Microbial reduction of FeII(EDTA)NO in nitric oxide removal with ferrous chelate absorption

A new promising method of NO removal by combined use of microbial reduction and metal complex absorption is presented. Fe-II(EDTA)NO will be reduced by microorganisms to the environmentally benign gaseous product of N-2, and Fe-II(EDTA) is regenerated simultaneously. The effects of the types and amount of carbon source, the biomass inoculation on bio-reduction efficiency were investigated in flask culture experiments. The results showed that the microorganisms exhibited good performance with the carbon sources of glucose, ethanol, sodium acetate or sodium citrate. 200 mg L-1 ethanol was enough for microorganism to reduce 9.9 mmol L-1 Feu(EDTA)NO completely. Fell(EDTA)NO reduction rate didn't increase with adding more amount of carbon source. When the biomass of inoculation was more than 80 mg L-1 (measured by dry weight of mix culture), there would be no "lag time" of bio-reduction with an initial Fe-II(EDTA)NO concentration of 7.3 mmol L-1. The kinetics of the bio-reaction could be described by Michaelis-Menten equation. The maximum reaction rate gamma(max) was 5.4 mmol L-1 h(-1) and the Michaelis constant k(m) was 63.8 mmol L-1 within an initial Fe-II(EDTA)NO concentration of 12.8 mmol(.) L-1.