A double electric field conductive membrane filtering device

Abstract

The present invention discloses a dual electric field conductive membrane filtration device, which belongs to the technical field of filtration equipment and can solve the problems that the existing filtration device has poor removal effect on pollutants and the filter membrane needs to be frequently replaced. The device comprises: a conductive filter element, which comprises a hollow filter cotton filter element and a first conductive adsorption layer formed on the surface of the filter cotton filter element; a conductive ultrafiltration membrane, which is arranged in a ring shape in the hollow area of ​​the filter cotton filter element, and comprises an organic membrane and a second conductive adsorption layer formed on the surface of the organic membrane; a hollow graphite rod, which is arranged on the inner side of the conductive ultrafiltration membrane and has a plurality of micropores thereon; a power source, which has a first positive electrode connection end, a second positive electrode connection end and a negative electrode connection end, the first positive electrode connection end is connected to the conductive filter element, the second positive electrode connection end is connected to the hollow graphite rod, and the negative electrode connection end is connected to the conductive ultrafiltration membrane. The present invention is used for water filtration.

Description

Technical Field

[0001] The invention relates to a double electric field conductive membrane filtering device, belonging to the technical field of filtering equipment. Background Art

[0002] With the rapid development of industry and the continuous improvement of people's living standards, environmental pollution problems are becoming increasingly serious, especially water pollution has become the focus of global attention. Water contains various harmful substances, such as heavy metal ions, organic pollutants, microorganisms, etc. These pollutants not only pose a threat to human health, but also cause great damage to the ecological environment. In order to obtain clean and safe water resources, efficient filtration devices have become an urgent need.

[0003] Traditional filtration methods often have certain limitations when dealing with complex water pollution situations. For example, sand filtration and activated carbon adsorption can only remove larger particles and some organic matter in the water, but have poor removal effects on tiny particles, harmful substances dissolved in water, and microorganisms such as bacteria and viruses. Although chemical treatment methods can remove some specific pollutants, they may introduce new chemicals and pose a risk of secondary pollution. In addition, existing filtration devices also have certain problems in terms of energy consumption and maintenance costs. Some filtration devices require a lot of energy to drive, which increases operating costs. Moreover, the frequent replacement and maintenance of filtration devices also bring inconvenience and economic burden to users. Summary of the invention

[0004] The invention provides a dual electric field conductive membrane filtering device, which can solve the problems that the existing filtering device has a poor pollutant removal effect and the filtering membrane needs to be frequently replaced.

[0005] The present invention provides a dual electric field conductive membrane filtering device, the device comprising:

[0006] A conductive filter element, comprising a hollow filter cotton filter element and a first conductive adsorption layer formed on the surface of the filter cotton filter element;

[0007] A conductive ultrafiltration membrane is arranged in a ring shape in the hollow area of ​​the filter cotton filter element, and comprises an organic membrane and a second conductive adsorption layer formed on the surface of the organic membrane;

[0008] A hollow graphite rod, arranged on the inner side of the conductive ultrafiltration membrane, and having a plurality of micropores;

[0009] The power source has a first positive connection end, a second positive connection end and a negative connection end, wherein the first positive connection end is connected to the conductive filter element, the second positive connection end is connected to the hollow graphite rod, and the negative connection end is connected to the conductive ultrafiltration membrane.

[0010] Optionally, the filter cotton filter element includes a hollow porous support column and filter cotton coated on the outer side wall of the porous support column, and the first conductive adsorption layer is formed on the surface of the filter cotton.

[0011] Optionally, the first conductive adsorption layer is formed by interfacial polymerization reaction between thiophene and the filter cotton.

[0012] Optionally, the second conductive adsorption layer is formed by interfacial polymerization of thiophene and the organic film.

[0013] Optionally, central axes of the conductive filter element, the conductive ultrafiltration membrane and the hollow graphite rod coincide with each other.

[0014] Optionally, the pore size of the micropores is 10 μm to 20 μm.

[0015] Optionally, the filter cotton is PP cotton.

[0016] Optionally, the organic membrane is a PVDF membrane.

[0017] Optionally, the power supply voltage is 0.5V~2V.

