Spherical In2S3 anchored on g-C3N4 nanosheets for efficient elemental mercury removal in the wide temperature range

Mercury emission from coal-fired power plants has posed a great threat to the environment and human, and reducing and controlling mercury emissions has become a global environmental issue. In this work, the In2S3/g-C3N4 adsorbent was prepared by simple hydrothermal method to achieve efficient removal of Hg0 from coal-fired flue gas. When the loading value of In2S3 was 40 %, the effect of removing Hg0 by as-synthesized IC-40 was the best. IC-40 showed excellent Hg0 adsorption performance in a temperature range of 80–240 °C. Under the condition of 120 °C and N2 atmosphere, the Hg0 adsorption capacity of the synthesized IC-40 reached 14.78 mg/g. The study on the impacts of flue gas components demonstrate that IC-40 has good resistance to nitric oxide, and has a slight inhibitory effect by SO2 and water vapor. According to the results of XPS and Hg-TPD, the formed main mercury compound is extremely stable HgS. In addition, DFT was conducted to calculate the adsorption energy of Hg0 on In2S3 (1 1 0) surface, which further illustrated the sulfur site served as stable adsorption site to convert Hg0 into HgS. From the above analysis, IC-40 as an efficient and scientific adsorbent to remove Hg0 from coal-fired power plants is a promising technical method.