کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
613654 880725 2006 11 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Diffusioosmosis of electrolyte solutions in a fine capillary slit
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی شیمی کلوئیدی و سطحی
پیش نمایش صفحه اول مقاله
Diffusioosmosis of electrolyte solutions in a fine capillary slit
چکیده انگلیسی

The steady diffusioosmotic flows of an electrolyte solution along a charged plane wall and in a capillary channel between two identical parallel charged plates generated by an imposed tangential concentration gradient are theoretically investigated. The plane walls may have either a constant surface potential or a constant surface charge density. The electrical double layers adjacent to the charged walls may have an arbitrary thickness and their electrostatic potential distributions are determined by the Poisson–Boltzmann equation. Solving a modified Navier–Stokes equation with the constraint of no net electric current arising from the cocurrent diffusion, electric migration, and diffusioosmotic convection of the electrolyte ions, the macroscopic electric field and the fluid velocity along the tangential direction induced by the imposed electrolyte concentration gradient are obtained semianalytically as a function of the lateral position in a self-consistent way. The direction of the diffusioosmotic flow relative to the concentration gradient is determined by the combination of the zeta potential (or surface charge density) of the wall, the properties of the electrolyte solution, and other relevant factors. For a given concentration gradient of an electrolyte along a plane wall, the magnitude of fluid velocity at a position in general increases with an increase in its electrokinetic distance from the wall, but there are exceptions. The effect of the lateral distribution of the induced tangential electric field and the relaxation effect in the double layer on the diffusioosmotic flow are found to be very significant.

The diffusioosmosis of an electrolyte solution in a capillary slit generated by an imposed tangential concentration gradient is theoretically studied in a self-consistent way.Figure optionsDownload high-quality image (113 K)Download as PowerPoint slide

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Colloid and Interface Science - Volume 298, Issue 1, 1 June 2006, Pages 476–486
نویسندگان
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