MFEDI device and method for treating water resources in karst region through MFEDI device

Abstract

The invention relates to the field of water resource treatment, in particular to an MFEDI device and a method for treating water resources in the karst region through the MFEDI device.A main body of the MFEDI device comprises a shell and an upper top cover, and the shell and the upper top cover are connected in a sealed mode; the upper top cover is provided with an upper interface and a ventilation valve; a treatment assembly is arranged in the shell and comprises an upper porous pressing plate, an upper electrode, an ion exchange resin layer, a conductive diatomite layer, a lower electrode and a lower porous pressing plate which are sequentially mounted in the shell from top to bottom; the bottom of the shell is provided with a lower connector, an air outlet and a water outlet. A screw rod penetrates through the upper porous pressing plate, the upper electrode, the ion exchange resin layer, the conductive diatomite layer, the lower electrode and the lower porous pressing plate; and the upper electrode and the lower electrode are connected with a direct-current power supply through a cable sealing joint after being respectively connected with leads. The MFEDI device is more stable after being used for a long time, and the defects that ion exchange resin is not tight and particles are prone to being broken due to the fact that an ion exchange resin layer is filled conventionally can be overcome.

Description

Technical Field

[0001] This invention relates to the field of water resource treatment, and in particular to an MFEDI device and a method for treating water resources in karst areas using the MFEDI device. Background Technology

[0002] Water scarcity and pollution have become global challenges. Dissolved ionic pollutants (such as heavy metals, calcium and magnesium salts, and nitrates) in industrial wastewater are particularly difficult to remove effectively through traditional physical filtration. While ion exchange resins can selectively adsorb ions, they suffer from frequent chemical regeneration, resin clogging, and concentrated wastewater discharge. Reverse osmosis (RO) technology, though widely used, suffers from a 25%-40% concentrated wastewater discharge rate, exacerbating water waste and environmental pressure. Furthermore, it is characterized by high energy consumption and membrane fouling. Against this backdrop, electro-driven ion separation technology has become a research hotspot due to its advantages such as no need for chemical regeneration and low carbon footprint. MFEDI technology, as an innovative branch of electro-deionization (EDI), achieves its core breakthrough by eliminating the ion exchange membrane and realizing efficient desalination through the synergistic effect of electrodes and resins. Its principle is based on the dynamic balance between capacitive adsorption and electro-regeneration: after applying a DC electric field, the active groups on the surface of the cation exchange resin (such as phosphonic acid-based resin) selectively adsorb cations (such as calcium ions) from the water. 2+ Ni 2+ ), while OH generated at the cathode - Ion-triggered adsorption and desorption enable in-situ regeneration of the resin. Compared to traditional EDI, MFEDI eliminates the need for expensive ion exchange membrane modules, avoids the risks of membrane fouling and rupture, and significantly reduces system costs.

[0003] Currently, MFEDI technology has been applied in fields such as high-purity water preparation, near-zero discharge of industrial wastewater, and heavy metal resource recovery. With the deepening of intelligent control and green processes, MFEDI is driving water resource treatment towards low-carbon, low-cost, and high-efficiency development. At present, research and development on MFEDI is increasing, and most of it focuses on equipment improvements.

[0004] For example, CN111422950B discloses a "structure of a membrane-free electro-deionization device". The device includes a composite top cover, a composite bottom cover, a cylindrical shell and an ion exchange resin layer. The composite top cover and composite bottom cover can uniformly compress the resin layer, and the upper and lower resin particles always maintain close contact, effectively reducing the unfavorable water flow distribution of the resin layer, effectively ensuring good resin regeneration, simplifying the structure and making installation and maintenance convenient.

[0005] For example, CN118978234A discloses "an apparatus for preparing high-purity water using membrane-free electro-deionization technology", which includes a power supply and a housing. The housing contains a first porous plate, an anode plate, a cathode plate, a second porous plate, and cation exchange resin and anion exchange resin disposed between the anode plate and the cathode plate. This apparatus can regenerate the ion exchange resin and has a low cost.

