Reverse Conversion Treatment of Gaseous Sulfur Trioxide Using Metastable Sulfides from Sulfur-Rich Flue Gas.
Reverse Conversion Treatment of Gaseous Sulfur Trioxide Using Metastable Sulfides from Sulfur-Rich Flue Gas.
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DOI：
10.1021/acs.est.2c02362
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发表时间：
2022-07
影响因子：
11.4
通讯作者：
Qinyuan Hong;Haomiao Xu;Xingyu Pang;W. Liu;Zhisong Liu;Wenjun Huang;Zan Qu;N. Yan
中科院分区：
文献类型：
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作者：
Qinyuan Hong;Haomiao Xu;Xingyu Pang;W. Liu;Zhisong Liu;Wenjun Huang;Zan Qu;N. Yan
三氧化硫(SO3)是一种不稳定的污染物，从工业烟气的气相中脱除SO3仍然是一个巨大的挑战。在这里，我们通过小试实验和理论研究相结合的方法，提出了一种将SO3中的S(VI)还原为S(IV)的反向转化处理策略。我们首先证明了亚稳态硫化物可以破坏SO3中的S-O键，导致二氧化硫(SO2)的重新生成。单一金属硫化物和二元金属硫化物的RCT性能不同，亚稳态CuS在200-300℃的温度范围内具有较高的SO3转化效率，相应地，Se的引入降低了CuS主体的电负性，增强了其对SO3的还原能力。在CuSe1-xSx复合材料中，CuSe0.3S0.7是最佳的RCT材料，120min的SO2产率为6.25 mmol/g。低价硒(Se2-/Se1-)对SO3的还原活性高于S2-/S1-，但过量的Se掺杂会使SO3的转化率降低，这是由于生成的SeO32-对SO2的二次氧化作用。密度泛函理论计算表明，CuSe0.3S0.7具有较强的SO3吸附性能(EADs=-2.76 eV)和较低的S-氧键断裂能(Ea=1.34 eV)。因此，CuSe1-xSx可以作为模型材料，RCT策略可以利用有色冶炼厂的现场温度条件来控制SO3排放。
Sulfur trioxide (SO3) is an unstable pollutant, and its removal from the gas phase of industrial flue gas remains a significant challenge. Herein, we propose a reverse conversion treatment (RCT) strategy to reduce S(VI) in SO3 to S(IV) by combining bench-scale experiments and theoretical studies. We first demonstrated that metastable sulfides can break the S-O bond in SO3, leading to the re-formation of sulfur dioxide (SO2). The RCT performance varied between mono- and binary-metal sulfides, and metastable CuS had a high SO3 conversion efficiency in the temperature range of 200-300 °C. Accordingly, the introduction of selenium (Se) lowered the electronegativity of the CuS host and enhanced its reducibility to SO3. Among the CuSe1-xSx composites, CuSe0.3S0.7 was the optimal RCT material and reached a SO2 yield of 6.25 mmol/g in 120 min. The low-valence state of selenium (Se2-/Se1-) exhibited a higher reduction activity for SO3 than did S2-/S1-; however, excessive Se doping degraded the SO3 conversion owing to the re-oxidation of SO2 by the generated SeO32-. The density functional theory calculations verified the stronger SO3 adsorption performance (Eads = -2.76 eV) and lower S-O bond breaking energy (Ea = 1.34 eV) over CuSe0.3S0.7 compared to those over CuS and CuSe. Thus, CuSe1-xSx can serve as a model material and the RCT strategy can make use of field temperature conditions in nonferrous smelters for SO3 emission control.