A method and device for separating polytetrahydrofuran surface wastewater

Abstract

The invention provides a separation device for polytetrahydrofuran surface wastewater, comprising a separation tank, wherein water inlets and water outlets are respectively arranged on both sides of the separation tank, and a plurality of overflow weirs are further arranged in the separation tank, wherein the overflow weir divides the separation tank into left and right independent sedimentation tanks and a sewage discharge tank, and the overflow weir is provided with a plurality of connecting ports for sewage circulation; the separation method thereof is as follows: S1. clean water is first added into the sedimentation tank, and the water level is not higher than the height of the water outlet; S2. sewage is discharged into the sedimentation tank, and adsorption material is added, wherein the adsorption material is obtained by depositing a barium ferrite layer on the surface of a melamine three-dimensional skeleton structure as a substrate; S3. the adsorbed substance floats on the upper liquid surface of the sedimentation tank, and then is separated out of the sedimentation tank; the bottom sewage is circulated into the sewage discharge tank through the connecting port; the invention can separate polytetrahydrofuran and oil pollution in the sewage, avoid direct discharge of the sewage into a sewage treatment system, and greatly reduce the burden of the sewage treatment system of the environmental protection device.

Description

Technical Field

[0001] The invention relates to the technical field of wastewater treatment, and in particular to a method and a device for separating polytetrahydrofuran surface wastewater. Background Art

[0002] In today's social environment, ecological environmental protection is a national event. It is particularly important to continue to fight the battle against pollution, adhere to precise pollution control, scientific pollution control, and pollution control in accordance with the law, maintain strength, extend depth, and expand breadth, and further promote the three major defense battles for blue sky, clear water, and clean land, and continuously improve the quality of the ecological environment. The treatment of the three wastes (waste gas, waste solids, and wastewater) generated by chemical companies in their production processes has become an important environmental protection issue of the most concern in the industry today. How to continue to fight the battle against pollution, how to accurately control pollution, scientifically control pollution, and control pollution in accordance with the law, and to support its high-quality development with a high-quality ecological environment is of great significance.

[0003] The domestic production technology of polytetrahydrofuran mainly comes from the INVISTA process and the BASF process. During the entire process (normal production, maintenance, equipment cleaning, leakage, etc.), it is difficult to avoid the generation of ground wastewater containing polytetrahydrofuran and oil pollution. Once these wastewaters enter the sewage pipe network, they will directly enter the sewage treatment system. Polytetrahydrofuran and oil pollution, as large molecules, will have poor biodegradability and will be harmful to microorganisms, directly causing sewage treatment to fail to meet standards and cause environmental accidents. Therefore, it is necessary to treat the wastewater. Summary of the invention

[0004] The object of the present invention is to provide a method and device for separating polytetrahydrofuran ground wastewater, which can quickly separate polytetrahydrofuran and oil pollution in sewage to avoid direct discharge into the sewage treatment system, thereby greatly reducing the burden of the sewage treatment system of the environmental protection device.

[0005] The embodiments of the present invention are implemented by the following technical solutions:

[0006] A separation device for polytetrahydrofuran surface wastewater, the separation device is arranged between the polytetrahydrofuran device sewage outlet and the sewage treatment system; the separation device comprises a separation tank, one side of the separation tank is provided with a water inlet, the opposite side is provided with a water outlet, the separation tank is also provided with a plurality of overflow weirs, the overflow weirs divide the separation tank into left and right independent sedimentation tanks and sewage tanks, and the overflow weir is provided with a plurality of connecting ports for sewage circulation.

[0007] A method for separating polytetrahydrofuran surface wastewater comprises the following steps:

[0008] S1. First add enough clean water into the sedimentation tank, the water level should not be higher than the outlet height, preferably near the outlet;

[0009] S2. The sewage is then discharged from the water inlet into the sedimentation tank, and an adsorbent material is added to the sedimentation tank, wherein the adsorbent material is a three-dimensional skeleton structure of melamine as a substrate, and a barium ferrite layer is deposited on its surface;

[0010] S3. The adsorbed substances float on the upper liquid surface of the sedimentation tank, and then the adsorbed substances on the upper liquid surface are separated out of the sedimentation tank; the bottom sewage flows from the connecting port to the sewage tank, and then flows from the outlet to the sewage treatment system.