[0006] However, the aging of ion exchange resins is a problem that needs to be considered. The aforementioned published patents do not mention or solve this problem. In addition, karst aquifers are special aquifers in karst regions with highly variable water abundance, uneven distribution of groundwater, and diverse and complex flow patterns. Due to erosion, a large amount of limestone suspended matter exists in the aquifer. Furthermore, karst water is rich in carbon dioxide, which can convert water-insoluble calcium carbonate into calcium carbonate, which dissolves in water. This results in high alkalinity, calcium ions, and other minerals in the water of karst regions. In order to rationally develop and utilize water resources in the southwestern karst region, it is urgent to develop an MFEDI device and water purification method that can be used for a long time and has high purification efficiency. Summary of the Invention

[0007] The purpose of this invention is to provide an MFEDI device and a method for treating water resources in karst areas using an MFEDI device, in order to solve the problems that current MFEDI devices experience aging during long-term use, leading to a decline in purification performance and loose contact of the ion exchange resin layer.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: This invention provides an MFEDI device, the main body of which includes a shell and an upper cover, the shell and the upper cover being sealed together; the upper cover has an upper interface and a vent valve; the shell contains a processing assembly, which includes, from top to bottom, an upper porous plate, an upper electrode, an ion exchange resin layer, a conductive diatomaceous earth layer, a lower electrode, and a lower porous plate installed inside the shell; the bottom of the shell has a lower interface, a vent, and a drain; a screw passes through the upper porous plate, the upper electrode, the ion exchange resin layer, the conductive diatomaceous earth layer, the lower electrode, and the lower porous plate; the lower porous plate is fixedly connected to the screw; the upper electrode and the lower electrode are connected to a DC power supply.

[0009] In some embodiments, the outer casing and the top cover are sealed together by a sealing ring.

[0010] In some embodiments, the top cover also includes a cable sealing connector.

[0011] In some embodiments, the upper perforated pressure plate is fixed by a limiting block.

[0012] In some embodiments, the ion exchange resin layer is filled by uniformly mixing anion and cation exchange resins; or, different proportions or different types of anion and cation exchange resins are uniformly mixed and then filled in multiple layers; or, multiple layers are filled by alternating cation exchange resins and anion exchange resins; or, multiple layers are filled by alternating uniformly mixed anion and cation exchange resins, anion exchange resins or cation exchange resins, uniformly mixed anion and cation exchange resins, anion exchange resins or cation exchange resins, wherein the uniformly mixed anion and cation exchange resins are composed of uniformly mixed anion and cation exchange resins.

[0013] In some embodiments, the cation exchange resin is one or more of the following: D001 macroporous cation exchange resin, DOWEX DR2030 cation exchange resin, CH-01 type acidic cation exchange resin, Purolite C100EDL8 resin, and UBK530 ion exchange resin.

[0014] In some embodiments, the method for preparing the anion exchange resin includes the following steps: S1. Under an inert protective gas atmosphere, styrene, DVB, 1-chloro-2-butene, 2-vinylnaphthalene, deionized water, and surfactant are mixed and heated to 80-90°C. Then, an initiator is added and the reaction is carried out for 5-7 hours. The product is washed three times with hot water, acetone, and deionized water, respectively, and then vacuum dried at 50-60°C for 26-30 hours to obtain the ion exchange resin matrix. S2. The ion exchange resin matrix obtained in step S1 is added to anhydrous ethanol, followed by the addition of imidazole compounds. The mixture is heated to reflux and stirred for 10-15 hours. After the stirring is complete, 2,2,6,6-tetramethylpiperidinamine and an acid-binding agent are added, and stirring is continued for 4-6 hours. After the stirring is complete, the mixture is washed three times with diethyl ether and deionized water, and then vacuum dried at 50-60°C for 24-28 hours to obtain anion exchange resin.

[0015] The anion exchange resin of this application has good high temperature resistance and aging resistance. This may be because the anion exchange resin contains a large number of phenyl groups in its structure, which can form a π-π stacking effect, thus improving the high temperature resistance of the anion exchange resin. At the same time, the presence of a large number of hindered amine structures in its structure improves the anti-photoaging effect of the anion exchange resin and reduces the storage conditions of the ion exchange resin.

[0016] In some embodiments, the mass ratio of styrene, DVB, 2-vinylnaphthalene, and 1-chloro-2-butene is 1:(0.1~0.3):(0.2~0.4):(0.2~0.5).

[0017] In some embodiments, the molar ratio of the 1-chloro-2-butene, the imidazole compound, and 2,2,6,6-tetramethylpiperidineamine is 1:(0.4~0.6):(0.4~0.6).

[0018] In some embodiments, the initiator is one or more of benzoyl peroxide, azobisisobutyronitrile, and persulfate.

[0019] In some embodiments, the surfactant is one or more of hexadecyltrimethylammonium bromide and / or sodium dodecyl sulfate.

[0020] In some embodiments, the amount of the surfactant is 0.01 to 0.02 times the mass of styrene.

