Removal of antimonate from wastewater by dissimilatory bacterial reduction: Role of the coexisting sulfate

• Published in: Journal of hazardous materials Vol. 341; pp. 36 - 45
• Main Authors: Zhu, Yanping, Wu, Min, Gao, Naiyun, Chu, Wenhai, An, Na, Wang, Qiongfang, Wang, Shuaifeng
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 05-01-2018
• Subjects: Antimonate reduction; Antimonite sulfide; Antimonite trioxide; Antimony - metabolism; Bacteria - genetics; Bacteria - metabolism; Bacteria - ultrastructure; Biodegradation, Environmental; Dissimilatory sulfate reduction; Microscopy, Electron, Scanning; Oxidation-Reduction; Phylogeny; Pseudomonas; Sulfates - metabolism; Waste Disposal, Fluid - methods; Waste Water; Water Pollutants, Chemical - metabolism; Antimonate reduction; Antimonite trioxide; Dissimilatory sulfate reduction; Antimonite sulfide; Pseudomonas
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2017.07.042

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•0.8mM Sb(V) could be completely reduced with 48.6% Sb(III) recovery within 20h.•SO42− can be simultaneously reduced to HS− in Sb-acclimated anaerobic sludge.•The formed S2− participated in both Sb(V) reduction and Sb(III) precipitation.•Formation of Sb2O3 and Sb2S3 precipitates were confirmed.•SO42− stimulated the growth of Pseudomonas and sulfate-reducing bacteria.
The priority pollutant antimony (Sb) exists primarily as Sb(V) and Sb(III) in natural waters, and Sb(III) is generally with greater mobility and toxicity than Sb(V). The bio-reduction of Sb(V) would not become a meaningful Sb-removal process unless the accumulation of produced dissolved Sb(III) could be controlled. Here, we examined the dissimilatory antimonate bio-reduction with or without the coexistence of sulfate using Sb-acclimated biomass. Results demonstrated that 0.8mM Sb(V) was almost completely bio-reduced within 20h along with 48.6% Sb(III) recovery. Kinetic parameters qmax and Ks calculated were 0.54mg-Sb mg-DW−1h−1 and 41.96mgL−1, respectively. When the concentrations of coexisting sulfate were 0.8mM, 1.6mM, and 4mM, the reduction of 0.8mM Sb(V) was accomplished within 17, 9, and 5h, respectively, along with no final Sb(III) recovery. Also, the bio-reduction of sulfate occurred synchronously. The precipitated Sb2O3 and Sb2S3 were characterized by scanning electron microscopy coupled with energy dispersive spectrometer, X-ray diffraction, and X-ray photoelectron spectroscopy. Compared with bacterial compositions of the seed sludge obtained from anaerobic digestion tank in a wastewater treatment plant, new genera of Pseudomonas and Geobacter emerged with large proportions in both Sb-fed and Sb-sulfate-fed sludge, and a small portion of sulfate reduction bacteria emerged only in Sb-sulfate-fed culture.