[0011] The technical solution of the embodiment of the present invention has at least the following advantages and beneficial effects:

[0012] 1. The present invention adds a sufficient amount of clean water into the separation tank in advance, and then uses the properties of polytetrahydrofuran and oil pollution to quickly separate polytetrahydrofuran and oil pollution in sewage, and at the same time adds adsorbent materials to quickly aggregate polytetrahydrofuran and oil pollution into blocks, which are convenient for subsequent salvage out of the separation tank and avoid direct discharge into the sewage treatment system, thereby greatly reducing the burden of the sewage treatment system of the back-end environmental protection device; reducing the waste of energy, materials and time in the sewage treatment system when treating sewage.

[0013] 2. The adsorption material of the present invention has excellent hydrophobicity and lipophilicity, can more efficiently adsorb the oil and polytetrahydrofuran on the upper liquid surface and can be reused, and can be separated from the liquid surface by an external magnetic field, that is, the mixture moves in the direction of the magnetic field under the action of the magnetic field, so that the separation effect of sewage, oil and polytetrahydrofuran is better. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0015] Figure 1 A schematic diagram of the structure of a separation device provided in Example 1 of the present invention;

[0016] Icon: 1-separation tank, 2-water inlet, 3-sedimentation tank, 4-overflow weir, 41-connecting port, 5-sewage tank, 6-water outlet. DETAILED DESCRIPTION

[0017] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be described clearly and completely below. If the specific conditions are not specified in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be purchased commercially.

[0018] The following is a detailed description of a separation device and a separation method for polytetrahydrofuran surface wastewater provided in an embodiment of the present invention.

[0019] A separation device for polytetrahydrofuran surface wastewater, the separation device is arranged between the polytetrahydrofuran device sewage outlet and the sewage treatment system; the separation device comprises a separation tank, one side of the separation tank is provided with a water inlet, the opposite side is provided with a water outlet, and the height of the water outlet is not higher than the height of the water inlet; a plurality of overflow weirs are also arranged in the separation tank, the overflow weirs divide the separation tank into left and right independent sedimentation tanks and sewage tanks, the overflow weir is provided with a plurality of connecting ports for sewage circulation, the connecting ports are located at the lower part of the overflow weir, and the height of the connecting ports is lower than the height of the water outlet.

[0020] Because the height of the water outlet is set less than or equal to the height of the water inlet of the sedimentation tank, when the polytetrahydrofuran device continues to generate wastewater, it enters the sedimentation tank and the liquid level rises accordingly. When the liquid level is higher than the height of the water outlet, the sewage will enter the rear-end sewage treatment system through the water outlet. As the sewage in the sewage tank is lost, the sewage inside the sedimentation tank will continuously enter the sewage tank through the connecting port, and the polytetrahydrofuran and oil accumulated on the upper liquid surface of the sedimentation tank will be collected and then treated harmlessly.

[0021] A method for separating polytetrahydrofuran surface wastewater comprises the following steps:

[0022] S1. First add clean water to the sedimentation tank. The water level should not be higher than the outlet height. If the water level is too high, it will be directly discharged to the sewage treatment system.

[0023] S2. Then the sewage is discharged from the water inlet into the sedimentation tank. According to the physical properties of polytetrahydrofuran and oil, they are insoluble in water and have a density less than that of water, so they will float on the water surface, and the temperature will condense into blocks at about 30 degrees. Therefore, after the wastewater at the front end enters the sedimentation tank, polytetrahydrofuran and oil gradually free and accumulate in the upper layer, and sewage accumulates in the lower layer. This is mainly because clean water has been introduced into the separation tank in advance, so that the sewage introduced later can make the water flow first from the connecting port at the bottom of the overflow weir to the sewage tank, that is, a U-shaped water flow path is formed, so that polytetrahydrofuran and oil are always free and accumulated in the upper layer; at this time, an adsorbent material can be added to the sedimentation tank to quickly unite polytetrahydrofuran and oil into blocks, which is convenient for subsequent salvage out of the separation tank, wherein the adsorbent material is made of a three-dimensional skeleton structure of melamine as a substrate and a barium ferrite layer is deposited on its surface;

