Granular Activated Carbon Supplier

Granular activated carbon is the most widely bought form of activated carbon on the planet, and also the easiest one to buy badly. Two carbons can both be labelled “GAC 8×30, iodine 1000” and behave nothing alike in your vessel — one runs eighteen months, the other channels and breaks through in five.

This page is written for the person who has to place the order. If you want the engineering side — bed depth, EBCT, vessel sizing — that lives in our GAC system design guide. If you want per-ton numbers, see the activated carbon price guide.

What Granular Activated Carbon Is

GAC is activated carbon crushed and screened into irregular granules, typically between 4 and 40 mesh, then steam-activated at 800–1000°C to open up an internal pore network of 800–1,200 m²/g. The granular form exists for one reason: it holds together in a packed bed under continuous flow, so water or gas can pass through at pressure without the media compacting, blinding, or washing out.

That is the dividing line against the other two forms. Powdered carbon is dosed into a tank and removed with the sludge — it works fast, but you can’t run flow through it. Pellet carbon is extruded into uniform cylinders with a lower pressure drop, which matters in gas phase. GAC sits in the middle and dominates liquid-phase filtration: municipal drinking water, industrial wastewater polishing, point-of-use cartridges, gold recovery columns, sugar and sweetener decolorization.

How to Read a GAC Datasheet

Most GAC disputes trace back to a buyer who compared only iodine number. These are the parameters that decide whether the carbon performs, in the order they usually matter.

Iodine number (mg/g)

The standard proxy for total micropore surface area, measured by iodine adsorption. Higher iodine means more capacity for small molecules. Our coal-based HojeeAqua BG series runs BG400 through BG1000 (iodine >500 to >1,000 mg/g); coconut-shell HojeePure CG grades run CG950 to CG1100 (iodine >950 to >1,100 mg/g).

Iodine number is necessary but not sufficient. It tells you nothing about pore size distribution, so it over-predicts performance on large molecules — humic acids, colour bodies, PFAS — which need mesopores the iodine test never sees.

Bulk density (kg/m³)

The parameter buyers forget and then get burned by. GAC is sold by weight and used by volume. A vessel holding 10 m³ of media needs 4,800 kg of a 480 kg/m³ coconut carbon, but 6,600 kg of a 660 kg/m³ coal carbon — a 37% difference in tonnage on the same purchase order.

Typical ranges: coconut-shell GAC 480–520 kg/m³, coal-based GAC 450–660 kg/m³ depending on grade, wood-based lower still. Always confirm the figure before you compare quotes per ton, because a cheap high-density carbon can cost more per cubic metre of bed filled.

Hardness and abrasion

How much of the granule survives handling, backwash and thermal reactivation. Coconut GAC typically tests above 98–99% hardness; our coal-based grades hold above 95%. Soft carbon generates fines, fines cause head loss and turbidity spikes, and if you plan to reactivate, soft carbon means you lose several percent of the bed every cycle. See the hardness and abrasion number guide for the test methods.

Ash and water-soluble content

Ash is the inorganic residue left after the carbon burns off. Coconut shell GAC runs under 3%; coal-based GAC typically under 12%. High ash means more leachable minerals, higher pH drift on start-up, and in gold recovery, more contaminants competing for adsorption sites. For drinking water and food contact, low ash plus low water-soluble content is what keeps you inside the spec.

Mesh size and uniformity

Mesh controls the trade-off between adsorption kinetics and pressure drop. Finer mesh adsorbs faster with more external surface; coarser mesh runs at lower head loss. What matters as much as the nominal size is how tightly the distribution is held — a sloppy 8×30 with 10% oversize and 8% fines will channel. Ask for the actual screen analysis, not just the label. Our mesh size guide maps common cuts to applications.

Moisture

Usually specified at ≤5%. It matters because you pay for it. Carbon shipped at 12% moisture instead of 5% means roughly 7% of every container is water.