The effect of N-doping and halide-doping on the activity of CuCoO4 for the oxidation of elemental mercury

The investigations for vapor-phase Hg0 oxidation ability of Al2O3 (AL) loaded with CuCoO4 (AL-C), CuCoO4 + NH4Cl (AL-CCl), and CuCoO4 + NH4Br (AL-CBr) are carried out in an attempt to produce more economical and effective sorbents for the control of Hg0 emission from combustion processes. According to the X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Brunauer–Emmett–Teller (BET) and mass balance analysis on mercury, we find that N-doped AL-C has bigger SBET than AL-C and the nitrogen doping greatly improves AL-C's Hg0 oxidation ability, especially at low temperatures. It is considered that nitrogen atoms in doped AL-C's polycrystalline are responsible for the significant enhancement in Hg0 oxidation ability of AL-CCl and AL-CBr. The Hg0 oxidation abilities of AL-CCl and AL-CBr under various adulteration values and adsorption temperatures were studied. When adulteration value is equal to 30%, AL-CCl and AL-CBr perform the best and their Hg0 oxidation abilities are remarkably higher than AL-C over wide range temperatures. AL-CCl and AL-CBr's breakthrough times increases from AL-C's 26 h to 158 h and 208 h, respectively. The effects of 0.31% SO2 on AL-C, AL-CCl and AL-CBr's Hg0 oxidation abilities are insignificant, which indicates that N-doping has no adverse effect on both Co3+ and Cu2+-octahedral cations structure.