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Do you know which properties of activated carbon are measurable?

As diverse as carbon is in the chemical world, just so is the diversity of activated charcoal in its applications. One activated charcoal manufacturing company logo goes “A thousand applications today, a thousand and one tomorrow”. It might also be said of charcoal “Imagine the Possibilities”.coconut shell-based activated carbons

In review, we drink water filtered by it; breath air scrubbed with it; eat food purified through it, wear clothes made with it; grow our food and flowers in it; go to war with it; preserve things in it; enjoy hundreds of dishes cooked by it; we move mountains with it; we make the night sky sparkle with it; we take it with us to the bottom of the deepest oceans and out into space; swim in water washed with it; paint or draw our inspirations with it; and we record man’s history of successes and mistakes dipped in it. Not least and not last, charcoal is called upon to clean up many of our technological mistakes. No wonder we naturally warm up to it.

Not all activated carbon are created equal. In fact there are well over 150 different specialized activated carbons for multiple more applications. But the desired end result is most often the ability to remove something that is deemed undesirable. It may be CO2 from the air in nuclear submarines, SO2 from fuel cells in the new hybrid cars, unwanted color from vegetable oil, unpleasant odor from pharmaceuticals, biological chemicals in combat suits, drug poisoning in cases of attempted suicide, liver toxins in liver dialysis machines... To do this manufacturers tailor make activated carbons to target specific sized molecules with specific chemical characteristics. To help differentiate these activated carbons the industry has recognized certain measurable properties.

Iodine Number
Many carbons prefer to adsorb small molecules. The Iodine number is a basic measurement used to characterize activated carbon performance. It is a measure of activity level (higher numbers indicate a higher degree of activation), often measured in mg/g (common range 500-1200 mg/g). The Iodine number represents the micropore content of the activated carbon relative to the amount of iodine adsorbed from solution. Iodine Number coincides with Surface Area measurements of activated carbon between 900 m²/g and 1100 m²/g. Iodine Number is the standard measure for water/liquid applications. The Iodine number is essentially a measure of the iodine adsorbed into the pores of an activated carbon of interest, indicating the pore volume that is available. For example, GAC used for water treatment have Iodine numbers ranging from 600 to 1100mg/g.

Some activated carbons are more inclined at adsorb large molecules. A molasses number indicates the macropore content of the activated carbon (larger than 20 Å or 2 nm) by adsorption of molasses from solution. A high molasses number indicates a high adsorption of big molecules (range 95-600). Since color molecules typically are large, the Molasses Number is a measure of the degree of decolorization. Due to the size of color bodies, the molasses number represents the potential pore volume available for larger adsorbing activated carbons.

Tannins have a mixture of large and medium size molecules. Activated carbons that combine macropores and mesopores adsorb tannins very well. This ability to adsorb tannins is reported in parts per million concentration (range 200 ppm-362 ppm).

Methylene blue
Activated carbons with a mesopore (20 Å - 50 Å, or 2 - 5 nm) structure adsorb medium size molecules like the dye Methylene Blue. Methylene Blue adsorption is reported in g/100g (range 11-28 g/100g).

Some activated carbons are evaluated on their ability to remove chlorine. The dechlorination half-value distance equals the depth of AC required to reduce the chlorine level of a liquid stream from 5 ppm to 3.5 ppm. The lower the half-value the better the performance.

Ash content
Ash content reduces an activated carbon's activity potential. Ash content reduces the ability to reactivate used carbons. If metal oxides (Fe2O3) are present in the activated carbon, they can leach out and cause discoloration. Acid or water soluble ash content is more problematic than total ash content. Soluble ash content can be very important for fish aquarium enthusiasts. A low soluble ash content is vital for marine, freshwater fish and reef tanks to minimize the risk of heavy metal poisoning and excessive plant/algal growth.granular activated carbon wholesale

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