Evaluation of Fe(II)EDTA-NO reduction by zinc powder in wet flue gas denitrification technology with Fe(II)EDTA

摘要

Regeneration of Fe(II) EDTA, converting Fe(III)-EDTA and Fe(II) EDTA-NO to Fe(II) EDTA, is the key process in a wet flue gas denitrification technology with Fe(II) EDTA solution. In this paper, Zn powder was first employed as a reductant to reduce Fe(II) EDTA-NO. The stoichiometry and kinetics of Fe(II) EDTA-NO reduction by Zn powder were investigated with respect to Zn powder concentration, pH value, and temperature. The effect of the particle size of the Zn powder on Fe(II) EDTA-NO reduction was also investigated. The experimental results indicated that Fe(II) EDTA-NO reduction rate increased with the decrease of pH value and elevated temperature, and small particle size is beneficial to Fe(II) EDTA NO reduction. Fe(II) EDTA-NO reduction with Zn powder showed a pseudo-second-order reaction concerning Fe(II) EDTA-NO. In addition, the energy of activation (Ea) and the entropy of activation (Delta S-double dagger) of the Fe(II) EDTA-NO reduction with Zn powder were estimated to be 19.853 kJ mol(-1) and -135.557 J K-1 mol(-1), respectively. Finally, the simultaneous reduction of Fe(III) EDTA and Fe(II) EDTA-NO with Zn powder was investigated. Results showed that Zn powder had better performance on simultaneous Fe(III) EDTA and Fe(II) EDTA-NO reduction as compared to the earlier related research. These fundamental researches can offer valuable guidance for industrial denitrification using mixed Fe(II) EDTA and Zn powder system. (C) 2017 Elsevier Ltd. All rights reserved.