You probably have heard reverse process as a water purifying process for many times now. You should know that it is a very important and very effective way of purifying water. In general, the process is used not just in residential and commercial water filtration.
Reverse osmosis is the top method used when desalinating seawater so it could be converted into a form that could be commercially drank and consumed by people. In many industries, the process is also used when purifying liquids, wherein water serves as the undesirable impurity that should be taken out (like in the case of ethanol).
To better understand the process, it would be appropriate to review osmosis. Back in the days when you were studying general science, you have discovered that there is diffusion to balance things out. Diffusion happens in the air, while osmosis on water or liquid. The idea is that through osmosis, molecules in water would move to balance two water bodies with different concentration.
For example, if a cell lack concentration of a substance that is abundant in its external, osmosis would work so that molecules from the outside would pass through cell’s semi-permeable membrane to enter the cell. The process goes on until concentration on both the outside and inside of the cell is equal.
Through the years, science has also discovered that the natural process of osmosis could be effectively slowed, stopped, prevented, and even reversed. Reversal of the osmosis process could be possible only if there would be adequate pressure to be applied to the involved membrane coming from the more concentrated side. In some instances, the reverse osmosis is referred to or described as a process of filtration, especially when it is used to purify water.
There is a need to force the solvent in a region where there is higher concentration into getting through the semi-permeable membrane so that it could transfer without much hassle into the region of lower solute concentration. This force is often called osmotic pressure. Membranes used have denser barrier layer to facilitate better separation. Usually, such membranes and designed specifically to allow passage of water only and prevent passing of solutes like in the case of salt ions in seawater desalination. In general, much higher pressure is applied when doing reverse osmosis to purify salt water than used to purify brackish or fresh water.
Reverse osmosis as a water purification process has gotten so popular that many households these days are investing in setups and devices to facilitate the process. Household reverse osmosis devices or units are using much water due to low back pressure.
Though such systems are economical and are convenient, experts assert that they are not as effective as intended. Water recovered is only at 5% to 15%, so the household may need to use more water to be able to fill the desired and required amount. Many people could attest that such devices are yet to be improved to bolster practicality for household use.
The process of reverse osmosis is very promising. But scientists and investors are still underway to discover and develop more effective and efficient ways to prompt and facilitate the process. In the end, this could be a hope to be used and applied in areas where pure and safe drinking water is much of a problem.