A study on the reduction of [Fe(III)‐EDTA]− catalyzed with activated carbon in a fixed‐bed. Issue 2 (17th February 2012) - Yang, Xiao‐Juan
Abstract The simultaneous control of SO2/NOX can be realized with the [Fe(II)‐EDTA]2− aqueous solution. However, the [Fe(II)‐EDTA]2− is easily oxidized to [Fe(III)‐EDTA] − by oxygen, which has no ability to bind NO. The reduction of [Fe(III)‐EDTA] − to [Fe(II)‐EDTA]2− is a key to the maintenance of the NO removal efficiency with the [Fe(II)‐EDTA]2− aqueous solution. The reduction of [Fe(III)‐EDTA]− can be accomplished by sulfite produced by SO2 dissolving in the aqueous solution under the catalysis of activated carbon. The experiments were performed in a fixed‐bed reactor to investigate the regeneration of [Fe(II)‐EDTA]2− catalyzed by activated carbon. The influences of [Fe(III)‐EDTA] − and sulfite concentrations, pH, liquid flow, temperature, on [Fe(III)‐EDTA] − catalytic reduction have been tested. The experimental results indicate that the [Fe(III)‐EDTA]− reduction increases with the [Fe(III)‐EDTA]− and sulfite concentrations. Raising the temperature can increase the [Fe(III)‐EDTA] − conversion. The optimal pH range for the reduction of [Fe(III)‐EDTA] − is 5.7–7.5. The apparent activation energy determined from the experimental results is 35.2 ± 0.5 kJ mol−1. The continuous experiment manifests that simultaneous removal of NO and SO2 with the [Fe(II)‐EDTA]2− solution coupled with the Fe(II) regeneration catalyzed by activated carbon can be maintained at a high NO removal efficiency for a long period of time. The kinetic equation of [Fe(III)‐EDTA]‐ reduction by sulfite catalyzed with activated carbon can be described as r=k2k1KC[Fe(III)−EDTA]−1/nCH+CSO32−k−1CEDTA(1+CH+/Kaθ)+k2CSO32−·ρbε © 2012 American Institute of Chemical Engineers Environ Prog, 32: 206‐212, 2013