Surface analysis of sulfur speciation on pyrite bioleached by extreme thermophile Acidianus manzaensis using Raman and XANES spectroscopy

Demineralization of Rajmahal Gondwana Coals by Bacteria: Revelations from X-Ray Diffraction (XRD) and Fourier Transform Infra Red (FTIR) Studies

“…2). This is further supported by the work of Ardejani et al (2008), Hong et al (2013), Pathak et al (2013) and Xia et al (2010). The peak intensity in the spectrum may be due to high precipitation of jarosite and a higher pyrite oxidation ratio.…”

Synchrotron-based XPS and NEXAFS study of surface chemical species during electrochemical oxidation of chalcopyrite

“…2469.8 eV, which suggests the oxidation of electrode surface, appeared after electrochemical oxidation, and rose with the increasing potential. According to the literature, this peak is higher than that of FeS 2 (S 2 2− ) but slightly lower than that of elemental sulfur (S 8 ) (Xia et al, 2010). Coupled with the results of XPS study, it can be inferred that this peak indicates the formation of polysulfide (S n 2− ) and/or elemental sulfur.…”

Differential utilization and transformation of sulfur allotropes, μ-S and α-S8, by moderate thermoacidophile Sulfobacillus thermosulfidooxidans

“…Previous studies indicate that the elemental sulfur formed in bioleaching was a-S 8 [4,7], which was probably transformed from unstable short chain polysulfides (S n 2À ) [4,16]. In this study, transformation of m-S to a-S 8 was observed by XRD, Raman and S K-edge XANES but no transformation of a-S 8 was found in the presence of S. thermosulfidooxidans.…”

“…The formation of S 0 layer on the mineral surface may obstruct the contact between microbial cells and the mineral and thus lower the bioleaching rate or even inhibit the bioleaching process [4e6]. The observed sulfur-rich compounds during bioleaching of metal sulfides were mostly reported as orthorhombic sulfur [4,7] and in few cases as short chain polysulfides (S n 2À ) and long sulfur chains terminated with organic groups [5]. Though sulfur speciation transformation during bioleaching of sulfide minerals, e.g., chalcopyrite, pyrite, sphalerite, has been studied [8], the role of the sulfur species and how it is utilized by SOM are still not clear.…”