Wastewater organic matter low-oxidation removal device utilizing enhanced electrolysis bubbles

Abstract

The utility model relates to a wastewater organic matter low-oxidation removal device utilizing enhanced electrolysis bubbles, which comprises an electrolytic tank, an organic matter collection tank and a surfactant collection tank, a diaphragm for dividing the inside of the electrolytic tank into an anode chamber and a cathode chamber is arranged in the middle of the electrolytic tank, and one of the anode chamber and the cathode chamber is selected as a wastewater treatment chamber; an anode electrode plate is arranged in the anode chamber, and a cathode electrode plate is arranged in the cathode chamber; a discharge groove is formed in one side of the upper opening of the wastewater treatment chamber, the discharge groove is connected with a first surfactant recovery pipe leading to the surfactant collection tank and a first discharge pipe leading to the organic matter collection tank, and the surfactant collection tank is connected with a surfactant feeding pipe leading to the wastewater treatment chamber. According to the device, electrolysis products (charged bubbles) are energized, organic matters are quickly removed in a low-oxidation manner, and the properties of the organic matters are not damaged, so that few byproducts of the organic matters are generated; meanwhile, compared with direct electrolytic oxidation of organic matters, the adhesion effect of the enhanced charged bubbles is quicker and more energy-saving.

Description

Technical Field

[0001] The utility model relates to the technical field of organic wastewater treatment, in particular to a device for low-oxidation removal of organic matter in wastewater by strengthening electrolytic bubbles. Background Art

[0002] Electrooxidation can rapidly and effectively degrade organic pollutants in wastewater. Humic acid is an organic pollutant ubiquitous in the aquatic environment. The organic load and toxicity of some high-concentration wastewaters (such as landfill leachate) are mainly caused by them because of their poor biodegradability. When treating these wastewaters by electrooxidation, the mineralization level of humic acid is affected by the treated water quality, especially when the water body contains hydroxyl radical scavengers; and when the mineralization degree of organic matter is low, toxic chlorinated organic by-products are easily formed.

[0003] In addition, the non-selective oxidation of organic matter during the electrooxidation process consumes a large amount of energy, and more energy is required for complete mineralization. According to thermodynamic analysis, more than 80% of the power consumption comes from the oxygen evolution reaction, which, however, is not directly related to the oxidation of organic matter. In order to improve the energy efficiency of the electrooxidation process, various current efforts focus on developing stable electrode materials and improving the performance of electrocatalysts that can achieve rapid electron transfer of organic matter. However, the bubbles generated during electrolysis have been ignored. Bubbles are rich in energy, and buoyancy is their most intuitive manifestation. Some bubbles can adsorb organic matter onto their surface, indicating that bubbles also have certain adhesion properties. The bubbles generated during electrolysis may exhibit a certain electric property under different pH conditions, and their zeta potential is -51.8~5.5 mV. The surface charge of bubbles can effectively enhance the adhesion force of bubbles to organic matter, making the bubbles more stable. However, the bubbles generated in traditional electrolysis are usually interlaced, which makes it difficult to analyze a single type of bubble. In addition, electrolytic bubbles with different surface charges are more likely to come into contact and merge, and the zeta potential of the bubbles will decrease as the bubble size increases, thus affecting the stability of the bubbles. Summary of the Utility Model

[0004] In view of this, the purpose of the utility model is to provide a device for low-oxidation removal of organic matter in wastewater by strengthening electrolytic bubbles, which can control the oxidation rate of organic matter at a relatively low level, produce fewer by-products, be fast and energy-saving, and have a low input cost.

