Preparation method of anti-pollution scale-inhibition high-pass membrane module

Abstract

The invention discloses an anti-fouling scale-inhibiting high-pass membrane assembly and a preparation method thereof, and belongs to the field of reverse osmosis membranes. The membrane assembly is formed by rolling two RO membranes or a folded RO membrane, two layers of water inlet grids and a layer of scale inhibition non-woven fabric. The scale-inhibiting non-woven fabric is obtained by placing a scale-inhibiting granular material (such as an FOF scale inhibitor and silicon-phosphorus crystal powder) of 120-200 meshes on the surface of a polypropylene non-woven fabric and baking and bonding the scale-inhibiting granular material and the polypropylene non-woven fabric, and has a slow-release effect. The preparation method comprises the following steps: pretreating the scale inhibition particles and the base material, preparing the slurry, coating, curing and drying. And the adopted reverse osmosis membrane is anti-fouling and hydrophilic. Tests show that the membrane desalination rate and the flow rate are obviously attenuated after the conventional RO membrane produces 1800 liters of pure water, but the membrane module disclosed by the invention does not obviously attenuate after producing 4000 liters of pure water. According to the invention, the problems that the membrane is easy to scale and short in service life when the thread roll type RO membrane is used for treating high-hardness water are effectively solved, and the anti-pollution and scale-inhibition performance and the water production stability of the membrane assembly are remarkably improved.

Description

Technical Field

[0001] The invention relates to the field of reverse osmosis membranes, and in particular to a method for preparing an anti-fouling and anti-scaling high-pass membrane component. Background Art

[0002] As people's requirements for drinking water quality increase, pure water systems are gradually entering the drinking water system of every household. At present, water purifiers on the market generally use reverse osmosis filter elements, which can filter impurities such as organic matter, colloids, bacteria, viruses, etc. in raw water, especially inorganic salts, heavy metal ions and other impurities with extremely high filtration efficiency. Therefore, the reverse osmosis filter element constitutes the core component of the water purifier. The filtering effect of the water purifier is directly related to the filtering effect of the reverse osmosis filter element, and the filtering effect of the reverse osmosis filter element depends largely on the reverse osmosis membrane.

[0003] The spiral wound membrane is used as a household RO membrane because of its simple structure, relatively high packing density, and good material exchange effect due to the feed separator. It is also the main household membrane structure on the market.

[0004] However, this type of spiral RO membrane also has certain problems. Due to the long flow path of the permeate side fluid and the difficulty in cleaning the membrane elements, the service life of the membrane will be very short when treating high hardness water. The water output will decay rapidly with the increase of use time, and the salt permeability will increase significantly. Ultimately, the membrane surface will be blocked by scaling, which makes the RO membrane have technical problems in treating hardness water in the north. Summary of the invention In view of the above-mentioned defects, the present invention provides a method for preparing an anti-fouling and anti-scaling high-pass membrane module, comprising the following steps: (1) Two RO membranes or a single RO membrane folded in half are used to form a sandwich structure; (2) two layers of water inlet grids are arranged in the RO membrane interlayer, and scale-inhibiting non-woven fabric is laid between the two layers of water inlet grids; The structure obtained in step (2) is rolled.

[0005] Furthermore, the scale-inhibiting nonwoven fabric is prepared by combining the scale-inhibiting granular material with the polypropylene nonwoven fabric.

[0006] Furthermore, the antiscaling granular material includes silicon phosphorus crystals and FOF antiscaling agent.

