Reference

Glossary

Every term here appears on a Suracsh datasheet. The point is not to define the industry — it is so you can read our numbers correctly, and know which one actually decides your selection.

Activity

Loose shorthand for adsorption capacity, usually expressed through iodine number or CTC. It is not a standard in itself — always ask which index a stated "activity" refers to, because 60 CTC and 1000 iodine describe different measurements of the same idea.

Apparent density

Also called: bulk density

The mass of carbon that fills a given volume, including the space between particles. It decides how much carbon your vessel actually holds, which is why it drives both fill weight and freight cost. Usually quoted in g/mL or kg/m³.

A denser carbon puts more mass in the same vessel, but mass is not capacity — read it alongside CTC or iodine number, never instead of them.

Ash

The inorganic residue left after complete combustion, as a percentage by weight. Low ash matters where extractable metals or acid solubility would contaminate a product stream. Coconut-shell carbon is naturally low in ash relative to coal-based grades.

Ball pan hardness

A measure of resistance to attrition, reported as a number out of 100. A hard carbon survives handling, backwashing and thermal cycling without generating fines. It is the parameter that predicts whether a bed will produce dust and pressure drop over a service life.

Method: ASTM D3802 is the usual reference method for abrasion.

Hardness is always a minimum specification. If you see it printed as a maximum, that is an error worth querying.

BET surface area

Also called: specific surface area

Internal surface area per unit mass, in m²/g, derived from nitrogen adsorption using the Brunauer–Emmett–Teller model. It is the headline measure of how much adsorption surface exists, though not all of it is accessible to every molecule.

A high BET figure does not guarantee performance for your contaminant — pore size distribution decides whether your molecule can reach that surface.

Breakthrough

The point at which the contaminant concentration leaving the bed rises to a defined limit. Breakthrough time is only meaningful with its test conditions attached: challenge concentration, flow rate, bed depth, temperature and humidity. A breakthrough figure without conditions cannot be compared with anything.

Carbon tetrachloride activity

Also called: CTC

The mass of carbon tetrachloride adsorbed at saturation, as a percentage of the carbon’s own weight. The standard gas-phase capacity index — a 60 CTC carbon adsorbs 60% of its weight under the test conditions. For vapor-phase work it is more informative than iodine number.

Contact time

Also called: EBCT, empty bed contact time

Bed volume divided by volumetric flow rate — how long the gas or liquid spends in the bed. Too short and the contaminant passes through unadsorbed regardless of how good the carbon is. It is a design parameter, not a property of the carbon.

Crushing strength

Also called: compressive strength

The force a pellet withstands before fracturing. It governs how deep a bed can be built before the lower layers collapse under the weight above, and how well the carbon survives pneumatic filling.

Impregnation

Depositing a reactive chemical — caustic, acid, a metal oxide, a metal salt or an amine — into the pore structure so the carbon removes contaminants it could not hold by physical adsorption alone. Ammonia, hydrogen sulfide and mercury all need it.

Impregnated carbon is consumed by the reaction rather than saturated by it, so it is changed out rather than regenerated. Loading percentage is the specification that matters.

Iodine number

Milligrams of iodine adsorbed per gram of carbon. The most widely quoted capacity index, and a good proxy for micropore volume — which makes it most useful for liquid-phase and small-molecule work.

Method: ASTM D4607.

Mesh size

Also called: particle size distribution

The sieve range the granules fall within, written as two numbers: 12 × 40 means the material passes a 12-mesh screen and is retained on a 40-mesh screen. Smaller particles adsorb faster but cost more pressure drop.

Moisture

Water content as packed, by weight. It matters commercially because you pay for water by the tonne, and technically because water occupies pore volume that would otherwise hold your contaminant.

Pressure drop

The loss of pressure across the bed, set by particle size, bed depth and face velocity. Pelletized carbon gives lower pressure drop than granular at the same bed depth, which is why vapor-phase systems tend to specify pellets.

Reactivation

Also called: regeneration

Thermally driving adsorbed material back off spent carbon so it can be reused. It is inherently local to where the spent carbon sits — an overseas manufacturer cannot practically serve it, and Suracsh does not offer it.

Virgin carbon

Activated carbon with no impregnation, working purely by physical adsorption. Suitable for organics and VOCs; largely ineffective against ammonia and only modestly effective against hydrogen sulfide.

A value without a method is not quotable Where our datasheets state a parameter without naming the test method, that is a gap we are closing at source rather than papering over. If you need the method named for a bid, ask and we will confirm it in writing.

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