Ion mixed membrane assembly and preparation method thereof

Abstract

The invention discloses an ion mixed membrane assembly and a preparation method and relates to the technical field of reverse osmosis membranes. A partition part is arranged in an inner cavity of the water guide pipe and divides the inner cavity of the water guide pipe into a water inlet cavity and a water outlet cavity; a plurality of outflow holes communicated with the water inlet cavity and a plurality of inflow holes communicated with the water outlet cavity are formed in the outer side of the water guide pipe; according to the scheme, the water guide pipe and the membrane structure are improved, and the water guide pipe is divided into the water inlet cavity and the water outlet cavity; a mixing flow channel is formed in the membrane; a divalent salt solution is introduced from the upper end of the water guide pipe, enters the membrane pure water bag from the upper end of the water guide pipe, flows along the glue line direction, enters the lower end of the pure water pipe and is mixed with pure water to be produced, so that the solute content of produced water in the membrane page is increased, the osmotic pressure of the concentrated water side and the pure water side of the membrane page is reduced, and the flux is increased.

Description

Technical Field

[0001] The invention relates to the technical field of reverse osmosis membranes, and in particular to an improvement of an ion mixing membrane component and a preparation method thereof. Background Art

[0002] Water treatment methods include physical treatment and chemical treatment. Humans have been treating water for many years. Physical methods include using filter materials with different pore sizes to remove impurities in the water by adsorption or barrier methods. The most important adsorption method is adsorption with activated carbon, and the barrier method is to pass water through the filter material so that larger impurities cannot pass through, thereby obtaining relatively clean water. Reverse osmosis technology is an emerging high-tech membrane separation technology in recent decades. It uses a highly selective permeable reverse osmosis membrane and uses the reverse osmosis principle of water molecules under pressure to pressurize part of the raw water through a high-pressure pump and pass it through a reverse osmosis membrane to form desalted water. The salts and macromolecular substances in the water will be concentrated on the membrane surface, and the remaining raw water will carry away the concentrated substances along the direction parallel to the membrane to form concentrated water for discharge. This method can achieve a removal rate of 99.5% or even higher for inorganic salts, hardness ions, organic matter, bacteria, etc. in water, and has the advantages of simple operation, low energy consumption, and low pollution.

[0003] Drinking water contains a proper amount of calcium and magnesium ions, which is beneficial to the human body. However, reverse osmosis and nanofiltration membranes have a high interception rate for divalent salt ions. Therefore, there are only very small amounts of calcium and magnesium ions in the produced water. At the same time, a proper amount of calcium and magnesium ions in the produced water can protect the equipment water production pipeline and extend its service life. In response to the above problems, the technical method currently commonly used in the industry is to directly add calcium and magnesium ions to the produced water. The calcium and magnesium ions in the produced water are unevenly distributed. In order to ensure the uniformity of the added ions, additional stirring equipment is required, so the equipment cost increases significantly. Summary of the invention

[0004] In view of the above problems, the present invention provides an ion mixing membrane component and a preparation method for improving the mixing uniformity of calcium and magnesium ions in pure water and reducing equipment costs.

[0005] The technical solution of the present invention is: An ion mixing membrane component, comprising: The water conduit has a partition portion in its inner cavity, which divides the inner cavity of the water conduit into a water inlet cavity and a water outlet cavity; the outer side of the water conduit is provided with a plurality of outflow holes connected to the water inlet cavity and a plurality of inflow holes connected to the water outlet cavity; The diaphragm is provided with multiple pieces, and the front and back sides form a raw water bag and a clean water bag respectively, and the raw water bag and the clean water bag are both installed with a guide net; a glue coating area 1 is provided in the middle of the back of the diaphragm in the clean water bag, and a glue coating area 2 forming a closed loop is provided at the four corners; a spacing is provided between the glue coating area 1 and the glue coating area 2; the water guide pipe is arranged in the clean water bag, and the calcium and magnesium ions flowing out of the water inlet cavity are mixed with the pure water that penetrates into the clean water bag, and flow out through the water outlet cavity.

