Archive for July 2016

Carbon Filters

Carbon filters use a bed of activated carbon to remove impurities. They are commonly used in water or air purification, in cigarette filters, in respirator masks and in the recovery of precious metals. Activated carbon is a form of carbon that is processed to have small pores which increase the surface area. Because it is so porous one gram has a surface area of one thousand three hundred square metres and this is why carbon filters are useful. This means that it is ideal for use in a filter system as the particles that are being removed have a lot of contact with it, increasing the level of filtration. The activated carbon works by a process called adsorption – where particles from a gas or liquid adhere to the surface of it. The filters often include silver as well in order to prevent bacterial growth and increase the lifespan of the filter.

This type of filtering has been used for several hundred years, particularly for water purification. It may even have been used by ancient Egyptians! They are most commonly found now in homes for to filter the water supply. Carbon filters are also widely sold for the purposes of odour removal as part of an air conditioning unit or extractor fan. This type of filter is easily available to anyone who wishes to purchase one, although there are different types to consider. They are also commonly used in hydroponics to control the odours associated with it.

Another major use of activated carbon as a filter is in the purification of biogas, for example from landfill or agricultural waste. This is a particularly important application of the technology as the biogas produced can be used to produce green energy which is an increasing concern around the world.

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