[0021] In some embodiments, the acid-binding agent is one or more of sodium bicarbonate, potassium bicarbonate, sodium carbonate, and potassium carbonate.

[0022] In some embodiments, the molar ratio of the acid-binding agent to 1-chloro-2-butene is (1.5~1.8):1.

[0023] In some embodiments, the imidazole compound is N-methylimidazole and / or 1-ethylimidazole.

[0024] This application does not impose any special limitation on the conductive diatomaceous earth for the conductive diatomaceous earth layer, and it can be prepared with reference to existing technologies, including but not limited to preparation with reference to CN104140095A.

[0025] In some embodiments, the upper and lower electrodes have different polarities.

[0026] In some embodiments, the thickness of the conductive diatomaceous earth layer is 50-100 mm.

[0027] In some embodiments, the thickness of the ion exchange resin layer is 350~450 mm.

[0028] Another aspect of the present invention provides a method for treating water resources in karst areas, using the aforementioned MFEDI device, comprising the following steps: firstly, a conductive diatomaceous earth layer is spread on the surface of the lower electrode and vibrated to level it; then, an ion exchange resin layer is slowly filled on top of the conductive diatomaceous earth layer and vibrated to level it; the ventilation valve is opened, the valve of the upper interface is closed, the air outlet is opened, and the lower interface and drain outlet are closed; nitrogen gas is slowly and continuously introduced until the height of the ion exchange resin layer no longer changes; after the gas pressure returns to normal pressure, the upper electrode and the upper porous pressure plate are placed in sequence, and then fixed with a limiting block; the ventilation valve and the air outlet are closed, at which point the MFEDI device is completed. The method for treating water resources in karst areas is divided into a treatment stage and an electroregeneration stage; the treatment stage and the electroregeneration stage are carried out alternately during the treatment process.

[0029] In conventional MFEDI devices, ion exchange resins are squeezed together by two porous plates under the action of springs to make the resins more tightly contacted. However, this method results in uneven force distribution, and the ion exchange resins at both ends are prone to particle structure damage, leading to defects.

[0030] This application uses nitrogen pressurization to not only make the resin layer more uniformly stressed, but also to avoid damaging the particle structure of the ion exchange resin under stress, thus making the ion exchange resin more stable during use.

[0031] In some embodiments, the processing stage includes the following operations: opening the upper interface, the water collection valve and the lower interface, closing the water supply valve and the drain outlet, introducing water resources from the karst region through the lower interface, allowing sewage to flow from bottom to top through the processing components, and collecting the purified water from the water collection valve. The electro-regeneration stage includes the following operations: opening the upper interface, drain outlet, and water supply valve; closing the water collection valve and lower interface; introducing high-purity water through the water supply valve; allowing the high-purity water to flow from top to bottom through the processing component; simultaneously connecting the upper electrode and lower electrode to a high-voltage DC power supply; and discharging impurity water from the drain outlet.

[0032] Compared with the prior art, the present invention has the following beneficial effects: (1) The anion exchange resin of the present invention uses styrene and DVB as raw materials, and co-polymerizes with 2-vinylnaphthalene and 1-chloro-2-butene to obtain an ion exchange resin matrix with active halogenated groups. Subsequently, the ion exchange resin matrix is ​​substituted and quaternized to obtain an anion exchange resin with good high temperature resistance and anti-aging properties. The reason may be that the structure of the anion exchange resin contains a large number of phenyl groups, which can form a π-π stacking effect, improving the high temperature resistance of the anion exchange resin. At the same time, the structure contains a large number of hindered amine structures, which improves the anti-photoaging effect of the anion exchange resin and reduces the storage conditions of the ion exchange resin.

[0033] (2) The MFEDI device of the present invention abandons the conventional method of squeezing ion exchange resin by two multi-hole pressure plates, and uses nitrogen pressure to make the ion exchange resin more compact, thus avoiding stress-induced ion exchange resin particle breakage and defects.

