Formation of Ni- and Zn-Sulfides in Cultures of Sulfate-Reducing Bacteria

Abstract

The purpose of this study was to characterize Ni-and Zn-sulfides precipitated in sulfate-reducing bacterial cultures. Fe-free media containing 58 mM SO 2− 4 were amended with Ni and Zn chloride followed by inoculation. Precipitates were sampled from cultures after two weeks of incubation at 22, 45, and 60 • C. Abiotic controls were prepared by reacting bacteria-free liquid media with Na 2 S solutions under otherwise identical conditions. Precipitates were collected anaerobically, freeze-dried and analyzed by x-ray diffraction (XRD), scanning electron microscopy, and for total Ni, Zn, and S. In Ni-containing media, biogenic sulfide precipitates were mostly heazelwoodite (Ni 3 S 2 ), whereas abiotic precipitates were mixed heazelwoodite and vaesite (NiS 2 ). The biogenic Niprecipitates were better crystalline than the corresponding abiotic samples. Sphalerite (ZnS) was identified by XRD in precipitates sampled from Zn-containing media. Scanning electron microscopy revealed disordered morphological features for the sulfides, which occurred mostly as aggregates of fine particles in biogenic samples, whereas abiotic precipitates contained more plate-and needle-like structures.

Metal precipitation in an ethanol-fed, fixed-bed sulphate-reducing bioreactor

“…Poorly crystalline covellite, biologically produced at ambient temperature, was also identified in the precipitates of sulphate-reducing processes [52,53]. The formation of heazlewoodite is consistent with the findings of Gramp et al [54] in biogenic sulphide precipitates.…”

Biologically-induced precipitation of minerals in a medium with zinc under sulfate-reducing conditions

“…Moreau et al (2007) suggest that formation of mineral aggregates is induced by extracellular metal-binding polypeptides and proteins. Disordered morphological features of zinc sulfides have been described by Gramp et al (2007), who tested for formation of Zn sulfides n cultures of SRB.…”

Study on the Effectiveness of Sulfate-Reducing Bacteria Combined with Coal Gangue in Repairing Acid Mine Drainage Containing Fe and Mn

“…The FeS diffraction peaks at 2θ = 43.2 • were all enhanced, among which Coal Gangue 3 was the most significant. It was reported that FeS and Fe 3 S 4 are the main iron sulfide stages formed in SRB cultures [60]. The XRD patterns of Coal Gangue 1-4 before and after AMD treatment, indicated that some minerals participated in the ion exchange reaction, resulting in reduced crystallinity of minerals.…”