Activated Charcoal
For Air Purification and Odor Removal
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 ever known. Activated charcoal, also
known as 'activated carbon' is made by burning hardwood, nutshells,
coconut husks, animal bones 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
adsorbents. 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 Ag (Angstroms),
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.