Technology » What is Reverse Osmosis

Reverse osmosis (RO) is a 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. In the normal osmosis process the solvent naturally moves from an area of low solute concentration, through a membrane, to an area of high solute concentration. The movement of a pure solvent to equalize solute concentrations on each side of a membrane generates a pressure and this is the "osmotic pressure." Applying an external pressure to reverse the natural flow of pure solvent, thus, is reverse osmosis. The process is similar to membrane filtration. However, there are key differences between reverse osmosis and filtration. The predominant removal mechanism in membrane filtration is straining, or size exclusion, so the process can theoretically achieve perfect exclusion of particles regardless of operational parameters such as influent pressure and concentration. Reverse osmosis, however, involves a diffusive mechanism so that separation efficiency is dependent on solute concentration, pressure, and water flux rate.[1] Reverse osmosis is most commonly known for its use in drinking water purification from seawater, removing the salt and other substances from the water molecules.

Benifits Reverse Osmosis
When trying to find a water filter system for the office or house, it is usually helpful to check out reverse osmosis water filter reviews to see what brands or types of reverse osmosis water filters are available on the market and which ones have been verified by a water purification organization. There are numerous forms of reverse osmosis water filters, like the countertop reverse osmosis water filter, so the type of filter fits the family or office's lifestyle and requirements.

Types of Systems
Reverse osmosis water filter reviews give useful information about what a reverse osmosis water filter does and the advantages of that filter versus some of the other filters on the market. A reverse osmosis water filter uses a fine membrane to clean the water. This allows the reverse osmosis water filter to sift out mineral, chemicals and dangerous metals from the water.

Reverse osmosis water filter reviews will also warn that a pre-filtration system might have to be purchased in addition to the reverse osmosis water filter if there is a high chlorine count in the water. The reason for this is that the membrane used in a reverse osmosis water filter system is really delicate and the chlorine in water can eat away at it and ruin the filter.

You will find three main kinds of reverse osmosis water filters mentioned in reverse osmosis water filter reviews. The first kind is the countertop water filtration system. This kind of system has a filtration device that sits on the countertop as its name implies. It is then hooked to the faucet so that water can flow into the system and keep the tank filled to capacity with filtered water. Although the system utilizes the same process of reverse osmosis, it is clumsy and bulky since it sits on the countertop that is taking up space and also only holding a great amount of water at a time. This is the least preferred model in most reviews.

This kind is almost in the same price bracket as the countertop systems, but the device is saved in the cabinet beneath the sink. The system is hooked in the water pipe under the sink by a plumbing technician and a new faucet is set up that will pump the purified water; leave the main faucet to be used with the unfiltered water. This system allows for unlimited amounts of purified water to be used during a day.

The other type of system mentioned in reverse osmosis water filter reviews is the point of entry system that is hooked in the water main for the house or office. This type of system is costlier and also has to be set up by a plumbing technician. Even though it is a good system, sometimes the cost could be a hindrance from use.