具有多级孔道结构的高比表面多孔炭活化策略及VOCs吸附性能

以废弃榛壳为前体，采用不同活化策略制备多孔炭，探究活化策略和活化温度对多孔炭挥发性有机化合物（VOCs）吸附性能的影响，以及多孔炭的结构、表面性质与VOCs吸附性能的构效关系。结果表明，H₃PO₄法制备的多孔炭介孔体积大，且炭结构缺陷较少，吸附位点较少； KOH法获得的微孔体积较大，孔径集中在0.5~0.7nm的微孔，不利于VOCs分子吸附位点的有效利用。H₃PO₄-KOH分步法在850℃下制备具有高比表面积，孔径集中在0.5~1nm的宽微介孔分布，且炭结构高度无序并含有丰富缺陷位的多孔炭，为VOCs吸附提供了充足的吸附位点并提高了吸附位点了利用率，相比于H₃PO₄与KOH活化法制备的多孔炭的VOCs饱和吸附量显著提升，特别是对于弱极性VOCs。另外，H₃PO₄-KOH分步法制备的多孔炭表面官能团含量较低，极性较低，对非极性VOCs的吸附量远大于极性VOCs。因此，H₃PO₄-KOH分步活化策略是制备具有高比表面积、高VOCs吸附性能多孔炭的最优策略与方案。

Activation strategies of the porous carbon with high specific surface area and hierarchical pore structure and its VOCs adsorption performance

Porous carbons were prepared by different activation strategies from waste hazelnut shells. The effects of activation strategy and activation temperature on the VOCs adsorption performance of porous carbon, and the structure-activity relationships between the structure of porous carbon and the adsorption performance of VOCs were investigated. The results showed that the porous carbon prepared by H₃PO₄ activation was dominated by mesopores, and the carbon matrix possessed few defects and adsorption sites. The porous carbon prepared by KOH activation obtained a larger micropores content and the pore size was mainly distributed at 0.5—0.7nm, which was not conducive to the effective utilization of adsorption sites for VOCs molecules. The porous carbon with high specific surface area, wide micro-mesopore size distribution concentrated in 0.5—1nm, and highly disordered carbon matrix with abundant defect sites was prepared by H₃PO₄-KOH activation at 850 ℃, and these structure characteristics provided sufficient adsorption sites for the VOCs adsorption and improved the utilization of adsorption sites, resulting in the increase of saturation adsorption capacity of VOCs compared with the porous carbon prepared by the H₃PO₄ and KOH activation. In addition, the porous carbon prepared by H₃PO₄-KOH activation was less polar because of its lower content of functional groups on the surface, so the absorption capacity for non-polar VOCs was much greater than that of polar VOCs. Therefore, the H₃PO₄-KOH activation strategy is the optimal method for the preparation of porous carbon with a high specific surface area and excellent VOCs adsorption performance.