有序介孔碳对低浓度气相萘的吸附特性分析

Adsorption characteristics of low concentration gaseous naphthalene on ordered mesoporous carbons

对3种常见有序介孔碳(OMCs)吸附脱除典型气相多环芳烃——萘进行了研究。分别采用吸附等温线模型(Langmuir、Freundlich、Sips)和恒定浓度波动力学模型对吸附等温线和穿透曲进行拟合分析。采用程序升温脱附法通过失重曲线分析了吸附剂的再生性能。结果表明:Langmuir模型和Sips模型能很好地描述低浓度气相萘在OMCs上的静态吸附行为(R^2>99%),吸附量呈CMK-5>CMK-3>FDU-15排列。恒定浓度波动力学模型具有较高的拟合度,介孔促使3种吸附剂对萘分子具有较高的吸附扩散系数。具有微通孔结构的CMK-5和FDU-15表现出更好的再生性能。综合吸脱附动力学分析,CMK-5在3种吸附剂中表现出更好的应用潜能。

Three kinds of ordered mesoporous carbons （OMCs） were used to remove low concentration of polycyclic aromatic hydrocarbons （PAHs） -- naphthalene （Nap）, by dynamic adsorption experiments. The adsorption isotherms were fitted with isotherm models （Langmuir, Freundlich, and Sips） and kinetic model based on the assumption of constant concentration wave, respectively. The regeneration performance of the adsorbents were analyzed by means of mass loss curve based on the temperature programmed desorption analysis. The results indicated that the static adsorption behavior of Nap on OMCs can be well predicted by Langrnuir and Sips isotherm models （R2 〉 99%）, and the adsorption capacity of CMK-5 （1.735 mol·kg^-1） is better than that of CMK-3 and FDU-15. The constant-pattern wave propagation model was found to well fit the breakthrough curves. And the existence of mesoporous in the adsorbents facilitated the adsorption mass transfer. With transversal micropores, CMK-5 and FDU-15 showed better regenerabilities, and the desorption activation energy follows the order： CMK-3 〉 CMK-5 〉 FDU-15. Based on the analysis of absorption and desorption kinetics, CMK-5 shows better application potential in the three kinds of adsorbents.