Evidences of arsenic (III) precipitation on iron (III) oxy-hydroxides from the combination of Raman spectroscopy, density functional theory calculations, and extended X-ray absorption fine structure spectroscopy

G. Duarte, V. Ciminelli, M. S.S. Dantas, I. F. Vasconcelos, K. Osseo-Asare, J. D. Kubicki, H. Watts

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Arsenite (As III) precipitation in iron (Fe III) systems was firstly suggested from the shape patterns of the isotherms obtained for As(III) immobilized on hematite and goethite at pH 7.0. Hence, Raman and EXAFS analyses were combined with Density Functional Theory (DFT) to investigate the mechanism of As(III) immobilization on Fe(III) oxy-hydroxides. XANES analyses confirmed As(III) as the sorbed species. The results from DFT calculations indicated a stable structure for As(III) precipitated on hematite with the following calculated interactions: As = O (1.70 å); As-O (1.78 å); As-As (3.30 å), and As-Fe (3.50 å). These distances were in agreement with EXAFS analyses of As(III) sorbed on hematite (0.014 mmol/m2) and goethite (0.010 mmol/m2) at pH 7. The As = O bond was also consistent with the Raman vibration at 860 cm-1. Therefore, the precipitation of As(III) as a mechanism involved in As fixation by Fe(III) oxy-hydroxides is supported by spectroscopic analyses combined with theoretical calculations. This is invoked as the main finding of the present investigation and it may help the prediction and control of arsenic mobility in iron-rich soils.

Original languageEnglish (US)
Title of host publicationUnderstanding the Geological and Medical Interface of Arsenic, As 2012 - 4th International Congress
Subtitle of host publicationArsenic in the Environment
PublisherTaylor and Francis - Balkema
Pages381-383
Number of pages3
ISBN (Print)9780415637633
DOIs
StatePublished - Jan 1 2012
Event4th International Congress on Arsenic in the Environment, As 2012 - Cairns, QLD, Australia
Duration: Jul 22 2012Jul 27 2012

Publication series

NameUnderstanding the Geological and Medical Interface of Arsenic, As 2012 - 4th International Congress: Arsenic in the Environment

Other

Other4th International Congress on Arsenic in the Environment, As 2012
CountryAustralia
CityCairns, QLD
Period7/22/127/27/12

All Science Journal Classification (ASJC) codes

  • Environmental Chemistry
  • Pollution

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    Duarte, G., Ciminelli, V., Dantas, M. S. S., Vasconcelos, I. F., Osseo-Asare, K., Kubicki, J. D., & Watts, H. (2012). Evidences of arsenic (III) precipitation on iron (III) oxy-hydroxides from the combination of Raman spectroscopy, density functional theory calculations, and extended X-ray absorption fine structure spectroscopy. In Understanding the Geological and Medical Interface of Arsenic, As 2012 - 4th International Congress: Arsenic in the Environment (pp. 381-383). (Understanding the Geological and Medical Interface of Arsenic, As 2012 - 4th International Congress: Arsenic in the Environment). Taylor and Francis - Balkema. https://doi.org/10.1201/b12522-153