Description

What is Reverse Osmosis plant?

Reverse osmosis (RO) is a membrane filtration method that removes many types of large molecules and ions from solutions by applying pressure to the solution, when it is on one side of a selective membrane. The result is that the solute is retained on the pressurized side of the membrane and the pure solvent is allowed to pass to the other side. To be “selective,” this membrane should not allow large molecules or ions through the pores (holes), but should allow smaller components of the solution (such as the solvent) to pass freely. Reverse osmosis is used to purify Water and remove salts and other impurities in order to improve the color, taste or properties of the fluid.

 

Principle

Osmosis is a natural process. When two liquids of different concentration are separated by a semi permeable membrane, the fluid has a tendency to move from low to high solute concentrations for chemical potential equilibrium.

Osmosis describes how solvent moves between two solutions separated by a permeable membrane to reduce concentration differences between the solutions. When two solutions with different concentrations of a solute are mixed, the total amount of solutes in the two solutions will be equally distributed in the total amount of solvent from the two solutions. Instead of mixing the two solutions together, they can be put in two compartments where they are separated from each other by a semipermeable membrane. The semi permeable membrane does not allow the solutes to move from one compartment to the other, but allows the solvent to move.

Formally, reverse osmosis is the process of forcing a solvent from a region of high solute concentration through a semipermeable membrane to a region of low solute concentration by applying a pressure in excess of the osmotic pressure. The membranes used for reverse osmosis have a dense layer in the polymer matrix where most separation occurs.