Characterization and optimization of Fe(II)Cit-No reduction by Pseudomonas sp.

Biological reduction of nitric oxide (NO), chelated by ferrous L (L: chelate reagent), to N2 is one of the core processes in a chemical absorption-biological reduction integrated technique for nitrogen oxide (NOx) removal from flue gases. In this study, a newly isolated strain, Pseudomonas sp., was used to reduce NO chelated by Fe(II)Cit (Cit: citrate) as Fe(II)Cit-NO, and some factors were investigated. The results showed that, at the NO concentration of 670 mg/m3, 65.9% of NO was totally reduced within 25 h under anaerobic conditions, and the optimal conditions for the bioreduction of NO were found. The strain of Pseudomonas sp. could efficiently use glucose as the carbon source for Fe(II)Cit-NO reduction. Though each complex could be reduced by its own dedicated bacterial strain, Fe(III)Cit could also be reduced by the strain of Pseudomonas sp. The nitrite ion, NO2-, could inhibit cell growth and thus affect the Fe(III) reduction process. These findings provide some useful data for Fe(II)Cit-NO reduction, scrubber solution regeneration and NOx removal process design.