[0005] The present utility model is implemented by the following scheme: A device for low-oxidation removal of organic matter in wastewater using enhanced electrolytic bubbles, comprising an electrolytic cell, an organic matter collection pool, and a surfactant collection pool. A diaphragm is provided in the middle of the electrolytic cell to divide the interior of the electrolytic cell into an anode chamber and a cathode chamber, and either the anode chamber or the cathode chamber is used as the wastewater treatment chamber; an anode electrode plate is provided in the anode chamber, and a cathode electrode plate is provided in the cathode chamber; on one side with an open top of the wastewater treatment chamber, there is a discharge trough, and the discharge trough is connected to a first surfactant recovery pipe leading to the surfactant collection pool and a first discharge pipe leading to the organic matter collection pool, and the surfactant collection pool is connected to a surfactant dosing pipe leading to the wastewater treatment chamber.

[0006] Furthermore, magnetic stirring rotors are respectively provided in the anode chamber and the cathode chamber, and magnetic stirrers are respectively provided on the lower sides of the anode chamber and the cathode chamber.

[0007] Furthermore, an aeration head A is provided at the bottom inside the organic matter collection pool, and an aeration head B is provided at the bottom inside the wastewater treatment chamber. The aeration head A and the aeration head B are respectively connected to the air outlet of an air pump through air supply pipes.

[0008] Furthermore, a slag scraping machine is provided above the wastewater treatment chamber to scrape the flotation substances floating on the liquid surface in the wastewater treatment chamber towards the discharge trough.

[0009] Furthermore, a discharge port A is provided on the side of the bottom of the wastewater treatment chamber, and a second discharge pipe is connected to the discharge port A. A discharge port B is provided on the side of the bottom of the organic matter collection pool, and a third discharge pipe communicating with the second discharge pipe is connected to the discharge port B. A pressure pump and a membrane filter are provided on the third discharge pipe.

[0010] Furthermore, the organic matter collection pool is connected to a second surfactant recovery pipe leading to the surfactant collection pool, and a water pump is provided on the surfactant dosing pipe.

[0011] Compared with the prior art, the present utility model has the following beneficial effects:

[0012] (1) The present utility model empowers the electrolytic products (charged bubbles) to rapidly remove organic matter in a low-oxidation manner. Since the properties of the organic matter are not damaged, fewer organic matter by-products are generated; at the same time, the adhesion effect of the enhanced charged bubbles is faster and more energy-saving compared to directly electrolyzing and oxidizing organic matter.

[0013] (2) The present utility model utilizes the oxygen evolution reaction that can be generated by most inert electrodes during the electrolysis process, that is, the electrolysis of water reaction. Although this reaction has nothing to do with the direct oxidation of organic substances, it generates a large number of micro-electric bubbles. Through membrane electrolysis, the utilization of these micro-electric bubbles is strengthened, enabling efficient removal of organic substances without the need to purchase electrodes with high oxidation potentials (such as boron-doped diamond electrodes), saving the high purchase cost of special oxidation electrodes.

[0014] (3) The membrane electrolysis system for strengthening electrolysis bubbles in the present utility model effectively utilizes the high-salt electrolyte in the wastewater to meet the conductivity of electrolysis. The device is compact, facilitating integration and large-scale operation, and the process of recovering resources is simple and effective.

[0015] To make the objectives, technical solutions, and advantages of the present utility model clearer and more understandable, the following will further elaborate on the present utility model through specific embodiments and relevant drawings. Description of the Drawings

[0016] Figure 1 Schematic diagram of the structure of the device for low-oxidation removal of organic substances in wastewater in the embodiment of the present utility model;

[0017] Figure 2 Oxidation situation of the treatment of humic acid by membrane electrolysis coupled with cationic surfactant CTAB;

[0018] Figure 3 Recovery situation of cationic surfactant CTAB by foam fractionation method;

[0019] Figure 4 Comparison chart of humic acid content;

[0020] Figure 5 Comparison chart of humic acid removal rates in the first cycle and the second cycle;

[0021] Explanation of the reference numerals in the figures: 1. Diaphragm; 2. Anode chamber; 3. Cathode chamber; 4. DC power supply; 5. Anode electrode plate; 6. Cathode electrode plate; 7. Magnetic stirring rotor; 8. Magnetic stirrer; 9. Scraper; 10. Discharge tank; 11. Organic matter collection pool; 12. Discharge port A; 13. Air pump; 14. Aeration head B; 15. Surfactant collection pool; 16. Aeration head A; 17. Water pump; 18. Discharge port B; 19. Pressure pump; 20. Membrane filter; 21. Stop valve. Specific Embodiments

[0022] It should be noted that the following detailed descriptions are all exemplary and are intended to provide further explanations for the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present application belongs.

