Efficient removal of Hg⁰ in flue gas using a novel Sn-based porphyrin polymer

A Sn-based porphyrin polymer (TAPP(Sn)-FAC) synthesized in a mild condition was introduced for the Hg⁰ removal in flue gas. The properties characterization of materials revealed the two-dimensional sheet structure, an amorphous structure and high stability of TAPP(Sn)-FAC, and Sn was successfully incorporated into TAPP-FAC in the form of SnN. The removal performance of Hg⁰ under different conditions was investigated using a lab-scale fixed-bed reactor. TAPP(Sn)-FAC presented an excellent Hg⁰ removal efficiency from 100 °C to 250 °C, which can reach 8 mg/g of Hg⁰ capture capacity at 100 °C for 300 min. Besides, TAPP(Sn)-FAC had a strong sulfur and water resistance, and the presence of NO and O₂ had a facilitating effect for Hg⁰ removal. Moreover, the existence of Sn can enhance the Hg⁰ adsorption and oxidation capacity of TAPP(Sn)-FAC by promoting the electron transfer process. Furthermore, TAPP(Sn)-FAC presented an excellent chemical stability, which was a promising material in the Hg⁰ removal in flue gas.