载钯磁性介孔碳的制备及其对氯酚类污染物催化脱氯机制研究

Magnetic mesoporous carbon supported Pd catalysts with high catalytic activity are employed for liquid-phase catalytic hydrodechlorination (HDC) of chlorophenols in this project. Properties of supports such as specific surface area, pore structure, surface charge and characterization of surface functional groups have an impact on the adsorption and HDC efficiency of chlorophenols. The impact of supports on adsorption and HDC efficiency will be illustrated and the correlation analysis with properties of supports, adsorption and HDC efficiency will be performed. In addition, the effect of magnetic characteristics on catalyst stability and recovery efficiency will be represented. Role of Pd particle size, valence and metal-support interaction will be revealed to clarify the structure-activity relationship between the nature of active component and HDC efficiency. Competitive catalytic hydrodechlorination mechanism will be determined under the HDC condition of coexistence of several pollutants, furthermore. In summary, the project will provide a theoretical guidance for the design of reusable catalysts with high catalytic activity, and offer a technical assistance for the treatment of chlorophenol-contaminated wastewater.

本课题拟制备具有高催化活性的载钯磁性介孔碳催化剂，用于氯酚类污染物的液相催化加氢脱氯(HDC)处理。通过探讨载体磁性介孔碳的比表面积、孔道结构、表面荷电性以及表面官能团性质对典型氯酚类污染物在催化剂表面的吸附作用和催化脱氯效率的影响，剖析催化剂载体特性、吸附作用与催化脱氯效率三者间的关联性，并研究催化剂磁性特征对催化剂稳定性和回收效率的影响；通过揭示钯粒径、价态以及金属-载体间的相互作用对催化脱氯过程的影响，阐明活性组分特性与催化脱氯效率间的构效关系；确定多种污染物共存条件下的竞争催化脱氯机制，为开发用于氯酚类污染物脱氯的高效易回收的催化剂提供理论指导，为实际氯酚污染废水的处理提供技术支撑。

本项目分别制备了载钯介孔氮化碳、载钯磁性氨基化介孔硅、载钯石墨相氮化碳、载钯磁性介孔碳等催化剂。通过调变载体的特性和催化剂的制备方法得到孔道结构不同、Pd粒径和价态各异的催化剂。将所得催化剂用于溴酸盐、氯酚和氯苯氧乙酸的催化加氢脱卤，研究了催化剂的特性与脱卤效率间的关系。基于本项目的研究，可得到以下结论：介孔材料较微孔材料更利于Pd分散和污染物吸附，以其为载体更利于催化脱卤；载体表面的氨基等含氮官能团与Pd之间存在作用力，利于Pd的分散，进而利于催化脱卤的进行；在催化剂的制备过程中可加入磁性粒子前驱体可制备介孔磁性催化剂，将磁性催化剂用于催化加氢脱卤具有较好的活性和稳定性，且催化剂可被磁选分离，证明了磁性催化剂的应用前景。