Abstract
• An innovative AOP method of MW-UVEL/NaClO 2 -O 2 was developed; • Higher efficiencies were obtained at a molar ratio of NaClO 2 to NO/Hg 0 of 1.3:1; • The distribution of N- and Hg-products was revealed; • The contribution order was •O 2 – > •OH > ClO•/ClO 2 > O 3 ; • NO and Hg 0 removal mechanism was speculated. Developing novel advanced oxidation process (AOP) to simultaneously remove various air pollutants has received considerable attention in past years. This paper develops a novel cost-efficient AOP method of microwave (MW) induced ultraviolet (UV) co-catalyzing trace NaClO 2 -O 2 to simultaneously remove NO and Hg 0 , the obtained removal efficiencies are 91.4% and 99%, respectively, under a molar ratio of NaClO 2 to NO/Hg 0 of 1.3:1. The effects of some key parameters including NaClO 2 dosage, reaction temperature, input MW power, UV light intensity, concentrations of O 2 , NO and SO 2 , and gas flow on the removal of NO and Hg 0 were studied. ESR and radical quenching tests demonstrated that superoxide radical (•O 2 – ), hydroxyl radical (•OH), oxychloride radical (ClO•), chlorine dioxide (ClO 2 ) and ozone (O 3 ) were the major reactive species. With the assistance of Na 2 SO 3 absorber, the produced NO 2 was efficiently absorbed and controlled to below 5 mg/m 3 . IC and AFS analyses revealed the distribution of removal products: (i) 51% of NO 3 – and 85% of Hg 2+ were preserved in the MW-UVEL reactor; (ii) the other NO 3 – and Hg 2+ as well as the NO 2 – generated via the redox reaction between NO 2 and SO 3 2- were totally absorbed by the Na 2 SO 3 solution. Mechanism analyses elucidated that the NO removal process was attributed to the radical-induced oxidation reaction, and the contribution order was •O 2 – > •OH > ClO•/ClO 2 > O 3 ; however, the Hg 0 removal process was mainly determined by the produced NO 2 /NO 3 – , and UV light coupled with other active species contributed less 40%.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
