Removal of As2O3 in coal-fired flue gas by metal oxides: Effects of adsorption temperature and flue gas components

Arsenic emitted from coal-fired power plants has attracted widespread attention. Metal oxides are promising adsorbents for arsenic removal , but the influence laws and mechanisms of temperature and flue gas components on their arsenic removal performance are unclear. In this work, systematic research on the effects of adsorption temperature and flue gas components on As 2 O 3 removal by Fe 2 O 3 , CaO, and γ-Al 2 O 3 was conducted. The results show that As 2 O 3 removal ability satisfies Fe 2 O 3  > CaO > γ-Al 2 O 3 at 300–900 °C, which is mainly related to their basic site strength. At 500 °C, Fe 2 O 3 has the largest As 2 O 3 removal capacity (adsorption capacity: 158.4 μg/g; removal efficiency: 84.68%). Increasing adsorption temperature is beneficial to the transformation of arsenic to high-valent arsenic (As(V)) on the surface of Fe 2 O 3 , CaO, and γ-Al 2 O 3 . Low-concentration SO 2 will compete with As 2 O 3 for adsorption on the three metal oxides surface, which thereby inhibits their As 2 O 3 removal ability. The presence of NO has an obvious inhibitory effect on the As 2 O 3 removal of Fe 2 O 3 , CaO, and γ-Al 2 O 3 , which is little affected by the change of NO concentration. Fe 2 O 3 is a metal oxide adsorbent with strong arsenic removal potential. Compared with basic simulated flue gas (BSFG) components, the presence of SO 2 , NO, and SO 2 +NO in the simulated flue gas all inhibits the adsorption of As 2 O 3 by Fe 2 O 3 . Finally, future work on arsenic removal from coal-fired flue gas adsorbents is presented. This work has important engineering applications and theoretical research guiding significance for the development of high-performance arsenic removal adsorbents.