DO ACTIVATED CARBON FILTERS WORK HOW TO

The problem with the activated carbon bed is that over time, the gaseous pollutants increasingly fill up the adsorption sites of the activated carbon. The process of adsorption allows carbon air filters to filter organic chemicals (gases) from the air. When a molecule of some gaseous substance comes through the carbon, it can stick to the surface of the bed, provided there is an open adsorption site. The activation process is so important because the increase in surface area gives gases a greater area to stick to. Whereas with absorption, the pollutants are absorbed inside the structure itself–as with the sponge.Ĭarbon is a lattice of carbon atoms connected to each other. The key difference here is that during adsorption the pollutants stick to the outside of the carbon. It just fills in the spaces inside it.Ĭarbon filters on the other hand use ad-sorption, not ab-sorption. Therefore, when you absorb water with a sponge, the water does not become chemically bonded to the sponge. In absorption, the substance you want to remove (let’s say water) is absorbed into the structure of the absorbent (like a sponge), but it doesn’t become a part of the absorbent on a molecular level. Note that this is different from absorption. Airborne gaseous chemicals (specifically volatile organic chemicals, or VOCs) stick the surface of carbon air filters until the filter surface is fully saturated.Īctivated carbon air filters remove pollutants from the air with a process known as adsorption. How do carbon air filters trap gaseous pollutants?ĭiagram: Adsorption is very different from absorption. The production and use of activated carbon grew dramatically only after World War II, eventually leading to the development of modern activated carbon air filters, as well as water filters. In World War I, gas masks utilized charcoal air filters to remove some of the deadly gases used against the troops, but it was only effective against some of the toxins. We know that sailors in the 16th through 18th centuries often stored their drinking water in barrels that had either been charred or smeared with charcoal on the inside to keep the water fresh on long voyages. The Egyptians appear to have been the first to use it in a medical way, to remove odors associated with infections.

How did humans figure out that carbon can be effective at filtering contaminants? It is likely the earliest use was to remove impurities in smelted metal for the manufacture of bronze. The colorful history of using carbon filtration Most activated carbon is also treated with a chemical that enhances its ability to filter specific pollutants. A study in the Annals of Internal Medicine notes that a single gram of activated carbon can have hundreds of square meters of internal surface area. This creates many more places for molecules to become trapped and makes the carbon far more effective as a filter medium. First, it is injected with hot air, carbon dioxide, or steam, which creates a lattice of tiny pores in the carbon, vastly increasing its surface area. Each substance creates a slightly different kind of charcoal.Īctivated carbon is carbon that has undergone some additional processing to make it better at trapping gas molecules. Wood is commonly used to make charcoal, but coconut shells and coal are also used. The industrial process of making charcoal accomplishes it by heating a substance in a vacuum chamber, which releases all the volatile compounds and leaves behind all the carbon. The black char that remains is mostly carbon. Only the readily combustible material in the wood has burned away, either because of insufficient heat or poor supply of oxygen. Picture the charred piece of wood that is left over after a campfire. These interchangeable terms refer to the remnants of incomplete combustion. Humans have been using charcoal to purify water–sometimes accidentally–for thousands of years. They cannot remove fine particles like mold, dust, or pollen from the air. They are also often used to remove odors from the air, such as the smell of tobacco smoke. They are designed to filter gases through a bed of activated carbon (also called activated charcoal) and are usually used to combat volatile organic compounds (VOCs) released from common household products. Drawbacks to using activated carbon filtersĬarbon air filters are the filters most commonly used to remove gases.

DO ACTIVATED CARBON FILTERS WORK HOW TO

How to effectively use an activated carbon air filter.How do carbon air filters trap gaseous pollutants?.The colorful history of using carbon filtration.The colorful history of carbon filtration.

Do activated carbon filters work