介孔碳对气相多环芳烃的吸附研究

Adsorption of Gaseous Polycyclic Aromatic Hydrocarbons by Mesoporous Carbon

选取两种典型多环芳烃(Polycyclic Aromatic Hydrocarbons,PAHs)菲、芘为研究对象,对其在CMK-3上的吸附特性进行了研究。通过实验得到各组吸附质—吸附剂的吸附等温线及不同浓度下的穿透曲线,并分别由吸附等温线模型(Langmuir、Freundlich、DR)以及基于恒定浓度波假设的动力学模型拟合,获得相应的吸附平衡及动力学参数。研究结果表明:Langmuir模型能很好的描述低浓度的菲在CMK-3的吸附行为,Freundlich模型能很好的描述低浓度的芘在CMK-3上的吸附行为(R^2>99%)。基于恒定浓度波假设的穿透曲线模型能较好的预测浓度较低时PAHs的穿透曲线;相同浓度的PAHs在其上吸附的内扩散系数呈现Pyr<Phe的规律,而总传质系数则呈现出相反的规律,且菲的浓度越大总传质系数越大,芘正好相反。

The adsorption natures for polycyclic aromatic hydrocarbons （PAHs） with different aromatic rings, phenanthrene and pyrene on mesocarbon CMK-3, were studied. The breakthrough curves of PAHs at different initial concentrations were measured by gas chromatography, and well predicted by the constant-pattern wave model. The adsorption isotherms were fitted with isotherm models of Langmuir, Freundlich, and DR. Then related adsorption kinetic parameters were calculated through the fitting parameters. Results show that Langmuir model can well describe the adsorption isotherms of Phe, Freun- dlich model can well describe the adsorption isotherms of Pyr （R2 〉 99% ）. The constant-patteru wave model can well pre- dict the breakthrough curves of PAHs on mesoporous adsorbents at low concentration. At similar Co, the value of kp tend to exhibit the order of Pyr 〈 Phe on mesocarbon CMK-3, while the overall mass transfer coefficient is opposite. And the higher the initial concentration of Phe is, the higher the overall mass transfer coefficient is, the faster the adsorption equilibrium is reached, while it shows opposite rule on Pyr.