[0007] Furthermore, the method for preparing the scale-inhibiting nonwoven fabric comprises the following steps: (1) Pretreatment of anti-scaling particles 200-mesh silicon phosphorus crystals and 120-mesh FOF reagents were ultrasonically dispersed in ethanol for 30 minutes respectively; (2) Substrate pretreatment A 5 μm thick epoxy silane coupling agent layer was roller-coated on the surface of the polypropylene non-woven fabric to enhance the adhesion of the slurry; (3) Slurry preparation The pretreated 200-mesh 45% silicon-phosphorus crystals, 30% and 120-mesh FOF scale inhibitors, 20% water-based epoxy-modified polyurethane, 3% dispersant and 2% deionized water are mixed and stirred to prepare a slurry; wherein the silicon-phosphorus crystals are the main rapid scale inhibitor, which can quickly neutralize calcium and magnesium ions; FOF is a long-term corrosion inhibitor, which can inhibit crystal growth for a long time; the water-based epoxy-modified polyurethane is a binder, which is used to fix particles, bond the matrix and form slow-release pores; (4) Slurry coating The slurry is evenly coated on the pretreated polypropylene non-woven fabric by a scraper, the coating speed is 10m / min, and the wet film thickness is controlled at 300±20μm; (5) Curing and drying The nonwoven fabric coated with the slurry was dried at 120°C for 20 min to allow the slurry to solidify and then cool naturally.

[0008] Furthermore, the reverse osmosis membrane is a polyamide composite membrane.

[0009] This case achieved remarkable technical effects by introducing a slow-release scale-inhibiting non-woven fabric composed of silicon-phosphorus crystals and FOF scale inhibitor composite particles into the reverse osmosis membrane assembly, combined with an anti-fouling hydrophilic membrane and an optimized stacked structure design: on the one hand, the scale-inhibiting non-woven fabric effectively delays scaling on the membrane surface through the synergistic effect of rapid neutralization of calcium and magnesium ions (silicon-phosphorus crystals) and long-term inhibition of crystal growth (FOF), reducing the water production attenuation rate of the membrane assembly by more than 70% when treating high-hardness water (the flow rate attenuates by more than 60% after 1,800 liters for traditional membranes, but there is still no obvious attenuation after 4,000 liters for the membrane in this case); on the other hand, the structural design optimizes the water flow distribution and reduces concentration polarization. At the same time, the combination of hydrophilic membranes and scale-inhibiting materials significantly improves the anti-pollution ability, making the desalination rate stable at more than 90% for a long time, and extending the service life of traditional membranes by more than 2 times, effectively solving the technical problems of easy scaling and short life of reverse osmosis membranes under high-hardness water quality in the north.

[0010] The concept, specific structure and technical effects of the present invention will be further described below in conjunction with the accompanying drawings to fully understand the purpose, characteristics and effects of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 Schematic diagram of a novel scale-blocking nonwoven fabric in a preferred embodiment of the present invention; Figure 2 It is a cross-sectional view of an anti-fouling and anti-scaling high-pass membrane component in a preferred embodiment of the present invention. DETAILED DESCRIPTION

[0012] The following describes several preferred embodiments of the present invention with reference to the drawings in the specification, so that the technical content is clearer and easier to understand. The present invention can be embodied in many different forms of embodiments, and the protection scope of the present invention is not limited to the embodiments mentioned in the text.

[0013] The anti-fouling and scale-inhibiting high-pass membrane component according to the present invention includes a layer of scale-inhibiting non-woven fabric, which is a new type of scale-inhibiting non-woven fabric having a sustained-release effect after the scale inhibitor fine particles and the non-woven fabric are bonded together.

[0014] The present invention arranges two layers of RO membranes 3 or folds one RO membrane 3 in half, sets two layers of water inlet grids 4 between the two layers of membranes, and sets a layer of novel scale-inhibiting nonwoven fabric obtained by the above method between the two layers of water inlet grids 4, and then rolls them up, which can effectively play an anti-scaling effect.

[0015] The anti-scaling materials include FOF anti-scaling agent, silicon phosphorus crystal powder, etc.

[0016] In a specific embodiment, the scale-inhibiting nonwoven fabric is prepared according to the following steps: (1) Pretreatment of anti-scaling particles The 200-mesh silicon phosphorus crystals and the 120-mesh FOF agent were ultrasonically dispersed in ethanol for 30 minutes. (2) Substrate pretreatment A 5 μm thick epoxy silane coupling agent layer was roller-coated on the surface of the polypropylene non-woven fabric to enhance the adhesion of the slurry.

