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Simultaneous removal of NO and SO 2 from flue gas by Fe II EDTA/sodium dithionite solutions
Author(s) -
He Feiqiang,
Zhu Xinyu,
Chen Xianchun,
Qian Yong,
Ding Jianhua
Publication year - 2020
Publication title -
journal of chemical technology and biotechnology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.64
H-Index - 117
eISSN - 1097-4660
pISSN - 0268-2575
DOI - 10.1002/jctb.6323
Subject(s) - chemistry , sodium dithionite , sodium sulfite , dithionite , ammonium , inorganic chemistry , nitrite , nuclear chemistry , nitrate , sodium , biochemistry , organic chemistry , enzyme
BACKGROUND The SO 2 and NO emitted from coal‐fired power plants have caused serious air pollution in China. Fe II EDTA complexation technology is one of the most promising processes to realize the simultaneous removal of SO 2 and NO. However, Fe II EDTA is easily oxidized to Fe III EDTA, causing loss of activity, which limits its further application. To solve this problem, sodium dithionite (SD) combined with Fe II EDTA was used for the simultaneous removal of SO 2 and NO. RESULTS Results showed that the SO 2 removal efficiencies were ≈92–99% in all experiments, whereas the NO removal fluctuated substantially under different operating conditions. Specifically, SD can markedly improve NO removal efficiency, and the optimal Fe II EDTA:SD ratio was 3 mmol L –1 :0.026 mol L –1 . With increasing temperature, pH value, SO 2 concentration or O 2 concentration, the NO removal efficiency increased first and then decreased. As the NO concentration increased, the NO removal efficiency continually decreased. Finally, based on the analysis of different ion concentrations, the main products were identified as sulfite, sulfate, ammonium, nitrite and nitrate. CONCLUSION The synergistic mechanism of SD and Fe II EDTA on SO 2 and NO was investigated. SD can regenerate Fe II EDTA solution by reducing Fe III EDTA and Fe II EDTA‐NO. These fundamental findings can offer valuable guidance for industrial denitrification and desulfurization by mixed Fe II EDTA and SD systems. © 2019 Society of Chemical Industry