Ag/MnO_x-CeO_2与等离子体协同脱除空气中甲醛

Synergistic removal of formaldehyde from air by combining Ag/MnO_x- CeO_2 with plasma

为更有效脱除空气中甲醛污染物,分别将CeO_2、MnO_x-CeO_2和Ag/MnO_x-CeO_2催化剂与介质阻挡放电等离子体结合,在大气压及35℃下脱除空气中甲醛,选取脱除效果最好的Ag/MnO_xCeO_2为催化剂,研究放电电压和HCHO初始体积分数以及空速对HCHO脱除率的影响。结果表明,当空气中甲醛的体积分数为2.0×10-4、水的体积分数为1.0%、空速为16 364 h-1、放电电压为18 k V时,Ag/MnO_x-CeO_2与等离子体结合的甲醛脱除率达99.0%,高出单纯等离子体和单纯Ag/MnO_x-CeO_2催化氧化(不放电)脱除率之和23.9%。实验证明,在脱除空气中HCHO的过程中,Ag/MnO_x-CeO_2与等离子体结合产生了很强的协同作用,且等离子体中的活性物种是协同作用的关键。

This paper is motivated by a more effective removal of formaldehyde pollutants in air. The research is focused on removing formaldehyde present in air at atmospheric pressure and 35 ℃ by combining the dielectric barrier discharge plasma with CeO2, MnOx-CeO2 and Ag/MnOx-CeO2catalysts; choosing Ag/MnOx-CeO2 with the best removal effect as catalyst and thereby investigating the law behind the effects of discharge voltage, initial volume fraction of formaldehyde, and GHSV（gas flow volume per hour per discharge volume） on formaldehyde removal rate. The results demonstrate that, in the presence of a mixture gas of 2.0×10-4HCHO, 1.0% H2 O, GHSV of 16 364 h-1, and input discharge voltage of 18 k V, the combination of the dielectric barrier discharge plasma and Ag/MnOx-CeO2 may provide the formaldehyde removal rate of 99.0%,23.9% higher than the combined rate of pure plasma-induced oxidation and pure catalytic oxidation（over Ag/MnOx-CeO2 without discharges）. The experiments verify that the process of removing HCHO from the air is accompanied by a very strong synergistic interaction occurring in the binding between Ag/MnOx-CeO2 and plasma whose active species holds the key to the synergistic effect.