[0034] (3) In this invention, a layer of conductive diatomaceous earth is laid on the surface of the lower electrode. Since there are a large number of tiny particulate impurities in the wastewater resources, the pores of the ion exchange resin will be blocked by tiny particles during long-term use, resulting in a decrease in purification rate, accelerated aging of the ion exchange resin and reduced lifespan. In this invention, the conductive diatomaceous earth adsorbs fine particles, which can keep the ion exchange resin recyclable and reduce maintenance costs. At the same time, the conductive diatomaceous earth can avoid the fact that conventional diatomaceous earth is non-conductive and cannot restore the ion exchange capacity of the ion exchange resin through electric regeneration. Attached Figure Description

[0035] Figure 1 These are schematic diagrams of the MFEDI device structures in Embodiments 1 and 2 of the present invention; In the diagram: 1. Upper interface; 2. Vent valve; 3. Cable sealing joint; 4. Upper top cover; 5. Sealing ring; 6. Limiting block; 7. Upper perforated pressure plate; 8. Upper electrode; 9. Screw; 10. Conductive diatomaceous earth layer; 11. Lower electrode; 12. Lower perforated pressure plate; 13. Lower interface; 14. Air outlet; 15. Drain outlet; 16. Ion exchange resin layer; 17. Outer shell; 18. Water supply valve; 19. Water collection valve. Detailed Implementation

[0036] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0037] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0038] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of the invention. Various modifications and variations to the specific embodiments described in this specification are apparent to those skilled in the art without departing from the scope or spirit of the invention. Other embodiments derived from this specification will be apparent to those skilled in the art. This application specification and embodiments are merely exemplary.

[0039] Unless otherwise specified, the post-processing operations such as "washing", "drying", and "vacuum" described below can be selected by those skilled in the art based on actual conditions, and are not further limited.

[0040] Preparation Example 1 A method for preparing an anti-aging modified anion exchange resin includes the following steps: S1. Under a N2 atmosphere, 10g styrene, 2g DVB, 3.5g 1-chloro-2-butene, 3g 2-vinylnaphthalene, 60g deionized water, and 0.1g cetyltrimethylammonium bromide were mixed and heated to 85°C. Then, 0.05g benzoyl peroxide was added and reacted for 6h. The product was washed three times each with hot water, acetone, and deionized water, and then vacuum dried at 55°C for 29h to obtain the ion exchange resin matrix. S2. The ion exchange resin matrix obtained in step S1 was added to 300 ml of anhydrous ethanol, followed by 1.6 g of N-methylimidazole. The mixture was heated to reflux and stirred for 13 h. After the reflux was completed, 6 g of 2,2,6,6-tetramethylpiperidinamine and 5.2 g of sodium bicarbonate were added, and the mixture was stirred for another 5 h. After the reflux was completed, the mixture was washed three times with diethyl ether and three times with deionized water. The mixture was then vacuum dried at 55 °C for 26 h to obtain the anti-aging modified anion exchange resin.

[0041] Example 1 See Figure 1 An MFEDI device is disclosed, the main body of which includes a housing 17 and an upper cover 4, the housing 17 and the upper cover 4 being sealed together by a sealing ring 5; the upper cover 4 has an upper interface 1, a vent valve 2 and a cable sealing connector 3; a processing assembly is provided inside the housing 17, the processing assembly including, from top to bottom, an upper porous pressure plate 7, an upper electrode 8, an ion exchange resin layer 16, a conductive diatomaceous earth layer 10, a lower electrode 11 and a lower porous pressure plate installed inside the housing 17. 12; The bottom of the outer shell 17 has a lower interface 13, an air outlet 14 and a drain outlet 15; the screw 9 passes through the upper porous pressure plate 7, the upper electrode 8, the ion exchange resin layer 16, the conductive diatomaceous earth layer 10, the lower electrode 11 and the lower porous pressure plate 12; the lower porous pressure plate 12 and the screw 9 are fixedly connected; the upper electrode 8 and the lower electrode 11 are respectively connected to wires and then connected to a DC power supply through a cable sealing connector 3; the upper porous pressure plate 7 is fixed by a limiting block 6; the upper electrode 8 is the anode and the lower electrode 11 is the cathode.

