Activated charcoal has been in use for centuries as an air/water purifier, health supplement and chemical ‘scrubber’, in fact activated carbon has some of the strongest physical adsorption properties of any material even known. Activated charcoal, also known as ‘activated carbon’ is made by burning hardwood, nutshells, coconut husks, animal cones and/or other carbonaceous materials. The charcoal becomes ‘activated’ by heating it with steam to high temperature levels in the absence of oxygen. This removes any non-carbon elements and produces a porous internal microstructure with an extremely high surface area. A single gram of a high quality activated charcoal can have 400 – 2000 square maters of surface area, 98% of which is internal. This means 5 g of activated charcoal can have an adsorption surface area greater than a football field. The actual active surface area, characteristics and performance of a particular activated carbon source depends largely on the nature of the material it was manufactured from and the process by which it was ‘activated’.
It is this huge surface area of activated charcoal where the unwanted molecules are adsorbed and trapped. ‘Adsorption’ means the impurities in the air are attached to the surface of the activated carbon by a chemical attraction. When certain chemicals pass next to the carbon surface they attach to the surface and are trapped. ‘Absorption’ is incorporation into the carbon’s structure through pores, this occurs before the process of adsorption. Activated carbon can adsorb an extremely wide spectrum of adsorbates. This is because activated carbon has different types and/or sizes of pores within it’s internal structure.
Activated carbon manufactured from coconut husk has one of the largest activated surface areas combined with a high percentage of micro pores in the size range 5 – 10 Ao (Angstoms), making it ideal for removal of odorous compounds, gases from volatile organic compounds (VOCs), and gases of a low molecular weight. Removal of gases originating from volatile organic compounds is important in many different situations, as these come from organic chemicals that have a high vapor pressure and easily form vapors at normal temperatures. Many industrial and consumer products ranging from office supplies, building materials and in particular many plants, trees and micro-organisms such as bacteria, produce volatile organic compounds and activated carbon is the most effective way of removing these from the air. For this reason activated charcoal manufactured from coconut husk is used in a wide range of air purification systems from fume hoods, respirators, gas masks, cooker hoods and air purifiers for indoor gardening. Where indoor air quality is being compromised by odors and gases from volatile organic compounds, air filtration with coconut husk activated carbon is the safest and most effective way of dealing with the problem.
In a grow room situation, there may be unwanted odors, and gaseous organic compounds which are best removed, but where plants are grown, there is usually also the occasional use of pesticide products. Many of the pesticides we use, particularly in a confined space, can in fact remain in the air for over 48 hours, depending on the droplet size used during application. This poses a potential danger to anyone entering that area and often there is no evidence that the pesticide is still present as tiny droplets in the air. Activated charcoal air filters are extremely effective at adsorbing and deactivating air borne pesticide residues so that they can not be inhaled. Once the pesticide, or any odor or other gaseous molecules has been adsorbed onto the activated charcoal it is biologically inactive and held in place until the filter is changed and replaced.
Since activated charcoal is no more than an amorphous form of carbon – meaning it has no regular atomic structure like the other forms of elemental carbon (diamond, graphite etc), it is completely safe to use and handle. The final thing to remember, that despite the huge adsorption capacity and surface area of coconut based activated carbon, eventually the material will need to be replaced, so always follow the manufactures recommendations on how often this should be carried out so that your growing environment stays clean and fresh smelling.