What is Reverse Osmosis?

In its most basic definition, reverse osmosis is the converse of the naturally-driven osmosis process and therefore to understand reverse osmosis, one must be familiar with the concept/dynamics involved in an osmosis process. Simply put, osmosis is the process when a weak saline solution migrates to a region where the salinity is higher. Migration of the weaker saline solution usually involves permeating through a ‘physical barrier’ normally termed as semi-permeable membrane.

This natural phenomenon is an important process and examples include, how plants absorb water and nutrients from the soil, how our kidneys absorb water from blood and the process of self-hydration- we are in fact causing osmosis so that our cells get the water they require. The illustration below provides a more intuitive understanding of osmosis:

Reverse osmosis does not happen naturally unlike osmosis, but has important implications nonetheless. In the Chemical Concept section, the mechanism of reverse osmosis with relation to drinking water will be explained in greater detail. Applications and significance will then be made known in the Implication to Society section.