Relationship between the structure and activity of ruthenium catalysts in the catalytic ozonation of dimethyl phthalate

Ruthenium catalysts on various activated carbon (AC) supports were prepared using conventional calcination and microwave irradiation. Their activity in the catalytic ozonation of dimethyl phthalate was studied. The relationship between the structure and activity was investigated. All the supports and catalysts increased total organic carbon removal. The activity order was Ru/coal-AC > nutshell-AC > Ru/nutshell-AC > Ru/coconut-AC ≈ coal-AC > coconut-AC. The supported Ru particles diffused into the macropores, which increased mass transfer resistance in catalytic ozonation and decreased the probability that the reactants can contact the active phase on the interior surface. This was one reason why the activity of nutshell-AC and Ru/nutshell-AC was lower than that of Ru/coal-AC. A difference in Ru dispersion on the surface of the catalyst also caused the activity difference. The active phase on the surface of nutshell-AC can be changed by microwave irradiation, which caused Ru/nutshell-AC to even be less active than the corresponding support. As compared to the use of conventional calcination, the use of microwave irradiation enhanced the metal dispersion and catalytic activity of Ru/coal-AC.

摘要采用传统焙烧和微波辐射制备了不同活性炭 (AC) 负载 Ru 催化剂, 并用于催化臭氧氧化降解邻苯二甲酸二甲酯 (DMP) 反应中, 探讨了催化剂的构效关系. 结果表明, 所有 AC 和催化剂均能提高臭氧氧化 DMP 过程中 TOC (总有机碳) 去除率, 其活性顺序为 Ru/coal-AC > nutshell-AC > Ru/nutshell-AC > Ru/coconut-AC ≈ coal-AC > coconut-AC. 负载的 Ru 颗粒扩散到 AC 大孔中, 增加了反应的传质阻力, 使得反应物与 AC 内表面的活性位和金属 Ru 的接触机会减少, 这是 Ru/nutshell-AC 和 Ru/coconut-AC 活性低于 Ru/coal-AC 的一个原因; 催化剂表面 Ru 分散度也是导致其活性差别的原因之一. 微波加热引起 nutshell-AC 表面活性官能团发生变化, 从而导致其负载的 Ru 催化活性降低. 相对于传统焙烧, 微波辐射热处理能够提高 coal-AC 表面 Ru 的分散度, 从而提高催化剂活性.

Graphical AbstractThe surface structure of the activated carbon (AC) support influenced the activity of Ru/AC catalysts in dimethyl phthalate ozonation. Microwave heating during catalyst preparation changed the catalyst activity by a modification of its surface structure.Figure optionsDownload as PowerPoint slide