How to Read an Activated Carbon Data Sheet: Iodine Number, CTC, Mesh and More

Two activated carbons can look identical in the bag and perform very differently in your plant. The technical data sheet is where the real differences show. Here is what the most important numbers mean and how to use them when choosing a grade.

Iodine number

Measured in mg/g, the iodine number indicates how much small-molecule adsorption capacity — mainly micropore volume — the carbon has. Water-treatment grades commonly fall somewhere between about 800 and 1,100 mg/g. A higher iodine number generally means more capacity for small organic molecules, but it is a guide rather than a guarantee for every contaminant.

CTC activity

Carbon tetrachloride (CTC) activity is expressed as a percentage of the carbon’s weight and is the classic measure for gas- and vapour-phase grades used in air purification, solvent recovery and respirators. Grades are often named by this value — for example CTC 50 or CTC 60. Higher CTC activity means greater capacity for organic vapours.

Methylene blue value

Methylene blue is a larger dye molecule, so this test reflects the carbon’s mesopores. It is especially useful for decolourisation work — sugar, edible oils, chemicals and pharmaceuticals — where the molecules to be removed are relatively large.

Particle size (mesh)

• Finer granules (such as 12×40) adsorb faster but create more pressure drop.
• Coarser granules (such as 8×30 or 6×12) allow higher flow with less head loss.
• Pellets (typically 3–4 mm cylinders) are preferred for deep gas-phase beds.
• Powder is dosed directly into liquids for the fastest kinetics.

Hardness

Hardness (or abrasion resistance) shows how well the carbon survives handling, backwashing and reactivation without breaking into fines. It is critical for gold recovery circuits and for filters that are backwashed often. Coconut-shell carbons are typically the hardest.

Ash, moisture and apparent density

• Ash is the non-carbon mineral content. Lower ash is preferred for food, beverage and pharmaceutical use.
• Moisture affects how much actual carbon you receive per kilogram purchased.
• Apparent density tells you how many kilograms are needed to fill a given filter volume.

Raw material: the starting point

• Coconut shell — rich in micropores, very hard, low ash. Excellent for drinking water, dechlorination and gold recovery.
• Coal — a broader pore range that handles a wide variety of contaminants; widely used in municipal and industrial treatment.
• Wood — a more open pore structure, ideal for decolourisation.

Test before you commit

Data sheets narrow the choice; a trial on your own water or process confirms it. For food, beverage and pharmaceutical applications, also check the supplier’s certifications such as Kosher, Halal, HACCP and ISO 9001:2015.

Compare our grades on the technical data sheets, or request a sample for your application.