[0023] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they specify the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0024] As Figure 1 shown, a device for low-oxidation removal of organic matter in wastewater using enhanced electrolytic bubbles includes an electrolytic cell, an organic matter collection tank 11, and a surfactant collection tank 15. A diaphragm is provided in the middle of the electrolytic cell to divide the interior of the electrolytic cell into an anode chamber 2 and a cathode chamber 3. Either the anode chamber 2 or the cathode chamber 3 serves as the wastewater treatment chamber. An anode electrode plate 5 is provided in the anode chamber 2, and a cathode electrode plate 6 is provided in the cathode chamber 3. The electrode plates can be immersed in the solution, and their manufacturing form can be mesh or sheet. Conventionally, the distance between the electrode plates and the diaphragm is 0.5 - 2 cm. When the anode chamber 2 or the cathode chamber 3 serves as the wastewater treatment chamber, the electrode plates therein are non-sacrificial electrode plates, such as inert electrode plates. On one side of the upper opening of the wastewater treatment chamber, there is a discharge tank 10. The discharge tank 10 is connected to a first surfactant recovery pipe leading to the surfactant collection tank 15 and a first discharge pipe leading to the organic matter collection tank. The surfactant collection tank is connected to a surfactant delivery pipe leading to the wastewater treatment chamber. The membrane electrolysis system adds a diaphragm compared to the traditional electrolysis system to separate the gases generated by the anode and cathode and avoid the mutual collision and contact of the gases. At the same time, the pH of the two chambers is regulated to make the electrolytic bubbles have a preliminary electrical property. By adding a surfactant to further empower the bubbles, the bubbles carry a stronger electrical charge and adhesion force. Compared with the traditional electrolytic oxidation system, it is not necessary to completely oxidize the organic matter, and the organic matter can be removed quickly with low oxidation. The discharge tank 10 is used to collect the flotation substances floating on the liquid surface. In the first stage, the main substances carried by the flotation substances are the organic matters in the wastewater, and at this time, the flotation substances are sent to the organic matter collection tank. In the second stage, the main substances carried by the flotation substances are the residual surfactants in the wastewater, and at this time, the flotation substances are sent to the surfactant collection tank to realize the recycling of the surfactant, saving the corresponding energy consumption, and at the same time, it is universal for most electrodes with low oxidation potentials.

[0025] To ensure the singleness of the bubble charge, a membrane electrolysis system is introduced. The membrane electrolysis system adds a diaphragm between the anode chamber and the cathode chamber, which can avoid the gas contact between the two chambers. In addition, it effectively reduces the H + / OH -Neutralization realizes the pH adjustment of a single chamber. The electrical properties of electrolytic bubbles can be further amplified instead of interfering with each other, and stronger electrostatic forces are imparted to the bubbles to carry more organic substances.

[0026] Surfactants with hydrophobic alkyl chains and hydrophilic heads are one of the most versatile organic compounds and can be used as bubble surface modifiers. The surfactant is located on the bubble surface, with its hydrophobic tail facing the inside of the bubble and its hydrophilic head facing the outside. The charged groups in the hydrophilic head can further enhance or reverse the electrical properties of the bubble. The hydrophobic interaction of the alkyl chains between surfactants maintains the cohesion of the surfactant layer. The presence of the surfactant layer reduces the gas-liquid surface tension, thereby reducing the Laplace pressure (ΔP Laplace = 2γ / r, where γ is the gas-liquid surface tension and r is the bubble radius), resulting in stable bubbles. In addition, ionic surfactants can bind charged organic substances (such as humic acid) in the aquatic environment and serve as a bridge connecting nanoparticles and organic substances. In particular, compared with other chemical additives, surfactants can be effectively recovered by foam fractionation.

