Biological Reduction of Nitric Oxide for Efficient Recovery of Nitrous Oxide as an Energy Source
Likun Wang, Xueming Chen, Wei Wei, Qiuxiang Xu, Jing Sun, Giorgio Mannina, Lan Song, Bing‐Jie Ni
Abstract
Chemical absorption–biological reduction based on Fe(II)EDTA is a promising technology to remove nitric oxide (NO) from flue gases. However, limited effort has been made to enable direct energy recovery from NO through production of nitrous oxide (N2O) as a potential renewable energy rather than greenhouse gas. In this work, the enhanced energy recovery in the form of N2O via biological NO reduction was investigated by conducting short-term and long-term experiments at different Fe(II)EDTA–NO and organic carbon levels. The results showed both NO reductase and N2O reductase were inhibited at Fe(II)EDTA–NO concentration up to 20 mM, with the latter being inhibited more significantly, thus facilitating N2O accumulation. Furthermore, N2O accumulation was enhanced under carbon-limiting conditions because of electron competition during short-term experiments. Up to 47.5% of NO–N could be converted to gaseous N2O–N, representing efficient N2O recovery. Fe(II)EDTA–NO reduced microbial diversity and altered the community structure toward Fe(II)EDTA–NO-reducing bacteria-dominated culture during long-term experiments. The most abundant bacterial genus Pseudomonas, which was able to resist the toxicity of Fe(II)EDTA–NO, was significantly enriched, with its relative abundance increased from 1.0 to 70.3%, suggesting Pseudomonas could be the typical microbe for the energy recovery technology in NO-based denitrification.