Ultrafiltration membrane pore size distribution determination method

Abstract

The invention relates to an ultrafiltration membrane pore size distribution determination method. Based on an existing liquid-liquid replacement principle, aiming at the pushing pressure of the obtained replaced liquid and the flow rate of the corresponding replaced liquid, a pore size distribution determination model is designed; compared with an original method, the method has the advantages that fluctuation of the obtained pore size distribution data is low, accuracy is high, implement is easy, and an obvious effect is achieved.

Description

technical field [0001] The invention relates to a method for measuring the pore size distribution of an ultrafiltration membrane. Background technique [0002] There are many methods for measuring membrane pore size, such as liquid flow rate method, mercury injection method, electron microscope method, gas adsorption and desorption method, bubble pressure method and osmotic porosity method, etc. or less disadvantages. Among them, when the liquid flow rate method is used to measure the pore size of the membrane, the porosity of the membrane needs to be determined in advance. This method is mainly suitable for microfiltration membranes. If it is used to measure the pore size of ultrafiltration membranes, it may cause distortion of the measurement results; It is a void hole, not all "active holes" that penetrate the membrane, and the required test pressure is relatively high, which may easily cause the deformation of the sample and make the result untrue; the electron microsco...

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Problems solved by technology

[0002] There are many methods for measuring membrane pore size, such as liquid flow rate method, mercury injection method, electron microscope method, gas adsorption and desorption method, bubble pressure method and osmotic porosity method, etc. or less disadvantage

Among them, when the liquid flow rate method is used to measure the pore size of the membrane, the porosity of the membrane needs to be determined in advance. This method is mainly suitable for microfiltration membranes. If it is used to measure the pore size of ultrafiltration membranes, it may cause distortion of the measurement results; It is a void hole, not all "active holes" that penetrate the membrane, and the required test pressure is relatively high, which may easily cause the deformation of the sample and make the result untrue; the electron microscope method is more intuitive, but it is a destructive test, and can only get Local information; the gas adsorption and desorption method measures the void pores, which is different from the through-hole of the separation membrane, and is not suitable for the determination of the pore size of the ultrafiltration membrane; the bubble pressure method (also known as the gas permeation method) is limited to the measurement of the membrane The maximum pore size of the pores, the pressure required for the determination of small pore ultrafiltration membranes is much higher than the operating pressure of the membrane, so it is generally considered only suitable for the determination of microfiltration membranes

The liquid-liquid displacement method, which utilizes the two-phase equilibrium and permeability properties in the membrane pores, belongs to the displacement detection technology, which can directly measure the pore size distribution of the membrane pores, but this method also has disadvantages: the measured pore size distribution data fluctuates greatly, which is different from the actual one. There is a certain error in the membrane pore size distribution data, the difference is large, and the accuracy is low

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