<br>硒在活性炭表面的转化机理：实验与密度泛函理论研究,Journal of Hazardous Materials

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硒在活性炭表面的转化机理：实验与密度泛函理论研究
Journal of Hazardous Materials ( IF 12.2 ) Pub Date : 2023-09-04 , DOI: 10.1016/j.jhazmat.2023.132482
Hao Liu ₁ , Yang Yu ₁ , Juan Chen ₁

Affiliation

通过结合实验与密度泛函理论（DFT）探讨活性炭（AC）捕获 SeO2 的机制。吸附实验证实，对 AC 进行质量损失系数校正后，AC 的硒捕获量在 350 °C 时达到 7.76 mg/g，AC 在 50 min 时达到饱和硒去除量 9.93 mg/g。失重曲线记录了 305 °C 左右 AC 表面硒脱附的温度窗口。 XPS 谱图显示，SeO2 在交流表面上的分解和还原行为促进了 Se0 形式的硒的存在。DFT 计算表明，SeO2 化学吸附在交流电的典型扶手椅和锯齿形表面上，最稳定结构的吸附能分别为 -89.77 和 -235.12 kcal/mol。通过热力学和动力学分析研究了温度对通过 AC 捕获硒的影响。温度升高促进了 SeO2 在交流表面的分解和还原。动力学分析进一步证实，Se4+→Se0 的转化更多地以分解行为为主。气相中的一部分 SeO2 被 CO 还原为 Se0，并在 AC 上富集为元素硒。

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Conversion mechanism of selenium on activated carbon surface: Experimental and density functional theory study

The mechanism of SeO2 capture by activated carbon (AC) was explored via combining experiments with density functional theory (DFT). Adsorption experiments confirmed that after mass loss coefficient correction of AC, the selenium capture capacity of AC reached 7.76 mg/g at 350 °C. AC reached a saturated selenium removal capacity of 9.93 mg/g at 50 min. The weight loss curve recorded the temperature window of selenium desorption on AC surface at about 305 °C. The XPS spectrum revealed that the decomposition and reduction behavior of SeO2 on the AC surface promoted the existence of selenium in the form of Se0. DFT calculations showed that SeO2 was chemically adsorbed on the typical Armchair and Zigzag surfaces of AC, and the adsorption energies of the most stable structures were − 89.77 and − 235.12 kcal/mol, respectively. The effect of temperature on selenium capture via AC was studied by thermodynamic and kinetic analysis. Temperature increase promoted the decomposition and reduction of SeO2 on the AC surface. Kinetic analysis further confirmed that the transformation of Se4+→Se0 was more dominated by decomposition behavior. A part of SeO2 in the gas phase was reduced to Se0 by CO and enriched on AC as elemental selenium.

更新日期：2023-09-04

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