Mechanism by which ferric iron promotes the bioleaching of arsenopyrite by the moderate thermophile Sulfobacillus thermosulfidooxidans

Abstract

Abstract In this study, the mechanisms by which ferric iron promotes bioleaching of arsenopyrite by the moderately thermoacidophilic strain Sulfobacillus thermosulfidooxidans YN-22 was evaluated for the first time by integrating Fe L-edge and As/S K-edge X-ray absorption near edge structure (XANES) spectroscopy with Fourier transform infrared spectroscopy (FT-IR), synchrotron radiation X-ray diffraction (SR-XRD), Raman spectroscopy, and scanning electron microscopy (SEM), and the leaching parameters were also determined. The results showed that the addition of Fe3+ (6 g/L) significantly promoted bioleaching of arsenopyrite by enhancing the cell growth and the (bio)degradation of elemental sulfur (S0) and orpiment (As2S3) intermediates on the mineral surface. In addition, an increased formation of loose particulate structures containing the Fe(III)-containing products jarosite (mainly ammoniojarosite), scorodite (ferric arsenate) and schwertmannite was observed.