Simultaneous removal of NO and Hg-0 from simulated flue gas over CoOx-CeO2 loaded biomass activated carbon derived from maize straw at low temperatures

To rationally utilize agricultural wastes and expediently simultaneous control of elemental mercury (Hg-0) and NO, a series of CoOx-CeO2 loaded maize straw derived biomass activated carbon (CoCe/BAC) samples were applied for simultaneous NO and Hg-0 removal. These samples' physicochemical characteristics were characterized by BET, SEM, XRD, NH3-TPD, H-2-TPR, XPS and FTIR. 15% Co0.4Ce0.6/BAC yielded prominent Hg-0 removal efficiency (96.8%) and superior NO removal efficiency (84.7%) at 230 degrees C. The separate or synchronous deactivation effects of 400 ppm SO2 and 5% H2O were detected. The interaction between NO removal and Hg-0 removal was investigated, the results demonstrated that abundant Hg-0 exhibited very slightly inhibitory effect on NO removal, and NH3 negatively affected Hg-0 removal, whereas NO mildly boosted Hg-0 removal in presence of O-2. The characterization analyses indicated the excellent performance of 15% Co0.4Ce0.6/BAC could be ascribed to its better texture properties, lower crystallinity and stronger redox ability. Besides, a synergetic effect appeared between cobalt oxide and cerium oxide, resulting in generating more Ce3+ and Co3+ to induce more anionic defects and produce more active oxygen and oxygen vacancies. The removal mechanisms of NO and Hg-0 were systematically investigated, and NO reduction reactions were mainly assigned to the Langmuir-Hinshlwood mechanism while both adsorption and Hg-0 oxidation contributed to Hg-0 removal. Meanwhile, Hg-0 oxidation corresponded to the Mars-Masson mechanism prevailed gradually with the increase of reaction time.