Absorption and Oxidation of Nitrogen Oxide in Ionic Liquids
Andreas J Kunov-Kruse1, Peter L Thomassen1, Anders Riisager1
1Centre for Catalysis and Sustainable Chemistry, Department of Chemistry, Technical University of Denmark, DK-2800, Kgs. Lyngby, Denmark.
Chemistry (Weinheim an Der Bergstrasse, Germany)
|July 8, 2016
Summary
A novel method captures nitrogen oxide (NO) using ionic liquids, converting it to nitric acid (HNO3) via catalytic oxidation. The ionic liquid is regenerated with high reproducibility, offering a sustainable solution for NO pollution control.
Area of Science:
- Environmental Chemistry
- Green Chemistry
- Materials Science
Background:
- Nitrogen oxide (NO) is a significant air pollutant contributing to smog and acid rain.
- Current NO removal methods can be energy-intensive or produce secondary pollutants.
- Ionic liquids offer unique properties for gas capture and chemical transformations.
Purpose of the Study:
- To present a new strategy for capturing nitrogen oxide (NO) from the gas phase.
- To investigate the catalytic oxidation of NO to nitric acid (HNO3) using ionic liquids.
- To demonstrate the regeneration and reusability of the ionic liquid for sustainable NO remediation.
Main Methods:
- Utilizing ionic liquids with nitrate anions for NO capture under ambient conditions.
- Employing atmospheric oxygen and water for the catalytic oxidation of NO to HNO3.
- Absorbing HNO3 into the ionic liquid via hydrogen bonding.
- Desorbing HNO3 by heating to regenerate the ionic liquid.
- Conducting time-resolved in-situ spectroscopic investigations.
Main Results:
- Efficient capture of dilute NO gas from the gas phase by ionic liquids.
- Catalytic oxidation of NO to HNO3 facilitated by the nitrate anion.
- High absorption capacity of HNO3 in the ionic liquid (approx. 1 mole HNO3 per mole of ionic liquid).
- Successful regeneration of the ionic liquid with excellent reproducibility through heating.
- Spectroscopic evidence confirming the reaction pathway and product formation.
Conclusions:
- A viable and sustainable strategy for removing NO pollutant has been developed.
- Ionic liquids can effectively capture NO and convert it into valuable nitric acid.
- The process demonstrates excellent recyclability of the ionic liquid, paving the way for industrial applications.
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