  The dispersion of anatase phase TiO2 powder in aqueous suspensions was
investigated by zeta-potential and agglomerate size analysis. The iso-electric
point (IEP) of anatase was determined to be at pH 2.8 using monoprotic acids
for pH adjustment. In comparison, it was found that the use of carboxylic
acids, citric and oxalic, caused a decrease in zeta-potential through the
adsorption of negatively charged groups to the particle surfaces. The use of
these reagents was shown to enable effective anodic electrophoretic deposition
(EPD) of TiO2 onto graphite substrates at low pH levels with a decreased level
of bubble damage in comparison with anodic EPD from basic suspensions. The
results obtained demonstrate that the IEP of TiO2 varies with the type of
reagent used for pH adjustment. The low pH level of the IEP and the ability to
decrease the zeta-potential through the use of carboxylic acids suggest that
the anodic EPD of anatase is more readily facilitated than cathodic EPD.
