US EPA

193454 

Journal Article 

Surface complexation of organic arsenic on nanocrystalline titanium oxide 

Jing, C; Meng, X; Liu, S; Baidas, S; Patraju, R; Christodoulator, C; Korfiatis, GP 

2005 

Yes 

Journal of Colloid and Interface Science
ISSN: 0021-9797
EISSN: 1095-7103 

290 

1 

14-21 

English 

16122542 

10.1016/j.jcis.2005.04.019 

WOS:000231680700002 

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 TiO2 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. 

Organic arsenic; TiO2; EXAFS; Surface charge; Zeta potential; CD-MUSIC model