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CN-122006503-A - Reverse osmosis membrane for high-pollution wastewater treatment and preparation method thereof

CN122006503ACN 122006503 ACN122006503 ACN 122006503ACN-122006503-A

Abstract

The invention discloses a reverse osmosis membrane for treating high-pollution wastewater and a preparation method thereof, and relates to the technical field of separation membranes. The reverse osmosis membrane is sequentially laminated and compounded from bottom to top to form the reinforced non-woven fabric supporting layer, the nanofiber reinforced porous polymer middle supporting layer, the polyamide active separating layer with high crosslinking degree and the protective layer. The invention obviously improves the mechanical strength, the chlorine-oxidation resistance, the pollution resistance and the chemical cleaning recovery rate of the membrane by the cooperative enhancement of the multilayer structure, and is suitable for reverse osmosis treatment of high-pollution water bodies such as landfill leachate, high-concentration industrial wastewater and the like.

Inventors

  • DONG XIAOKANG

Assignees

  • 无锡特仁科环保科技有限公司

Dates

Publication Date
20260512
Application Date
20260326

Claims (10)

  1. 1. A reverse osmosis membrane for high-pollution wastewater treatment is formed by sequentially laminating and compounding a reinforced non-woven fabric supporting layer, a nanofiber-reinforced porous polymer middle supporting layer, a high-crosslinking-degree polyamide active separating layer and a protective layer from bottom to top, and is characterized in that the reinforced non-woven fabric supporting layer is prepared by carding polyester fibers, polytrimethylene terephthalate fibers and reinforced fibers into a fiber web, and then carrying out needling and hydroentanglement; The protective layer is prepared by sequentially soaking a silane solution and a modified solution after plasma treatment of a polyamide active separation layer with high crosslinking degree.
  2. 2. The reverse osmosis membrane for treating highly contaminated wastewater according to claim 1, wherein the reinforcing fiber is produced by melt-mixing polypropylene and modified carbon nanotubes, extruding, spinning, and drawing.
  3. 3. The reverse osmosis membrane for treating highly contaminated wastewater according to claim 2, wherein the modified carbon nanotubes are prepared by modifying carbon nanotubes with acrylic acid or methyl methacrylate.
  4. 4. The reverse osmosis membrane for high pollution wastewater treatment according to claim 1, wherein the nanofiber-reinforced porous polymer intermediate support layer is a polysulfone porous membrane layer doped with silica nanofibers.
  5. 5. The reverse osmosis membrane for treating highly polluted wastewater as claimed in claim 4, wherein the nanofiber reinforced porous polymer intermediate support layer has a porosity of 60% -80% and an average pore diameter of 10-50nm.
  6. 6. The reverse osmosis membrane for treating highly contaminated wastewater according to claim 1, wherein said polyamide active separation layer having a high degree of crosslinking is a piperidinyl polyamide membrane layer.
  7. 7. The reverse osmosis membrane for treating highly contaminated wastewater according to claim 1, wherein the silane solution is a silane compound having a double bond and the polyvinylpyrrolidone is prepared as an ethanol solution.
  8. 8. The reverse osmosis membrane for treating highly contaminated wastewater according to claim 1, wherein the modified solution is prepared by adding terminal alkenyl polyethylene glycol ether and double bond-containing amphoteric ion to a mixed solvent of tetrahydrofuran and chloroform in a volume ratio of 1:1.
  9. 9. The reverse osmosis membrane for highly contaminated wastewater treatment according to claim 7 or 8, wherein said double bond-containing silane compound comprises at least one of allyldimethoxysilane, bis (trimethoxysilylmethyl) ethylene, methacryloxymethyltrimethoxysilane, acryloxypropyltrimethoxysilane, and said double bond-containing zwitterion is at least one of [2- (methacryloxyethyl ] dimethyl- (3-sulfopropyl) ammonium hydroxide, methacryloxyethyltrimethylammonium chloride, 2-methacryloxyethyl choline phosphate, or 3- ((3-acrylamidopropyl) dimethylammonium) propionate.
  10. 10. The reverse osmosis membrane for treating highly contaminated wastewater according to claim 7 or 8, wherein the molar ratio of said terminal alkenylpolyethylene glycol ether, double bond-containing zwitterionic, double bond-containing silane compound, polyvinylpyrrolidone is 3-5:1:0.5-1:1-3.

