烟气脱氮体系中Fe^Ⅱ（NTA）的氧化分析

Oxidation of Fe^Ⅱ（NTA） in the Process of NO Removal

在填料吸收塔中，考察O2的体积分数、温度和pH值等对Fe^Ⅱ（NTA）氧化的影响，并与Fe^Ⅱ（EDTA）的氧化进行比较．结果表明，在实验考察的Fe^Ⅱ（NTA）浓度范围（0-10mmol·L^-1），氧化过程对Fe^Ⅱ（NTA）浓度和O2的体积分数均为一级反应，反应活化能为17．5kJ·mol^-1，小于Fe^Ⅱ（EDTA）的氧化活化能，从而使Fe^Ⅱ（NTA）的氧化更快，同一条件下的氧化速率常数比Fe^Ⅱ（EDTA）的氧化速率常数大10倍以上．当该值小于5时，由于溶液中游离态Fe件和络合态Fe^Ⅱ（NTA）共存，氧化过程中溶液pH值呈先升后降的趋势，而在pH值为6～9时，Fe件均形成FeⅡ（NTA）络合物，氧化过程中反应液pH值持续下降，但氧化速率随pH值的增加而加快．

The oxidation kinetics of Fe^Ⅱ（NTA） by O2 in packed absorption column was investigated. The results showed that the reaction was first order to Fe^Ⅱ（NTA） concentration and oxygen concentration respectively. The effect of temperature followed arrhenius equation and the activation energy was 17.5 kJ·mol^-1 , lower than that of Fe^Ⅱ（EDTA） oxidation, which caused the faster oxidation of Fe^Ⅱ（NTA）. Oxidation reaction rate increased with the increasing of pH and amount of absorption solution. The chelating complex of Fe^2＋ and NTA was dependence in solution pH value, which caused the solution pH elevation at first, and than fallen down in Fe^Ⅱ（NTA） oxidation with an initial pH lower than 5, while the solution pH decreased continually in the oxidation process with an initial pH from 6 to 9.