Method for detecting PVA coating on surface of composite reverse osmosis membrane

A reverse osmosis membrane and membrane surface technology, which is applied in the direction of measuring devices, analyzing materials through chemical reactions, and analyzing materials through observing the influence of chemical indicators, can solve the problem of time-consuming and inability to accurately judge surface coating. Substance and other problems, to achieve the effect of lower detection limit, stable color development, and PVA color sensitivity

Pending Publication Date: 2022-02-15
WANHUA CHEM GRP CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] At present, the overall development of domestic reverse osmosis membrane-related detection technologies lags behind that of developed countries, especially the detection of reverse osmosis membrane surface coatings. Although PVA is widely used in the field of reverse osmosis membranes, the main detection method for surface coatings Focus on reflecting the changes in the hydrophilic properties of the membrane surface by measuring the surface contact angle, Zeta potential and other indirect means, or reflect the coating of the surface coating on the side of the anti-pollution performance through long-term operation, but the above methods such as contact angle and Zeta potential can only be obtained from The side surface reflects the change of surface hydrophilicity, and it is impossible to accurately judge that the surface coating material is PVA. The anti-pollution experiment is the most realistic simulation of the anti-pollution performance environment of the membrane. However, this method takes a long time. For now, there is no A method that can directly, quickly and accurately detect the PVA coating on the surface of a reverse osmosis membrane and the uniformity of coverage

Method used

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  • Method for detecting PVA coating on surface of composite reverse osmosis membrane
  • Method for detecting PVA coating on surface of composite reverse osmosis membrane
  • Method for detecting PVA coating on surface of composite reverse osmosis membrane

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0064] Test the distribution and amount of PVA coating on the surface of Dow Chemical Company No. BW30 diaphragm

[0065] Cut a 1m length from the BW30-400 membrane element broken membrane of Dow Chemical Company 8040 for use.

[0066] The specific test steps are as follows:

[0067] 1) Reverse osmosis membrane sampling: Use a disc sampler with a diameter of 7.8cm to randomly cut 5 discs from the membrane;

[0068] 2) Preparation of developer: prepare 10g / L octylphenyl polyoxyethylene ether solution, iodine-potassium iodide solution with iodine and potassium iodide concentrations of 12.7g / L and 25g / L respectively, and boric acid solution with a concentration of 40g / L , as a color developer, for use;

[0069] 3) Rapid color development judgment: Soak the disc in the mixed octylphenyl polyoxyethylene ether-iodine-boric acid color reagent solution with a volume ratio of 1:1:3 for 30 seconds, take it out and rinse it repeatedly with pure water until The washing solution is colo...

Embodiment 2

[0080] Test the distribution and amount of PVA coating on the surface of Dow Chemical Company No. TW30 diaphragm

[0081] Cut a 1m length from the broken diaphragm of TW30-1812-100 membrane element of Dow Chemical Company 1812 for use. The specific test steps are as follows:

[0082] 1) Reverse osmosis membrane sampling: randomly cut 15 discs from the membrane with a disc sampler with a diameter of 5.0 cm;

[0083] 2) Preparation of developer: prepare 5.0g / L nonylphenol polyoxyethylene ether solution, iodine-potassium iodide solution with iodine and potassium iodide concentrations of 10.0g / L and 20g / L respectively, and boric acid solution with a concentration of 30g / L , as a color developer, for use;

[0084] 3) Rapid color development judgment: Soak the disc in the mixed nonylphenol polyoxyethylene ether-iodine-boric acid color reagent solution with a volume ratio of 2:3:3 for 60 seconds, take it out and rinse it repeatedly with pure water until it is washed. The liquid is ...

Embodiment 3

[0095] The distribution and amount of PVA coating on the surface of Wharton Technology Co., Ltd. No. LP21 diaphragm during testing

[0096] Cut a 1m length from the LP21-4040 membrane element ruptured diaphragm of Times Wharton Technology Co., Ltd. 4040 for use. The specific test steps are as follows:

[0097] 1) Reverse osmosis membrane sampling: randomly cut 10 discs from the membrane with a disc sampler with a diameter of 10.0 cm;

[0098] 2) Chromogenic agent preparation: preparation of 20g / L polyoxyethylene lauryl ether solution, iodine, potassium iodide concentration is respectively the iodine-potassium iodide solution of 20.0g / L, 30g / L and the boric acid solution with concentration of 50g / L, as a developer Toner, for use;

[0099] 3) Rapid color development judgment: Soak the disc in the polyoxyethylene lauryl ether-iodine-boric acid color developer solution with a volume ratio of 1:0.1:1 for 120s, take it out and rinse it repeatedly with pure water until the washing l...

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Abstract

The invention discloses a method for detecting a PVA coating on the surface of a composite reverse osmosis membrane, which comprises the following steps of: soaking a reverse osmosis membrane slice to be detected in a color developing agent, taking out the membrane, washing the membrane with pure water until a washing solution is colorless, observing the color change of the surface of the membrane, and showing that the surface of the membrane is coated with the PVA coating when the surface of the membrane is blue-green, wherein the color developing agent is a mixture of a polyoxyethylene ether substance solution, an iodine-potassium iodide solution and a boric acid solution. The method has the advantages that the PVA layer coated on the surface of the reverse osmosis membrane is directly, rapidly and quantitatively evaluated, the PVA coated on the surface and the covering uniformity can be rapidly detected through direct color development on the surface of the membrane, the ultraviolet spectrophotometric quantitative detection is good in linearity, the operation is relatively simple, the PVA anti-pollution coating of the reverse osmosis membrane gets rid of the traditional indirect method for judging only through hydrophilicity, Zeta potential and the like, and the timeliness and the accuracy of PVA detection on the surface of the reverse osmosis membrane are improved.

Description

technical field [0001] The invention relates to the field of detection of reverse osmosis membrane surface coatings, in particular to a method for detecting PVA coatings on the surface of composite reverse osmosis membranes. Background technique [0002] As an excellent separation, concentration, purification and refining method, reverse osmosis membrane technology has been widely used in various industries of the national economy such as electronics, semiconductors, pharmaceuticals, medical care, food, beverages, alcohol, chemicals, and environmental protection. One of the broadest and fastest growing membrane technologies. [0003] However, reverse osmosis membranes are limited by the problem of membrane fouling during use. Membrane fouling refers to the physical and chemical interaction between particles, colloidal particles or solute macromolecules in the raw material liquid and the membrane surface to form scaling, filter cake and other adhesion layers on the membrane ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N21/78G01N21/01
CPCG01N21/78G01N21/01
Inventor 陈静许胜杰苏蕾高翔孙世琛邬军辉赵伟国
Owner WANHUA CHEM GRP CO LTD
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