[0018] Optionally, the porous support column is a porous polyethylene or polyvinyl chloride cylinder.

[0019] The beneficial effects that the present invention can produce include:

[0020] The dual electric field conductive membrane filtration device provided by the present invention is provided with a conductive filter element, a conductive ultrafiltration membrane and a hollow graphite rod which are sequentially arranged, and an electric field is formed between the conductive filter element of the outer layer and the conductive ultrafiltration membrane of the middle layer, and an electric field is formed between the hollow graphite rod of the inner layer and the conductive ultrafiltration membrane of the middle layer. The raw water first enters the positively charged conductive filter element, and under the action of the electric field, the particles in the raw water are absorbed by the filter cotton in the conductive filter element, and at the same time, the thiophene composite improved filter cotton can enhance the adsorption effect. After the water flows through the conductive filter element, it enters the conductive ultrafiltration membrane, and the negatively charged conductive ultrafiltration membrane has a repulsive effect on the negatively charged particles under the action of the electric field. After the water passes through the surface of the conductive ultrafiltration membrane, the positively charged multi-microporous hollow graphite rod adsorbs the negatively charged particles again. The dual electric field action promotes the migration of ions in the water, improves the filtration efficiency, avoids the accumulation of impurities on the membrane surface, enhances the water treatment effect, and increases the service life of the membrane. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A schematic structural diagram of a dual electric field conductive membrane filtration device provided in an embodiment of the present invention.

[0022] Reference numerals:

[0023] 1. Hollow graphite rod; 2. Conductive ultrafiltration membrane; 3. Conductive filter element; 4. Power supply. DETAILED DESCRIPTION

[0024] The present invention is described in detail below in conjunction with embodiments, but the present invention is not limited to these embodiments.

[0025] The embodiment of the present invention provides a dual electric field conductive membrane filtering device, such as Figure 1 As shown, the device comprises:

[0026] The conductive filter element 3 comprises a hollow filter cotton filter element and a first conductive adsorption layer formed on the surface of the filter cotton filter element.

[0027] The filter cotton filter element includes a hollow porous support column and filter cotton coated on the outer side wall of the porous support column, and the first conductive adsorption layer is formed on the surface of the filter cotton.

[0028] Specifically, the first conductive adsorption layer is formed by interfacial polymerization of thiophene and filter cotton.

[0029] In practical applications, the filter cotton can be PP cotton or polyester fiber cotton, etc., which is not limited in the embodiment of the present invention. The porous support column is a porous polyethylene or polyvinyl chloride cylinder.

[0030] The conductive ultrafiltration membrane 2 is arranged in a ring shape in the hollow area of ​​the filter cotton filter element, and comprises an organic membrane and a second conductive adsorption layer formed on the surface of the organic membrane.

[0031] Specifically, the second conductive adsorption layer is formed by interfacial polymerization of thiophene and an organic film.

[0032] In practical applications, the organic membrane may be a PVDF membrane or polysulfone, etc., which is not limited in the embodiment of the present invention.

[0033] The hollow graphite rod 1 is arranged on the inner side of the conductive ultrafiltration membrane 2 and has a plurality of micropores.

[0034] In practical applications, the pore size of the micropores can be 10 μm to 20 μm.

[0035] The power source 4 has a first positive connection end, a second positive connection end and a negative connection end, the first positive connection end is connected to the conductive filter element 3, the second positive connection end is connected to the hollow graphite rod 1, and the negative connection end is connected to the conductive ultrafiltration membrane 2.

[0036] In practical applications, the voltage of the power supply 4 can be 0.5V~2V.

[0037] In the embodiment of the present invention, the central axes of the conductive filter element 3, the conductive ultrafiltration membrane 2 and the hollow graphite rod 1 coincide with each other.

