A chemical filter works by capturing soluble materials, such as: gas, dissolved organic matter, and the like. This mechanism is done with the help of filter media such as activated charcoal, ion resin, and zeolites, or by fractionation of water.
Absorption is a process where a particle is trapped into the structure of the media and as if a part of the whole media. This process is found mainly in the activated carbon media. Activated carbon has a pore space is very much of a certain size. These pores can capture very fine particles (molecules) and trapped him there. With the passage of time these pores will eventually be saturated with particles so fine that will not work anymore.
To a certain extent some types of activated charcoal can be reactivated again, though not infrequently suggested for disposables. Reactivation of activated carbon is highly dependent on the prior activation method, therefore, to note information on the product packaging. In general, carbon / activated charcoal is usually made of charcoal by heating at a temperature of 600-2000 ° C at high pressure.
In this condition will form fracture-fracture (cavity) is very smooth with a very large number, so that the surface area of the charcoal becomes large. 1gram activated carbon, generally has a surface area measuring 500-1500m2, so it is very effective in capturing particles of very fine size 0.01-0.0000001 mm. Activated carbon is a very active and will absorb any contact with the carbon, both in the water and in the air.
If left in the open air, it will soon absorb fine dust contained in the air (pollution). Within 60 hours of the activated carbon is usually widened saturated and no longer active. Therefore, it is usually activated charcoal packed in airtight packaging.
2) adsorption (Adsorption)
The entrapment is a process where a particle “stuck” on a surface as a result of their “difference” weak charge between two objects (Van der Waals forces), so that eventually will form a thin layer of fine particles on the surface. Carbon surface that is able to attract organic molecules, for example is one example of the adsorption mechanisms, such as occurs in the water-air interface, which is the mechanism which occurs in a protein skimmer.
Organic molecules are polar so that one end will tend to be attracted to water (referred to as hydrophilic / Like water) while the other end is hydrophobic (hates water). Such surface active molecules will be attracted to the water-gas interface on the surface of air bubbles, so that these molecules will form a thin layer there and forming froth / foam.
In a protein skimmer; when air bubbles leave the water to the pitcher foam, air bubble will collapse and eventually organic ingredients will be left in the bin foam concerned.