What does the term "adsorption" mean in the context of carbon filters?

In the context of carbon filters, "adsorption" refers to the physical process where contaminants adhere to the surface of the carbon material. This is a crucial mechanism in water treatment, especially when using activated carbon filters. The activated carbon has a high surface area and porous structure, allowing it to attract and hold onto various impurities, such as volatile organic compounds, chlorine, and some heavy metals through van der Waals forces and other interactions.

Adsorption differs from absorption, where a substance permeates or is dissolved in another. In water treatment, the effectiveness of carbon filters largely depends on the adsorbent properties of the activated carbon, which capture pollutants without changing their chemical composition. This ensures that the water is purified without introducing new substances into the system, making it an efficient solution for removing unwanted contaminants.