[0006] Specifically, the membrane is a nanofiltration membrane.

[0007] Specifically, the outer side of the diaphragm is wrapped by a sleeve; A wastewater diversion net is arranged between the envelope and the diaphragm.

[0008] Specifically, the distance between the first glue coating area and the second glue coating area forms a mixing channel.

[0009] Specifically, the width of the first glue coating area is 1-3 cm.

[0010] Specifically, the distance between the first glue coating area and the second glue coating area is 2-3 cm.

[0011] Specifically, the diversion net inside the raw water bag is a wastewater diversion net; The guide net in the water purification bag is a water purification guide net.

[0012] A method for preparing an ion mixing membrane assembly, the preparation steps comprising: Step 1, preparing a casting solution; Step 2, preparing a basement membrane; Step 3, preparing a nanofiltration membrane; The prepared base membrane is sequentially passed through an aqueous solution, an oily solution, an oven 1, a post-treatment water tank and an oven 2 to prepare a nanofiltration membrane sheet; Step 4: membrane assembly rolling; 4.1. Cut the membrane into the set size, fold the membrane surface inward, and place a wastewater diversion net on the folded surface; 4.2. Use glue to stick the center tube and the guide cloth together and lay the guide cloth flat; 4.3. Lay the folded membrane flat on the guide cloth, place the water purification guide net on the membrane, apply glue around the membrane and in the middle area, that is, set the glue coating area 1 (210) and the glue coating area 2 (220) distributed at intervals to form a mixing flow channel; continue to stack several membranes in this way; 4.4. Fix the water pipe on the film rolling machine, start the machine, rotate the water pipe, tighten the diaphragm to the water pipe, so that the diaphragm surrounds the water pipe to form a cylinder, and wrap the side of the cylinder with waterproof tape; The cylinder diameter is 1.8 inches or 3 inches.

[0013] 4.5. After the glue is dry and solidified, trim the edges and insert the Y-shaped sealing ring outside the cylinder.

[0014] Specifically, the method for preparing the casting solution in step 1 includes: adding polyethylene glycol to N,N-dimethylformamide and stirring, and then adding polyethersulfone.

[0015] Specifically, the preparation method of the base film in step 2 includes: using a scraper to evenly coat the casting liquid on the non-woven fabric, then immersing it in water, and then performing cold water phase transformation to form it, and then washing it with hot water to complete the preparation.

[0016] Specifically, the preparation method of the aqueous phase solution in step three is: adding piperazine and sodium hydroxide into water and stirring until completely dissolved; the concentration of piperazine is 0.1-1%, and the concentration of sodium hydroxide is 0.05-0.5%.

[0017] Beneficial effects of the present invention: In this case, the water pipe and the diaphragm structure are improved to separate the water pipe into an inlet chamber and an outlet chamber; a mixing flow channel is formed on the diaphragm; a divalent salt solution is introduced from the upper end of the water pipe, and the divalent salt solution enters the membrane pure water bag from the upper end of the water pipe, flows along the direction of the glue line, enters the lower end of the pure water pipe and mixes with the pure water for output, thereby increasing the solute content of the produced water in the membrane page, reducing the osmotic pressure on the concentrated water side and the pure water side of the membrane page, and increasing the flux.

[0018] This method uses an extremely low water-oil phase concentration, which makes the polypiperazineamide have a looser structure and its water production flow rate can reach 80l / m 2 *h, far exceeding conventional nanofiltration membranes, has a lower interception effect on divalent salt ions, increasing the calcium and magnesium ion content in the produced water. At the same time, the center tube structure and the position of the glue line are optimized so that calcium and magnesium ions can be added into the membrane pure water bag and fully mixed, thereby reducing the osmotic pressure and increasing the flux of the membrane element. And the calcium and magnesium ion content in the produced water meets the use requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic diagram of the three-dimensional structure of the membrane element in its unfolded state. Figure 2 It is a schematic diagram of the water flow direction inside the nanofiltration membrane element; In the figure, 100 is a water pipe, 110 is a partition, 120 is a water inlet cavity, and 130 is a water outlet cavity. 200 is the diaphragm, 210 is the glue coating area 1, 220 is the glue coating area 2, 300 is the envelope, 400 is the wastewater diversion network, 500 is the water purification diversion network. DETAILED DESCRIPTION

