Clay cleans water primarily through its ability to remove contaminants by ion exchange, adsorption, or a combination of both.
Here's a more detailed explanation:
-
Ion Exchange: Clay minerals possess a net negative charge due to their structure. This allows them to attract and hold positively charged ions (cations) like heavy metals (e.g., lead, cadmium) and ammonium. These harmful cations are exchanged for less harmful ones already present in the clay structure, effectively removing them from the water.
-
Adsorption: Clay surfaces have a large surface area and are capable of attracting and holding pollutants onto their surfaces. This process, known as adsorption, can remove various contaminants, including organic molecules, bacteria, and viruses, from the water. The attraction is due to physical forces (van der Waals forces) or chemical bonding.
-
Combination of Ion Exchange and Adsorption: In many cases, both ion exchange and adsorption mechanisms work together to remove pollutants from water. For instance, a clay mineral might first adsorb an organic pollutant onto its surface and then bind it more strongly through ion exchange.
In summary, clay's effectiveness in water purification stems from its unique structure and properties, which enable it to bind and remove a wide range of pollutants through ion exchange, adsorption, or a combination of the two.
