Flue gases emitted from the industries and other emission sources are considered the main atmospheric issues. The main Flue gases emitted are sulfur oxides SOX and Nitrogen oxides NOX. The study was about methods of removing SOX and NOX from emitted gases and the possibility of deriving useful byproducts. The process for removing was investigated using different absorbers, process conditions, and phosphorus allotropes. The yellow phosphorus (P4) was applied for removal accompanied by Potash. The simultaneous removal achieved higher removing efficiency for SOX than NOX. Yellow phosphorus emulsion proved to be one of the effective SOX and NOX removal techniques. Byproducts produced from SOX and NOX proved to contain the complete fertiliser Nitrogen Phosphorus Potassium NPK. The obtained results showed that several useful byproducts can be derived from SOX and NOX removal process.

Recycling hazardous gas of H2S is one of the most important strategies to promote sustainable development. Herein, a novel method regarding purifying H2S is proposed by using yellow phosphorus and phosphate rock slurry as absorbent. The H2SO4, formed in situ by H2S conversion, can be devoted to decompose phosphate rock, and the spent absorption slurry was applied as raw material for the production of phosphorus chemical products. According to the characterization analysis, it was found that H2S was first oxidized to SO2 via O2 as well as O3 induced by P4. Subsequently, the generated SO2 dissolved rapidly in water to form H2SO4, and then reacted with the main component of phosphate rock, CaMg(CO3)2. Most notably, the active substances, such as, O3, SO4•- and OH•, produced in the reaction process, can oxidize H2S and HS- to these sulfur products. In addition, trace amounts of Fe3+ and Mn2+ that were dissolved from phosphate rock displayed a promotional effect on the formation of active substances. Consequently, as high as 85% of H2S removal efficiency can be obtained even under acidic condition and low temperature. The proposed H2S purification method offers a promising option for sulfur recovery and H2S pollution control.

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.