Papers by Keyword: Streaming Potential

Abstract: An analytical solution for pressure-driven electrokinetic flows in a narrow capillary is presented based on the Poisson–Boltzmann equation for electrical double layer and the Navier–Stokes equations for incompressible viscous fluid. The analytical solutions indicate that pressure-driven flow of an electrolyte solution in microchannel with charged solid wall induces a streaming potential, which is proportional to the flowrate and induces an electroviscous effect on flow. A device for measuring the electrokinetic flow rate and streaming potential is proposed.

Abstract: Slip casting is a well-established ceramic casting technique used for large scale fabrication of ceramic products with complex shapes. A homogenous slip with a desired level of stability is required, which is controlled using a dispersant. This paper describes the selection and optimisation of various dispersants used to produce Ti powder slips. A consideration of the effect of concentration and pH of the solvent on the dispersion of anionic polyelectrolyte dispersants (Dispex N-40, Synthecol SD375 & Dolapix CE64) was examined by measuring the sedimentation height and rate, the streaming potential and the slip viscosity. It was found that Dolapix CE64 showed the best deflocculating effect at 0.3dw.% with pH of 7. In particular, the measurements on Dolapix CE64 gave consistent results. This indicated that Dolapix CE64 is an effective dispersant in the preparation of a titanium slip.

Abstract: The electrokinetic effects are important in the understanding of electric properties in porous medium. In this study, the streaming potential and streaming current of saturated samples are measured at different concentrations, then three methods are applied to obtain the zeta-potential and electrokinetic coupling coefficient. The study shows that the results obtained from streaming potential and streaming current methods agree well with each other, but the results obtained from simplified streaming potential method become seriously inaccurate at low concentrations due to the influence of surface conductance. This experimental study also provides a reliable estimate of the surface conductivity and its contribution to zeta-potential at given concentrations.

Abstract: The sulfonated-polyethersulfone (SPES)/nano-TiO2 composite ultrafiltration (UF) membranes were prepared by phase inversion method with nano-TiO2 as additive. The TiO2 self-assembly on the SPES membrane was confirmed by FT-IR and the isoelectric point’s analysis (IEPs). The electrokinetic phenomena of composite membrane in the different single electrolyte solution were investigated by the streaming potential method. The results showed that the IEP of the SPES-UF membrane modified by nano-TiO2 shifts from 3.5 to 2.9, and the composite membrane shows a stronger electronegativity, which indicates the antifouling performance improvement of the SPES-UF membrane modified by nano-TiO2. The valences of the cations and anions have an important influence on the streaming potential of the composite UF membrane.

Abstract: Based on the physiological structure of osteon, a single fluid-filled osteon model under only time-dependent axial loading is modeled for calculating the streaming potential induced by canaliculi fluid flow. Solid matrix is modeled as an elastic transverse isotropic thick-walled cylinder and fluid phase is considered as an incompressible Newtonian fluid. Close-form solution of the streaming potential for a single osteon model was obtained and used to study the electromechanical properties on intraosseous pressure and potential distribution. The solution can also be used as a benchmark for numerical studies of other osteon models.

Abstract: The process of electrophoretic deposition depends strongly on the electrokinetic properties and with it the surface properties of the material that will be processed. Different additives, conditioners but also the suspending liquid influence the surface of the applied material by adsorption. Electrokinetic investigations reflect changes in properties at the outermost solid surface very sensitive. Streaming potential measurements are especially suited for studying such changes of surface chemistry at solids with different shapes. Two approaches are applicable: 1. The adsorption process was done before measuring. The result of this process should be shown. In this case it will be interesting to see differences in the functionality of the solid surface. The zeta potential will be measured versus different pH value. 2. The adsorption process will be studied directly. The zeta potential will be determined versus the concentration of the adsorptive. The second approach can be used for investigation of adsorption of multicomponent mixtures. Competing adsorption processes are detectable.