[0027] By strengthening the electrolytic bubbles in this way, the low oxidative removal of stubborn organic substances is enhanced to save the unnecessary energy consumption brought by traditional electrolysis. At the same time, the use cost of the electrodes is saved, enabling electrodes with lower oxidation potentials to also be used as one of the electrode materials for electrooxidation to meet the economic requirements of practical applications.

[0028] By using the bubbles generated during the electrolysis process, performing single separation of the electrical properties of the electrolytic bubbles, and endowing them with surfactants, the electrolytic bubbles have excellent organic substance adhesion properties, and the strengthened electrolytic bubbles are relatively stable. Even when the oxidation or mineralization level of organic substances is low, they can be removed in large quantities from the water body and maintain the original properties of the organic substances, avoiding the generation of toxic organic by-products.

[0029] The anode electrode plate 5 and the cathode electrode plate 6 are respectively connected to the positive and negative poles of the DC power supply. According to the charged properties of the organic substances in the wastewater, the wastewater treatment chamber and the ionic surfactant with the opposite charged property are selected. The principle for using the surfactant is that the charge of the target organic substance and the used surfactant is of opposite sign. For example, if the charged organic substance is of the cation type, anionic surfactant can be selected. For wastewater with negatively charged organic substances, the anode chamber is selected as the wastewater treatment chamber for treatment, and the current density of the electrode plate is 1 - 100 mA / cm 2, the anolyte is wastewater, the volume of the anolyte and the cathode can be adjusted to 1:1~10:1, the cathode chamber can use KCl, K2SO4, NaCl, Na2SO4 electrolyte to directly configure the solution, and its concentration is acceptable in the range of 10~1000 mmol / L, the anode electrode plate needs to use a non-sacrificial anode plate (such as an inert electrode plate, such as titanium, ruthenium, iridium, graphite, iridium-tantalum composite, ruthenium-iridium composite electrode, etc.), the material of the cathode plate needs to ensure a certain conductivity material is not limited to an inert electrode or a sacrificial electrode (it can be a conventional metal sheet, such as copper, iron, aluminum, titanium plate, etc. can also be the above-mentioned inert electrodes, etc.), and the current and voltage are controlled by a DC power supply. Otherwise, the cathode chamber is selected as the wastewater treatment chamber for treatment. At this time, the cathode liquid is wastewater, the anolyte can be configured with K2SO4, Na2SO4, the cathode electrode plate needs to use a non-sacrificial anode plate (such as an inert electrode plate), and the anode plate is not limited to an inert electrode or a sacrificial electrode.

[0030] The wastewater organic matter low-oxidation removal device using enhanced electrolytic bubbles can be used to remove negatively charged organic matter (such as humic acid and fulvic acid) in wastewater, and can also be used to remove positively charged organic matter (such as ammonium salt organic matter); the selected anionic surfactant can be sodium dodecyl sulfate and sodium dodecyl sulfonate, and the selected cationic surfactant can be hexadecyl ammonium bromide and dodecyl ammonium bromide.

[0031] In this embodiment, the diaphragm may be a diaphragm-like membrane formed by stacking a commercially available pressure-driven membrane, an ion exchange membrane, or a porous material layer (such as nylon, non-woven fabric, polyester, or stainless steel mesh).

[0032] In this embodiment, the anode chamber and cathode chamber are respectively provided with magnetic stirring rotors 7, and the lower sides of the anode chamber and cathode chamber are respectively provided with magnetic stirrers 8; the magnetic stirring rotors 7 stir the solution to reduce the concentration polarization on both sides of the membrane to avoid the difficulty of ion transmission during the membrane electrolysis process, and the stirring position should try to avoid overlapping with the aeration position. In practical applications, stirring can also be achieved by means of water flow disturbance without built-in stirring.

