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Types of Carbon Filters

Carbon filters are commonly used to remove sediment, rust and chlorine from drinking water to make it cleaner and better tasting. Different types of carbon filtration systems offer different levels of efficiency at varying costs. While no carbon filter is capable of eliminating bacteria, radioactive materials or heavy metals, they are nonetheless quite useful for basic water purification in domestic settings.

  1. Carbon-Pleated Filters

    • Carbon-pleated filters are cartridges in which the cellulose or polyester pleating has been saturated with powdered activated carbon. Often the cheapest type of carbon filter, carbon-pleated cartridges are most effective at filtering the sediment and chlorine out of household water for improved odor and taste. While carbon-pleated filters are reasonably priced, they are not considered to be the most thorough method of household carbon filtration.

    Granular Carbon Filters

    • Granular activated carbon particles are larger than powdered activated carbon particles cartridges and are better at filtering slower water flows. Granular activated carbon filters usually take the form of a canister with a compression pad and a post-filtration secondary filter. The compression pad in these canisters serves to keep the water in the filter longer for more thorough filtration, while the secondary filter picks up finer particulates not initially absorbed as the water passes out the other end of the canister. Because they are ineffective with filtering heavy and rapid water flow, they are more useful in applications such as filtering water in municipal water treatment pools for taste, odor and chemical reduction.

    Carbon Block Filters

    • Carbon block filters are manufactured by grinding granular activated carbon, powdered activated carbon and plastic polymers together, pouring them into a mold and then heating them until they've bonded together. After the mixture has cooled into a solid block, the block is wrapped in a sediment filter screen and then placed in a cartridge container. Incoming water flows in through the side of the cartridge and moves to the carbon block in the center to be filtered. Some carbon block filter designs are advanced enough to remove volatile organic compounds and pesticides as well as sediment and chlorine.

    Impregnated Carbon Filters

    • With these types of filters, porous carbons are saturated with an inorganic, antimicrobial substance such as silver, with water being filtered through this impregnated carbon by means of adsorption, the binding of molecules or particles to a surface. Another substance that is sometimes combined with porous carbon in an impregnated carbon filter system is aluminum hydroxide, which collects water impurities and transforms them into easily removed clumps.

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