Author: Leon Zhou
Editors: Shamsia Ahmed and Kira Tian
Artist: Aurora Chen
Water is one of the most vital substances for living organisms and is undoubtedly common in human beings’ life. Every individual needs water to survive, but here’s a cruel fact: even though water covers about 71% of the earth's surface, only 3% of the earth's water is fresh, and about 2.5% of the earth's freshwater is unavailable (locked up in glaciers, polar ice caps, atmosphere, and soil; highly polluted; or lies too far under the earth's surface to be extracted at an affordable cost). In addition to the little amount of freshwater available, a large proportion of water is polluted and can lead to health problems when drunk by people. As a result, the depletion of freshwater resources becomes one of the severest issues waiting to be solved. Researchers are now applying both physical and chemical methods for water purifications. This article will mainly discuss three prevalent chemical methods for purifying water.
Flocculation is the collection of cells into aggregates by the addition of multivalent cations, metal salts, or polymers . During flocculation, fine particles will clump together into a floc. The floc will either fl