Method for measuring microcellular plate-type membrane porosity

A measurement method and porosity technology, which is applied in the field of accurate determination of the porosity of membrane materials, can solve problems such as laborious, time-consuming, and large error in results, and achieve the effects of simple measurement equipment, accurate measurement values, and low cost

Inactive Publication Date: 2004-07-07
BEIJING UNIV OF CHEM TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, this method is not only time-consuming and labor-intensive, but also results in large errors

Method used

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  • Method for measuring microcellular plate-type membrane porosity
  • Method for measuring microcellular plate-type membrane porosity
  • Method for measuring microcellular plate-type membrane porosity

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0039] A. to SO 2 / Air mixed gas-clear water is the measurement test system, and the German sulfonated polyethersulfone flat membrane experiment membrane is selected, and its volume porosity is known to be 72.0%; SO 2 The flow rate of air / air mixture is 400L / h, the flow rate of clear water absorption liquid is 24L / h, when the two phases are in direct contact, the gas phase inlet and outlet concentrations measured by the pararosaniline method are: C g1 =126.86ppm, C g2 =98.04ppm, known SO 2 / Henry coefficient H of the air mixture-clean water system A =24.2, calculated by formula (1), (2), (3): K G =1.997×10 -3 , so as to obtain point P, and draw the linear relationship between the total mass transfer coefficient of the mass transfer system and the membrane porosity image 3 ;

[0040] B. After adding the side membrane, under the same experimental conditions as step A, measure SO according to the method of step 1 2 The inlet and outlet concentrations of / air mixture are C...

Embodiment 2

[0042] A. Change the experimental membrane to be tested into the polyacrylonitrile flat membrane of Zhejiang University Membrane Engineering Company. It is known that its volume porosity is 40.0%. Other conditions are the same as in Example 1, so its total mass transfer coefficient - membrane porosity The linear relationship diagram of the rate is also the same as that of Example 1 image 3 unanimous.

[0043] B. Add the side film to be treated, record the gas phase inlet and outlet concentrations by the method of embodiment 1 and be respectively: C g1 '=126.86ppm, C g2 '=111.01ppm, calculate K G '=0.843×10 -3 ,exist image 3 The M2 point is obtained, and its corresponding porosity value is 41.8%.

Embodiment 3

[0045] A. change the liquid phase flow velocity in embodiment 1 into 32L / h, other conditions are all unchanged, when two phases directly contact, record gas phase inlet and outlet concentration to be respectively: C g1 =126.86ppm, C g2 = 95.13 ppm. Calculate K G =2.276×10 -3 , from which the linear relationship between total mass transfer coefficient and membrane porosity is plotted Figure 4 .

[0046] B. After adding the side membrane, under the same experimental conditions as in step A, the gas phase inlet and outlet concentrations measured according to A are: C g1 '=126.86ppm, C g2 '=102.38ppm, K is calculated G '=1.592×10 -3 . According to K G ’ has a value of Figure 4 The M3 point can be determined in , and its corresponding porosity value is 70.3%. This value is in good agreement with the value of Example 1.

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Abstract

A method utilizes strict linear relationship features between film porosity and overall mass transfer in film absorption course to determine and calculate overall mass transfer coefficient Kg value in advance under condition of the used mass transfer system without film through film absorption test so drawing of relationship between the porosity and the system overall mass transfer coefficient can be drawn out. Under the same system and the same test condition, film to be tested is added on to determine and calculate out mass transfer Kg value under condition with film so the porosity value of film to be tested can be read out from relationship drawing of mass transfer coefficient to porosity.

Description

Technical field: [0001] The invention relates to a method for accurately measuring the porosity of membrane materials. technical background: [0002] Membrane porosity refers to the size of micropore volume (or area) contained in unit membrane volume (or area), also known as volume porosity (or area) porosity, and its value is between 0 and 1. Membrane porosity is related to the microstructure such as micropore size, micropore distribution and micropore tortuosity in the membrane, and its value is generally difficult to accurately measure. [0003] At present, the main measuring methods of porosity are as follows: [0004] 1. Direct microscopic observation method: SEM, TEM and other methods are commonly used, that is, directly measure the surface microstructure of the membrane to calculate the porosity. This method cannot detect the structure of the inner wall of the membrane micropore, because there may be bends, protrusions, and depressions in the inner wall of the membr...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N15/08
Inventor 张卫东郝欣张慧峰张泽廷徐静年史季芬
Owner BEIJING UNIV OF CHEM TECH
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