A pilot study on the regeneration of ferrous chelate complex in NOx scrubber solution by a biofilm electrode reactor
ABSTRACT A chemical absorption-biological reduction integrated process has been proposed for the removal of nitrogen oxides (NO(x)) from flue gases. In this study, we report a new approach using biofilm electrode reactor (BER) to regenerate Fe(II)EDTA via simultaneously reducing Fe(II)EDTA-NO and Fe(III)EDTA in NO(x) scrubber solution. Biofilm formed on the surface of the cathode was confirmed by Environmental Scan Electro-Microscope. Experimental results demonstrated that it was effective and feasible to utilize the BER to promote the reduction of Fe(II)EDTA-NO and Fe(III)EDTA simultaneously. The reduction efficiency of Fe(II)EDTA-NO and Fe(III)EDTA was up to 85% and 78%, respectively when the BER was continuously operated with electricity current at 30 mA. The absence of electricity induced an immediate decrease in reduction efficiency, indicating that the bio-regeneration of ferrous chelate complex was electrochemically accelerated. The present approach is considered advantageous for the enhanced bio-reduction in the NO(x) scrubber solution.
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ABSTRACT: Anthropogenic nitrogen oxides (NO x ) emitted from the fossil-fuel-fired power plants cause adverse environmental issues such as acid rain, urban ozone smoke, and photochemical smog. A novel chemical absorption-biological reduction (CABR) integrated process under development is regarded as a promising alternative to the conventional selective catalytic reduction processes for NO x removal from the flue gas because it is economic and environmentally friendly. CABR process employs ferrous ethylenediaminetetraacetate [Fe(II)EDTA] as a solvent to absorb the NO x following microbial denitrification of NO x to harmless nitrogen gas. Meanwhile, the absorbent Fe(II)EDTA is biologically regenerated to sustain the adequate NO x removal. Compared with conventional denitrification process, CABR not only enhances the mass transfer of NO from gas to liquid phase but also minimize the impact of oxygen on the microorganisms. This review provides the current advances of the development of the CABR process for NO x removal from the flue gas.Applied Microbiology and Biotechnology 08/2014; 98(20). DOI:10.1007/s00253-014-6016-9 · 3.81 Impact Factor
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ABSTRACT: A chemical absorption–biofilm electrode reactor (CABER) integrated system was used for removal of nitrogen monoxide (NO) from flue gas. Effects of the electric current on NO removal efficiency, concentration of Fe(II)EDTA, and consumption rate of glucose in the stabilization phase were investigated. Results indicate that the optimum impressed current was 0.04 A [i.e., 66.7 A m–3 net cathodic compartment (NCC) of the current density]. Under this condition, the consumption rate of glucose was 0.462 g h–1. Performance evaluation of this new approach was investigated under optimum conditions as well. It is noted that minimum residence time was only 20 s, maximum oxygen tolerability was 10%, and maximum elimination capacity of NO was 104.2 g of NO m–3 h–1. The contribution of H2 and glucose in reduction of Fe(III)EDTA was also studied. The results indicated that increasing the H2 supply appropriately could reduce the consumption of glucose. This new approach showed a better performance on NO removal and a larger processing load than those of the chemical absorption–biological reduction (CABR) integrated system.Energy & Fuels 05/2014; 28(5):3332–3338. DOI:10.1021/ef500604d · 2.73 Impact Factor
Asian Journal of Chemistry 01/2013; 25(14). DOI:10.14233/ajchem.2013.14629 · 0.36 Impact Factor