[0024] The present invention selects melamine foam with a three-dimensional network structure inside as a matrix, which has a strong absorption capacity. More importantly, after the surface of the melamine foam is coated with polypropylene, a barium ferrite layer is deposited on the surface of the melamine foam, so that a network-shaped barium ferrite coating layer with magnetism is formed on the surface of the obtained modified melamine foam, so that the hydrophobicity and lipophilicity of the modified melamine foam are greatly improved, so that the oil and polytetrahydrofuran on the upper liquid surface can be more efficiently adsorbed, showing high oil absorption and can be reused. Specifically, after being dispersed in the upper liquid surface of the sedimentation tank, the melamine foam can form a uniform mixture with the oil and polytetrahydrofuran and be suspended on the water surface, and can be separated from the liquid surface by using an external magnetic field, that is, under the action of the magnetic field, the mixture moves in the direction of the magnetic field, so that the separation effect of sewage, oil and polytetrahydrofuran is better.

[0025] S3. The adsorbed substances float on the upper liquid surface of the sedimentation tank, and then the adsorbed substances on the upper liquid surface are separated out of the sedimentation tank; the bottom sewage flows from the connecting port to the sewage tank, and then flows from the outlet to the sewage treatment system.

[0026] Furthermore, the adsorption material is put into the sewage pool and the sewage treatment system, so that the oil pollution and polytetrahydrofuran can be removed more deeply.

[0027] Furthermore, the preparation method of the adsorption material is:

[0028] (1) dissolving polypropylene in toluene at room temperature and heating to dissolve it, then dispersing octadecyltrichlorosilane in the solution, and subjecting the solution to ultrasonic dispersion for 15 to 60 minutes to obtain a dispersion;

[0029] (2) using citric acid to complex iron nitrate and barium nitrate to obtain a barium ferrite precursor, and then adding the barium ferrite precursor to step (1) to obtain a composite dispersion;

[0030] (3) The melamine foam is immersed in the composite dispersion liquid, and after being refluxed for 15 to 60 minutes, the melamine foam is taken out and squeezed to remove the toluene, and after being left in the air for 24 hours, it is dried at 120° C. to constant weight to obtain a modified melamine foam, i.e., an adsorption material.

[0031] The present invention prepares a strong super-hydrophobic sponge by silanizing and coating a polypropylene layer on a commercial melamine sponge. The silanization is achieved by forming a self-assembled monolayer with a secondary amine group on the surface of the sponge skeleton and an alkyl silane compound (such as octadecyltrichlorosilane, hexadecyltrichlorosilane, and dodecyltrichlorosilane), thereby making the surface of the sponge super-hydrophobic and oleophilic, so as to exert a more efficient adsorption effect on oil stains and polytetrahydrofuran.

[0032] Furthermore, in step (1), the mass percentage of polypropylene to toluene is 1-3%, and the mass percentage of octadecyltrichlorosilane to toluene is 1-5%.

[0033] Furthermore, in step (2), the molar ratio of ferric nitrate, barium nitrate and citric acid is 10-15:1:16-22.

[0034] Furthermore, in step (3), the mass ratio of the melamine foam to the barium ferrite precursor is 1:1-2.

[0035] Example 1

[0036] A separation device for polytetrahydrofuran surface wastewater, the separation device is arranged between the polytetrahydrofuran device sewage outlet and the sewage treatment system; the separation device comprises a separation tank, one side of the separation tank is provided with a water inlet, the opposite side is provided with a water outlet, and the height of the water outlet is not higher than the height of the water inlet; a plurality of overflow weirs are also arranged in the separation tank, the overflow weirs divide the separation tank into left and right independent sedimentation tanks and sewage tanks, the overflow weir is provided with a plurality of connecting ports for sewage circulation, the connecting ports are located at the lower part of the overflow weir, and the height of the connecting ports is lower than the height of the water outlet.