[0038] refer to Figure 1As shown, the filter cotton filter element is subjected to interfacial polymerization treatment with thiophene, and the support of the filter cotton filter element can be a porous polyethylene (PE) or polyvinyl chloride (PVC) cylinder. The middle layer is a conductive ultrafiltration membrane 2. Under chemical action, thiophene interfacial polymerization reaction is used on the surface of the organic membrane to generate a conductive polythiophene layer (i.e., the second conductive adsorption layer), which is installed in a roll-type membrane manner. The inner layer is a microporous hollow graphite rod 1. The first positive connection end of the power supply 4 is connected to the conductive filter element 3, and the negative connection end is connected to the conductive ultrafiltration membrane 2 to form an electric field. The second positive connection end of the power supply 4 is connected to the microporous hollow graphite rod 1 in the inner layer, and an electric field is formed between the conductive ultrafiltration membrane 2. The raw water enters the conductive filter element 3 from both sides, passes through the conductive filter element 3, the conductive ultrafiltration membrane 2, and the microporous hollow graphite rod 1 in sequence, and then produces water and flows out from the bottom of the hollow graphite rod 1.

[0039] In practical applications, the diameter of the conductive filter element 3 can be set to 40cm~60cm, and the length is 60cm~80cm. The diameter of the middle rolled conductive ultrafiltration membrane 2 is 30cm~50cm, and the length is 60cm~80cm. The diameter of the inner layer multi-porous hollow graphite rod 1 is 10cm~30cm, and the length is 60cm~80cm.

[0040] Taking the organic membrane of the conductive ultrafiltration membrane 2 as a PVDF membrane as an example, a method for preparing a conductive ultrafiltration membrane 2 is provided, which specifically includes the following steps:

[0041] Step 1: Prepare PVDF membrane.

[0042] Step 1.1, 65% to 70% by mass of dimethylacetamide (DMAC), 15% to 20% by mass of polyvinylidene fluoride (PVDF) and 10% to 20% by mass of polyvinyl pyrrolidone (PVP) are mixed evenly, and stirred for 10 h to 12 h in an oil bath at 60°C to obtain a uniform casting solution. Let stand for 8 h to 12 h for degassing and set aside.

[0043] Step 1.2, coating the casting liquid treated in step 1.1 on a glass plate, and then evenly placing the coated glass plate in deionized water to perform solid-liquid phase conversion to volatilize the residual solvent, and finally obtain a PVDF membrane, and soak the PVDF membrane in deionized water for later use.

[0044] Step 2: Prepare a solution for surface polymerization.

[0045] Step 2.1, prepare a conductive polymer monomer solution, wherein the conductive polymer monomer solution is a thiophene solution with a concentration of 0.1 mol / L to 0.2 mol / L, and add 20% to 30% by mass ethanol solution to the conductive polymer monomer solution to accelerate the dissolution of the thiophene solution.

[0046] Step 2.2, preparing an ammonium persulfate solution with a concentration of 1 mol / L to 1.5 mol / L and sulfuric acid with a mass fraction of 3% to 6%, and then mixing them to obtain an acidic ammonium persulfate mixed solution for standby use.

[0047] Step 3: Prepare a conductive ultrafiltration membrane 2 by polymerizing a second conductive adsorption layer on the surface of a PVDF membrane.

[0048] Step 3.1, soak the PVDF membrane obtained in step 1 in the solution in step 2.1 for a period of time.

[0049] Step 3.2, take out the PVDF membrane soaked in step 3.1 and soak it in an acidic ammonium persulfate solution for a period of time, at which time a polymer conductive adsorption layer is generated on the surface of the PVDF membrane.

[0050] Step 3.3, take out the PVDF membrane with the polymer conductive adsorption layer polymerized on the surface in step 3.2, and fully soak it in pure water.

[0051] Step 3.4: prepare an ethanol solution with a concentration of 20% to 30%.

[0052] Step 3.5, soak the membrane with polymerized conductive adsorption layer on the surface after soaking in pure water in step 3.3 in the ethanol solution prepared in step 3.4 for a period of time, and black substances will fall off the surface. At this time, the hydrophilic conductive ultrafiltration membrane 2 with polymerized conductive adsorption layer on the surface of PVDF membrane is successfully prepared.

[0053] Among them, when the PVDF membrane is immersed in the above steps 3.1 and 3.2, the PVDF membrane is required to be suspended in the entire solution, and the immersion time is 90s to 150s; in the above step 3.5, the membrane with a polymer conductive adsorption layer on the surface is immersed in the ethanol solution prepared in step 3.4 for 4min to 6min.

