BRGM, UMR BRGM/CNRS/ISTO 7327, Orléans, France.
J Colloid Interface Sci. 2012 Dec 15;388(1):243-56. doi: 10.1016/j.jcis.2012.07.029. Epub 2012 Jul 20.
Zeta potential is a physico-chemical parameter of particular importance to describe sorption of contaminants at the surface of gas bubbles. Nevertheless, the interpretation of electrophoretic mobilities of gas bubbles is complex. This is due to the specific behavior of the gas at interface and to the excess of electrical charge at interface, which is responsible for surface conductivity. We developed a surface complexation model based on the presence of negative surface sites because the balance of accepting and donating hydrogen bonds is broken at interface. By considering protons adsorbed on these sites followed by a diffuse layer, the electrical potential at the head-end of the diffuse layer is computed and considered to be equal to the zeta potential. The predicted zeta potential values are in very good agreement with the experimental data of H(2) bubbles for a broad range of pH and NaCl concentrations. This implies that the shear plane is located at the head-end of the diffuse layer, contradicting the assumption of the presence of a stagnant diffuse layer at the gas/water interface. Our model also successfully predicts the surface tension of air bubbles in a KCl solution.
Zeta 电位是描述气体气泡表面污染物吸附的物理化学参数，具有重要意义。然而，气体电泳迁移率的解释非常复杂。这是由于气体在界面处的特殊行为以及界面处过多的电荷，这导致了表面导电性。我们开发了一种基于存在负表面位点的表面络合模型，因为在界面处打破了接受和提供氢键的平衡。通过考虑吸附在这些位点上的质子以及扩散层，计算了扩散层前端的电势，并认为其等于 Zeta 电位。对于广泛的 pH 和 NaCl 浓度范围，预测的 Zeta 电位值与 H(2)气泡的实验数据非常吻合。这意味着滑移面位于扩散层的前端，与气体/水界面处存在静止扩散层的假设相矛盾。我们的模型还成功预测了 KCl 溶液中空气气泡的表面张力。
