含氮官能团种类对活性碳纤维吸附催化SO2的影响

活性碳纤维(ACF)可用于低温吸附催化脱除燃煤烟气中的SO₂,大量实验证明对ACF表面进行掺氮改性可显著提高其脱硫率,但理论研究相对较少,且不同种类含氮官能团对脱硫的影响仍未有定论.为此,采用密度泛函理论(DFT)和波函数分析对不同种类含氮官能团修饰的ACF的表面结构、静电相互作用、极化和分子轨道进行了对比研究.结果表明氮修饰不仅有利于增强ACF与吸附质分子SO₂间的静电相互作用,其催化氧化和感应SO₂分子的能力也有所提高.其中,石墨化氮掺杂的ACF的极性指数相较掺杂前提高了71.33%,性能改善最为显著,作为SO₂分子的选择性传感器和吸附催化剂颇具潜力.

Effects of the types of nitrogen-containing functional groups on the adsorption and catalytic of SO2 by activated carbon fibers

Activated carbon fiber (ACF) can be used for low-temperature adsorption and catalytic removal of SO2 in coal-fired flue gas. A large number of experiments have proved that the surface modification of ACF can significantly improve its desulfurization rate, but there are relatively few theoretical studies and the effect of different types of nitrogen functional groups on desulfurization is still inconclusive. To this end, density functional theory (DFT) and wavefunction analysis were used to compare the surface structure, electrostatic interaction, polarization and molecular orbital of different types of ACF modified with nitrogen-containing functional groups. The results show that nitrogen modification not only helps to enhance the electrostatic interaction between ACF and adsorbate molecules SO2, but also improves its ability to catalyze oxidation and sense SO2 molecules. Among them, the performance improvement of graphitic nitrogen-doped ACF is the most significant, its polarity index of graphitic nitrogen-doped ACF is increased by 71.33% compared with that before doping, and has great potential as a selective sensor and adsorption catalyst for SO2 molecules.