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

CoMoS/γ-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 Hg0 capture. It was observed that the CoMoO/γ-Al2O3 showed a Hg0 capture efficiency around 75% at a temperature between 175 and 325 °C while CoMoS/γ-Al2O3 achieved almost 100% Hg0 removal efficiency at 50 °C. The high removal efficiency for CoMoS/γ-Al2O3 remained unchanged for 2000 min in the test. Its theoretical capacity for Hg0 capture was found to be 18.95 mg/g based on the Elovich model. The ability of this material for Hg0 capture is atributed to the MoS2 nanosheets coated on surface of the maro- and meso-pores of γ-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 Hg0 capture. The removal of Hg0 at low temperatures was achieved via the combination of Hg0 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.