H₂O₂-based oxidation processes for the regeneration of activated carbons saturated with volatile organic compounds of different polarity

This study reports the sequential regeneration treatment of activated carbons (ACs) saturated with volatile organic compounds (VOCs) of different polarity using H₂O₂ as oxidizing agent. In this process, VOCs were adsorbed onto the AC and further oxidized by H₂O₂. A commercial AC was selected and saturated with three different VOCs: two non-polar and hydrophobic VOCs, toluene and limonene, and one polar and hydrophilic VOC, methyl ethyl ketone (MEK). The saturated AC was regenerated with H₂O₂, and the Fenton reagent for comparison. It was found that regeneration efficiencies obtained with the H₂O₂ treatment were equal to or even higher than those obtained with the Fenton treatment. The fate of the pre-adsorbed VOCs, once the regeneration process is completed was studied. It was found that this regeneration treatment is limited for non-polar VOCs such as toluene and limonene, as they tend to remain adsorbed onto the ACs after regeneration treatment. Contrarily, MEK tend to be transferred to the bulk phase and react with the generated oxidant species.