Surface complexation of organic arsenic on nanocrystalline titanium oxide

Chuanyong Jing, Xiaoguang Meng, Suqin Liu, Salem Baidas, Ravi Patraju, Christos Christodoulatos, George P. Korfiatis

Research output: Contribution to journalArticlepeer-review

126 Scopus citations

Abstract

The adsorption mechanisms of monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA) on nanocrystalline titanium oxide (TiO2) were investigated with X-ray absorption spectroscopy (XAS), surface charge and zeta potential measurements, adsorption edge, and surface complexation modeling. XAS data demonstrated that MMA and DMA formed bidentate and monodentate inner sphere complexes with the TiO2 surface, respectively. The charge and zeta potential behaviors of TiO2 as a function of ionic strength suggested that the point of zero charge (PZC) and isoelectric point (IEP) of TiO2 were identical at pH 5.8. Adsorption of MMA and DMA on TiO 2 shifted the IEP to pH 4.1 and 4.8, respectively, indicating the formation of negatively charged surface complexes. A satisfactory interpretation of the experimental data was provided by the charge distribution (CD) multi-site complexation (MUSIC) model with the triple plane option under the constraint of the XAS evidence.

Original languageEnglish
Pages (from-to)14-21
Number of pages8
JournalJournal of Colloid and Interface Science
Volume290
Issue number1
DOIs
StatePublished - 1 Oct 2005

Keywords

  • CD-MUSIC model
  • EXAFS
  • Organic arsenic
  • Surface charge
  • TiO
  • Zeta potential

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