Novel Process of Simultaneous Removal of Nitric Oxide and Sulfur Dioxide Using a Vacuum Ultraviolet (VUV)-Activated O 2 /H 2 O/H 2 O 2 System in A Wet VUV-Spraying Reactor

• Published in: Environmental science & technology Vol. 50; no. 23; pp. 12966 - 12975
• Main Authors: Liu, Yangxian, Wang, Qian, Pan, Jianfeng
• Format: Journal Article
• Language: English
• Published: United States 06.12.2016
• Subjects: Hydrogen Peroxide; Nitric Acid; Nitric Oxide; Sulfur Dioxide; Vacuum
• ISSN: 0013-936X; 1520-5851
• DOI: 10.1021/acs.est.6b02753

A novel process for NO and SO simultaneous removal using a vacuum ultraviolet (VUV, with 185 nm wavelength)-activated O /H O/H O system in a wet VUV-spraying reactor was developed. The influence of different process variables on NO and SO removal was evaluated. Active species (O and ·OH) and liquid products (SO , NO , SO , and NO ) were analyzed. The chemistry and routes of NO and SO removal were investigated. The oxidation removal system exhibits excellent simultaneous removal capacity for NO and SO , and a maximum removal of 96.8% for NO and complete SO removal were obtained under optimized conditions. SO reaches 100% removal efficiency under most of test conditions. NO removal is obviously affected by several process variables. Increasing VUV power, H O concentration, solution pH, liquid-to-gas ratio, and O concentration greatly enhances NO removal. Increasing NO and SO concentration obviously reduces NO removal. Temperature has a dual impact on NO removal, which has an optimal temperature of 318 K. Sulfuric acid and nitric acid are the main removal products of NO and SO . NO removals by oxidation of O , O·, and ·OH are the primary routes. NO removals by H O oxidation and VUV photolysis are the complementary routes. A potential scaled-up removal process was also proposed initially.