A study on the reduction of [Fe(III)‐EDTA]− catalyzed with activated carbon in a fixed‐bed. Issue 2 (17th February 2012)

• Record Type: Journal Article
• Authors: Yang, Xiao‐Juan; Zhu, Hai‐Song; Yang, Lin; Long, Xiang‐Li; Yuan, Wei‐Kang
• Is Part Of: Environmental progress & sustainable energy. Volume 32:Issue 2(2013:Jul.)
• Page Start: 206
• Page End: 212
• Publication Date: 2012-02-17
• Subjects: Environmental engineering -- Periodicals; Sustainable engineering -- Periodicals; Environmental chemistry -- Periodicals; 333.7
• DOI: 10.1002/ep.10636
• Languages: English
• ISSNs: 1944-7442

Abstract

<abstract abstract-type="main"> <title> <x xml:space="preserve">Abstract</x> </title> <p>The simultaneous control of SO<sub>2</sub>/NO<sub>X</sub> can be realized with the [Fe(II)‐EDTA]<sup>2−</sup> aqueous solution. However, the [Fe(II)‐EDTA]<sup>2−</sup> is easily oxidized to [Fe(III)‐EDTA] <sup>−</sup> by oxygen, which has no ability to bind NO. The reduction of [Fe(III)‐EDTA] <sup>−</sup> to [Fe(II)‐EDTA]<sup>2−</sup> is a key to the maintenance of the NO removal efficiency with the [Fe(II)‐EDTA]<sup>2−</sup> aqueous solution. The reduction of [Fe(III)‐EDTA]<sup>−</sup> can be accomplished by sulfite produced by SO<sub>2</sub> 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]<sup>2−</sup> catalyzed by activated carbon. The influences of [Fe(III)‐EDTA] <sup>−</sup> and sulfite concentrations, pH, liquid flow, temperature, on [Fe(III)‐EDTA] <sup>−</sup> catalytic reduction have been tested. The experimental results indicate that the [Fe(III)‐EDTA]<sup>−</sup> reduction increases with the [Fe(III)‐EDTA]<sup>−</sup> and sulfite concentrations. Raising the temperature can increase the [Fe(III)‐EDTA] <sup>−</sup> conversion. The optimal pH range for the reduction of [Fe(III)‐EDTA] <sup>−</sup> is 5.7–7.5. The apparent activation energy determined from the experimental results is 35.2 ± 0.5 kJ mol<sup>−1</sup>. The continuous experiment manifests that simultaneous removal of NO and SO<sub>2</sub> with the [Fe(II)‐EDTA]<sup>2−</sup> 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]<sup>‐</sup> reduction by sulfite catalyzed with activated carbon can be described as <disp-formula content-type="mathematics" id="ep10636-disp-0001"><inline-graphic mimetype="image" xlink:href="ark:/27927/pgg1xq9v2mb" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink" /><mml:math display="block" altimg="urn:x-wiley:19447442:media:ep10636:ep10636-math-0001" overflow="scroll" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>r</mml:mi><mml:mo>=</mml:mo><mml:mfrac><mml:mrow><mml:msub><mml:mrow><mml:mi>k</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub><mml:msub><mml:mrow><mml:mi>k</mml:mi></mml:mrow><mml:mrow><mml:mn>1</mml:mn></mml:mrow></mml:msub><mml:msubsup><mml:mrow><mml:mi>KC</mml:mi></mml:mrow><mml:mrow><mml:mo stretchy="false">[</mml:mo><mml:mtext>Fe</mml:mtext><mml:mo stretchy="false">(</mml:mo><mml:mtext>III</mml:mtext><mml:mo stretchy="false">)</mml:mo><mml:mo>−</mml:mo><mml:mtext>EDTA</mml:mtext><mml:mo stretchy="false">]</mml:mo><mml:msup><mml:mi /><mml:mrow><mml:mo>−</mml:mo></mml:mrow></mml:msup></mml:mrow><mml:mrow><mml:mn>1</mml:mn><mml:mo>/</mml:mo><mml:mi>n</mml:mi></mml:mrow></mml:msubsup><mml:msub><mml:mrow><mml:mi>C</mml:mi></mml:mrow><mml:mrow><mml:msup><mml:mrow><mml:mi mathvariant="normal">H</mml:mi></mml:mrow><mml:mrow><mml:mo>+</mml:mo></mml:mrow></mml:msup></mml:mrow></mml:msub><mml:msub><mml:mrow><mml:mi>C</mml:mi></mml:mrow><mml:mrow><mml:msubsup><mml:mrow><mml:mtext>SO</mml:mtext></mml:mrow><mml:mrow><mml:mn>3</mml:mn></mml:mrow><mml:mrow><mml:mn>2</mml:mn><mml:mo>−</mml:mo></mml:mrow></mml:msubsup></mml:mrow></mml:msub></mml:mrow><mml:mrow><mml:msub><mml:mrow><mml:mi>k</mml:mi></mml:mrow><mml:mrow><mml:mo>−</mml:mo><mml:mn>1</mml:mn></mml:mrow></mml:msub><mml:msub><mml:mrow><mml:mi>C</mml:mi></mml:mrow><mml:mrow><mml:mtext>EDTA</mml:mtext></mml:mrow></mml:msub><mml:mrow><mml:mo stretchy="true">(</mml:mo><mml:mn>1</mml:mn><mml:mo>+</mml:mo><mml:msub><mml:mrow><mml:mi>C</mml:mi></mml:mrow><mml:mrow><mml:msup><mml:mrow><mml:mi mathvariant="normal">H</mml:mi></mml:mrow><mml:mrow><mml:mo>+</mml:mo></mml:mrow></mml:msup></mml:mrow></mml:msub><mml:mo>/</mml:mo><mml:msubsup><mml:mrow><mml:mi>K</mml:mi></mml:mrow><mml:mrow><mml:mi mathvariant="normal">a</mml:mi></mml:mrow><mml:mrow><mml:mi>θ</mml:mi></mml:mrow></mml:msubsup><mml:mo stretchy="true">)</mml:mo></mml:mrow><mml:mo>+</mml:mo><mml:msub><mml:mrow><mml:mi>k</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub><mml:msub><mml:mrow><mml:mi>C</mml:mi></mml:mrow><mml:mrow><mml:msubsup><mml:mrow><mml:mtext>SO</mml:mtext></mml:mrow><mml:mrow><mml:mn>3</mml:mn></mml:mrow><mml:mrow><mml:mn>2</mml:mn><mml:mo>−</mml:mo></mml:mrow></mml:msubsup></mml:mrow></mml:msub></mml:mrow></mml:mfrac><mml:mo>·</mml:mo><mml:mfrac><mml:mrow><mml:msub><mml:mrow><mml:mi>ρ</mml:mi></mml:mrow><mml:mrow><mml:mi mathvariant="normal">b</mml:mi></mml:mrow></mml:msub></mml:mrow><mml:mrow><mml:mi>ε</mml:mi></mml:mrow></mml:mfrac></mml:mrow></mml:math></disp-formula> © 2012 American Institute of Chemical Engineers Environ Prog, 32: 206‐212, 2013</p> </abstract>