O3 oxidation excited by yellow phosphorus emulsion coupling with red mud absorption for denitration

Abstract

Directing to unwieldiness NOx emitted by the industry, the removal of NOx was implemented using yellow phosphorus (P4) emulsion and red mud slurry as composite absorbent. Where yellow phosphorus is considered to stimulate formation of the ecological ozone (O3) from O2, the oxidation of insoluble NO into water-soluble NOx species by O3, and the red mud as a pH buffer can be used to maintain the pH of the absorption liquid in a range that better absorbs NOx. NO is finally converted into NO2− and NO3−, whereas the yellow phosphorus is mainly PO43−. Single-factor influencing on the efficiency of denitration include the concentration of yellow phosphorus, reaction temperature, stirring intensity, gas flow rate, O2 content, and red mud solid-liquid ratio were investigated. Response surface methodology (RSM) was used to optimize the process parameters. It was indicated that the removal rate of NOx can reach 99.3% under the optimal conditions. Moreover, the possible denitration reaction mechanism was also discussed.