APPARATUS FOR STREAMING POTENTIAL MEASUREMENTS ON GRANULAR FILTER MEDIA

This paper is intended to provide the necessary information to constru ct and properly operate a simple streaming potential apparatus capable of measuring the zeta potential of granular media. Through an underst anding of the principles of the technique, such a device can readily b e used in the study of a variety of granular materials including unsta ble and dynamic surfaces, as shown for surface coatings and even biofi lm growth. The simplified mathematical theory of the streaming potenti al is herein explained, as well as operational factors and the general reasons for nonreproducible measurements such as electrode maintenanc e, electrode polarization, nonzero rest potentials, and sample equilib ration. This specific apparatus design is intended for use with granul ar materials and has intentionally been developed in a simplistic fash ion to encourage wider usage of the technique. The overall precision o f this instrument was +/-10% based on a 95% confidence interval. In ad dition, the accuracy of the device was found to be very good based on comparisons with literature values.