Abstract
The movement of charged particles occurs in a salt concentration gradient by the mechanism of diffusiophoresis. Current analytical models for diffusiophoresis have been developed for a gradient generated by a symmetric Z:Z electrolyte at steady state. Recently, our lab has reported diffusioosmotic flows due to dissolving calcium carbonate (CaCO3) which generates three ions (Ca2+, HCO3-, and OH-), and this fluid motion cannot be described by current analytical models. In this communication, we derive an expression for the diffusioosmotic flow in a gradient involving multiple ions of different valences, assuming infinitesimally thin double layers. We also solve numerically the time-dependent concentration profiles for the three-ion case and find that the concentration profile of HCO3- is non-monotonic in solution. Finally, we examine quantitatively the assumption of electroneutrality in solution, finding that electroneutrality is a good approximation even for the multi-ion case, indicating that our electric field derived from the ion migration equation is quite accurate.
Original language | English (US) |
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Pages (from-to) | 120-123 |
Number of pages | 4 |
Journal | Journal of Colloid And Interface Science |
Volume | 424 |
DOIs | |
State | Published - Jun 15 2014 |
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Biomaterials
- Surfaces, Coatings and Films
- Colloid and Surface Chemistry