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Title: Differential Pair Distribution Function Study of the Structure of Arsenate Adsorbed on Nanocrystalline [gamma]-Alumina

Abstract

Structural information is important for understanding surface adsorption mechanisms of contaminants on metal (hydr)oxides. In this work, a novel technique was employed to study the interfacial structure of arsenate oxyanions adsorbed on {gamma}-alumina nanoparticles, namely, differential pair distribution function (d-PDF) analysis of synchrotron X-ray total scattering. The d-PDF is the difference of properly normalized PDFs obtained for samples with and without arsenate adsorbed, otherwise identically prepared. The real space pattern contains information on atomic pair correlations between adsorbed arsenate and the atoms on {gamma}-alumina surface (Al, O, etc.). PDF results on the arsenate adsorption sample on {gamma}-alumina prepared at 1 mM As concentration and pH 5 revealed two peaks at 1.66 {angstrom} and 3.09 {angstrom}, corresponding to As-O and As-Al atomic pair correlations. This observation is consistent with those measured by extended X-ray absorption fine structure (EXAFS) spectroscopy, which suggests a first shell of As-O at 1.69 {+-} 0.01 {angstrom} with a coordination number of 4 and a second shell of As-Al at 3.13 {+-} 0.04 {angstrom} with a coordination number of 2. These results are in agreement with a bidentate binuclear coordination environment to the octahedral Al of {gamma}-alumina as predicted by density functional theory (DFT) calculation.

Authors:
; ; ; ; ; ; ;  [1];  [2]
  1. (SBU)
  2. (
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
Sponsoring Org.:
National Science Foundation (NSF)
OSTI Identifier:
1034558
Resource Type:
Journal Article
Resource Relation:
Journal Name: Environ. Sci. Technol.; Journal Volume: 45; Journal Issue: (22) ; 11, 2011
Country of Publication:
United States
Language:
ENGLISH
Subject:
54 ENVIRONMENTAL SCIENCES; ABSORPTION; ADSORPTION; ARSENATES; ATOMS; COORDINATION NUMBER; DISTRIBUTION FUNCTIONS; FINE STRUCTURE; FUNCTIONALS; SCATTERING; SPECTROSCOPY; SYNCHROTRONS

Citation Formats

Li, Wei, Harrington, Richard, Tang, Yuanzhi, Kubicki, James D., Aryanpour, Masoud, Reeder, Richard J., Parise, John B., Phillips, Brian L., and Penn). Differential Pair Distribution Function Study of the Structure of Arsenate Adsorbed on Nanocrystalline [gamma]-Alumina. United States: N. p., 2012. Web. doi:10.1021/es200750b.
Li, Wei, Harrington, Richard, Tang, Yuanzhi, Kubicki, James D., Aryanpour, Masoud, Reeder, Richard J., Parise, John B., Phillips, Brian L., & Penn). Differential Pair Distribution Function Study of the Structure of Arsenate Adsorbed on Nanocrystalline [gamma]-Alumina. United States. doi:10.1021/es200750b.
Li, Wei, Harrington, Richard, Tang, Yuanzhi, Kubicki, James D., Aryanpour, Masoud, Reeder, Richard J., Parise, John B., Phillips, Brian L., and Penn). Thu . "Differential Pair Distribution Function Study of the Structure of Arsenate Adsorbed on Nanocrystalline [gamma]-Alumina". United States. doi:10.1021/es200750b.
@article{osti_1034558,
title = {Differential Pair Distribution Function Study of the Structure of Arsenate Adsorbed on Nanocrystalline [gamma]-Alumina},
author = {Li, Wei and Harrington, Richard and Tang, Yuanzhi and Kubicki, James D. and Aryanpour, Masoud and Reeder, Richard J. and Parise, John B. and Phillips, Brian L. and Penn)},
abstractNote = {Structural information is important for understanding surface adsorption mechanisms of contaminants on metal (hydr)oxides. In this work, a novel technique was employed to study the interfacial structure of arsenate oxyanions adsorbed on {gamma}-alumina nanoparticles, namely, differential pair distribution function (d-PDF) analysis of synchrotron X-ray total scattering. The d-PDF is the difference of properly normalized PDFs obtained for samples with and without arsenate adsorbed, otherwise identically prepared. The real space pattern contains information on atomic pair correlations between adsorbed arsenate and the atoms on {gamma}-alumina surface (Al, O, etc.). PDF results on the arsenate adsorption sample on {gamma}-alumina prepared at 1 mM As concentration and pH 5 revealed two peaks at 1.66 {angstrom} and 3.09 {angstrom}, corresponding to As-O and As-Al atomic pair correlations. This observation is consistent with those measured by extended X-ray absorption fine structure (EXAFS) spectroscopy, which suggests a first shell of As-O at 1.69 {+-} 0.01 {angstrom} with a coordination number of 4 and a second shell of As-Al at 3.13 {+-} 0.04 {angstrom} with a coordination number of 2. These results are in agreement with a bidentate binuclear coordination environment to the octahedral Al of {gamma}-alumina as predicted by density functional theory (DFT) calculation.},
doi = {10.1021/es200750b},
journal = {Environ. Sci. Technol.},
number = (22) ; 11, 2011,
volume = 45,
place = {United States},
year = {Thu Mar 15 00:00:00 EDT 2012},
month = {Thu Mar 15 00:00:00 EDT 2012}
}