[0054] Taking the filter cotton of the conductive filter element 3 as PP cotton as an example, a preparation method of the conductive filter element 3 is provided, which specifically includes the following steps:

[0055] Step 4.1, prepare a conductive polymer monomer solution, wherein the conductive polymer monomer solution is a thiophene solution with a concentration of 0.2 mol / L to 0.3 mol / L, and add 20% to 30% by mass ethanol solution to the conductive polymer monomer solution to accelerate the dissolution of the thiophene solution.

[0056] Step 4.2, preparing an ammonium persulfate solution with a concentration of 1 mol / L to 1.5 mol / L and sulfuric acid with a mass fraction of 3% to 6%, and then mixing them to obtain an acidic ammonium persulfate mixed solution for standby use.

[0057] Step 4.3: Soak the purchased PP cotton filter element in the solution in step 4.1 for a period of time.

[0058] Step 4.4, take out the PP cotton filter element soaked in step 4.3 and soak it in an acidic ammonium persulfate solution for a period of time. At this time, a polymer conductive adsorption layer (i.e., the first conductive adsorption layer) is generated on the surface of the PP cotton filter element.

[0059] Step 4.5, take out the PP cotton filter element with the polymer conductive adsorption layer polymerized on the surface in step 4.4, and soak it in pure water.

[0060] Step 4.6: prepare an ethanol solution with a concentration of 20% to 30%.

[0061] Step 4.7, soak the PP cotton filter element with a polymer conductive adsorption layer polymerized on the surface after being soaked in pure water in step 4.5 in the ethanol solution prepared in step 4.6 for a period of time, and black substances will fall off the surface. At this time, the hydrophilic conductive filter element 3 with a polymer conductive adsorption layer polymerized on the surface of the PP cotton filter element is successfully prepared.

[0062] Among them, when the PP cotton filter element is immersed in the above steps 4.3 and 4.4, the PP cotton filter element is required to be suspended in the entire solution, and the immersion time is 90s to 150s; in the above step 4.4, the membrane with a polymer conductive adsorption layer on the surface is immersed in the ethanol solution prepared in step 4.6 for 4min to 6min.

[0063] The following provides an assembly method of a dual electric field conductive membrane filtration device, which specifically includes the following steps:

[0064] Step 5.1, the conductive filter element 3, the conductive ultrafiltration membrane 2, and the microporous hollow graphite rod 1 prepared above are placed in a Figure 1 Install in the combination shown.

[0065] Step 5.2: During the filtration process, the voltage of the external power supply 4 is controlled to be 0.5V-2V, the conductive filter element 3 and the microporous hollow graphite rod 1 are connected to the positive electrode, and the conductive ultrafiltration membrane 2 is connected to the negative electrode.

[0066] The present invention provides two specific embodiments to illustrate the dual electric field conductive membrane filtration device, wherein the filter cotton of the conductive filter element 3 is made of PP cotton, and the organic membrane of the conductive ultrafiltration membrane 2 is made of PVDF membrane.

[0067] Example 1

[0068] The PP cotton filter element is treated with interfacial polymerization by thiophene, and the support of the PP cotton filter element is a PE cylinder. The middle layer is a conductive ultrafiltration membrane 2, and its organic membrane is installed by interfacial polymerization of thiophene using a roll-type membrane. The inner layer is a microporous hollow graphite rod 1. One end of the positive electrode of the power supply 4 is connected to the conductive filter element 3, and one end of the negative electrode is connected to the conductive ultrafiltration membrane 2 to form an electric field. The other end of the positive electrode of the power supply 4 is connected to the inner layer of the microporous hollow graphite rod 1, and an electric field is formed between the conductive ultrafiltration membrane 2. Water enters from both sides, and water flows out from the bottom of the middle microporous hollow graphite rod 1. The diameter of the conductive filter element 3 is 40cm and the length is 60cm. The diameter of the middle roll-type conductive ultrafiltration membrane 2 is 30cm and the length is 60cm. The diameter of the microporous hollow graphite rod 1 is 10cm and the length is 60cm. The micropore diameter is 10μm. The voltage of the power supply 4 is 0.5V.

