Evaluation of simultaneous reduction of Fe( II ) EDTA‐NO and Fe( III ) EDTA by a bacterial pure culture

BACKGROUND The integrated approach of using metal chelate (e.g. Fe( II ) EDTA ) absorption combined with microbial reduction for nitric oxide ( NO ) removal has been a frequent topic of much recent study. The present study was undertaken to evaluate simultaneous Fe( II ) EDTA‐NO and Fe( III ) EDTA with Paracoccus denitrificans as a model microorganism . RESULTS The experimental results suggested that Fe( III ) EDTA reduction was severely inhibited by Fe( II ) EDTA‐NO while the addition of Fe( III ) EDTA could have a positive effect on the reduction of Fe( II ) EDTA‐NO . Riboflavin, AQDS and vitamin B12 at 0.1 mmol L −1 did not have significant effects on simultaneous reduction of Fe( II ) EDTA‐NO and Fe( III ) EDTA . Addition of sulfide not only could directly react with Fe( II ) EDTA‐NO and Fe( III ) EDTA but also might play multiple roles in biological Fe( II ) EDTA‐NO reduction and Fe( III ) EDTA reduction. The respiratory inhibitor CuCl 2 inhibited Fe( II ) EDTA‐NO reduction as well as Fe( III ) EDTA reduction while NaN 3 and rotenone showed no measurable effects . CONCLUSIONS The present study showed that Fe( II ) EDTA‐NO reduction and Fe( III ) EDTA reduction reacted upon each other. The roles of sulfide were divided in terms of biological and chemical interactions during the simultaneous reduction. CuCl 2 could inhibit the simultaneous reduction rates. © 2013 Society of Chemical Industry