Regeneration of carbonaceous adsorbents. Part II: Chemical, Microbiological and Vacuum Regeneration

• The dual criterion allows the methods to be classified in a rigorous form.
• Each method has a unique regeneration mechanism/regeneration agent combination.
• This second article addresses Chemical, Microbiological and Vacuum Regenerations.
• Chemical Regeneration’s mechanisms are degradation, extraction and pH change.
• The employment of microorganisms and vacuum leads to the other two major groups.

Due to their excellent adsorbent properties, porous carbonaceous materials are employed in separation applications, especially in the purification of polluted liquid and gaseous streams. The progressive accumulation of pollutants on the surface of these materials reduces their adsorption capacity until they are finally exhausted. The regeneration of these carbonaceous adsorbents is an economically and environmentally attractive option. Numerous regeneration methods have been developed, but until now, they had not been properly classified or deeply reviewed. In this work, all existing methods are described in-depth, and a double-criterion is proposed to allow clear and rigorous classification of current and future regeneration methods. This classification is based on the traditional division which distinguishes among Thermal, Chemical and Microbiological Regeneration, and a fourth major group, Vacuum Regeneration, is added. Thermal Regeneration has already been considered in a previous review. This second review considers both Chemical Regeneration (within which Regeneration with Liquid Water and NaOH, Electrochemical, Solvent, Supercritical and Oxidative Regeneration are identified) and Microbiological and Vacuum Regeneration.

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