[0020] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0021] In the description of the present invention, it should be understood that the terms "upper", "lower", "left", "right", "vertical", "horizontal" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific position, be constructed and operated in a specific position, and therefore cannot be understood as limiting the present invention. In the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0022] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0023] The present invention is described below with reference to Figures 1 and 2; An ion mixing membrane component, comprising: The water conduit 100 has a partition 110 in its inner cavity, which divides the inner cavity of the water conduit 100 into a water inlet cavity 120 and a water outlet cavity 130; the outer side of the water conduit 100 is provided with a plurality of outflow holes connected to the water inlet cavity 120, and a plurality of inflow holes connected to the water outlet cavity 130; The diaphragm 200 is provided with multiple pieces, and the front and back sides form a raw water bag and a clean water bag respectively, and diversion nets are installed in the raw water bag and the clean water bag; a glue coating area 1 210 is provided in the middle of the back of the diaphragm 200 in the clean water bag, and a glue coating area 2 220 forming a closed loop is provided at the four corners; a spacing is provided between the glue coating area 1 210 and the glue coating area 2 220; the water guide pipe 100 is arranged in the clean water bag, and the calcium and magnesium ions flowing out of the water inlet cavity 120 are mixed with the pure water that penetrates into the clean water bag, and flow out through the water outlet cavity 130.

[0024] A membrane assembly consists of multiple membrane sheets, with the membrane surfaces attached to each other; the membrane backs attached to each other, and the membrane surfaces separated by a wastewater diversion net 400 to ensure the flow of raw water; there is a clean water diversion net 500 between the membrane backs to provide a channel for the flow of pure water.

[0025] In this case, the membrane 200 is a nanofiltration membrane.

[0026] The distance between the first glue coating area 210 and the second glue coating area 220 forms a mixing channel.

[0027] The width of the glue coating area 210 is 1-3 cm. The narrower the value is, the better it is without water leakage. The narrower the film, the larger the effective area.

[0028] The distance between the first glue coating area 210 and the second glue coating area 220 is 2-3 cm.

[0029] like Figure 2 As shown, the raw water is filtered through the membrane and then penetrates into the water purification bag. The calcium and magnesium ions flow out from the outflow hole of the water inlet chamber 120, flow in the direction of the arrow, and after being fully mixed, enter the inflow hole, and pure water containing calcium and magnesium ions flows out from the bottom of the water outlet chamber 130.

[0030] A method for preparing an ion mixing membrane assembly comprises: Step 1, preparing a casting solution; The method for preparing the casting solution in step 1 includes: adding polyethylene glycol to N,N-dimethylformamide (DMF) and stirring for ten minutes, and then adding polyethersulfone.

[0031] Specifically, the mixture was stirred in a closed vacuum for 12 hours, the rotation speed was adjusted during the stirring process, and the solution temperature was controlled at about 85°C; after the stirring was completed, the mixture was allowed to stand for degassing and naturally cooled to 30°C. In this case, the molecular weight of polyethylene glycol was 400-6000Da, and the concentration was 5-15%; the concentration of DMF was 83-65%; and the concentration of polyethersulfone was 12-25%.

[0032] Step 2, preparing a basement membrane; The preparation method of the base film in step 2 includes: using a scraper to evenly coat the casting liquid on the non-woven fabric, then immersing it in water, and then performing cold water phase transformation to form it, and then washing it with hot water to complete the preparation.

[0033] In this case, the cold water temperature is 5-20°C, the hot water temperature is 50-70°C, and the base film thickness is 20-50 microns.

