Regeneration of carbonaceous adsorbents. Part I: Thermal Regeneration

Abstract

Porous carbonaceous materials are widely used in the removal of pollutants present in liquid and gaseous effluents due to their excellent adsorbent properties and large surface areas. Once exhausted, these materials become hazardous residues which are usually incinerated or disposed of in landfills, resulting in risks of pollution. For energetic and environmental purposes their regeneration is a more attractive alternative. Thus, this field has generated great interest and has led to the proposal of numerous methods of regeneration. Nevertheless, no in-depth review of the state of the art of this topic has been made. In this work, more than 300 scientific sources are reviewed with a view to developing an exhaustive collection and description of all such methods. The review establishes a series of criteria to classify existing methods (as well as any method that may be proposed in the future) in a clear and precise form. All methods are classified in four major groups: Thermal, Chemical, Microbiological and Vacuum Regeneration. The first fraction of this article exclusively addresses Thermal Regeneration. Both the most traditional (regeneration with hot inert gases and steam) and novel methods (regeneration with microwaves, ultrasound, electrical currents, etc.) appear under Thermal Regeneration. In the second part of the work, not included here, the review will address Chemical, Microbiological and Vacuum Regeneration.