Speciation of arsenic, chromium, and vanadium in red mud samples from the Ajka spill site, Hungary

Burke, Ian T.; Mayes, William M.; Peacock, Caroline L.; Brown, Andrew P.; Jarvis, Adam P.; Gruiz, Katalin

Abstract

Results are presented from X-ray absorption spectroscopy based analysis of As, Cr and V speciation within samples of bauxite ore processing residue (red mud) collected from the spill site at Ajka, Western Hungary. Cr K-edge XANES analysis found that Cr is present as Cr3+ substituted into hematite, consistent with TEM analysis. V K-edge XANES spectra have E½ position and pre-edge features consistent with the presence of V5+ species, possibly associated with Ca-aluminosilicate phases. As K-edge XANES spectra identified As present as As5+. EXAFS analysis reveals arsenate phases in red mud samples. When alkaline leachate from the spill site is neutralised with HCl, 94 % As and 71 % V is removed from solution during the formation of amorphous Al-oxyhydroxide. EXAFS analysis of As in this precipitate reveals the presence of arsenate Al-oxyhydroxide surface complexes. These results suggest that in the circumneutral pH, oxic conditions found in the Torna and Upper Marcal catchments, incorporation and sorption respectively will restrict the environmental mobility of Cr and As. V is inefficiently removed from solution by neutralisation, therefore, the red mud may act as a source of mobile V5+ where the red mud deposits are not removed from affected land.

Citation

Burke, I. T., Mayes, W. M., Peacock, C. L., Brown, A. P., Jarvis, A. P., & Gruiz, K. (2012). Speciation of arsenic, chromium, and vanadium in red mud samples from the Ajka spill site, Hungary. Environmental Science and Technology, 46(6), 3085-3092. https://doi.org/10.1021/es3003475

• Journal Article Type: Article
• Online Publication Date: Feb 27, 2012
• Publication Date: Mar 20, 2012
• Deposit Date: Nov 13, 2014
• Journal: Environmental Science And Technology
• Print ISSN: 0013-936X
• Electronic ISSN: 1520-5851
• Publisher: American Chemical Society
• Peer Reviewed: Peer Reviewed
• Volume: 46
• Issue: 6
• Pages: 3085-3092
• DOI: https://doi.org/10.1021/es3003475
• Keywords: General Chemistry; Environmental Chemistry
• Public URL: https://hull-repository.worktribe.com/output/464827
• Contract Date: Nov 13, 2014