[0033] In this embodiment, an aeration head A16 is provided at the bottom of the organic matter collection tank 11, and an aeration head B14 is provided at the bottom of the wastewater treatment chamber. The aeration head A and the aeration head B are respectively connected to the air outlet of the air pump 13 through an air supply pipe; the aeration head is provided to recover the surfactant in the wastewater treatment chamber and the organic matter collection tank by using the foam fractionation method, and foam fractionation is performed by the air pump and the aeration head. The surfactant after foam fractionation is enriched in the surfactant collection tank, and the enriched surfactant can be used for the next cycle of membrane electrolysis treatment. The air flow rate of the air pump is between 150 and 1000 mL / min, and the aeration time can be adjusted according to the amount of foam.

[0034] In this embodiment, a slag scraper 9 is provided above the wastewater treatment chamber, which scrapes the flotation substances floating on the liquid surface in the wastewater treatment chamber towards the discharge tank. The flotation substances on the surface are collected by the slag scraper 9 to separate the organic matter or surfactant from the wastewater. The slag scraper 9 is a prior art, and its structure and principle will not be specifically described here; the scraper can be driven by a chain or a traveling crane; the scraper in contact with the liquid needs to be made of a safe acid-resistant material. Due to the amphiphilic nature of the surfactant, the hydrophobic end will face the air end, so the bubbles formed by a large amount of surfactant can be scraped off by the slag scraper on the liquid surface.

[0035] In this embodiment, a discharge port A12 is provided on the side of the bottom of the wastewater treatment chamber, and a second discharge pipe is connected to the discharge port A. The clarified liquid in the lower part of the membrane electrolysis is discharged through the discharge port A12; a discharge port B18 is provided on the side of the bottom of the organic matter collection tank, and a third discharge pipe connected to the second discharge pipe is connected to the discharge port B. A pressure pump 19 and a membrane filter 20 are provided on the third discharge pipe. The effluent from the membrane recovery of the bottom sludge can be discharged together with the clarified liquid under the membrane electrolysis; the membrane filter 20 is used for the filtration and recovery of the bottom sludge, and the filter membrane used can be a commercially available pressure-driven membrane, namely, microfiltration membrane, ultrafiltration membrane, nanofiltration membrane, reverse osmosis membrane, etc., and the form can be flat membrane or hollow fiber membrane; when the membrane flux is reduced by 40%, it is backwashed with an alkali solution.

[0036] In this embodiment, the organic matter collection tank 11 is connected to a second surfactant recovery pipe leading to the surfactant collection tank. When the liquid level in the organic matter collection tank reaches 50%, the surfactant can also be recovered by foam fractionation. The surfactant is sent to the surfactant collection tank through the second surfactant recovery pipe. The organic matter collection tank can also carry the surfactant-containing flotation substances through the slag scraper. A water pump 17 is provided on the surfactant delivery pipe.

[0037] In this embodiment, stop valves 21 are provided on the first discharge pipe, the second discharge pipe, the third discharge pipe, the first surfactant recovery pipe, the second surfactant recovery pipe, the surfactant delivery pipe, and the air pipe.

