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Temperature-gradient condensation promotes As2O3 particle growth to reduce the escapable risk
Qingzhu Li1, Shengtu Li1, Kaizhong Li2
1School of Metallurgy and Environment, Central South University, Changsha 410083, China.
Journal of Hazardous Materials
|August 4, 2026
Summary
Temperature-gradient condensation significantly increases arsenic trioxide (As2O3) particle size, reducing their potential to escape flue gas. This method offers a way to control arsenic particle morphology and lower environmental risks.
Area of Science:
- Environmental Science
- Materials Science
- Chemical Engineering
Background:
- Volatile arsenic trioxide (As2O3) forms fine particles during flue-gas cooling.
- These fine particles increase arsenic mobility and escape tendency.
- Controlling particle size is crucial for mitigating arsenic release.
Purpose of the Study:
- To investigate the effect of different cooling methods on As2O3 particle growth.
- To evaluate the influence of sulfur dioxide (SO2) on As2O3 condensation.
- To assess the physical escapability of As2O3 particles under various conditions.
Main Methods:
- Utilized a double-tube, dual-temperature-zone system for controlled As2O3 condensation.
- Compared natural cooling, temperature-gradient condensation, and SO2 coexistence.
- Employed Density Functional Theory (DFT) calculations to study SO2-As2O3 interactions.
- Applied a size-dependent attenuation model to estimate particle escapability.
Main Results:
- Natural cooling resulted in limited particle growth (mean size 33.97 μm).
- Temperature-gradient condensation (200°C) produced large octahedral crystals (mean size 267.28 μm).
- SO2 presence decreased particle size (mean 230.49 μm) but still yielded larger particles than natural cooling.
- DFT revealed weak SO2-As2O3 interaction affecting surface deposition.
- Physical escapability indices were significantly reduced by temperature-gradient condensation (0.0026) and SO2 coexistence (0.0064) compared to natural cooling (0.6373).
Conclusions:
- Temperature-gradient condensation effectively converts fine As2O3 into larger particles.
- This process markedly reduces the estimated physical escapability of arsenic-bearing particles.
- Findings support particle morphology regulation and risk-oriented process control for arsenic-laden flue gas.
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