Highly Efficient Heterogeneous Catalytic Reduction of Fe(II)EDTA-NO in Industrial Denitrification Solution over Pd/AC Catalyst

Abstract

Fe(II)EDTA-based liquid-phase denitrification has been demonstrated as a very promising research direction in controlling NO x emission. However, a highly efficient method for simultaneous conversion of Fe(II)EDTA-NO and Fe(III)EDTA in industrial denitrification solution is currently imperative yet with great challenges. In this work, the commercial Pd/AC catalyst was first employed to realize the simultaneous deoxidization of Fe(II)EDTA-NO and Fe(III)EDTA by adopting sodium formate as the indirect hydrogen source. The effects of initial solution pH, reaction temperature, catalyst dosage, and sodium formate dosage on Fe(II)EDTA-NO reduction were systematically scrutinized. An excellent catalytic performance with 95% conversion of Fe(II)EDTA-NO, 81% reduction rate of Fe(III)EDTA, and 100% denitrification rate belonging to regenerated solution could be restored under the optimum conditions (pH ≈ 6, reaction temperature at 60 °C, 1.5 g/L Pd/AC catalyst, and 10 g/L sodium formate). Furthermore, it provides valuable guidance for the regeneration technology of Fe(II)EDTA complex solution.

N-Doped Porous Carbon-Anchored Pd Nanoparticles: A Highly Efficient Catalyst for Fe(II)EDTA-NO Reduction

“…It can be concluded that H 2 cannot reduce Fe­(II)­EDTA-NO under these reaction conditions. According to the reaction mechanism of hydrogen production from FA, Pd­[H] − in eqs and reactions was reductive. ,, Therefore, we can assume that Pd­[H] − reacted with NO­(aq) that from eq to change NO into N 2 . …”

“…According to the reaction mechanism of hydrogen production from FA, Pd[H] − in eqs 5 and 6 reactions was reductive. 19,29,50…”

“…Herein, to achieve the regeneration of complex solution without introducing new ions into the complex solution, we first report the use of Pd nanoparticles (NPs) as a catalyst to reduce the denitrification of complex solution by formic acid (FA). , FA was oxidized to CO 2 , NO­(aq) was reduced to N 2 , and the complex solution can obtain the ability to adsorb NO again. − Furthermore, higher activity and selectivity were obtained by the selection of N-doped porous carbons (NPCs) as the support. − Different from activated carbon (AC), the dispersion, particle size, and binding stability of Pd NPs (2.31 ± 0.43 nm) were improved by the interaction between Pd and N atoms in NPCs. − Fe­(II)­EDTA was used as the chelating agent because of its cheap price and simple preparation . As expected, at an Fe­(II)­EDTA-NO concentration of 30 mmol/L, the denitrification rate reached 90.4% with an N 2 selectivity of 99.6% within 5 min.…”

“…Herein, to achieve the regeneration of complex solution without introducing new ions into the complex solution, we first report the use of Pd nanoparticles (NPs) as a catalyst to reduce the denitrification of complex solution by formic acid (FA). 19,20 FA was oxidized to CO 2 , NO(aq) was reduced to N 2 , and the complex solution can obtain the ability to adsorb NO again. 21−23 between Pd and N atoms in NPCs.…”

Hydrochloric Acid‐Assisted Regeneration of Cobalt Ethylenediamine for NOx Remediation in Flue Gas

“…Therefore, to enable large-scale industrial applications of cobalt ethylenediamine, it is essential to find a way to regenerate the denitrification agent under complex flue gas conditions and prolong the denitrification time. Microbial methods, chemical reduction methods, activated carbon catalytic reduction methods, and dissociation methods are some of the popular approaches for the regeneration of denitrification solution [35][36][37]. However, high costs are incurred in the reduction using a reducing agent or activated carbon.…”