Nitric oxide can be scrubbed from the exhausted gases with [Fe(II)NTA]− solution. However, the ability of combining NO will be lost because [Fe(II)NTA]− is oxidized to [Fe(III)NTA] by the oxygen coexisting with NO in the exhausted gases. The regeneration of [Fe(II)NTA]− can be realized by reducing [Fe(III)NTA] with sulfite under the catalysis of activated carbon. In this study, the catalytic reduction of [Fe(III)NTA] has been studied in a stirred cell systematically. The experiments indicate that the intrinsic kinetics of this catalytic reaction can be obtained with a stirring speed over 300 r min− 1 and a particle size of activated carbon smaller than 100–120 mesh. The optimal carbon dosage is 15 g L− 1. The [Fe(II)NTA]− regeneration rate increases with the initial concentrations of [Fe(III)NTA] and sulfite. The [Fe(III)NTA] conversion decreases with the rise of pH. The [Fe(II)NTA]− regeneration is enhanced with the molar Fe3+/NTA3− ratio. The [Fe(IIINTA] reduction is enhanced with temperature. The kinetic equation of this catalytic reaction can be illustrated as<Equation ID="Equa"> <EquationSource Format="TEX">$r{\text{=}}\frac{{{k_1}{k_2}m{K_f}{C_{{\text{Fe}}\left( {{\text{III}}} \right){\text{NTA}}}}^{{{\raise0.7ex\hbox{$1$} \!\mathord{\left/ {\vphantom {1 n}}\right.\kern-0pt}\!\lower0.7ex\hbox{$n$}}}}{C_{{H^{\text{+}}}}}{C_{S{O_3}^{{2 - }}}}^{{0.5}}}}{{{k_{{\text{-}}1}}m{C_{NTA}}{{{\text{(}}1+{{{C_{{H^+}}}} \mathord{\left/ {\vphantom {{{C_{{H^+}}}} {{K_{a2}}^{\theta }}}} \right. \kern-0pt} {{K_{a2}}^{\theta }}}{\text{)}}}^{0.5}}{\text{+}}{k_2}{C_{S{O_3}^{{2 - }}}}^{{0.5}}}}$</EquationSource> </Equation>The parameters estimated at 80 ℃ are k1Kf = 4.50<InlineEquation ID="IEq1"> <EquationSource Format="TEX">$\times$</EquationSource> </InlineEquation>105 L2.2− 1.2 min− 1 g− 1, k− 1=24.13 L2 g− 1− 1 min− 1, k2 = 1.59 L mol− 1 min− 1, 1/n = 0.87. The intrinsic activation energy Ea is 65.37 kJ mol− 1. The NO removal efficiency can be kept at a high level for a long period of time with the [Fe(II)NTA]− solution when the [Fe(II)NTA]− regeneration is made with activated carbon as a catalyst.

A study on the kinetics of [Fe(III)NTA] reduction catalyzed by activated carbon in a stirred reactor

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2025年12月8日

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Xiang-li Long,
Peng Wang,
Cong Li,
Tao huang

摘要

Nitric oxide can be scrubbed from the exhausted gases with [Fe(II)NTA]⁻ solution. However, the ability of combining NO will be lost because [Fe(II)NTA]⁻ is oxidized to [Fe(III)NTA] by the oxygen coexisting with NO in the exhausted gases. The regeneration of [Fe(II)NTA]⁻ can be realized by reducing [Fe(III)NTA] with sulfite under the catalysis of activated carbon. In this study, the catalytic reduction of [Fe(III)NTA] has been studied in a stirred cell systematically. The experiments indicate that the intrinsic kinetics of this catalytic reaction can be obtained with a stirring speed over 300 r min^− 1 and a particle size of activated carbon smaller than 100–120 mesh. The optimal carbon dosage is 15 g L^− 1. The [Fe(II)NTA]⁻ regeneration rate increases with the initial concentrations of [Fe(III)NTA] and sulfite. The [Fe(III)NTA] conversion decreases with the rise of pH. The [Fe(II)NTA]⁻ regeneration is enhanced with the molar Fe³⁺/NTA³⁻ ratio. The [Fe(IIINTA] reduction is enhanced with temperature. The kinetic equation of this catalytic reaction can be illustrated as $r{\text{=}}\frac{{{k_1}{k_2}m{K_f}{C_{{\text{Fe}}\left( {{\text{III}}} \right){\text{NTA}}}}^{{{\raise0.7ex\hbox{$1$} \!\mathord{\left/ {\vphantom {1 n}}\right.\kern-0pt}\!\lower0.7ex\hbox{$n$}}}}{C_{{H^{\text{+}}}}}{C_{S{O_3}^{{2 - }}}}^{{0.5}}}}{{{k_{{\text{-}}1}}m{C_{NTA}}{{{\text{(}}1+{{{C_{{H^+}}}} \mathord{\left/ {\vphantom {{{C_{{H^+}}}} {{K_{a2}}^{\theta }}}} \right. \kern-0pt} {{K_{a2}}^{\theta }}}{\text{)}}}^{0.5}}{\text{+}}{k_2}{C_{S{O_3}^{{2 - }}}}^{{0.5}}}}$ The parameters estimated at 80 ℃ are k₁K_f = 4.50 $\times$ 10⁵ L^2.2^− 1.2 min^− 1 g^− 1, k_− 1=24.13 L² g^− 1^− 1 min^− 1, k₂ = 1.59 L mol^− 1 min^− 1, 1/n = 0.87. The intrinsic activation energy Ea is 65.37 kJ mol^− 1. The NO removal efficiency can be kept at a high level for a long period of time with the [Fe(II)NTA]⁻ solution when the [Fe(II)NTA]⁻ regeneration is made with activated carbon as a catalyst.