Formation of Fe-sulfides in cultures of sulfate-reducing bacteria

• Published in: Journal of hazardous materials 2010-03, Vol.175 (1), p.1062-1067
• Main Authors: Gramp, Jonathan P., Bigham, Jerry M., Jones, F. Sandy, Tuovinen, Olli H.
• Format: Article
• Language: English
• Subjects: Applied sciences; Biofilms; Exact sciences and technology; Ferrous Compounds - chemistry; Greigite; Iron - chemistry; Iron sulfides; Mackinawite; Microscopy, Electron, Scanning; Pollution; Sulfate reduction; Sulfates - chemistry; Sulfides - chemistry; Sulfur - chemistry; Sulfur-Reducing Bacteria - metabolism; Sulfur-Reducing Bacteria - physiology; Temperature; Time Factors; X-Ray Diffraction
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2009.10.119

The purpose of this study was to synthesize Fe-sulfides produced with sulfate-reducing bacteria under experimental laboratory conditions. Fe-sulfides were precipitated with biologically produced sulfide in cultures growing at 22, 45, and 60 °C for up to 16 weeks. Abiotic controls were prepared by reacting liquid media with Na 2S solutions. Precipitates were collected anaerobically, freeze-dried and analyzed by X-ray diffraction. Additional analyses included total Fe and S content, magnetic susceptibility, specific surface area, and scanning electron microscopy. Mackinawite (FeS) and greigite (Fe 3S 4) were the dominant iron sulfide phases formed in sulfate-reducing bacterial cultures. An increase in the incubation temperature from 22 to 60 °C enhanced the crystallinity of the Fe-sulfides. Generally, greigite was more prevalent in abiotic samples and mackinawite in biogenic materials. Pyrite (FeS 2) was also found in abiotic precipitates. Abiotic samples had a higher magnetic susceptibility because of the greigite and displayed improved crystallinity compared to biotic materials.