[0038] A method for low-oxidation removal of humic acid from wastewater, using the above-described device for low-oxidation removal of organic matter from wastewater utilizing enhanced electrolytic bubbles, comprising the following steps: (1) The wastewater is externally filtered (with a pore size up to 15 μm) to remove suspended particles in the water body; (2) The anode chamber is selected as the wastewater treatment chamber and a cationic surfactant. The filtered wastewater is fed into the anode chamber of the electrolytic cell, and the cationic surfactant is added into the anode chamber. The anode electrode plate uses an inert electrode plate, and the cathode electrode plate also uses an inert electrode plate 6; (3) The anode electrode plate and the cathode electrode plate are energized to start operation; the final pH of the anolyte can reach 1.7 - 2.5, and the final pH of the catholyte can reach 11.7 - 12.4; the bubbles generated by electrolysis in the anode chamber have excellent organic matter adhesion performance under the enhancement of the surfactant's electric property. During the rising process of the bubbles, a large amount of humic acid will be carried and float on the liquid surface; (4) The skimmer is used to scrape the flotation substances into the discharge tank and send them into the organic matter collection pool through the first discharge pipe, realizing the removal of humic acid from the wastewater; (5) After the humic acid removal work is completed (generally when the humic acid removal reaches about 90%), the residual cationic surfactant in the wastewater is recovered by foam fractionation, that is, a large number of bubbles are generated by aeration. During the rising process of the bubbles, the cationic surfactant will be carried away and float on the liquid surface. The skimmer is used to scrape the flotation substances into the discharge tank and send them into the surfactant collection pool through the first surfactant recovery pipe; (6) When the liquid level of the solution in the organic matter collection pool is 50%, the cationic surfactant in the turbid liquid is recovered by foam fractionation; the turbid liquid in the organic matter collection pool is further statically separated. When the bottom mud exceeds 20 - 30%, the precipitated humic acid is filtered and collected, and the filtered humic acid can be washed and recovered with an alkali solution.

[0039] In this embodiment, in step (2), sacrificial electrodes such as iron and aluminum cannot be used, and the cathode liquid is prepared with common electrolytes such as (KCl, K2SO4, NaCl, Na2SO4), and the concentration can reach 10~1000 mmol / L. In step (3), during operation, the solutions on both sides of the diaphragm need to be stirred to reduce the concentration gradient on both sides of the membrane and control the occurrence of concentration polarization. In step (5), when the removal rate of organic matter reaches about 90%, the air pump 13 is turned on, and the aeration head 14 is aerated for 10 minutes. The aeration air flow rate is 150~1000 mL / min. The residual surfactant quickly reaches the liquid surface under the action of aeration, is scraped to the discharge tank by the scraper 9, and then enters the surfactant collection tank 15. In step (6), when the liquid level of the solution in the organic matter collection tank is 50%, the air pump 13 is turned on to aerate the aeration head 16 connected to the organic matter collection tank, so as to collect the residual surfactant in the organic matter collection tank and adjust the liquid level. The collected surfactant enters the surfactant collection tank 15. When the sludge in the organic matter collection tank exceeds 20-30%, membrane filtration can be performed to recover humic acid, and the sludge is discharged through the organic matter collection tank discharge port B18. Under the action of the pressure pump 19, it is filtered through the membrane filter 20 at a pressure of 0.2-0.8 MPa.

[0040] Under the action of membrane electrolysis, the pH on both sides of the diaphragm can be quickly regulated. The pH of the anode chamber is acidic, which makes the bubbles in the anode chamber of the membrane electrolysis initially positively charged and causes humic acid to aggregate under acidic conditions. At the same time, the addition of cationic surfactants can enhance the positive charge of the bubble surface, further amplify the charge of the bubbles, enhance the electrostatic force to adhere to organic matter, and thus increase the adhesion of bubbles to humic acid. Bubbles with a large amount of humic acid adhere to form a stable protective layer on the surface due to the hydrophobicity of the pollutants, thus showing stronger stability. With the large-scale removal of organic matter, some surfactants still remain in the wastewater, which can be simply aerated and recovered by foam fractionation. There are also certain surfactants on the bubbles bonded to humic acid in the organic matter collection tank. When the liquid level of the organic matter collection tank reaches 50%, the surfactant can also be recovered by foam fractionation. Finally, efficient organic pollutant removal is achieved with low energy consumption, and the added surfactant is recovered.

