Activated carbon filtering is the process of cleaning the air or gas flow by removing any impurities and contaminants to further purify and clean it. In activated carbon filters, carbon elements are used to absorb vapors. Activated carbon filters are also available for purification of water by removing elements such as chlorine, volatile organic compounds and sediments.
The working mechanism of activated carbon filters is simple and elegant. The contaminated water passes through the carbon and during its passage, chemicals and other impurities are hold by the carbon and hence, leaving the water clean and free from all such impurities. How efficiently, such chemicals are absorbed, depends upon various factors including physical properties and nature of activated carbon, the amount of oxygen and hydrogen, actual chemistry of the contaminants being absorbed and the pH of water.
There are two types of activated carbons used by activated carbon filters for purification purposes. One is powdered activated carbon while the other is granular activated carbon. In powdered activated carbon, very small size particles are used. The purification process involves addition of this powdered carbon in the water so that contaminants interact with the PAC and then, this PAC is filtered out from the water, leaving contamination free water. The effectiveness of PAC based filtering depends upon the way PAC is mixed with water, the filtration process followed and the amount of contamination in the water.
Granular activated carbons have relatively large particle size and they are also widely used in activated carbon filters to purify water from odors and contaminations. Granular Activated Carbons (GAC) filters have a high initial cost compared to PAC but they surpass PAC in efficiency and their operating cost is also lower than PAC. GAC is a better choice for larger purification systems and when both contamination and odor need to be treated at the same time.