Systems for measuring electric resistance and relation between applied pressure and streaming potential across the membrane and utility thereof

摘要

The present invention provides a method for measuring net charge density of membrane and apparatus thereof. The method measures the net charge density of a membrane by utilizing the relation between the mechanical pressure difference applied across the membrane and the generated streaming potential or the relation between the applied electric field and the generated electroosmotic flow. The present invention also provides a method and an apparatus for measuring the resistance of a membrane.

主权项

1. An apparatus for measuring a net charge density of a membrane, comprising:
a membrane permeation measurement module, comprising a chamber, two electrodes disposed in the chamber, a target membrane to be measured, and a solution, for measuring permeation rate caused by a pressure difference ΔP between two surfaces of the target membrane and electroosmotic volumetric flow rate caused by an electric field applying across the target membrane; a pressure measurement module, for measuring the mechanical pressure difference ΔP between the two surfaces of the target membrane; and a streaming potential measurement module, for measuring the streaming potential Ē across the target membrane; and a control module, for controlling measurement procedures and collecting data from each module to calculate the net charge density ρE of the target membrane per unit volume according to the relation of the mechanical pressure difference ΔP and the streaming potential Ē, by the following equation (7):
ρE=−(Ē/ΔP)*(μεkm/Kp)  (7) where εkm represents the product of the porosity ε and average electrical conductivity km of the target membrane, μ represents viscosity of the solution, and Kp represents permeability; and wherein the product of the porosity ε and average electrical conductivity km of the target membrane is acquired by measuring electric resistance of the target membrane.