[0034] Step 3, preparing a nanofiltration membrane; The prepared base membrane is sequentially passed through an aqueous solution, an oily solution, an oven 1, a post-treatment water tank and an oven 2 to prepare a nanofiltration membrane sheet; Preparation method of aqueous phase solution: add piperazine and sodium hydroxide into water and stir until completely dissolved; the concentration of piperazine is 0.1-1%, and the concentration of sodium hydroxide is 0.05-0.5%.

[0035] Preparation method of oil phase solution: add polyacyl chloride to oil phase solvent and stir until completely dissolved; polyacyl chloride is trimesoyl chloride or diformyl chloride or a mixture of the two, with a concentration of 0.01-0.1%, and the oil phase solvent is ethylcyclohexane or n-hexane.

[0036] In this case, the temperature of oven 1 is 30-80°C, and the temperature of oven 2 is 50-60°C.

[0037] Step 4: membrane assembly rolling; 4.1. Cut the membrane into the set size, fold the membrane surface inward, and place a wastewater diversion net on the folded surface; In this case, the diaphragm cutting size is 270*1060mm, the concentrated water diversion net size is 270*550mm, and the thickness is 17-33mil.

[0038] 4.2. Use glue to stick the center tube and the guide cloth together and lay the guide cloth flat; In this case, the glue is composed of polyurethane glue and curing agent, with a ratio of 100:8 to 100:15; the center tube is 12 inches long and has an outer diameter of 15-20mm.

[0039] 4.3. Lay the folded membrane flat on the guide cloth, place the water purification guide net on the membrane, apply glue around the membrane and in the middle area, that is, set the glue coating area 1 (210) and the glue coating area 2 (220) distributed at intervals to form a mixing flow channel; continue to stack several membranes in this way; The amount of glue used should be as small as possible while ensuring the bonding effect. The general width of the glue line is 1-2cm. The membrane is usually 2-8 pages; the water guide cloth size is 270*510mm, the thickness is 30-35mil; the length of the glue line in the middle area is 45-48cm.

[0040] 4.4. Fix the water pipe on the film rolling machine, start the machine, rotate the water pipe, tighten the diaphragm to the water pipe, so that the diaphragm surrounds the water pipe to form a cylinder, and wrap the side of the cylinder with waterproof tape; The cylinder diameter is 1.8 inches or 3 inches.

[0041] 4.5. After the glue is dried and solidified, trim the edges and cut off 8mm from both ends of the cylinder; and insert a Y-shaped sealing ring outside the cylinder. The Y-shaped sealing ring should be inserted 1.5-5cm away from one end of the cylinder.

[0042] The extremely low water-oil concentration in this case makes the polypiperazineamide have a looser structure, and its water production flow rate can reach 80l / m 2 *h, far exceeding conventional nanofiltration membranes, has a lower interception effect on divalent salt ions, increasing the calcium and magnesium ion content in the produced water. At the same time, the center tube structure and the position of the glue line are optimized so that calcium and magnesium ions can be added into the membrane pure water bag and fully mixed, thereby reducing the osmotic pressure and increasing the flux of the membrane element. And the calcium and magnesium ion content in the produced water meets the use requirements.

[0043] The pressure difference is the driving force for water to pass through the reverse osmosis membrane. The osmotic pressure is the minimum pressure difference required for water to pass through the membrane. Reducing the osmotic pressure can reduce the minimum pressure difference required for water to pass through the membrane. The osmotic pressure is determined by the solute type and concentration on both sides of the membrane. The smaller the solute concentration difference, the smaller the osmotic pressure.

[0044] Regarding the contents disclosed in this case, there are a few points that need to be explained: (1) The drawings of the embodiments disclosed in this case only involve the structures involved in the embodiments disclosed in this case. Other structures can refer to the general design; (2) In the absence of conflict, the embodiments and features of the embodiments disclosed in this case may be combined with each other to obtain new embodiments; The above are only specific implementation methods disclosed in this case, but the protection scope of the present disclosure is not limited thereto. The protection scope disclosed in this case should be based on the protection scope of the claims.

