membranes. The NF membrane is a variant of the RO membrane. Univalent ions such as Na+ and Cl- are selectively filtered, but multivalent ions such as SO42- and polyvalent substances such as pigments are blocked.