NO_2促进碱液吸收NO的作用机理

Reaction Mechanism of NO_2 in NO Absorption into Alkaline Solution

在鼓泡床反应器中实验研究了碱液吸收NOx过程中NO2对NO吸收的促进作用,考察了NaOH浓度、NOx体积分数、NO/NO2体积比及反应温度(283～358K)对NOx吸收效率的影响.结果表明,在NOx≥600×106(),NO/NO2≤2(φ)的条件下,NO2有效促进了碱液对NO的吸收,且吸收NO的效率高于NO2.反应体系气相与液相产物分析表明,吸收过程产生的暂态中间活性组分存在类催化作用,其反应机理为NO2与气相中H2O反应生成HONO(+M),其部分在液膜分解生成NO(aq)和·OH,生成的NO(aq)进入液相,·OH与气相中的NO反应,促进了NO的吸收.

The promoting effect of NO2 on NO absorbing into alkaline solution was studied in a bubble column reactor operated in continuous flow mode and the effects of different process variables such as concentration of alkaline solution, feed concentration of NOx, ratio of NO to NO2 and reaction temperature （283-358 K） were investigated. The results indicated that the absorption of NOx was increased observably in the presence of NO2 and the removal efficiency of NO was higher than that of NO2 when the feed concentration of NOx was above 600× 10-6 and the volume ratio of NO/NO2 in the range from 0.5 to 2.0. Furthermore, the ion chromatography analysis on the products showed that there were some non-stationary intermediate species formed from NO absorption induced by NO2 and there may be some novel similar-catalysis mechanisms in the removal of NO by injecting NO2 into alkaline solution.