Novel low-temperature H₂S removal technology by developing yellow phosphorus and phosphate rock slurry as absorbent

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.