[0069] Step 1: Prepare PVDF membrane.

[0070] Step 1.1: 65% by mass of DMAC, 15% by mass of PVDF and 10% by mass of PVP were mixed evenly, and stirred for 10 hours in an oil bath at 60°C to obtain a uniform casting solution. The solution was allowed to stand for 8 hours for degassing and then used for later use.

[0071] Step 1.2, coating the casting liquid treated in step 1.1 on a glass plate, and then evenly placing the coated glass plate in deionized water to perform solid-liquid phase conversion to volatilize the residual solvent, and finally obtain a PVDF membrane, and soak the PVDF membrane in deionized water for later use.

[0072] Step 2: Prepare a solution for surface polymerization.

[0073] Step 2.1, prepare a conductive polymer monomer solution, wherein the conductive polymer monomer solution is a thiophene solution with a concentration of 0.1 mol / L, and add a 20% by mass ethanol solution to the conductive polymer monomer solution to accelerate the dissolution of the thiophene solution.

[0074] Step 2.2, prepare an ammonium persulfate solution with a concentration of 1 mol / L and sulfuric acid with a mass fraction of 3%, and then mix them to obtain an acidic ammonium persulfate mixed solution for standby use.

[0075] Step 3: Prepare a conductive ultrafiltration membrane 2 by polymerizing a second conductive adsorption layer on the surface of a PVDF membrane.

[0076] Step 3.1, soak the PVDF membrane obtained in step 1 in the solution in step 2.1 for a period of time.

[0077] Step 3.2, take out the PVDF membrane soaked in step 3.1 and soak it in an acidic ammonium persulfate solution for a period of time, at which time a polymer conductive adsorption layer is generated on the surface of the PVDF membrane.

[0078] Step 3.3, take out the PVDF membrane with the polymer conductive adsorption layer polymerized on the surface in step 3.2, and fully soak it in pure water.

[0079] Step 3.4: prepare an ethanol solution with a concentration of 20%.

[0080] Step 3.5, soak the membrane with polymerized conductive adsorption layer on the surface after soaking in pure water in step 3.3 in the ethanol solution prepared in step 3.4 for a period of time, and black substances will fall off the surface. At this time, the hydrophilic conductive ultrafiltration membrane 2 with polymerized conductive adsorption layer on the surface of PVDF membrane is successfully prepared.

[0081] In the above steps 3.1 and 3.2, the PVDF membrane is required to be suspended in the entire solution, and the immersion time is 90 seconds. In the above step 3.5, the membrane with a polymer conductive adsorption layer on the surface is immersed in the ethanol solution prepared in step 3.4 for 4 minutes.

[0082] Step 4: prepare a conductive filter element 3.

[0083] Step 4.1, prepare a conductive polymer monomer solution, wherein the conductive polymer monomer solution is a thiophene solution with a concentration of 0.2 mol / L, and add a 20% by mass ethanol solution to the conductive polymer monomer solution to accelerate the dissolution of the thiophene solution.

[0084] Step 4.2, prepare an ammonium persulfate solution with a concentration of 1 mol / L and sulfuric acid with a mass fraction of 3%, and then mix them to obtain an acidic ammonium persulfate mixed solution for standby use.

[0085] Step 4.3: Soak the purchased PP cotton filter element in the solution in step 4.1 for a period of time.

[0086] Step 4.4, take out the PP cotton filter element soaked in step 4.3 and soak it in an acidic ammonium persulfate solution for a period of time. At this time, a polymer conductive adsorption layer (i.e., the first conductive adsorption layer) is generated on the surface of the PP cotton filter element.

[0087] Step 4.5, take out the PP cotton filter element with the polymer conductive adsorption layer polymerized on the surface in step 4.4, and soak it in pure water.

[0088] Step 4.6: Prepare an ethanol solution with a concentration of 20%.

[0089] Step 4.7, soak the PP cotton filter element with a polymer conductive adsorption layer polymerized on the surface after being soaked in pure water in step 4.5 in the ethanol solution prepared in step 4.6 for a period of time, and black substances will fall off the surface. At this time, the hydrophilic conductive filter element 3 with a polymer conductive adsorption layer polymerized on the surface of the PP cotton filter element is successfully prepared.

