Hg0 Capture over CoMoS/γ-Al2O3 with MoS2 Nanosheets at Low Temperatures

CoMoS/gamma-Al2O3 sorbent was prepared via incipient wetness impregnation (IWI) and sulfur-chemical vapor reaction (S-CVR) methods and tested in terms of its potential for Hg-0 capture. It was observed that the CoMoO/gamma-Al2O3 showed a Hg-0 capture efficiency around 75% at a temperature between 175 and 325 degrees C while CoMoS/gamma-Al2O3 achieved almost 100% Hg-0 removal efficiency at 50 degrees C. The high removal efficiency for CoMoS/gamma-Al2O3 remained unchanged for 2000 min in the test. Its theoretical capacity for Hg-0 capture was found to be 18.95 mg/g based on the Elovich model. The ability of this material for Hg-0 capture is atributed to the MoS2 nanosheets coated on surface of the maro- and meso-pores of gamma-Al2O3. These MoS2 are two-dimensional transition-metal dichalcogenide (2D TMDC) assembled with unsulfided cobalt atoms at the edges. It is believed that these MoS2 nanosheets provided dense active sites for Hg-0 capture. The removal of Hg-0 at low temperatures was achieved via the combination of Hg-0 with the chalcogen (S) atoms on the entire basal plane of the MoS2 nanosheets with coordinative unsaturated sites (CUS) to form a stable compound, HgS.