Abstract
Zeta potential identifies the electric charge of hollow-fiber dialysis membranes; however, there is no well established method to measure it. The objective of the present study is to improve the method of measuring streaming potential necessary for determination of the zeta potential. Both streaming potential and pressure drop were dependent on the packing of hollow fibers in a test cell, its assembled form and aqueous electrolyte concentration. Time-dependent streaming potentials were observed using commonly used aqueous 0.01N KCl. Much time was then required to attain equilibrium. An aqueous electrolyte, the concentration of which is 1/1000 of the aqueous 0.01N KCl was suited for stable and exact determination of streaming potential with the improved cell. Using the improved method, the zeta potential of seven different hollow-fiber dialysis membranes was determined, with a good relationship between the zeta potential and HPO42- permeability. We conclude that performance of charged hollow-fiber dialysis membranes can be evaluated by the zeta potential calculated from the streaming potential measured by the improved method.