[0037] A method for separating polytetrahydrofuran surface wastewater comprises the following steps:

[0038] S1. First add clean water into the sedimentation tank, and the water level should be level with the outlet height;

[0039] S2. The sewage is then discharged from the water inlet into the sedimentation tank, and an adsorbent material is added to the sedimentation tank, wherein the adsorbent material is a melamine three-dimensional skeleton structure as a substrate, and a barium ferrite layer is deposited on its surface;

[0040] Specifically, the preparation method of the adsorbent material is:

[0041] (1) dissolving polypropylene in toluene at room temperature and heating to dissolve it, then dispersing octadecyltrichlorosilane in the solution, and dispersing it by ultrasonic for 40 minutes to obtain a dispersion; wherein the mass percentage of polypropylene to toluene is 2%, and the mass percentage of octadecyltrichlorosilane to toluene is 3%;

[0042] (2) using citric acid to complex iron nitrate and barium nitrate to obtain a barium ferrite precursor, wherein the molar ratio of iron nitrate, barium nitrate and citric acid is 12:1:19; then adding the barium ferrite precursor to step (1) to obtain a composite dispersion;

[0043] (3) immersing melamine foam in the composite dispersion, wherein the mass ratio of melamine foam to barium ferrite precursor is 1:1.5; after reflux immersion for 40 minutes, taking out the melamine foam to remove toluene, leaving it in the air for 24 hours, placing it in an oven and baking it at 120° C. for 4 hours to constant weight, thereby obtaining modified melamine foam, i.e., adsorption material;

[0044] S3. The adsorbed substances float on the upper liquid surface of the sedimentation tank in the form of clumps, and then the clumps of substances adsorbed on the upper liquid surface are separated from the sedimentation tank by magnetic adsorption method; the bottom sewage flows from the connecting port to the sewage tank, and then flows from the outlet to the sewage treatment system; there is no obvious oil pollution in the water at the outlet.

[0045] Example 2

[0046] The difference between this embodiment and embodiment 1 is that the mass percentage of polypropylene to toluene is 1%, the mass percentage of alkylsilane compound to toluene is 1%, the molar ratio of ferric nitrate, barium nitrate and citric acid is 10:1:16, and the mass ratio of melamine foam to barium ferrite precursor is 1:1; there is no obvious oil stain in the water at the outlet.

[0047] Example 3

[0048] The difference between this embodiment and embodiment 1 is that the mass percentage of polypropylene to toluene is 3%, the mass percentage of alkyl silane compound to toluene is 2%, the molar ratio of ferric nitrate, barium nitrate and citric acid is 11:1:17, and the mass ratio of melamine foam to barium ferrite precursor is 1:2; and there is no obvious oil stain in the water at the outlet.

[0049] Example 4

[0050] The difference between this embodiment and embodiment 1 is that the mass percentage of polypropylene to toluene is 2%, the mass percentage of alkylsilane compound to toluene is 5%, the molar ratio of ferric nitrate, barium nitrate and citric acid is 14:1:20, and the mass ratio of melamine foam to barium ferrite precursor is 1:1.3; and there is no obvious oil stain on the water at the outlet.

[0051] Example 5

[0052] The difference between this embodiment and embodiment 1 is that the mass percentage of polypropylene to toluene is 2.2%, the mass percentage of alkylsilane compound to toluene is 4%, the molar ratio of ferric nitrate, barium nitrate and citric acid is 13:1:18, and the mass ratio of melamine foam to barium ferrite precursor is 1:1; there is no obvious oil stain in the water at the outlet.