Description

Reverse osmosis membrane for high-pollution wastewater treatment and preparation method thereof Technical Field The invention relates to the technical field of separation membranes, in particular to a reverse osmosis membrane for treating high-pollution wastewater and a preparation method thereof. Background The disk reverse osmosis (DTRO) technology has become one of the core processes in the field of special wastewater treatment of landfill leachate, high-concentration industrial wastewater and the like because of the capability of tolerating high-flux, high-salt content and high-pollution inflow water. The performance of the DT membrane as a core separation element of a DTRO system directly determines the desalination rate, water production flux, cleaning cycle and service life of the system. The traditional DT reverse osmosis membrane adopts a composite structure, and comprises a non-woven fabric supporting layer, a porous polymer middle supporting layer such as polysulfone and a polyamide active separating layer from bottom to top. However, when treating industrial highly polluted wastewater with complex and variable components, the conventional aromatic polyamide desalting layer has excellent desalting performance, but amide bonds in the molecular structure and acyl chloride groups possibly remained after interfacial polymerization are easily attacked by active chlorine in the inflow water to generate chlorine substitution or amide bond degradation, so that the desalting rate is permanently and irreversibly reduced. Meanwhile, when dealing with frequent chemical cleaning, especially in strong acid or alkali environments, the long-term chemical stability of the cleaning agent is also under serious examination. The polyamide separation layer surface typically exhibits a certain roughness and electronegativity, which makes it easy to adsorb positively charged organic pollutants, colloidal particles and microorganisms in the wastewater by electrostatic action and physical entrapment, forming a dense pollution layer, i.e. fouling. The physicochemical properties of the surface are not optimized for anti-fouling in extreme conditions, resulting in rapid decay of the membrane flux and an increase in operating pressure. DTRO systems are typically operated at pressures up to 80-120bar with severe water impingement. Under long-term high pressure and turbulent impact, the traditional membrane supporting layer is easy to generate structural compaction or fatigue damage, so that the water production flux is accelerated and attenuated along with the running time, and even in extreme cases, the membrane is broken, and the stability of a system and the service life of the membrane are seriously influenced. Once the contamination occurs, the contaminants are easily embedded in the roughened "peak-to-valley" structure of the polyamide layer, forming irreversible contaminants that are difficult to clean. Conventional chemical cleaning is difficult to completely remove the embedded pollutants, so that the cleaning recovery rate of the membrane is gradually reduced, and finally the membrane performance cannot meet the operation requirement and is scrapped in advance. Therefore, the DT reverse osmosis membrane with high desalination rate, excellent chemical stability, strong pollution resistance and super strong mechanical strength is developed, and has important significance for promoting the progress of high-difficulty wastewater treatment technology and reducing the system operation cost and maintenance frequency. Disclosure of Invention The invention aims to provide a reverse osmosis membrane for treating high-pollution wastewater and a preparation method thereof, so as to solve the problems in the prior art. In order to solve the technical problems, the invention provides the technical scheme that a reverse osmosis membrane for treating high-pollution wastewater is formed by sequentially laminating and compounding a reinforced non-woven fabric supporting layer, a nanofiber-reinforced porous polymer middle supporting layer, a high-crosslinking-degree polyamide active separating layer and a protective layer from bottom to top, wherein the reinforced non-woven fabric supporting layer is formed by carding polyester fibers, polytrimethylene terephthalate fibers and reinforced fibers into a fiber net, and then needling and hydroentangling are carried out, and the longitudinal and transverse tearing strength and creep resistance of a membrane substrate are obviously improved by adding the reinforced fibers; The protective layer is prepared by sequentially soaking a silane solution and a modified solution after plasma treatment of a polyamide active separation layer with high crosslinking degree. Further, the reinforced fiber is prepared by melting and mixing polypropylene and modified carbon nano tubes, extruding, spinning and drawing. Further, the polypropylene is selected from polypropylene resin with a melt index of 10-40g