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

Abstract

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. Ce0.5Mn0.5O y showed the best performance at 100 °C (about 5.6 mg g–1 adsorption capacity), and Ce–Mn binary metal oxides could adsorb more elemental mercury than MnO y . Furthermore, it was found that captured mercury can be released from the sorbent in the form of elemental mercury by heating to 350 °C. Meanwhile, the sorbent can be regenerated and repeatedly used. Powder X-ray diffractometer (PXRD), transmission electron microscopy (TEM), hydrogen temperature-programmed reduction (H2-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.

CeO2-Decorated α-MnO2 Nanotubes: A Highly Efficient and Regenerable Sorbent for Elemental Mercury Removal from Natural Gas

“…Consecutive sorption–desorption experiments were then performed at both 300 and 350 °C. In the latter case, the amount of recovered mercury was high, in agreement with previous reports …”

“…In the latter case, the amount of recovered mercury was high, in agreement with previous reports. 38 Figure 9a,b shows that on average, ∼66% of Hg 0 undergoing sorption in each cycle was desorbed upon the completion of each of the successive sorption−desorption cycles. With the number of cycles, the amount of desorbed Hg 0 is moderately increasing, as a result of the increasing Hg in 0 .…”

“…This is due to its unique properties related to the reversible Ce 3+ /Ce 4+ redox pair, surface acid−base properties, and defects that primarily consist of oxygen vacancies. 37 Considering the above, Qu et al 38 prepared a series of Ce− Mn binary metal oxides by a template method and tested them for Hg 0 capture from flue gas. The Hg 0 uptake of Ce 0.5 Mn 0.5 O y reached 5.6 mg•g −1 at 100 °C in N 2 and O 2 atmosphere, and the sorbent could be regenerated at 350 °C.…”

“…Considering the above, Qu et al prepared a series of Ce–Mn binary metal oxides by a template method and tested them for Hg 0 capture from flue gas. The Hg 0 uptake of Ce 0.5 Mn 0.5 O y reached 5.6 mg·g –1 at 100 °C in N 2 and O 2 atmosphere, and the sorbent could be regenerated at 350 °C.…”

Simultaneous Removal of Elemental Mercury and Arsine from a Reducing Atmosphere Using Chloride and Cerium Modified Activated Carbon

“…The results indicated that catalytic oxidation and chemical adsorption played an important role in the process of elemental mercury removal. Without ammonia chloride modified, the efficiency of Hg 0 oxidation is higher . As the ammonia chloride loading value increased, most of the mercury was captured by the samples, which were formed HgO and HgCl 2 and adsorbed on the surface of the samples.…”