Activation of persulfate by CuO-sludge-derived carbon dispersed on silicon carbide foams for odorous methyl mercaptan elimination: identification of reactive oxygen species.

In this work, sludge-derived carbon (SC) was innovatively integrated with copper oxide (CuO) on macroporous silicon carbide foams to construct a distinctive catalyst (CuO/SC) with strong catalytic activity, which can effectively activate persulfate (PS) for the removal of methyl mercaptan (CH3SH). The structure and morphology of CuO/SC were investigated by means of XRD, SEM, and EDS. The effects of initial pH values, copper contents, PS dosages, and flow rates on CH3SH removal were also investigated. Under optimal condition, more than 90% of CH3SH was removed by CuO/SC-PS combined system within 10-min reaction due to the synergistic function of CuO and SC. More importantly, on the basis of reactive species trapping and ESR spectroscopy, it is revealed that the responsible reactive species for catalytic CH3SH composition were ·SO4-, ·OH, 1O2, and ·O2- in CuO/SC-PS system. Finally, the possible PS activation scheme of CuO/SC samples was proposed.