10" Glacier Carbon Polisher Filter Cartridge - GAC is made mainly from wood, coal, peat or coconut shell. The carbon‐based material is converted to activated carbon by thermal decomposition in a furnace using a controlled atmosphere and heat.

The activation process dramatically increases the surface area per unit volume and produces a network of sub microscopic pores where absorption takes place. One gram of activated carbon has an approximated surface area of 500m2 or a rugby field.

Physical absorption is the primary means by which activated carbon works to remove contaminants from water. Carbons highly porous nature provides a large surface area for contaminants to collect. The physical absorption accurse because all molecules exert attractive forces. The surface molecules of the carbon attract the molecules dissolved in the water by surface attractive forces similar to gravitational forces.

Water contaminants absorb because the attraction of the carbon surface for them is stronger than the attraction forces that keep them in solution.

Besides physical absorption, chemical reactions also occur on the carbon surface. One such reaction is chlorine removal from water. This involves the chemical reaction of chlorine with carbon to form chloride ions.

The raw materials, method of activation and granular size all have a significant influence on the carbon`s ability to remove contaminants from the water. The heat activated granulated coconut shell carbon has the greatest capacity to remove carcinogenic THM`s from the water.

GAC made from coconut shells is the preferred carbon for POU water purifiers. The limited supply and strong worldwide demand, make it very expensive compared to coal and wood based carbons.

•GAC has a finite capacity to remove contaminants from water. When the available absorption sites are “taken” then the contaminants just pass through untouched. The capacity of the GAC to remove contaminants is dependent on the granular size, the source of the carbon, the method of activation, the contact time with the water and the type of contaminants being removed.

It is important to remember that GAC removes chlorine while trapping organic matter. This created a suitable place for pathogens to accumulate and multiply. This is why it is so important to change carbon purifiers when recommended by the manufacturer.