Investigation into enhanced performance of toluene and Hg stimulative abatement over Cr-Mn oxides co-modified columnar activated coke.

In this study, a string of Cr-Mn co-modified activated coke catalysts (XCrMn/AC) were prepared to investigate toluene and Hg removal performance. Multifarious characterizations including XRD, TEM, SEM, in situ DRIFTS, BET, XPS and H-TPR showed that 4%CrMn/AC had excellent physicochemical properties and exhibited the best toluene and Hg removal efficiency at 200℃. By varying the experimental gas components and conditions, it was found that too large weight hourly space velocity would reduce the removal efficiency of toluene and Hg. Although O promoted the abatement of toluene and Hg, the inhibitory role of HO and SO offset the promoting effect of O to some extent. Toluene significantly inhibited Hg removal, resulting from that toluene was present at concentrations orders of magnitude greater than mercury's or the catalyst was more prone to adsorb toluene, while Hg almost exerted non-existent influence on toluene elimination. The mechanistic analysis showed that the forms of toluene and Hg removal included both adsorption and oxidation, where the high-valent metal cations and oxygen vacancy clusters promoted the redox cycle of Cr + Mn/Mn ↔ Cr + Mn, which facilitated the conversion and replenishment of reactive oxygen species in the oxidation process, and even the CrMnO spinel structure could provide a larger catalytic interface, thus enhancing the adsorption/oxidation of toluene and Hg. Therefore, its excellent physicochemical properties make it a cost-effective potential industrial catalyst with outstanding synergistic toluene and Hg removal performance and preeminent resistance to HO and SO.