Regeneration of siloxane-exhausted activated carbon by advanced oxidation processes

[Display omitted] •Both H2O2 and O3 treatments achieve regeneration efficiencies up to 40%.•The iron incorporation on the AC leads to 92% recovery of the adsorption capacity.•Soluble silanols are formed as by-product of the AOP regeneration. In the context of the biogas upgrading, siloxane exhausted activated carbons need to be regenerated in order to avoid them becoming a residue. In this work, two commercial activate carbons which were proved to be efficient in the removal of octamethylcyclotetrasiloxane (D4) from biogas, have been regenerated through advanced oxidation processes using both O3 and H2O2. After the treatment with O3, the activated carbon recovered up to 40% of the original adsorption capacity while by the oxidation with H2O2 the regeneration efficiency achieved was up to 45%. In order to enhance the H2O2 oxidation, activated carbon was amended with iron. In this case, the regeneration efficiency increased up to 92%.