Mercury removal from flue gas by a MoS/HO heterogeneous system based on its absorption kinetics.

An enhanced MoS/CTAB/HO system was built and investigated for Hg removal based on strengthening the Hg gas-liquid mass transfer. The results showed that adding 7 mg/L CTAB can improve the Hg removal efficiency from 76.5 to 88.7% as decrease of the solution surface tension. Keeping 2000 rpm of stirring rate accelerated the renewal rate of gas-liquid interface, thereby enhancing Hg removal. SO slightly promoted the Hg removal efficiency to 91% because of the absorption of SO causing a decrease in the solution pH from 6.9 to 4.3. NO participated in Hg removal reactions but not removed in this system which visibly enhanced the Hg removal efficiency to 94%. The Hg mass transfer kinetics were analyzed to determine how CTAB promoted Hg removal. The Hg-TPD, Hg fate, and species results revealed that Hg was first oxidized to Hg, then bonded with S to generate HgS and enrich on the MoS. Therefore, improving the Hg gas-liquid mass transfer can enhance Hg removal in MoS/HO system, which can provide reference for purification of other insoluble pollutants in absorption system.