Highly efficient simultaneous removal of HCHO and elemental mercury over Mn-Co oxides promoted Zr-AC samples.

MnCo/Zr-AC prepared by impregnation method was investigated on the simultaneous removal of HCHO and Hg. The samples were characterized by BET, SEM, XRD, H pulse chemisorption, H-TPR, XPS, Hg-TPD and in-situ DRIFTS. Thereinto, the optimal MnCo/Zr-AC achieved 99.87% HCHO removal efficiency and 82.41% Hg removal efficiency at 240 °C, respectively. With increased surface area and pore volume, Zr-AC support facilitated higher dispersion of MnO-CoO. Moreover, the co-doping of MnO-CoO endowed the sample with more active oxygen species and higher reducibility, which further facilitated the removal of HCHO and Hg. Chemisorption was proved to predominate in Hg removal, and oxidation also worked as Hg was detected in outlet gas. Besides, HCHO predominated in the competition of active oxygen species, especially for lattice oxygen, thus suppressed the Hg removal. According to in-situ DRIFTS, HCHO removal proceeded as HCHO → DOM → formate species → CO + HO, and was boosted by active oxygen species. Furthermore, MnCo/Zr-AC was proved with excellent regeneration performance, indicating its potential in practical application.