Evaluation of complexed NO reduction mechanism in a chemical absorption–biological reduction integrated NOx removal system

Abstract

Biological reduction of nitric oxide (NO) from Fe(II) ethylenediaminetetraacetic acid (EDTA)-NO to dinitrogen (N(2)) is a core process for the continual nitrogen oxides (NO(x)) removal in the chemical absorption-biological reduction integrated approach. To explore the biological reduction of Fe(II)EDTA-NO, the stoichiometry and mechanism of Fe(II)EDTA-NO reduction with glucose or Fe(II)EDTA as electron donor were investigated. The experimental results indicate that the main product of complexed NO reduction is N(2), as there was no accumulation of nitrous oxide, ammonia, nitrite, or nitrate after the complete depletion of Fe(II)EDTA-NO. A transient accumulation of nitrous oxide (N(2)O) suggests reduction of complexed NO proceeds with N(2)O as an intermediate. Some quantitative data on the stoichiometry of the reaction are experimental support that reduction of complexed NO to N(2) actually works. In addition, glucose is the preferred and primary electron donor for complexed NO reduction. Fe(II)EDTA served as electron donor for the reduction of Fe(II)EDTA-NO even in the glucose excessive condition. A maximum reduction capacity as measured by NO (0.818 mM h(-1)) is obtained at 4 mM of Fe(II)EDTA-NO using 5.6 mM of glucose as primary electron donor. These findings impact on the understanding of the mechanism of bacterial anaerobic Fe(II)EDTA-NO reduction and have implication for improving treatment methods of this integrated approach.

A pilot study on the regeneration of ferrous chelate complex in NOx scrubber solution by a biofilm electrode reactor

“…It also confirms that Fe(II)EDTA can serve as electron donor for the biological reduction of complexed NO to N 2 , as reported by Van der Mass et al (2003) and Zhang et al (2007Zhang et al ( , 2008. In sole electrochemical reaction, Fe(II)EDTA formation by reduction of Fe(III)EDTA proceeded at the cathode according to:…”

“…However, in this study the improvement of Fe(II)EDTA-NO reduction by electric current is not so evident as that of Fe(III)EDTA reduction, indicating that hydrogen was not an active electron donor for Fe(II)EDTA-NO reduction. Moreover, Zhang et al (2008) has demonstrated that glucose compared with Fe(II)EDTA is the preferred and primary electron donor for the reduction of Fe(II)EDTA-NO. Therefore, glucose served as the major electron donor compared with hydrogen and Fe(II)EDTA.…”

“…One promising technique for the NO x removal from flue gases is the chemical absorption-biological reduction integrated approach (Buisman et al, 1999;Li et al, 2006;Zhang et al, 2008), which involves absorption of NO (the primary component of NO x in the flue gas) into the scrubber liquid by ferrous complex and regeneration of ferrous complex by two groups of heterotrophic bacteria Zhang et al, 2007). This integrated process mainly consists of four reactions as follows:…”

Dynamic model for nitric oxide removal by a rotating drum biofilter

“…(14)) in aqueous phase. Zhang et al [39] reported that NO had low solubility in the water, while the NO 2 − production in the water could be rapidly denitrified to N 2 by denitrifiers in the drum [40]. Therefore, the NO transfer limited process was more important than the reaction limited process for the NO removal process…”

Reduction of ethylenediaminetetraacetic acid iron(III) by Klebsiella sp. FD-3 immobilized on iron(II, III) oxide poly (styrene-glycidyl methacrylate) magnetic porous microspheres: Effects of inorganic compounds and kinetic study of effective diffusion in porous media

“…Fe(II)EDTA (EDTA: ethylenediaminetetraacetate) absorption combined with microbial reduction had been proposed and researched in recent years (Li et al, 2006;Zhang et al, 2007Zhang et al, , 2008. There are some unfavorable problems by free bacteria because of the inhibition of microbial Fe(III)EDTA reduction with the components in the scrubbing solution.…”