สินค้าใหม่

           Reverse osmosis (RO) is a water purification technology that uses

a sempiermeable membrane to remove ions , molecules, and larger particles

from drinking water. In reverse osmosis, an applied pressure is used to

overcome osmotic pressure, a colligative property, that is driven by chemical

potential differences of the solvent, a thermodynamic parameter. Reverse

osmosis can remove many types of dissolved and suspended species from

water, including bacteria, and is used in both industrial processes and the

production of potable water. The result is that the solute is retained on the

pressurized side of the membrane and the pure soolvent 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 solvent molecules) to pass freely.

           In the normal osmosis process, the solvent naturally moves from an

area of low solute concentration (high water potential), through a membrane,

to an area of high solute concentration (low water potential). The driving force

for the movement of the solvent is the reduction in the free energy of the

system when the difference in solvent concentration on either side of a

membrane is reduced, generating osmotic pressure due to the solvent moving

into the more concentrated solution. Applying an external pressure to reverse

the natural flow of pure solvent, thus, is reverse osmosis. The process is

similar to other membrane technology applications. However, key differences

are found between reverse osmosis and filtration. The predominant removal

mechanism in membrane filtration is straining, or size exclusion, so the

process can theoretically achieve perfect efficiency regardless of parameters

such as the solution's pressure and concentration. Reverse osmosis also

involves diffusion, making the process dependent on pressure, flow rate, and

other conditions. Reverse osmosis is most commonly known for its use in

drinking water purification from seawater, removing the salt and other

effluent materials from the water molecules.