Física Aplicada I, Universidad de Málaga, Spain.
Phys Chem Chem Phys. 2011 May 28;13(20):9644-54. doi: 10.1039/c1cp20100j. Epub 2011 Apr 14.
A new modified Poisson-Boltzmann equation accounting for the finite size of the ions valid for realistic salt-free concentrated suspensions has been derived, extending the formalism developed for pure salt-free suspensions [Roa et al., Phys. Chem. Chem. Phys., 2011, 13, 3960-3968] to real experimental conditions. These realistic suspensions include water dissociation ions and those generated by atmospheric carbon dioxide contamination, in addition to the added counterions released by the particles to the solution. The electric potential at the particle surface will be calculated for different ion sizes and compared with classical Poisson-Boltzmann predictions for point-like ions, as a function of particle charge and volume fraction. The realistic predictions turn out to be essential to achieve a closer picture of real salt-free suspensions, and even more important when ionic size effects are incorporated to the electric double layer description. We think that both corrections have to be taken into account when developing new realistic electrokinetic models, and surely will help in the comparison with experiments for low-salt or realistic salt-free systems.
已经推导出了一个新的修正泊松-玻尔兹曼方程，用于考虑离子的有限大小，适用于现实的无盐浓缩悬浮液，该方程扩展了为纯无盐悬浮液[Roa 等人，Phys. Chem. Chem. Phys.，2011，13，3960-3968]开发的形式体系，以适应实际的实验条件。这些现实的悬浮液包括水离解离子和大气二氧化碳污染产生的离子，以及颗粒向溶液中释放的外加抗衡离子。将计算不同离子大小的颗粒表面的电势，并将其与点状离子的经典泊松-玻尔兹曼预测进行比较，作为颗粒电荷和体积分数的函数。现实的预测对于更接近真实无盐悬浮液的情况至关重要，而当将离子大小效应纳入双电层描述时则更为重要。我们认为，在开发新的现实电动模型时，必须考虑这两个修正，并且肯定会有助于与低盐或现实无盐系统的实验进行比较。
