Which of the following is used in water purification?

Reverse Osmosis (RO) is a widely used and highly efficient process for water purification. It works on the principle of osmosis but in the opposite direction. In natural osmosis, water moves from a region of lower solute concentration to a region of higher solute concentration through a semi-permeable membrane. However, in reverse osmosis, external pressure is applied to the solution with higher solute concentration, forcing water molecules to move through the membrane to the pure side, leaving impurities behind.

This process effectively removes dissolved salts, heavy metals, microorganisms, and other contaminants from water. The semi-permeable membrane used in RO systems has microscopic pores that allow only water molecules to pass through, ensuring that impurities like lead, arsenic, nitrates, and chlorine are filtered out. This makes RO one of the most reliable methods for producing safe drinking water.

RO is commonly used in households, industries, and desalination plants. In domestic water purifiers, it helps ensure clean and safe drinking water by eliminating harmful chemicals and pathogens. In industries, RO systems purify water for manufacturing processes, pharmaceuticals, and food production. In coastal areas, RO-based desalination plants convert seawater into freshwater, addressing water scarcity issues.

While RO is highly effective, it also has certain limitations. It can waste some amount of water and remove beneficial minerals like calcium and magnesium, which are essential for human health. To counter this, many modern systems add mineral cartridges that reintroduce essential minerals after purification.

In summary, Reverse Osmosis is the process used in water purification because it efficiently removes a wide range of impurities through a physical filtration method. It plays a vital role in ensuring water safety, environmental sustainability, and public health.