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En Face Detection of Nitric Oxide and Superoxide in Endothelial Layer of Intact Arteries
Published on: February 25, 2016
Nitric oxide reduction in BioDeNOx reactors: kinetics and mechanism
Peter van der Maas1, Isabella Manconi, Bram Klapwijk
1Sub-Department of Environmental Technology, Wageningen University, PO Box 8129, 6700 EV Wageningen, The Netherlands.
Biotechnology and Bioengineering
|June 17, 2008
Summary
The BioDeNOx process efficiently removes nitrogen oxides (NOx) by biologically reducing nitric oxide (NO) to nitrous oxide (N2O). Iron(II)EDTA acts as the primary electron donor, enhancing NO denitrification rates.
Area of Science:
- Environmental biotechnology
- Chemical engineering
Background:
- The BioDeNOx process utilizes biological reduction for NOx removal from flue gases.
- Nitric oxide (NO) reduction to di-nitrogen (N2) gas is a critical step in this process, particularly the initial conversion to nitrous oxide (N2O).
Purpose of the Study:
- To elucidate the mechanism and kinetics of the initial NO reduction step (NO to N2O) in aqueous Fe(II)EDTA(2-) solutions.
- To identify the primary electron donor in the BioDeNOx system under specific reactor conditions.
Main Methods:
- Batch experiments were conducted using various inocula in Fe(II)EDTA(2-) medium (5-25 mM) at 55°C and pH 7.2.
- Ethanol was used as an external electron donor, and kinetic parameters like NO reduction rates and Km for NO were determined.
Main Results:
- BioDeNOx reactor mixed liquor exhibited high NO reduction rates (+/-0.34 nmol s(-1) mg(prot)(-1)) with a low Km for NO (<10 nM).
- NO reduction rates were influenced by NO(aq), Fe(II)EDTA(2-) concentration, and temperature.
- Kinetic and thermodynamic analyses confirmed Fe(II)EDTA(2-) as the primary electron donor, not ethanol.
Conclusions:
- The Fe(II)EDTA(2-)/Fe(III)EDTA(-) redox system directly interferes with the NO reduction electron transfer chain.
- This interference significantly enhances the NO denitrification rate within the BioDeNOx process.
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