[0042] Example 2 See Figure 1A method for treating water resources in karst areas using an MFEDI device includes the following steps: First, a conductive diatomaceous earth layer 10 is spread on the surface of the lower electrode 11 in the MFEDI device and leveled by vibration to a thickness of 70 mm. Then, an ion exchange resin layer 16 is slowly filled on top of the conductive diatomaceous earth layer 10 and leveled by vibration to a thickness of 400 mm. The ventilation valve 2 is opened, the valve of the upper interface 1 is closed, the air outlet 14 is opened, and the lower interface 13 and the drain outlet 15 are closed. Nitrogen gas is slowly and continuously introduced until the height of the ion exchange resin layer 16 no longer changes. After the gas pressure returns to normal, the upper electrode 8 and the upper porous pressure plate 7 are placed in sequence and then fixed with the limiting block 6. The ventilation valve 2 and the air outlet 14 are closed. At this time, the MFEDI device is filled. The processing stage includes the following operations: opening the upper interface 1, the water collection valve 19 and the lower interface 13, closing the water supply valve 18 and the drain outlet 15, introducing water resources from a certain place in the karst area through the lower interface 13, and the sewage flowing from bottom to top through the processing components, and the purified pure water flowing out from the water collection valve 19 for collection. The electro-regeneration stage includes the following operations: opening the upper interface 1, drain outlet 15 and water supply valve 18, closing the water collection valve 19 and lower interface 13, introducing high-purity water through the water supply valve 18, and allowing the high-purity water to flow from top to bottom through the processing component. At the same time, connecting the upper electrode 8 and lower electrode 11 to a high-voltage DC power supply, and discharging impurity water from the drain outlet 15.

[0043] The treatment stage and the electro-regeneration stage were alternated 5 times; the MFEDI device was prepared according to Example 1; the ion exchange resin layer 16 was filled by uniformly mixing Purolite resin C100EDL8 and anion exchange resin at a mass ratio of 1:1; the anion exchange resin was prepared according to Preparation Example 1; the conductive diatomite in the conductive diatomite layer was prepared according to CN104140095A.

[0044] The processing components used in this embodiment are the same as those in Embodiment 1.

[0045] For the pretreatment of Purolite C100EDL8 resin and anion exchange resin, refer to Section 2.4.1 of the paper "Preparation of a medium-strong basicity value and its application in MFEDI".

[0046] Comparative Example 1 A method for treating water resources in karst areas using an MFEDI device is described. The specific implementation method is the same as in Example 1, except that a compression method using springs at both ends is used instead of nitrogen pressurization to make the ion exchange resin layer compact.

[0047] Performance testing: (1) Thermal stability test: The thermal degradation rate was tested according to DL / T953-2018 "Determination of heat resistance and antioxidant properties of strong basic anion exchange resin for water treatment".

[0048] (2) Anti-aging test: The ion exchange resin was placed under a xenon lamp light source (humidity 50%, light intensity 550W / m). 2 After aging for 300 hours, the initial crushing strength and the crushing strength after aging of the ion exchange resin were tested according to DL / T 771-2014 "Guidelines for the Selection of Ion Exchange Resins for Water Treatment in Power Plants".

[0049] (3) Exchange capacity test: Prepare 200 mL of DSD sodium solution with a concentration of 1000 mg / L and pH = 7 (DSD is also known as 4,4-dimethylformamide). Diaminostilbene-2,2-disulfonic acid was added to 0.1 g of dry anion exchange resin and the mixture was shaken at 25 °C for 24 h at a shaking frequency of 150 rpm until adsorption equilibrium was reached. The concentration of the remaining sodium disulfate in the solution was determined by HPLC, and the adsorption capacity was calculated.

[0050] The anion exchange resins prepared in the example were tested according to the above method, and the test results are shown in Table 1.

[0051] Table 1 According to the data in Table 1, the anion exchange resin prepared in Example 1 has good heat resistance, crushing strength, resistance to light aging and adsorption capacity.

[0052] (4) The conductivity of water resources and produced water at a certain location in the karst area was measured using an online conductivity meter and a portable conductivity meter. The test results are shown in Table 2.

[0053] Table 2 According to the data analysis in Table 2, the MFEDI device of this application produces water with good quality. However, the replacement of nitrogen pressurization with the compression method using springs at both ends results in the middle part of the ion exchange resin layer not being tightly filled and the ion exchange resin particles at the top and bottom being prone to breakage, which leads to a decline in the quality of the produced water.

[0054] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. An MFEDI device, characterized in that, The main body of the MFEDI device includes a shell (17) and an upper cover (4), which are sealed together. The upper cover (4) has an upper interface (1) and a vent valve (2). The shell (17) is equipped with a processing assembly, which includes, from top to bottom, an upper porous pressure plate (7), an upper electrode (8), an ion exchange resin layer (16), a conductive diatomaceous earth layer (10), and a lower electrode (8), all installed inside the shell (17). 11) Lower porous pressure plate (12); The bottom of the outer shell (17) is equipped with a lower interface (13), an air outlet (14) and a drain outlet (15); The screw (9) passes through the upper porous pressure plate (7), the upper electrode (8), the ion exchange resin layer (16), the conductive diatomaceous earth layer (10), the lower electrode (11) and the lower porous pressure plate (12); The lower porous pressure plate (12) and the screw (9) are fixedly connected; The upper electrode (8) and the lower electrode (11) are connected to a DC power supply.

