Regeneration of spent NOx scrubber liquor using a dual-chamber microbial fuel cell

Abstract

BACKGROUND Wet absorption via addition of Fe(II)EDTA combined with biological reduction for nitric oxide removal is a promising approach. Based on existing issues and related studies of NOx scrubber solution, a dual-chamber MFC system with a biocathode was utilized to perform simultaneous and continuous reduction of Fe(III)EDTA and Fe(II)EDTA-NO with energy recovery. RESULTS The experimental results showed that in this system almost all of the Fe(II)EDTA-NO was removed and the spent NOx scrubber liquor (consisting of Fe(II)EDTA-NO and Fe(III)EDTA) was regenerated 50%, combined with electricity generation of 15.3 Am-3 NCC at the same time. Microorganisms utilized Fe(II)EDTA and cathodic electrodes as electron donor for Fe(II)EDTA-NO reduction and, different from the complicated Fe(II)EDTA-NO reduction process, the electrode was the sole electron donor for Fe(III)EDTA reduction. Additionally, Fe(II)EDTA-NO and Fe(III)EDTA mutually inhibits each other, mostly due to the competition for electrons. The microbial community of the biocathode was dominated by members of the Betaproteobacteria class. CONCLUSION This study first proposed and confirmed that microbial fuel cells could be utilized for the regeneration of NOx removal liquor which provided a novel pathway for NO removal combined with energy recovery. © 2014 Society of Chemical Industry