[0090] Among them, the PP cotton filter element is required to be suspended in the entire solution during immersion in the above steps 4.3 and 4.4, and the immersion time is 90s; the membrane with a polymer conductive adsorption layer polymerized on the surface in the above step 4.4 is immersed in the ethanol solution prepared in step 4.6 for 4 minutes.

[0091] Step 5: Power on and filter.

[0092] Step 5.1, the conductive filter element 3, the conductive ultrafiltration membrane 2, and the microporous hollow graphite rod 1 prepared above are placed in a Figure 1 Install in the combination shown.

[0093] Step 5.2: During the filtration process, the voltage of the external power supply 4 is controlled to be 0.5V, the conductive filter element 3 and the microporous hollow graphite rod 1 are connected to the positive electrode, and the conductive ultrafiltration membrane 2 is connected to the negative electrode.

[0094] The membrane operating pressure of the effluent before treatment by the double electric field conductive membrane filtration device was -35.6kap ~-57.9kap, DOC (dissolved organic carbon) was 70.54mg / l, COD (chemical oxygen demand) was 57.62mg / l, total phosphorus was 1.85mg / l, and total nitrogen was 34.9mg / l.

[0095] After treatment by the double electric field conductive membrane filtration device, the membrane operating pressure of the effluent is -10.1kap ~-21.9kap, DOC (dissolved organic carbon) is 8.62mg / l, COD (chemical oxygen demand) is 22.51mg / l, total phosphorus is 1.53mg / l, and total nitrogen is 29.5mg / l.

[0096] After 30 minutes of the experiment, according to the experimental results, the membrane operating pressure, DOC, COD, total phosphorus and total nitrogen decreased to a certain extent after treatment by the dual electric field conductive membrane filtration device.

[0097] Example 2

[0098] The PP cotton filter element is treated with interfacial polymerization by thiophene, and the support of the PP cotton filter element is a PE cylinder. The middle layer is a conductive ultrafiltration membrane 2, and its organic membrane is installed by interfacial polymerization of thiophene using a roll-type membrane. The inner layer is a microporous hollow graphite rod 1. One end of the positive electrode of the power supply 4 is connected to the conductive filter element 3, and one end of the negative electrode is connected to the conductive ultrafiltration membrane 2 to form an electric field. The other end of the positive electrode of the power supply 4 is connected to the inner layer of the microporous hollow graphite rod 1, and an electric field is formed between the conductive ultrafiltration membrane 2. Water enters from both sides, and water flows out from the bottom of the middle microporous hollow graphite rod 1. The diameter of the conductive filter element 3 is 60cm and the length is 80cm. The diameter of the middle roll-type conductive ultrafiltration membrane 2 is 50cm and the length is 80cm. The diameter of the microporous hollow graphite rod 1 is 30cm and the length is 80cm. The micropore diameter is 20μm. The voltage of the power supply 4 is 2V.

[0099] Step 1: Prepare PVDF membrane.

[0100] Step 1.1, 70% by mass of DMAC, 20% by mass of PVDF and 20% by mass of PVP were mixed evenly, and stirred for 12 hours in an oil bath at 60°C to obtain a uniform casting solution, which was left to stand for 12 hours for degassing and then used.

[0101] Step 1.2, coating the casting liquid treated in step 1.1 on a glass plate, and then evenly placing the coated glass plate in deionized water to perform solid-liquid phase conversion to volatilize the residual solvent, and finally obtain a PVDF membrane, and soak the PVDF membrane in deionized water for later use.

[0102] Step 2: Prepare a solution for surface polymerization.

[0103] Step 2.1, prepare a conductive polymer monomer solution, wherein the conductive polymer monomer solution is a thiophene solution with a concentration of 0.2 mol / L, and add a 30% by mass ethanol solution to the conductive polymer monomer solution to accelerate the dissolution of the thiophene solution.

[0104] Step 2.2, prepare an ammonium persulfate solution with a concentration of 1.5 mol / L and sulfuric acid with a mass fraction of 6%, and then mix them to obtain an acidic ammonium persulfate mixed solution for standby use.

