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分别采用沉淀-沉积法和浸渍法合成了Pd/TiO2催化剂,采用透射电镜(TEM)、X射线衍射(XRD)和电感耦合等离子体发射光谱(ICP-AES)对材料进行了表征,并对2,4-二氯酚的催化加氢脱氯反应进行了研究.结果表明,2种方法制备的催化剂在加氢脱氯反应中均具有较好的效果,沉淀-沉积法制备的催化剂活性更高,当反应物初始浓度为3.11 mmol.L-1,pH为12,催化剂用量为50 mg时,45 min内2,4-二氯酚可以完成脱氯过程.酸性条件有利于反应的进行.当催化剂用量在15～80 mg时,反应初活性没有明显变化,因此催化反应过程不受传质阻力的影响.当反应物初始浓度在0.62～3.11 mmol.L-1时反应初活性随浓度的提高显著增加,但进一步增加反应物的浓度时初活性没有明显提高,因此2,4-二氯酚在催化剂上的加氢脱氯行为符合Langmuir-Hinshelwood模型,表明2,4-二氯酚的加氢脱氯受表面吸附所控制.
The Pd / TiO2 catalysts were synthesized by precipitation-deposition method and impregnation method respectively. The materials were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD) and inductively coupled plasma atomic emission spectrometry (ICP-AES) , 4-dichlorophenol was studied.The results showed that the catalysts prepared by the two methods all had good effect in the hydrodechlorination reaction and the catalyst prepared by the precipitation-deposition method was more active When the initial concentration of the reactants was 3.11 mmol.L-1, the pH was 12, and the catalyst dosage was 50 mg, 2,4-dichlorophenol could complete the dechlorination within 45 min. The acidic conditions were favorable for the reaction. When the amount of catalyst was 15 ~ 80 mg, the initial activity of the reaction did not change significantly, so the catalytic reaction process was not affected by the mass transfer resistance.When the initial concentration of the reactant was 0.62 ~ 3.11 mmol.L-1, the initial activity increased with the concentration But no significant increase in the initial activity when the concentration of the reactants was further increased. Therefore, the hydrodechlorination behavior of 2,4-dichlorophenol on the catalyst conformed to the Langmuir-Hinshelwood model, indicating that 2,4-dichlorophenol Hydrogen dechlorination is controlled by surface adsorption.