Insight into High Temperature Gas-Phase Arsenic Capture by a CaO–Ca₁₂Al₁₄O₃₃ Synthetic Sorbent

Abstract

Concerns about arsenic emission issues are growing as the arsenic discharged from coal-fired power plants seriously endangers the ecological environment and public health. The gas-phase arsenic capture by a CaO–Ca12Al14O33 synthetic sorbent at 1000–1200 °C in the simulated flue gas was conducted, with the influence of the addition ratio of Ca12Al14O33, temperature, retention time, and acid gases NO/SO2 considered in the study. The results indicated that the synthetic sorbent containing 15 wt % Ca12Al14O33 (Ca85Al15) exhibited much better arsenic adsorption performance than CaO, which was ascribed to the greatly strengthened sintering resistance of CaO particles by adding Ca12Al14O33, enabling arsenic adsorption and chemical reactions. Both the increasing temperature and retention time facilitated arsenic adsorption by Ca85Al15, and the hypertoxic arsenic vapor (As3+) was converted into arsenate (Ca3(AsO4)2) with less toxicity. In the presence of NO, the arsenic capture was gradually suppressed with increasing retention time. On the other hand, SO2 could slightly facilitate the capture of arsenic at 1000–1100 °C for 10 min; nevertheless, due to the formation of Ca4Al6O12SO4, the promotion effect was inhibited at a higher temperature and a longer retention time. In general, the study provided a basis for developing highly efficient solid sorbents toward controlling arsenic vapor emission derived from coal combustion, and the appropriate conditions for arsenic capture were at 1000–1100 °C.

Gaseous Arsenic Capture in Flue Gas by CuCl2-Modified Halloysite Nanotube Composites with High-Temperature NOx and SOx Resistance

“…The lower the binding energy between HNTs and CuO, the higher the adsorption energy between the adsorbent and arsenic vapor . The adsorption energy difference and selectivity of the prepared sorbent for As 2 O 3 , SO 2 , SO 3 , NO, and NO 2 determined the mechanism of NO x and SO x resistance , (Figure S9; detail analysis presented in Supporting Information).…”

Nickel-Doped CaO to Improve Its Antisintering Property and Electron-Transfer Ability for the Removal of As2O3 from Flue Gas: Experiments and DFT Simulations

“…Using citric acid and calcination method, Hong et al created an Al 2 O 3 /CaO adsorbent with sintering resistance, and its adsorption capacity reached 534 mg/kg at 1173 K . He et al created a CaO-Ca 12 Al 14 O 33 adsorbent and demonstrated that it performed better at adsorbing arsenic than CaO, which they attributed to the addition of Ca 12 Al 14 O 33 greatly enhancing the sintering resistance of CaO particles, which could adsorb arsenic and undergo chemical reactions . The synthesis of composite adsorbents with Ni-doped metal oxides has received a great deal of attention recently.…”