[0105] Step 3: Prepare a conductive ultrafiltration membrane 2 by polymerizing a second conductive adsorption layer on the surface of a PVDF membrane.

[0106] Step 3.1, soak the PVDF membrane obtained in step 1 in the solution in step 2.1 for a period of time.

[0107] Step 3.2, take out the PVDF membrane soaked in step 3.1 and soak it in an acidic ammonium persulfate solution for a period of time, at which time a polymer conductive adsorption layer is generated on the surface of the PVDF membrane.

[0108] Step 3.3, take out the PVDF membrane with the polymer conductive adsorption layer polymerized on the surface in step 3.2, and fully soak it in pure water.

[0109] Step 3.4: prepare a 30% ethanol solution.

[0110] Step 3.5, soak the membrane with polymerized conductive adsorption layer on the surface after soaking in pure water in step 3.3 in the ethanol solution prepared in step 3.4 for a period of time, and black substances will fall off the surface. At this time, the hydrophilic conductive ultrafiltration membrane 2 with polymerized conductive adsorption layer on the surface of PVDF membrane is successfully prepared.

[0111] In the above steps 3.1 and 3.2, the PVDF membrane is required to be suspended in the entire solution, and the immersion time is 150s. In the above step 3.5, the membrane with a polymer conductive adsorption layer on the surface is immersed in the ethanol solution prepared in step 3.4 for 6 minutes.

[0112] Step 4: prepare a conductive filter element 3.

[0113] Step 4.1, prepare a conductive polymer monomer solution, wherein the conductive polymer monomer solution is a thiophene solution with a concentration of 0.3 mol / L, and add a 30% by mass ethanol solution to the conductive polymer monomer solution to accelerate the dissolution of the thiophene solution.

[0114] Step 4.2, preparing an ammonium persulfate solution with a concentration of 1.5 mol / L and sulfuric acid with a mass fraction of 6%, and then mixing them to obtain an acidic ammonium persulfate mixed solution for standby use.

[0115] Step 4.3: Soak the purchased PP cotton filter element in the solution in step 4.1 for a period of time.

[0116] Step 4.4, take out the PP cotton filter element soaked in step 4.3 and soak it in an acidic ammonium persulfate solution for a period of time. At this time, a polymer conductive adsorption layer (i.e., the first conductive adsorption layer) is generated on the surface of the PP cotton filter element.

[0117] Step 4.5, take out the PP cotton filter element with the polymer conductive adsorption layer polymerized on the surface in step 4.4, and soak it in pure water.

[0118] Step 4.6: Prepare a 30% ethanol solution.

[0119] Step 4.7, soak the PP cotton filter element with a polymer conductive adsorption layer polymerized on the surface after being soaked in pure water in step 4.5 in the ethanol solution prepared in step 4.6 for a period of time, and black substances will fall off the surface. At this time, the hydrophilic conductive filter element 3 with a polymer conductive adsorption layer polymerized on the surface of the PP cotton filter element is successfully prepared.

[0120] Among them, the PP cotton filter element is required to be suspended in the entire solution during immersion in the above steps 4.3 and 4.4, and the immersion time is 150s; the membrane with a polymer conductive adsorption layer polymerized on the surface in the above step 4.4 is immersed in the ethanol solution prepared in step 4.6 for 6 minutes.

[0121] Step 5: Power on and filter.

[0122] Step 5.1, the conductive filter element 3, the conductive ultrafiltration membrane 2, and the microporous hollow graphite rod 1 prepared above are placed in a Figure 1 Install in the combination shown.

[0123] Step 5.2: During the filtration process, the voltage of the external power supply 4 is controlled to be 2V, the conductive filter element 3 and the microporous hollow graphite rod 1 are connected to the positive electrode, and the conductive ultrafiltration membrane 2 is connected to the negative electrode.

[0124] The membrane operating pressure of the effluent before treatment by the double electric field conductive membrane filtration device was -35.6kap ~-57.9kap, DOC (dissolved organic carbon) was 70.54mg / l, COD (chemical oxygen demand) was 57.62mg / l, total phosphorus was 1.85mg / l, and total nitrogen was 34.9mg / l.

