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Simultaneous absorption of NO and SO2 into hexamminecobalt(II)/iodide solution
Xiang-Li Long1, Wen-De Xiao, Wei-kang Yuan
1UNILAB, State Key Laboratory of Chemical Reaction Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, People's Republic of China.
Chemosphere
|April 7, 2005
Summary
A novel catalyst system effectively removes nitrogen oxides (NO) and sulfur dioxide (SO2) from flue gas using ammonia. This innovation converts pollutants into valuable fertilizer materials, enhancing existing scrubbers.
Area of Science:
- Environmental Chemistry
- Catalysis
- Chemical Engineering
Background:
- Combustion flue gases contain harmful pollutants like nitrogen oxides (NO) and sulfur dioxide (SO2).
- Existing wet ammonia flue-gas-desulfurization (FGD) scrubbers require efficient methods for simultaneous pollutant removal.
Purpose of the Study:
- To develop an innovative catalyst system for the simultaneous removal of NO and SO2 from combustion flue gas.
- To investigate the conversion of NO and SO2 into usable fertilizer materials.
Main Methods:
- A catalyst system using cobalt(II) hexammine ions [Co(NH3)6]2+ as the catalyst and iodide ions (I-) as the co-catalyst was introduced into an ammonia scrubbing solution.
- Sequential absorption and catalytic oxidation of NO and SO2 were performed in the same reactor, utilizing dissolved oxygen as the oxidant and enhanced by UV irradiation (365 nm).
Main Results:
- Over 95% NO removal was achieved at feed concentrations of 250-900 ppm.
- Nearly 100% SO2 removal was achieved at feed concentrations of 800-2500 ppm.
- The presence of SO2 was found to benefit NO absorption.
Conclusions:
- The developed catalyst system enables simultaneous removal of NO and SO2 from flue gas.
- The process converts pollutants into ammonium sulfate and ammonium nitrate, suitable for fertilizer applications.
- This method offers a feasible retrofit for existing wet ammonia FGD scrubbers.