Assessment of zeta-potential in TiO2 aqueous suspensions: A comparative study based on thermodynamic and rheological methods

作者：Gomez Merino A I^*; Rubio Hernandez F J; Velazquez Navarro J F; Aguiar J

来源：Ceramics International, 2015, 41(4): 5331-5340.

DOI：10.1016/j.ceramint.2014.12.088

• Critical zeta-potential
• Titanium dioxide
• Gibbs free energy
• Yield stress
• Rheology

It is widely demonstrated that the distinct electrokinetic techniques lead to different values of zeta-potential despite what should be expected from the classical theory. Electrophoresis and conductivity measurements were used to estimate the zeta-potential and the electrical double layer parameters of TiO2 aqueous suspensions. An assessment of the results was made following thermodynamic and rheological methods. In the first case, the Gibbs free energy increment was compared. In the second one, the yield stress/zeta-potential plots were used. In spite of the zeta-potentials obtained from conductivity, electrophoresis and electrophoresis-conductivity combined techniques are different, the Gibbs free energy increment values do not discriminate the best zeta-potential value. Moreover, the correlation between the yield stress and the square of the zeta-potential has shown that all the zeta-potentials can physically be acceptable. Therefore, the only reasonably conclusion from this study is that the use of combined techniques, like electrophoresis-conductivity, should always be taken as the more cautious approach of evaluating zeta-potentials.

• 出版日期2015-5