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.