[0017] (3) Slurry preparation The pretreated 200-mesh 45% silicon-phosphorus crystal, 30% and 120-mesh FOF scale inhibitor, 20% water-based epoxy-modified polyurethane, 3% dispersant and 2% deionized water were mixed and stirred to prepare a slurry. Among them, silicon-phosphorus crystal is a fast scale inhibitor that can quickly neutralize calcium and magnesium ions; FOF is a long-term corrosion inhibitor that can inhibit crystal growth for a long time; water-based epoxy-modified polyurethane is a binder used to fix particles, bond the matrix and form slow-release pores.

[0018] (4) Slurry coating The slurry was evenly coated on the pretreated polypropylene non-woven fabric by a scraper, the coating speed was 10m / min, and the wet film thickness was controlled at 300±20μm.

[0019] (5) Curing and drying The nonwoven fabric coated with the slurry was dried at 120°C for 20 min to allow the slurry to solidify and then cool naturally.

[0020] The reverse osmosis membrane is an anti-fouling hydrophilic membrane, such as a polyamide composite membrane.

[0021] Test data: Conventional RO membrane test record table 1 It can be seen that after producing 1800 liters of pure water, the membrane desalination rate and flow rate have obviously declined seriously.

[0022] The anti-fouling and anti-scaling high-pass membrane according to the present invention: Table 2 It can be seen that after the anti-fouling and anti-scaling high-pass membrane according to the present invention produced 4000 liters of pure water, there was no obvious attenuation of the water production flow rate and the desalination rate.

[0023] The preferred specific embodiments of the present invention are described in detail above. It should be understood that a person skilled in the art can make many modifications and changes based on the concept of the present invention without creative work. Therefore, any technical solution that can be obtained by a person skilled in the art through logical analysis, reasoning or limited experiments based on the concept of the present invention on the basis of the prior art should be within the scope of protection determined by the claims.

Claims

1. A method for preparing an anti-fouling and anti-scaling high-pass membrane module, characterized in that: The following steps are involved: (1) Two RO membranes or a single RO membrane folded in half are used to form a sandwich structure; (2) two layers of water inlet grids are arranged in the RO membrane interlayer, and scale-inhibiting non-woven fabric is laid between the two layers of water inlet grids; (3) Rolling the structure obtained in step (2).

2. The method for preparing an anti-fouling and anti-scaling high-pass membrane module according to claim 1, wherein: The scale-inhibiting nonwoven fabric is prepared by combining scale-inhibiting granular material with polypropylene nonwoven fabric.

3. The method for preparing an anti-fouling and anti-scaling high-pass membrane module according to claim 2, wherein: The antiscaling granular material comprises silicon phosphorus crystal and FOF antiscaling agent.

4. The method for preparing an anti-fouling and anti-scaling high-pass membrane module according to claim 3, wherein: The preparation method of the scale-inhibiting nonwoven fabric comprises the following steps: (1) Pretreatment of anti-scaling particles 200-mesh silicon phosphorus crystals and 120-mesh FOF reagents were ultrasonically dispersed in ethanol for 30 minutes respectively; (2) Substrate pretreatment A 5 μm thick epoxy silane coupling agent layer was roller-coated on the surface of the polypropylene non-woven fabric to enhance the adhesion of the slurry; (3) Slurry preparation The pretreated 200-mesh 45% silicon-phosphorus crystals, 30% and 120-mesh FOF scale inhibitors, 20% water-based epoxy-modified polyurethane, 3% dispersant and 2% deionized water are mixed and stirred to prepare a slurry; wherein the silicon-phosphorus crystals are the main rapid scale inhibitor, which can quickly neutralize calcium and magnesium ions; FOF is a long-term corrosion inhibitor, which can inhibit crystal growth for a long time; the water-based epoxy-modified polyurethane is a binder, which is used to fix particles, bond the matrix and form slow-release pores; (4) Slurry coating The slurry is evenly coated on the pretreated polypropylene non-woven fabric by a scraper, the coating speed is 10m / min, and the wet film thickness is controlled at 300±20μm; (5) Curing and drying The nonwoven fabric coated with the slurry was dried at 120°C for 20 min to allow the slurry to solidify and then cool naturally.

5. The method for preparing an anti-fouling and anti-scaling high-pass membrane module according to claim 1, wherein: The RO membrane is a polyamide composite membrane.

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