Activated carbon can be produced from various organic substances. Typical materials are coal, shells, sawdust, etc. These materials are changed to the desired particle size through molding/crushing as required then they are at 700 to 800 degree Celsius to produce carbides (i.e. coke or char).
Then, making the obtained coke react with steam or carbon dioxide at 900 to 1100 degree Celsius creates very small pores. This manufacturing method is called gas activation.
In addition to this gas activation method, there is a chemical activation method for manufacturing activated carbon. The chemical activation method mixes chemicals such as phosphoric acid or zinc chloride with organic materials such as sawdust and burns them at 400 to 600 degree Celsius to make small pores with the dehydrating reaction of chemicals.
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Reactivation Activated carbon that has dropped its adsorbing capability can be recovered in its performance by the reactivation process and can be used in the adsorption process again. When activated carbon adsorbs impurities, a balanced relationship of adsorption is established among the adsorbate (i.e. substance adsorbed by activated carbon), activated carbon, and medium (i.e. substance surrounding the adsorbate and activated carbon such as water or gas). Reactivationg means that this balanced relationship of adsorption is changed and adsorbate is separated from activated carbon. Depending on the reaction mechanism, there are 6 types of reactivation; decompression reactivation, heating and leaving reactivation, chemical reactivation, solvent reactivation, substitutive reactivation, and oxidation and decomposition reactivation. |