2. The MFEDI device according to claim 1, characterized in that, The upper perforated pressure plate (7) is fixed by a limiting block (6).

3. The MFEDI device according to claim 1, characterized in that, The ion exchange resin layer (16) is filled by uniformly mixing anion and cation exchange resins; Alternatively, different proportions or types of anion and cation exchange resins can be uniformly mixed and then packed in multiple layers. Alternatively, multiple layers can be filled using alternating cation exchange resins and anion exchange resins. Alternatively, it may be filled in multiple layers using alternating layers of uniformly mixed cation and anion exchange resins, or anion exchange resins or cation exchange resins, wherein the uniformly mixed cation and anion exchange resin is composed of uniformly mixed cation and anion exchange resins.

4. An MFEDI device according to claim 3, characterized in that, The cation exchange resin is one or more of the following: D001 macroporous cation exchange resin, DOWEX DR 2030 cation exchange resin, CH-01 type acidic cation exchange resin, Purolite resin C100EDL8, and UBK530 ion exchange resin.

5. An MFEDI device according to claim 3, characterized in that, The preparation method of the anion exchange resin includes the following steps: S1. Under an inert protective gas atmosphere, styrene, DVB, 1-chloro-2-butene, 2-vinylnaphthalene, deionized water, and surfactant are mixed and heated to 80-90°C. Then, an initiator is added and the reaction is carried out for 5-7 hours. The product is washed three times with hot water, acetone, and deionized water, respectively, and then vacuum dried at 50-60°C for 26-30 hours to obtain the ion exchange resin matrix. S2. The ion exchange resin matrix obtained in step S1 is added to anhydrous ethanol, followed by the addition of imidazole compounds. The mixture is heated to reflux and stirred for 10-15 hours. After the stirring is complete, 2,2,6,6-tetramethylpiperidinamine and an acid-binding agent are added, and stirring is continued for 4-6 hours. After the stirring is complete, the mixture is washed three times with ether and three times with deionized water, and then vacuum dried at 50-60°C for 24-28 hours to obtain an anti-aging modified anion exchange resin.

6. An MFEDI device according to claim 1, characterized in that, The upper electrode (8) and the lower electrode (11) have different polarities.

7. An MFEDI device according to claim 1, characterized in that, The thickness of the conductive diatomaceous earth layer (10) is 50~100mm.

8. An MFEDI device according to claim 1, characterized in that, The thickness of the ion exchange resin layer (16) is 350~450mm.

9. A method for treating water resources in karst areas using an MFEDI device, characterized in that, The MFEDI device according to any one of claims 1 to 8 includes the following steps: First, a conductive diatomaceous earth layer (10) is spread on the surface of the lower electrode (11) and leveled by vibration. Then, an ion exchange resin layer (16) is slowly filled on top of the conductive diatomaceous earth layer (10) and leveled by vibration. The ventilation valve (2) is opened, the valve of the upper interface (1) is closed, the outlet (14) is opened, the lower interface (13) and the drain (15) are closed, and nitrogen gas is slowly and continuously introduced until the height of the ion exchange resin layer (16) no longer changes. After the gas pressure returns to normal pressure, the upper electrode (8) and the upper porous pressure plate (7) are placed in sequence and then fixed with the limiting block (6). The ventilation valve (2) and the outlet (14) are closed. At this time, the MFEDI device is filled. The method for treating water resources in karst areas is divided into a treatment stage and an electroregeneration stage; the treatment stage and the electroregeneration stage are carried out alternately during the treatment process.

10. A method for treating water resources in karst areas using an MFEDI device according to claim 9, characterized in that, The processing stage includes the following operations: opening the upper interface (1), water collection valve (19) and lower interface (13), closing the water supply valve (18) and drain outlet (15), introducing water resources from the karst region through the lower interface (13), and allowing sewage to flow from bottom to top through the processing components. The purified pure water flows out from the water collection valve (19) and is collected. The electro-regeneration stage includes the following operations: opening the upper interface (1), drain outlet (15) and water supply valve (18), closing the water collection valve (19) and lower interface (13), introducing high-purity water through the water supply valve (18), and the high-purity water passing through the processing component from top to bottom. At the same time, connecting the upper electrode (8) and lower electrode (11) to a high-voltage DC power supply, and discharging impurity water from the drain outlet (15).

Images