Enhanced flue-gas denitrification using ferrous.cntdot.EDTA and a polyphenolic compound in an aqueous scrubber system

Abstract

Previous work in this laboratory has involved studying the possibility of combined N0,/S02 scrubbing using various aqueous chemistries with a metal chelate additive. Recently, we have focused our work on the metal chelate ferrous.EDTA [Fe(II).EDTA]. A problem encountered in the practical application of Fe(I1)-EDTA is that the ferrous ion has been found to oxidize to the corresponding ferric species, leading to a decrease in NO, removal for the scrubbing solution containing the additive. We have found that addition of a polyphenolic compound leads to a sustained high NO, removal under various oxidizing conditions. We believe that the improved performance of Fe(II).EDTA is due to the known capabilities of these organic compounds both to inhibit oxidation of ferrous chelates by dissolved oxygen and to rapidly reduce any ferric ions back to the original ferrous species. These effects are illustrated by the following chemical reactions: 02(1) + organic -oxidized organic, and Fe(II1) + organic -Fe(I1) + oxidized organic. IntroductionThe use of metal chelate additives in an aqueous

The regeneration of Fe-EDTA denitration solutions by nanoscale zero-valent iron

“…1 Therefore, developing a method to recycle or regenerate the nitrosyl complex solution is of great interest for many research groups in this eld. [1][2][3][4][5][6] Biological reduction of NO chelated by Fe(II)-EDTA, a novel chemical absorption-biological reduction integrated process, is regarded as a promising alternative to the conventional selective catalytic reduction process. The ferrous chelate absorbent can be regenerated by microorganisms to sustain a persistent NO removal capacity.…”

Reduction of [Fe(III)EDTA]− catalyzed by activated carbon modified with ammonia solution

“…It is necessary to search for methods to regenerate [Fe(II)-EDTA] 22 to maintain the NO removal efficiency at a high level for a long time. Some agents such as Na 2 S 2 O 4 [10], polyphenolic compounds [11], Na 2 SO 3 [12], and hydrazine [13] have been tested to regenerate [Fe(II)-EDTA] 22 . A chemical absorption-biological reduction integrated approach has been tried to bioreduce [Fe(III)-EDTA] 2 into [Fe(II)-EDTA] 22 once again [14][15][16][17].…”

Kinetic study on regeneration of FeIIEDTA in the wet process of NO removal

“…As a consequence, the regeneration of absorption solution becomes a fundamental part of this method. Various reducing agents such as polyphenolic compounds [12], Na 2 S 2 O 4 [13] and Na 2 SO 3 [7] have been tested. * Corresponding author.…”