Integrated strategy for efficient simultaneous desulfurization and denitrification of flue gas and high value conversion of sulfur and nitrogen resources

• Published in: Journal of hazardous materials 2022-10, Vol.440, p.129827, Article 129827
• Main Authors: Tian, Senlin, Yang, Shanshan, Wang, Jianfei, Li, Qiuxian, Li, Chen, Cui, Xiangfen, Ning, Ping
• Format: Article
• Language: English
• Subjects: Conversion of sulfur and nitrogen resources in flue gas; Fertilizers production; Nitrate reduction; Persulfate regeneration; Simultaneous desulfurization and denitrification
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2022.129827

Nitrogen and sulfur oxides have been considered as major air pollutants, which has raised concerns. In this study, an integrated strategy is proposed for simultaneous desulfurization and denitrification of simulated flue gas and high value conversion of sulfur and nitrogen resources. The high oxidation capacity of the thermal-electric coactivated (NH4)2S2O8 made the process highly effective for SO2 and NO removal, with efficiencies of 100 % and 98 %, respectively. Mechanistic studies have revealed that highly reactive free radicals were the major participants in promoting oxidation, among which 47.65 % and 27.75 % of NO were oxidized by SO4.- and ˙OH, respectively, and 14.3 % and 10.3 % removal were accounted for O2.- and 1O2, respectively. The products of desulfurization and denitrification (SO42- and NO3-) were further converted into NH4+ (maximum conversion efficiency of 83.80 %) and S2O82- (maximum conversion efficiency of 70 %) in an electrolytic reactor, and the regenerated (NH4)2S2O8 could be recycled for gas purification to extend the service life of the oxidant. Consequently, a complete conversion cycle of S and N species was obtained, and its conversion pathways were proposed. After several cycles, the SO42- and NO3- enriched in the solution were post-processed into a compound fertilizer, thereby partially recovering the economic cost. [Display omitted] •An integrated strategy for fuel gas purification and resources reuse was proposed.•100 % of SO2 and 98 % of NO was simultaneously removed in this system.•The regeneration and recycling of (NH4)2S2O8 was achieved to extended the service life of the oxidant.•A compound fertilizer was final produced after several cycles.•A complete conversion cycle of S and N species was obtained, and its conversion pathways were proposed.