Introduction to Reverse Osmosis
Reverse osmosis is one of the oldest and most popular separation techniques used mainly for the purification of water. The process was mainly adopted for desalination of seawater in the year 1950, where the whole process was relatively slow and limited to certain laboratories. However, after a lot of research and advancements in technology, there were significant developments especially in the field of polymers and production of efficient membranes. Today, this technique is extensively used by many around the world to purify water for industrial, residential, commercial and scientific purposes. While reverse osmosis technology is one of humanity’s important scientific innovations we will develop a basic understanding of the whole process here on this page.
What is Reverse Osmosis?
Reverse osmosis which is also commonly referred to as RO is a type of filtration method used for the removal of molecules and ions from a certain solution. It involves the application of pressure (usually greater than the osmotic pressure) on one side of the solution where a semipermeable membrane is placed in between the solutions. This membrane is used to filter out contaminants down to the smallest particles. The contaminants are often referred to as RO concentrate.
Reverse Osmosis Principle
To break down the process further, due to the presence of membrane, large molecules of the solute are not able to cross through it and they remain on the pressurized side. The pure solvent, on the other hand, is allowed to pass through the membrane. When this happens the molecules of the solute start becoming concentrated on one side while the other side of the membrane becomes dilute. Furthermore, the levels of solutions also change to some degree.
In essence, reverse osmosis takes place when the solvent passes through the membrane against the concentration gradient. It basically moves from a lower to a higher concentration.
The reverse osmosis process is explained below with the help of an experiment.
How does Reverse Osmosis work?
An easy experiment can be conducted taking some freshwater and a concentrated aqueous solution. The solutions should be kept on opposite sides with a semipermeable membrane placed in between to separate the two solutions. Pressure should be applied on the side with the concentrated solution. Now this will result in water molecules moving through the membrane to the freshwater side. This basically sums up the process of reverse osmosis.
Benefits of Reverse Osmosis
Below we have discussed some of the benefits of reverse osmosis –
1. This process can be used to effectively remove many types of dissolved and suspended chemical particles as well as biological entities (like bacteria) from the water
2. This technique has a wide application in treating liquid wastes or discharge
3. It is used in purifying water to prevent diseases
4. It helps in the desalinating seawater
5. It is beneficial in the medical field.