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Post-treatment method for improving stability of reverse osmosis membrane and reverse osmosis membrane product
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A reverse osmosis membrane and stability technology, applied in the direction of osmosis/dialysis water/sewage treatment, reverse osmosis, semi-permeable membrane separation, etc., can solve the problems of decreased desalination rate, unqualified performance, high molecular viscosity, etc.
Active Publication Date: 2022-03-29
HUNAN KEENSEN TECH CO LTD
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[0005] However, as a humectant, glycerin has strong hygroscopicity. Under high temperature and high humidity environment, glycerin is easy to absorb water and swell, which leads to the occurrence of glycerol attached in the membrane pores when the polyamide reverse osmosis membrane is stored under high temperature and high humidity in summer. Swelling, resulting in the destruction of the polyamide structure on the surface of the membrane, air leakage of the membrane element rolled by the membrane, and a decrease in the desalination rate, resulting in unqualified performance
This technology is extremely harsh on the storage and transportation conditions of the diaphragm, which has caused great trouble to the product.
However, if the concentration of glycerin in the PVA solution is reduced or glycerol is not added, on the one hand, due to the high molecular viscosity of PVA, the viscosity of the PVA solution is too high, which in turn leads to serious uneven coating of the coating solution; on the other hand, PVA contains a large amount of Hydrophilic hydroxyl group has poor affinity with the membrane surface, which seriously affects the appearance of the product
Therefore, the polyvinyl alcohol (PVA) solution faces a dilemma: if glycerin is not added, the solution will be unevenly coated and affect the appearance of the product; if glycerin is added, it will easily lead to air leakage of the diaphragm when stored under high temperature and high humidity in summer. Poor storage stability also leads to unqualified performance
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[0116] The PVA particles, surfactants, additives and water are stirred and heated to dissolve at 80° C. and 1200 rpm stirring speed to obtain a uniform and transparent PVA solution. Cool to 25°C and set aside.
[0118] S1. Rinse the nascent reverse osmosis membrane through a rinsing tank. The rinsing solution is RO water at a temperature of 50° C. for 5 minutes.
[0119] S2. At an ambient humidity of 80% RH, pour the PVA solution on the surface of the reverse osmosis membrane, and use a roller to remove excess solution on the surface.
[0120] S3. Place in an oven and dry at 60° C. for 2 minutes to obtain a reverse osmosis membrane product with a smooth and uniform surface.
[0127] The PVA particles, surfactants, additives and water are stirred and heated to dissolve at 80° C. and 1200 rpm stirring speed to obtain a uniform and transparent PVA solution. Cool to 25°C and set aside.
[0128] 2, post-treatment process: with embodiment 1.
[0135] The PVA particles, surfactants, additives and water are stirred and heated to dissolve at 80° C. and 1200 rpm stirring speed to obtain a uniform and transparent PVA solution. Cool to 25°C and set aside.
[0136] 2, post-treatment process: with embodiment 1.
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Abstract
The invention provides a post-treatment method for improving the stability of a reverse osmosis membrane and a reverse osmosis membrane product. The post-treatment method provided by the invention comprises the following steps: a) impregnating a nascent reverse osmosis membrane with a PVA solution, and removing excess solution on the surface of the nascent reverse osmosis membrane; b) drying the reverse osmosis membrane obtained in the step a) to obtain a post-treated reverse osmosis membrane product; wherein the PVA solution is prepared from the following components in parts by mass: 0.5 to 3 parts of PVA particles, 0.02 to 1.0 part of a surfactant, 0.05 to 5.0 parts of an additive and 91 to 99 parts of water; the additive is selected from one or more of polyacrylic acid, acrylic acid derivatives, celluloseether and silicone oil. The PVA particles, the surfactant, the specific additive and the water are matched according to a certain proportion to prepare the PVA solution, so that the problems of diaphragm air leakage, poor storage stability and non-uniform coating which are respectively caused when glycerol is added or not added into the conventional PVA solution are solved.
Description
technical field [0001] The invention relates to the technical field of water treatment, in particular to a post-treatment method for improving the stability of a reverse osmosis membrane and a reverse osmosis membrane product. Background technique [0002] Seawaterdesalination is an important way to obtain fresh water resources. The commonly used seawaterdesalination methods include: seawater freezing method, electrodialysis method, distillation method, reverse osmosis method, and ammoniumcarbonateion exchange method, among which reverse osmosis membrane method is one of the mainstream technologies . The principle of reverse osmosis technology is: under the pressure higher than the osmotic pressure of the solution, the solute in the solution is separated from the solvent by means of the selective interception of the semi-permeable membrane that only allows water to pass through and does not allow other substances to pass through. Using the separation characteristics of ...
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