Regenerable Sorbent with a High Capacity for Elemental Mercury Removal and Recycling from the Simulated Flue Gas at a Low Temperature

摘要

To remove and recycle elemental mercury from flue gas, a serial of Ce-Mn binary metal oxides was prepared and tested as the regenerable sorbents for mercury capture. Ce0.5Mn0.5Oy showed the best performance at 100 degrees C (about 5.6 mg g(-1) adsorption capacity), and Ce-Mn binary metal oxides could adsorb more elemental mercury than MnOy. Furthermore, it was found that captured mercury can be released from the sorbent in the form of elemental mercury by heating to 350 degrees C. Meanwhile, the sorbent can be regenerated and repeatedly used. Powder X-ray diffractometer (PXRD), transmission electron microscopy (TEM), hydrogen temperature-programmed reduction (H-2-TPR), ammonia temperature-programmed desorption (NH3-TPD), X-ray photoelectron spectroscopy (XPS), and nitrogen adsorption methods were employed to characterize the sorbents. A model based on mercury temperature-programmed desorption (Hg-TPD) data was built to calculate mercury desorption activation energy from the sorbent. Additionally, the impacts of the temperature and flue gas components on the adsorption capacity were investigated. NO had negligible impact on mercury adsorption, while the presence of SO2 slightly inhibited the capability of sorbents for mercury capture. The results indicated that Ce-Mn binary metal oxides are a promising sorbent for the mercury removal and recycling from flue gas.