[0125] After treatment by the double electric field conductive membrane filtration device, the membrane operating pressure of the effluent is -8.1kap ~-19.7kap, DOC (dissolved organic carbon) is 7.91mg / l, COD (chemical oxygen demand) is 22.38mg / l, total phosphorus is 1.49mg / l, and total nitrogen is 27.6mg / l.

[0126] After 40 minutes of the experiment, according to the experimental results, the membrane operating pressure, DOC, COD, total phosphorus and total nitrogen decreased to a certain extent after treatment by the dual electric field conductive membrane filtration device.

[0127] The double electric field conductive membrane filtration device provided by the present invention is provided with a conductive filter element 3, a conductive ultrafiltration membrane 2 and a hollow graphite rod 1 which are sequentially sleeved, and an electric field is formed between the conductive filter element 3 of the outer layer and the conductive ultrafiltration membrane 2 of the middle layer, and an electric field is formed between the hollow graphite rod 1 of the inner layer and the conductive ultrafiltration membrane 2 of the middle layer. The raw water first enters the positively charged conductive filter element 3, and under the action of the electric field, the particles in the raw water are absorbed by the filter cotton in the conductive filter element 3, and the thiophene composite improved filter cotton can enhance the adsorption effect. After the water flows through the conductive filter element 3, it enters the conductive ultrafiltration membrane 2, and the negatively charged conductive ultrafiltration membrane 2 has a repelling effect on the negatively charged particles under the action of the electric field. When the water passes through the surface of the conductive ultrafiltration membrane 2, the positively charged multi-microporous hollow graphite rod 1 adsorbs the negatively charged particles again. The double electric field action promotes the migration of ions in the water, improves the filtration efficiency, avoids the accumulation of impurities on the membrane surface, enhances the water treatment effect, and increases the service life of the membrane.

[0128] The above are only a few embodiments of the present application and do not constitute any form of limitation to the present application. Although the present application is disclosed as above with preferred embodiments, it is not intended to limit the present application. Any technician familiar with the profession, without departing from the scope of the technical solution of the present application, using the technical content disclosed above to make slight changes or modifications are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A dual electric field conductive membrane filtration device, characterized in that: The device comprises: A conductive filter element, the conductive filter element comprising a hollow filter cotton filter element and a first conductive adsorption layer formed on the surface of the filter cotton filter element; A conductive ultrafiltration membrane is arranged in a ring shape in the hollow area of ​​the filter cotton filter element, and the conductive ultrafiltration membrane includes an organic membrane and a second conductive adsorption layer formed on the surface of the organic membrane; A hollow graphite rod is arranged on the inner side of the conductive ultrafiltration membrane, and the hollow graphite rod has a plurality of micropores; A power source, the power source having a first positive connection end, a second positive connection end and a negative connection end, the first positive connection end is connected to the conductive filter element, the second positive connection end is connected to the hollow graphite rod, and the negative connection end is connected to the conductive ultrafiltration membrane.

2. The device according to claim 1, characterized in that The filter cotton filter element includes a hollow porous support column and filter cotton coated on the outer side wall of the porous support column, and the first conductive adsorption layer is formed on the surface of the filter cotton.

3. The device according to claim 2, characterized in that The first conductive adsorption layer is formed by interfacial polymerization of thiophene and the filter cotton.

4. The device according to claim 1, characterized in that The second conductive adsorption layer is formed by interfacial polymerization of thiophene and the organic film.

5. The device according to claim 1, characterized in that The central axes of the conductive filter element, the conductive ultrafiltration membrane and the hollow graphite rod coincide with each other.

6. The device according to claim 1, characterized in that The pore size of the micropores is 10 μm to 20 μm.

7. The device according to claim 2, characterized in that The filter cotton is PP cotton.

8. The device according to claim 1, characterized in that The organic membrane is a PVDF membrane.

9. The device according to claim 1, characterized in that The power supply voltage is 0.5V~2V.

10. The device according to claim 2, characterized in that The porous support column is a porous polyethylene or polyvinyl chloride cylinder.

Images