[0053] Example 6

[0054] The difference between this embodiment and embodiment 1 is that the mass percentage of polypropylene to toluene is 2.5%, the mass percentage of alkylsilane compound to toluene is 4%, the molar ratio of ferric nitrate, barium nitrate and citric acid is 15:1:22, and the mass ratio of melamine foam to barium ferrite precursor is 1:2; no obvious oil stain is observed in the water at the outlet.

[0055] Comparative Example 1

[0056] The difference between this comparative example and Example 1 is that the mass percentage of polypropylene to toluene is 8%, the mass percentage of alkylsilane compound to toluene is 0.1%, the molar ratio of ferric nitrate, barium nitrate and citric acid is 1:1:, the mass ratio of melamine foam to barium ferrite precursor is 10:1; obvious oil stains can be seen in the water at the outlet.

[0057] Comparative Example 2

[0058] The difference between this comparative example and Example 1 is that the adsorption material is melamine foam; and obvious oil stains can be seen in the water at the water outlet.

[0059] Comparative Example 3

[0060] The difference between this comparative example and Example 1 is that: the preparation of the adsorbent material does not include step (1); and obvious oil stains can be seen in the water at the water outlet.

[0061] Comparative Example 4

[0062] The difference between this comparative example and Example 1 is that: step (2) is not included in the preparation of the adsorption material; and obvious oil stains can be seen in the water at the water outlet.

[0063] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for separating polytetrahydrofuran surface wastewater, characterized in that: The separation device used in the separation method is arranged between the sewage outlet of the polytetrahydrofuran device and the sewage treatment system; the separation device comprises a separation tank, a water inlet is arranged on one side of the separation tank, a water outlet is arranged on the opposite side, and a plurality of overflow weirs are arranged in the separation tank, the overflow weir divides the separation tank into left and right independent sedimentation tanks and sewage discharge tanks, and a plurality of connecting ports for sewage circulation are opened on the overflow weir, the connecting ports are located at the lower part of the overflow weir, and the height of the connecting ports is lower than the height of the water outlet; The separation method comprises the following steps: S1. First add clean water into the sedimentation tank, and the water level should not be higher than the outlet height; S2. The sewage is then discharged from the water inlet into the sedimentation tank, and an adsorbent material is added to the sedimentation tank, wherein the adsorbent material is a three-dimensional skeleton structure of melamine as a substrate, and a barium ferrite layer is deposited on its surface; S3. The adsorbed substances float on the upper liquid surface of the sedimentation tank, and then the adsorbed substances on the upper liquid surface are separated out of the sedimentation tank; the bottom sewage flows from the connecting port to the sewage tank, and then flows from the outlet to the sewage treatment system; The preparation method of the adsorption material is: (1) dissolving polypropylene in toluene at room temperature and heating to dissolve it, then adding an alkylsilane compound to disperse it, and obtaining a dispersion after ultrasonic dispersion; the mass percentage of the polypropylene in toluene is 1-3%, and the mass percentage of the alkylsilane compound in toluene is 1-5%; (2) using citric acid to complex iron nitrate and barium nitrate to obtain a barium ferrite precursor, and then adding the barium ferrite precursor to step (1) to obtain a composite dispersion; (3) The melamine foam is immersed in the composite dispersion liquid. After refluxing and immersing for a period of time, the melamine foam is taken out to remove the toluene. After being left in the air for a period of time, the melamine foam is dried to a constant weight to obtain a modified melamine foam, i.e., an adsorption material.

2. The method for separating polytetrahydrofuran surface wastewater according to claim 1, characterized in that: The height of the water outlet is not higher than that of the water inlet.

3. The method for separating polytetrahydrofuran surface wastewater according to claim 1, characterized in that: The adsorption material is put into the sewage tank and the sewage treatment system.

4. The method for separating polytetrahydrofuran surface wastewater according to claim 1, characterized in that: In step (2), the molar ratio of ferric nitrate, barium nitrate and citric acid is 10-15:1:16-22.

5. The method for separating polytetrahydrofuran surface wastewater according to claim 1, characterized in that: In step (3), the mass ratio of the melamine foam to the barium ferrite precursor is 1:1-2.

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