Why the membrane material pore size test should choose bubble point tester - Database & Sql Blog Articles

There are various methods for testing the pore size of the material, such as nitrogen adsorption, mercury intrusion, and bubble pressure. However, the most suitable method for testing the pore size of the membrane is to use a bubble pressure method (gas-liquid flooding method) for testing. The reasons are as follows: 1. Disadvantages of nitrogen adsorption method 1. Aperture range: 0.35-500 nm, which cannot be tested for micron-sized pores. 2. The nitrogen adsorption of the diaphragm also has a large error. The reason is that the inner and outer surfaces of the diaphragm are smooth, smaller than the surface, and the adsorption amount is small, so the error is large. 3. The diameter of the hole in the diaphragm material (ie the diameter at the narrowest point of the through hole) is the most critical and most important, while the nitrogen adsorption test is the through hole and blind hole of the material, so the aperture test error will be very large. . Second, the disadvantages of mercury intrusion method 1, the pore size range: 50nm-500um; if you want to test a smaller pore size, such as below 100nm, you need a very large pressure (20MPa or more) to inject mercury into the material pores, so the pressure is generally Under the high pressure, the pore structure of the membrane material will deform or even collapse, resulting in a deviation from the theoretical value; however, for the bubble pressure method, the pressure applied to the material is much smaller, generally below 0.1 MPa. 2. Like nitrogen adsorption, the mercury intrusion method is also a through hole and a blind hole, but not the diameter of the hole throat. 3. The bubble pressure method 1. The test aperture range is 10 nm-500 um; 2. The hole for the through hole is tested. Diameter at the throat (minimum pore size), maximum pore size, average pore size, pore size distribution and permeability; 3. The test principle is applicable to the test of the pore diameter of the membrane material.