Regeneration of [Fe(II)EDTA] for absorbent for continuous NO$_X$ Removal

Abstract

As the industry has developed, a lot of energy demand has increased, and many environmental problems have occurred in energy consumption. Among environmental problems, air pollution is emerging as a serious risk worldwide. Specially, in Korea, it is drawting great attention as the damage caused by fine dust increases.

Nitrogen oxide (NO$_X$), which is the most common air pollutant in Korea, is a major air pollutant that adversely affects buildings, ecosystems, and the human body, and has been identified as a precursor of fine dust, increasing the need for NO$_X$ reduction technology. Scrubbing technology using Fe(II)EDTA solution promotes the reaction with divalent iron ethylenediaminetetraacetic acid (Fe(II)EDTA) and nitrogen monoxide (NO) to form the nitrosyl compound Fe(II)EDTA-NO. , Nitrogen monoxide is effective and can be absorbed environmentally. However, there a limitation of NOx removal by using Fe(II)EDTA absorbent. The reverse reaction of Fe(II)EDTA-NO can be promoted by high-temperature exhaust gas and the oxidation of Fe(II)EDTA by oxygen in the exhaust gas occur rapidly. Therefore, in order to continuously remove NOX in exhaust gas through the NOX removal process based on Fe(II)EDTA absorbent liquid, regeneration process of active absorbents Fe(II)EDTA is necessary which convert inactivated absorbents Fe(II)EDTA-NO and Fe(III) EDTA into Fe(II)EDTA

In this study, in order to continuously remove NO in exhaust gas, it was proposed to reduce Fe(II)EDTA-NO and Fe(III)EDTA to Fe(II) EDTA by regenerating process. The regeneration reactions of Fe(II)EDTA was analyzed in the electrolysis cell and chemical reaction with reducing agents SO$_3^{2-}$, S$_2$O$_3^{2-}$, NH$_2$OH and activated carbon catalyst.