Stable and efficient As2O3 removal from simulated flue gas using Al2O3/CaSiO3 prepared by anhydrous grinding and calcination method

Abstract

CaSiO3 exhibits good arsenic capture performance, but it falls short of meeting the actual needs of power plants due to its susceptibility to acidic gases that inhibit its arsenic capture ability. In this study, an Al2O3/CaSiO3 adsorbent was prepared by combining the anhydrous grinding and calcining methods. Arsenic vapor capture was conducted in flue gas containing or free of SO2 and HCl within the temperature range of 800–1000 ℃. The research indicated that the preparation method used in this study resulted in uniform Al2O3 doping that was less prone to agglomeration, thereby creating a good pore structure. The Al2O3/CaSiO3 adsorbent exhibited the strongest arsenic capture capacity when the atomic molar ratio of Al/Si was 1:5, with an arsenic capture amount of 871.2 mg/kg, which was significantly higher than the capture capacity of the control group calcium silicate. The doping of Al atoms altered the structure and charge distribution of CaSiO3 silica-oxygen chains, resulting in the formation of Al active sites with higher adsorption energy, which is more favorable for the adsorption of arsenic. Although the Al2O3/CaSiO3 adsorbent reacts with acidic gases to form CaSO4 and CaCl2, which can inhibit arsenic capture, it still maintains a high arsenic capture rate. Al2O3/CaSiO3 has excellent arsenic removal, sintering resistance, and acid resistance, making it a promising composite adsorption material for arsenic removal.