Microscopic Spherical α-Fe₂O₃ for Highly Efficient Gaseous Arsenic Capture in Simulated Flue Gas Under a Wide Temperature Range

Abstract

Arsenic emitted from coal-fired flue gas poses a threat to human health and the ecological environment due to its high toxicity and bioaccumulation. In this work, the microscopic spherical α-Fe2O3 sorbent was prepared by a one-step hydrothermal method to effectively capture arsenic in the flue gas. The effects of reaction temperature, sulfur dioxide (SO2), nitric oxide (NO), oxygen (O2), and inlet arsenic concentration on its adsorption performance were investigated. The results showed that the most suitable adsorption temperature was 600 °C, and As2O3(g) was finally fixed in the product in the form of FeAsO4. SO2 and O2 played a positive role in the adsorption of arsenic, while NO displayed a slight effect on the adsorption of arsenic. In addition, the arsenic adsorption capacity improved with the increase of the inlet arsenic concentration. Based on its excellent arsenic removal performance and SO2 resistance performance, the α-Fe2O3 sorbent can be considered a promising material for arsenic removal.

Preparation of CeO2/CaO with Anti-sintering for Efficient Capture of As2O3 from Flue Gas at a High Temperature

“…The adsorption of arsenic by CaO occurs mainly by chemisorption, and arsenic adsorbed in the reaction product is As 5+ . 11 Elevated temperatures promote the capture of arsenic by CaO, and the same phenomenon was also observed in the capture process of CeO 2 /CaO. CeO 2 /CaO can provide enough active sites for arsenic capture than untreated CaO.…”

“…The capture trends for CeO 2 /CaO and CaO are similar, with increasing temperatures promoting the trapping of arsenic, with CeO 2 /CaO capture significantly higher than CaO in the same temperature range. The adsorption of arsenic by CaO occurs mainly by chemisorption, and arsenic adsorbed in the reaction product is As 5+ . Elevated temperatures promote the capture of arsenic by CaO, and the same phenomenon was also observed in the capture process of CeO 2 /CaO.…”

“…To reduce the coal combustion process generating As 2 O 3 (g) emissions to the environment, the addition of metal oxides is a very effective method to capture As 2 O 3 (g) emitted from coal-fired power plants. , Calcium-based materials are widely used as sorbents because of their low cost and non-toxicity. In the process of capture, the sorbent not only physically absorbs As 2 O 3 (g) but also performs chemisorption that converts As­(III) to As­(V) with low toxicity .…”

Arsenic Emission Control from Coal Combustion Flue Gas

“…The results of the DFT study by Zhang et al [50] also showed that As 2 O 3 (g) could form eight stable adsorption structures on the (001) surface of Fe 2 O 3 with a minimum adsorption energy of 275.52 kJ mol À1 . One-step hydrothermal preparation was used by Zhao et al [51] to create a tiny, spherical α-Fe 2 O 3 adsorbent, and the effects of reaction temperature, nitric oxide (NO), oxygen (O 2 ), nitric dioxide (NO), sulfur dioxide (SO 2 ), and inlet arsenic concentration on the adsorption performance were investigated. The effect of its temperature on the capture of As 2 O 3 (g) by α-Fe 2 O 3 is shown in Figure 2 [51].…”

Thermodynamic research on the effect of CaO on the transformation of arsenic and sulfur in coal in different pyrolysis atmospheres

“…Arsenic stays with a particular matter, which goes to the environment as ash. There are a few technologies to control its release, such as coal washing before combustion, arsenic capture sorbent, 2–4 and so forth. Besides, atmosphere and temperature have a great effect on arsenic distribution during the reaction 5 .…”