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.

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► The influence of VOC polarity on H2O2 regeneration treatment is studied.
► The regeneration efficiencies are equal/higher with H2O2 treatment than with Fenton.
► H2O2 treatment is more effective for ACs saturated with polar and hydrophilic VOCs.
► High regeneration efficiency is related to the partial transfer to the liquid phase.
► H2O2 treatment increases the mesoporosity of the ACs.