Claims

1. An ion mixing membrane assembly, characterized in that: include: A water conduit (100) is provided with a partition portion (110) in its inner cavity, dividing the inner cavity of the water conduit (100) into a water inlet cavity (120) and a water outlet cavity (130); the outer side of the water conduit (100) is provided with a plurality of outflow holes communicating with the water inlet cavity (120), and a plurality of inflow holes communicating with the water outlet cavity (130); The diaphragm (200) is provided with a plurality of pieces, and the front and back sides respectively form a raw water bag and a purified water bag, wherein the raw water bag and the purified water bag are both provided with a guide net; a first glue coating area (210) is provided in the middle of the back of the diaphragm (200) in the purified water bag, and a second glue coating area (220) forming a closed loop is provided at the four corners; a spacing is provided between the first glue coating area (210) and the second glue coating area (220) to form a mixing flow channel; the water guide pipe (100) is provided in the purified water bag, and the calcium and magnesium ions flowing out of the water inlet chamber (120) are mixed with the pure water that penetrates into the purified water bag and flow out through the water outlet chamber (130).

2. An ion mixing membrane assembly according to claim 1, characterized in that: The membrane (200) is a nanofiltration membrane.

3. An ion mixing membrane assembly according to claim 1, characterized in that: The outer side of the membrane (200) is wrapped by a cover (300).

4. The ion mixing membrane assembly according to claim 1, characterized in that: The width of the glue coating area 1 (210) is 1-3 cm.

5. The ion mixing membrane assembly according to claim 1, characterized in that: The distance between the first glue coating area (210) and the second glue coating area (220) is 2-3 cm.

6. The ion mixing membrane assembly according to claim 1, characterized in that: The diversion net inside the raw water bag is a wastewater diversion net (400); The diversion net in the water purification bag is a water purification diversion net (500).

7. A method for preparing an ion mixing membrane assembly, characterized in that: The steps for preparing an ion mixing membrane assembly according to claim 2 include: Step 1, preparing a casting solution; Step 2, preparing a basement membrane; Step 3, preparing a nanofiltration membrane; The prepared base membrane is sequentially passed through an aqueous solution, an oily solution, an oven 1, a post-treatment water tank and an oven 2 to prepare a nanofiltration membrane sheet; Step 4: membrane assembly rolling; 4.

1. Cut the membrane into the set size, fold the membrane surface inward, and place a wastewater diversion net on the folded surface; 4.

2. Use glue to stick the center tube and the guide cloth together and lay the guide cloth flat; 4.

3. Lay the folded membrane flat on the guide cloth, place the water purification guide net on the membrane, apply glue around the membrane and in the middle area, that is, set the glue coating area 1 (210) and the glue coating area 2 (220) distributed at intervals to form a mixing flow channel; continue to stack several membranes in this way; 4.

4. Fix the water pipe on the film rolling machine, start the machine, rotate the water pipe, tighten the diaphragm to the water pipe, so that the diaphragm surrounds the water pipe to form a cylinder, and wrap the side of the cylinder with waterproof tape; 4.

5. After the glue is dry and solidified, trim the edges and insert the Y-shaped sealing ring outside the cylinder.

8. The method for preparing an ion mixing membrane assembly according to claim 1, characterized in that: The method for preparing the casting solution in step 1 includes: adding polyethylene glycol to N,N-dimethylformamide and stirring, and then adding polyethersulfone.

9. The method for preparing an ion mixing membrane assembly according to claim 1, characterized in that: The preparation method of the base film in step 2 includes: using a scraper to evenly coat the casting liquid on the non-woven fabric, then immersing it in water, and then performing cold water phase transformation to form it, and then washing it with hot water to complete the preparation.

10. The method for preparing an ion mixing membrane assembly according to claim 1, characterized in that: The preparation method of the aqueous phase solution in step 3 is as follows: piperazine and sodium hydroxide are added to water and stirred until completely dissolved; the concentration of piperazine is 0.1-1%, and the concentration of sodium hydroxide is 0.05-0.5%.

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