Method for determining ultramicro filter membrane pore size and pore size distribution

Abstract

The invention relates to a method for determining ultramicro filter membrane pore size and pore size distribution. The method comprises the following steps: 1) selecting a primary standard substance; 2) scanning maximum absorption wavelengths of nanoparticles with various particle sizes in an ultraviolet-visible wavelength range, and accordingly drawing a standard curve under the maximum absorption wavelengths; 3) selecting polystyrene nanoparticles with single particle size and preparing into solution with mass concentration of C0, uniformly dispersing the nanoparticles with the particle size in water by adopting ultrasound, carrying out a filtration experiment on an ultramicro filter membrane by adopting a suspension liquid filtration method, selecting filtered solution, determining absorbance of the polystyrene nanoparticles with the particle size under the maximum absorption wavelength, calculating concentration Ct of the nanoparticles with the particle size in the filtered solution by adopting a standard curve, and further calculating retention rate R of the ultramicro filter membrane on the polystyrene nanoparticles on the polystyrene nanoparticles with the particle size; and 4) selecting the polystyrene nanoparticles with different particle sizes, repeating the step 3), retaining, and calculating membrane pore diameter of the ultramicro filter membrane according to the determined retention rate. The method provided by the invention is simple in principle and easy to operate and can determine the ultramicro filter membrane pore size and the pore size distribution more accurately.

Description

technical field [0001] The invention relates to a method for measuring the pore size and pore size distribution of an ultramicrofiltration membrane. Background technique [0002] Membrane pore size refers to the channel diameter at the narrowest part of the pores running through the entire membrane surface, and the membrane pores of a specific membrane are not uniform in size, but have a certain pore size distribution. Membrane pore size is often expressed by maximum pore size, average pore size and pore size distribution. The nominal pore size and absolute pore size are also used to indicate the membrane pore size. The nominal pore size means that particles or molecules of this size are intercepted by a certain percentage (90% or 95%). The absolute pore size refers to the largest pore size or particle size equal to or greater than the membrane. were all detained. The geometric mean pore size refers to the most distributed pores, and when the pore size is normally distribu...

AI Technical Summary

Problems solved by technology

Permeation porosimetry can detect the effective pores of the membrane, but the device and operation are more complicated, and it is difficult to keep the pressure on both sides of the membrane the same.

Holes measured by thermal porosimetry include dead-end holes, which cannot accurately detect effective holes

The molecular weight cut-off method is suitable for the determination of ultrafiltration membranes with small pore sizes, but the results of different standard substances will be different

The suspension filtration method is suitable for ultrafiltration membranes and microfiltration membranes with large pore sizes, and can directly measure the separation performance of the membrane, but it is necessary to select a suitable reference material

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