Activated Carbon comes in powdered, granular, pellet and spherical forms, ground to various sizes. The pores resulting from the preparation process are classified into three size groups:
Micropores ( 0-20 Angstroms)
Transitional Pores ( 20-500 Angstroms )
Macropores ( >500 Angstroms )
While all activated carbons contain pore sizes in the three size groups, pore size distribution will vary depending on the raw material used. Below is a table that illustrates the pore size distribution of several raw materials from which activated carbon is made.
No single type of activated carbon is best for all applications. The carbon product selected for a specific application will be tailored to the size of the molecules to be removed from the liquid stream. In some instances, the concentration of the substance will also affect product selection. Coal base activated carbon has the widest pore size distribution, so it is often considered the "catch-all" carbon.
How Does Activated Carbon Work?
Activated Carbon works by means of adsorption — a process by which molecules are attracted to and become attached to the surface of the carbon. The molecule is held in contact with the surface of the carbon by a combination of physical, ionic and chemical forces. Because adsorption is a surface phenomenon, the amount of surface area provided by the pore structure of the carbon is an important factor in determining efficiency of molecular removal. Once the activated carbon has adsorbed the maximum amount, it must be replaced. Spent carbon is removed from the pressure vessel and can be regenerated or sent to a landfill.
* Carbon works by adsorption — attracting molecules out of the liquid and attaching them to the carbon surfaces.
To discuss more information regarding Everfilt® Water Filtration Systems, talk with an Everfilt® Applications Engineer: 1.800.360.8380 / everfilt@everfilt.com