Granular Activated Carbon Coal Based 25kg

Granular Activated Carbon Water Filtration Media
 
Coconut shell base activated carbons have a much higher pore size in the micro-porous region and a slightly lower pore volume in the macro-porous region. This is because coconut char is less amorphous (harder, more crystalline-like) than coal. The result is that coconut based activated carbon adsorbs smaller organic molecules, such as chloroform and other trihalomethanes (THMs), trichloroethylene (TCE), carbon tetrachloride and MTBE (methyl tertiary-butyl ether), while coal-based carbons more effectively remove larger molecules, such as colour-producing compounds (tannins and humics). The predominance of micro-pours in coconut shell carbon gives it tight structure and provides good mechanical strength and hardness and also high resistance to resist attrition or wearing away by friction.
 
Granular Activated Carbon Filter Media Products
Granular Activated Carbon (GAC) is commonly used for removing organic compounds and residual disinfectants such as chlorine from water supplies. GAC improves taste, smell and minimises health risks, it also protects other water treatment systems such as reverse osmosis membranes and ion-exchange resins from possible damage due to oxidation or organic fouling. Granular Activated carbon is a widely used water treatment technique because of its multifunctional nature and the fact that it adds nothing to the purified water.
 
The two principal mechanisms by which GAC removes contaminants from water are adsorption and catalytic reduction. Organics are removed by adsorption and residual disinfectants are removed by catalytic reduction.
 
Factors that affect the performance of activated carbon are
 
Water feed pH for GAC
Most organics are less soluble and more readily adsorbed at a lower pH. As the pH increases, removal decreases. A rule of thumb is to increase the size of the granular activated carbon filter media bed by twenty percent for every pH unit above neutral (7.0).
GAC Contaminant concentration
 
The higher the contaminant concentration, the greater the removal capacity of granular activated carbon. The contaminant molecule is more likely to diffuse into a pore and become adsorbed. As concentrations increase, however, so do effluent leakages. The upper limit for contaminants is a few hundred parts per million. Higher contaminant concentration may require more contact time with the GAC filter media. Also, the removal of organics is enhanced by the presence of hardness in the water, so whenever possible, place the granular activated carbon filtration units upstream of the ion removal units. This is usually the case anyway since GAC filter water media is often used prior to ion exchange or membranes to remove chlorine.
 
GAC Grain size
Granular Activated Carbon is commonly available in 8 by 30 mesh (largest), 12 by 40 mesh (most common), and 20 by 50 mesh (finest). The finer mesh gives the better contact and the best removal, but at the expense of higher pressure drop. A rule of thumb here is that the 8 by 30 mesh gives two to three times better removal than the 12 by 40, and 10 to 20 times better kinetic removal than the 8 by 30 mesh.
 
GAC Flow rate
The lower the feed water flow rate, the more time the contaminants will have to diffuse into a pore and be adsorbed by the granular activated carbon. Adsorption by activated carbon is almost always improved by a longer contact time with the filter media. Again, in general terms, a GAC bed of 20 by 50 mesh can be run at twice the flow rate of a bed of 12 by 40 mesh, and a carbon bed of 12 by 40 mesh can be run at twice the flow rate of a bed of 8 by 30 mesh. Whenever considering higher flow rates with finer mesh carbons, watch for an increased pressure drop!
 

Temperature
Higher water temperatures decrease the solution viscosity and can increase die diffusion rate of GAC, thereby increasing adsorption. Higher temperatures can also disrupt the adsorptive bond and slightly decrease adsorption. It depends on the organic compound being removed, but generally, lower temperatures seem to favour granular activated carbons adsorption.
 
Organic Removal with GAC
Organic material in public water supplies comes from decaying plant life, which becomes more soluble in water over time and exists as large, high-molecular weight organic acids (non-polar weak acids). Eventually, smaller molecular weight acids of varying sizes form. Typical organic acid molecules range in molecular weight from a few hundred to tens of thousands.
The size, number and chemical structure of organic acid molecules depend on a large number of factors, including water pH and temperature. Accordingly, there exists an almost infinite number of organic acids. As a result, removing organics can be difficult and is
always site-specific.
 
Granular activated carbon's adsorptive properties are used to remove organics. Generally, adsorption takes place because all molecules exert forces to adhere to each other. GAC filter media adsorbs organic material because the attractive forces between the carbon surface (non-polar) and the contaminant (non-polar) are stronger than the forces keeping the contaminant dissolved in water (polar).

The adsorptive forces arc weak and cannot occur unless the organic molecules are close to the carbon's surface. The large surface am of the activated carbon, due to its particle size and pore configuration, allows for the adsorption to take place.
 
GAC’s Ability to Remove Residual Disinfectants
Granular Activated Carbon can remove and destroy residual disinfectants (chlorine and chloramine) through a catalytic reduction reaction. This is a chemical reaction that involves a transfer of electrons from the activated carbon surface to the residual disinfectant. In other words, GAC acts as a reducing agent.
 
Activated carbon's removal of chlorine reduces the chlorine to a non-oxidative chloride ion. The reaction is very fast and takes place in the first few inches of a new activated carbon bed. (Where removal of organics by activated carbon takes minutes, removal of chlorine literally takes seconds). The chlorine capacity of new activated carbon is 500 gram of chlorine per 500 gram of granular activated carbon at a flow rate of 11 to 18 l / min and a bed depth of 900mm.
 

Activated carbon is a proven technology for the removal of naturally occurring organics and residual disinfectants. Designing an activated carbon filtration system needs to take into account the differences in the water to be treated, the type of activated carbon used, and the effluent quality and operating parameters.
 
Catalytic Activated Carbon
IndoCarb offers a wide range of activated carbons for catalyst markets. The range comprises of standard high activity coconut shell based granular grades, and acid washed grades that have enhanced catalytic carrier properties.
 
Chloramine removal - Chloramines are disinfectants used to treat drinking water formed when ammonia is added to chlorine to treat drinking water. The typical purpose of chloramines is to provide longer-lasting water treatment as the water moves through pipes to consumers. Unfortunately, chloramine is not without harmful side-effects. These include compromises of the immune system, respiratory problems, skin problems, digestive problems and even kidney and blood disorders have been reported. Chloramines cannot be removed by passing water through the same activated carbon filters used for chlorine removal because these filters are too small at their designed flow rates.