[Effect of Hematite on the Inhibition of Hydrogen Sulfide Formation and Its Mechanism During Anaerobic Digestion and Methanogenesis of Sulfate Wastewater]

In order to achieve the high value production of methane, this paper investigated the effect and mechanism of hematite on the inhibitation of the formation of hydrogen sulfide during the anaerobic digestion of high-concentration sulfate wastewater. Different dosages of hematite were added to artificially prepared sulfate wastewater to analyze the migration and transformation pathways of sulfur in the reaction system. The results showed that the delay time of the anaerobic digestion process and the hydrogen sulfide concentration in the control reactor were 1.64 times and 180 times those in the reactor with the optimal hematite dosage of 0.5 g·(30 mL)^-1, respectively. Thus, the addition of hematite effectively shortened the delay time and reduced the concentration of hydrogen sulfide. Dynamic equilibrium analysis of sulfur in different anaerobic digestion reactors showed that the solid sulfur content in the reactor accounted for 96.9% of the total sulfur. XPS results further demonstrated that hematite mainly enhanced the fixation of S^2- in the form of FeS₂. Therefore, the addition of hematite can effectively accelerate the anaerobic digestion of sulfate wastewater while reducing the concentration of hydrogen sulfide in the reactor.