Validation of the new fluidization potential technique for ζ potential measurement in the nonlaminar flow regime using spherical particles

Abstract

A detailed experimental investigation of flow characteristics and their influence on ζ potential measurement by the new fluidization potential technique is presented. The governing equation of this technique derived from the classical Helmholtz-Smoluchowski streaming potential equation assumes laminar flow through a steady-state uniform solid-liquid fluidized bed. The results from model suspensions of Ballotini glass spheres (82–280 μm) in deionized water show that a transition from laminar to nonlaminar flow may occur in some fluidization potential tests. Especially with the large size spheres (200–280 μm), fluidization potential measurements have taken place entirely in the nonlaminar flow regime. It was found that the hydrodynamic flow transition does not affect the ζ potential observed from the fluidization potential gradient in relation to volumetric fraction of solids, c within the limits of linearity (0 < c < c max) of the governing equation. c max was the limit of linear dependence of the governing equation and its value up to 0.304 was observed.