Screening of Metal Oxides for Hg~0 Capture

摘要

Fossil fuel related industries are the major anthropogenic sources of Hg~0 emission. Due to awareness of the detrimental impact, there is an increasing interest in discovering potential materials for Hg~0 removal. In this paper, the first-row transition metals (from V to Zn), Mo and rare earth metals (La and Ce) in the oxidation states supported by γ-Al2O3 were prepared and studied as potential candidates for Hg~0 capture. Based on evolution of the parameters of enthalpies (△H), Gibbs free energy (△G), adsorption peaks (T_(a, peak)), maximum Hg~0 capture efficiencies (μ_(max)) and activation energy (E_a) etc, the samples of Cr, Ni, Fe, Mn, Co, Ce and Cu showed better performances for Hg~0 capture amongst the 11 metal oxides. The results also indicated that MoO3 has potential to promote Hg~0 capture since the activation energy is relatively low. Consequently, most of the Mo-based binary metal oxides have relatively high Hg~0 removal efficiencies coupled with low activation energies. Particularly, the binary metal oxides of CrMo, MnMo, CuMo, CeMo and CoMo could be selected as appropriate candidates for Hg~0 capture within specific temperature windows.