Activated carbon
WHAT IS ACTVATED CARBON?
Activated carbon in a porous form of carbon can be produced from various carbonaceous raw materials. The main commercial products are made of coconut, coal, peat or wood. Currently, one of the most widespread production methods is the so-called. steam activation procedure. where the raw material is activated by steam in special equipment at 900-1000°C under steam conditions to form the pore structure, but there are also two types of chemical activation processes:
Zinc-chloride activation
Phosphoric-acid activation.
During the Chemical Activation Process, non-combustible charcoal (eg sawdust) is pre-mixed with dehydrating or oxidizing chemicals (e.g., zinc-chloride or phosphoric-acid) and heated to 400 to 800 ° C with the exclusion of oxygen. The activating agent is then washed and regenerated.
Activated charcoal is characterized by a vast system of molecular size carbon particles within its pores, the material thus formed having an extremely wide internal surface. Commercially available activated carbon has a specific surface area ranging from 400m2/g to more than 2000m2/g.
HOW DOES IT WORK?
Adsorption is the attachment or adhesion of atoms, ions and molecules (adsorbates) from a gaseous, liquid or solution medium onto the surface of an adsorbent – activated carbon. The porosity of activated carbons offers a vast surface on which this adsorption can take place. Adsorption occurs in pores slightly larger than the molecules that are being adsorbed, which is why it is very important to match the molecule you are trying to adsorb with the pore size of the activated carbon. These molecules are then trapped within the carbon's internal pore structure by Van Der Waals Forces or other bonds of attraction and accumulate onto a solid surface.
Physical Adsorption - During this process, the adsorbates are held on the surface of the pore walls by weak forces of attraction known as Van Der Waals Forces or London dispersion forces.
Chemisorption - This involves relatively strong forces of attraction, actual chemical bonds between adsorbates and chemical complexes on the pore wall of the activated carbon.
SELECTING THE RIGHT CARBON FOR YOU
In order to recommend the most appropriate type of activated carbon for your application, we’ll need to know the characteristics of the chemicals you need to remove in the adsorption process, or a series of laboratory tests should be performed to assess the right carbon.
For general adsorption system design systems granular carbons, column system for finer sizes and pellet activated carbons (1mm to 4mm) are used in fixed or moving bed filters. For activated carbon powders most suitable applications include flotation systems and batch process where used carbon is removed by filtration after an appropriate contact time.
Finer sizes accelerate diffusion rate of the adsorbates into the pores, hence improves kinetics, but wettability/filtration on powders, pressure drop or screening problems with granules, are limiting factors.
We distribute a wide range of premium quality powdered, granular and extruded activated carbon products.
