The influence mechanism of SO2 on the capture of gaseous arsenic by pyrolusite

Abstract

Removal of gaseous arsenic from copper smelting flue gas by solid-phase adsorption effectively reduces the emission of arsenic-containing pollutants into the atmosphere. Nevertheless, the high concentration of SO2 in the flue gas unavoidably impacts the effectiveness of the adsorbent in capturing gaseous arsenic. Currently, there is no research focusing on the adsorption capacity of pyrolusite (PY) for As2O3(g), including the influence of SO2. This study examines the capacities of PY to capture As2O3(g) with and without SO2 under different conditions and delves into the mechanism by which SO2 affects the capture of As2O3(g) by PY. Compared to the states without SO2, the As2O3(g) capture by PY in an atmosphere containing SO2 (2.5 v/v% SO2) decreased to 89.1 % at 400 °C. SO2 can diminish the As2O3(g) capture capacity of PY by competing for active sites, generating sulfate (MnSO4), inhibiting arsenic oxidation, and obstructing the pores of the adsorbent. In addition, SO2 enhances PY's As2O3(g) capture capacity by creating (As2O2)SO4 and forming new active centers. Moreover, the phase transition of PY guided by the high concentration of SO2 during As2O3(g) capture also favors arsenic capture. This research confirms that PY has substantial potential for effectively removing As2O3(g) from high-SO2 flue gas.