Suppression of Hydrogen Sulfide Generation via the Coexistence of Anaerobic Sludge and Goethite-Rich Limonite/Polyethersulfone Composite Fibers.

Limonite-polyethersulfone (PES) composite fibers were prepared by the wet spinning method to suppress hydrogen sulfide (H2S) generation from anaerobic microbial sludge. The H2S adsorption of the prepared limonite composite fibers followed the Langmuir type, with a maximum adsorption capacity of 3.7-4.4 g H2S/g, indicating mesopore adsorption. The in vitro H2S fermentation environment with anaerobic microbial sludge with the coexistence of limonite composite fibers exhibited suppression of H2S generation. The coexistence of limonite composite fibers also suppressed the amount of CO generation produced by microbial fermentation, so the fibers also affected the metabolism of anaerobic microorganisms. During the anaerobic digestion process, particularly at 672-840 h (28-35 days), the mesopores of limonite in the composite fibers disappeared and changed to macropore adsorption, and the reaction of limonite with hydrogen sulfide produced pyrite (FeS2) and iron sulfate (Fe2(SO4)3) as products, which remained in the fiber with conversion efficiencies of 6.8 and 32.4%, respectively. The in vitro hydrogen disulfide action of limonite composite fibers was found to be able to suppress the generated environment of about 300 ppm to about 0.4 ppm.