Enhancement effects of O2− and OH radicals on NOX removal in the presence of SO2 by using an O3/H2O2 AOP system with inadequate O3 (O3/NO molar ratio = 0.5). (1st December 2018)

• Record Type: Journal Article
• Authors: Guo, Lina; Han, Chenyang; Zhang, Shule; Zhong, Qin; Ding, Jie; Zhang, Baoqiang; Zeng, Yiqing
• Is Part Of: Fuel. Volume 233(2018)
• Page Start: 769
• Page End: 777
• Publication Date: 2018-12-01
• Subjects: Ozone -- Advanced oxidation process -- Superoxide anion radical -- Nitrogen oxides -- Mechanism; Fuel -- Periodicals; Coal -- Periodicals; Coal; Fuel; Periodicals; 662.6
• DOI: 10.1016/j.fuel.2018.06.099
• Languages: English
• ISSNs: 0016-2361

Abstract

Graphical abstract: Highlights: An O3 /H2 O2 method was utilized for denitrification to decrease O3 dosage. The NOX removal of O3 /H2 O2 was 58% higher than the sum of O3 and H2 O2 . The high activity of O3 /H2 O2 was due to the generation of OH and O2 − radicals. The SO2 in the flue gas did not decrease the NOX removal for O3 /H2 O2 method. Abstract: The O3 /H2 O2 advanced oxidation process (AOP) was, for the first time, utilized for low-temperature NOX removal. The present method has a high NOX removal, which is 58% higher than the sum of that for single O3 and H2 O2 method with O3 /NO molar ratio of 0.5. Besides, much O3 consumption, together with operating costs will be saved. The improved activity in O3 /H2 O2 is due to the increased generation amount of OH and O2 − /HO2 radicals than the consumption amount of O3 when the molar ratio of O3 /NO < 1, and the O2 − /HO2 radical can selectively oxidize NO into HNO3 with a fast rate constant in a single step, while OH can non-selectively oxidize NO and NO2 also at a fast rate constant. The SO2 in the flue gas even poses a positive effect on the NOX removal. Absorption by NaOH solution is generally followed by the O3 /H2 O2 method, resulting in the final 95% NOX removal with the O3 /NO molar ratio of 0.5. Only NO3 − ions can be detected as the liquid production through ion chromatography for the O3 /H2 O2 method. We expect that this study can shed some lights on the route design for simultaneous NOX and SO2 removal.