ZETA-POTENTIAL MEASUREMENTS WITH FIBER PLUGS IN 1 1 ELECTROLYTE-SOLUTIONS/

The aim of this paper is correct calculation of zeta potential values from streaming potential measurements in aqueous electrolyte solutions . To determine correct zeta potential values it is very important to m easure the total electric conductivity exactly and to consider the ele ctrode polarization. The streaming potential measurements of various f ibre samples in KCl solution of different concentrations were carried out by means of two different measuring devices working in very differ ent pressure ranges. The calculated zeta potential values show that th e measuring method gives well reproducible results independent of the applied pressure and the kind of device. In addition, we discuss, the possibility of, and the reason for, a maximum observed sometimes in th e dependence of zeta potential values on the electrolyte concentration in the case of 1:1 electrolytes by means of measurements of a fibre d iaphragm and by using computer simulations based on a Gouy-Chapman-Ste rn-Grahame model.