Activated Carbon Density: Everything You Should Know

The activated carbon density or what some would say the activated charcoal density is all about filling a filter or filling a silo. This means that the density of a product is important to understand, and this is not different with activated carbon compared to any other material.

The density of activated carbon in an important characteristic of both powder (PAC), extruded (EAC) and granular activated carbon (GAC). For powder activated carbon it is important to know the density for example for volumetric dosing in water purification and for extruded and granular activated carbon it is important to know the density when filling a filter with carbon for example for siloxane removal from biogas ( gas purification ). To understand the “density of carbon” a bit better we will briefly discuss the following density’s;

• Apparent density of activated carbon (bulk density)
• Apparent density backwashed and drained of activated carbon
• Reactor density of activated carbon

Apparent density or activated carbon bulk density

The apparent density, sometimes called the bulk density of activated carbon, or volumetric density is defined as the mass of many particles of the activated carbon divided by the total volume they occupy. The total volume includes particle volume, inter-particle void volume, and internal pore volume.

If not tested in the same way then this density can vary greatly, so it is important that when the density is compared to other activated carbons this is done according to a standard like ASTM D 2854 -09(2019). With powders often it is also mentioned if it is "freely settled" (or "poured" density) and "tapped" density(where the tapped density refers to the bulk density of the powder after a specified compaction process, usually involving vibration of the container.

Apparent density backwashed and drained of activated carbon

The backwashed and drained density of activated carbon (GAC or EAC) is the parameter which is often used for sizing of adsorption equipment and to determine the weight of carbon required for liquid phase application like potable water purification. The backwashed and drained density will be lower than the apparent density because the space between the activated carbon particles will increase during the backwashing process.

As a reference point we can say that typically the apparent density of activated carbon will be in the range of 300 to 500 kg/m3, however this can also be outside of this spectrum because of for example raw materials used or activation level of the product.

Reactor density of activated carbon

This is the density of the activated carbon in the reactor (adsorber, filter or silo). This density is often slightly lower than the apparent density because there are no specific conditions that let the carbon bed settle and this results in slightly more space between the particles compared to the way the apparent density is measured.

We expect that this additional understanding of density can support you in your product selection, compare apples with apples in terms of density, and to know the right amount of weight that you need for filling your silo or filter.

Follow below links to learn more about purification techniques:

Activatedcarbon , Aeration , Coagulants , Recrystallization , Ionexchangers , Molecularsieves , Ozoneoxidation , UVDisinfection , Rapidand slow sand filtration .