[0041] Since these processes do not require the destruction of organic substances and additives, the properties of the original compounds are retained. The recycled substances can still be used. The recycled humic acid can be used as a soil conditioner or as a fertilizer. Since the oxidation in the membrane electrolysis process is relatively low and does not change the properties of organic substances, the generation of toxic organic by-products is avoided. Compared with traditional electrolysis which requires large-scale oxidation or mineralization of organic substances, more energy can be saved, and through the recycling of organic substances and the reuse of additives, the economy of the whole system is stronger.

[0042] Compared with the traditional electro-oxidation process, the O2 generated by the electrolysis of water at the anode and the H2 generated at the cathode are mixed with each other. At the same time, H + generated at the anode and OH - generated at the cathode are mixed with each other, causing the mutual neutralization of the surface charges on the bubbles, and the electrolysis bubbles with different electricities attract each other, which easily causes the aggregation and fragmentation of the bubbles, thus reducing the stability of the bubbles. In the present utility model, through the membrane electrolysis system, the bubbles are separated by means of an internal diaphragm, so that the bubbles in a single chamber are relatively single. For example, only oxygen exists in the anode chamber during the electrolysis of water, and only hydrogen exists in the cathode chamber, which can avoid the interlacing of two different-electricity bubbles, maintain the charged property of a single bubble, and enhance the bubble stability. The slightly positive charge of the anode bubbles can initially adsorb negatively charged humic acid. At the same time, the membrane electrolysis can regulate the pH of the separated chambers. The anode continuously consumes hydroxide ions to make the water body acidic, and the cathode continuously consumes hydrogen ions in the water to make the solution alkaline. The presence of the diaphragm can limit the neutralization of acid-base ions on both sides, but maintain a certain ion migration. Under the acidic conditions in the anode chamber of the membrane electrolysis system, humic acid can aggregate.

[0043] Surfactants can further strengthen or reverse the charge of the bubbles. Using a positively charged cationic surfactant in the anode chamber of the membrane electrolysis system can strengthen the positive charge of the bubbles and at the same time enhance the stability of the bubbles. Since the oxygen generated at the anode of the membrane electrolysis initially has a certain positive charge, the attachment of the cationic surfactant to the bubbles is connected by a hydrophobic force, that is, the hydrophobic alkyl chain is connected to the gas in the bubbles. The charged head of the cationic surfactant may form a repulsion with the positive charge on the bubble liquid film, making the whole bubble have a larger contact surface area to carry humic acid. The aggregation of humic acid in the acidified state enables the bubbles to carry a large amount of organic substances at one time, thereby greatly improving the removal efficiency of humic acid. The organic substances adhered to the bubbles can form a natural protective layer for the bubbles, making it difficult for the gas to be transmitted inside and outside the bubbles, further enhancing the stability of the bubbles. The surfactant connects the bubbles and humic acid in the form of a bridge.

[0044] The following is a comparison between a test group using a membrane electrolysis system and a control group using a traditional electrolysis system:

[0045] In the experimental group, an ultrafiltration membrane was selected as the diaphragm in the membrane electrolysis system. 250 mL of wastewater (pH = 7.1) was introduced into the anode side of the membrane electrolysis system. The wastewater mainly contained 0.25 g / L of humic acid and 5 g / L of sodium sulfate. The cationic surfactant used was cetyltrimethylammonium bromide (CTAB), and the added concentration was 80 mg / L. A sodium sulfate solution with a concentration of 2.13 g / L was introduced into the cathode side. The reticulated electrode plate (Ti / Pt) was completely immersed (3.5 cm × 5 cm), the electrode spacing was 2 cm, and the current density calculated according to the electrode plate area was 10.28 mA / cm 2 , and the effective membrane area was 9 cm 2 . The DC power supply could provide two operating modes: constant current and constant voltage. The magnetic stirring intensity in both the anode chamber and the cathode chamber was 500 rpm. The aeration intensity had two gears, which were 150 / 600 mL / min respectively, and the aeration time was 10 min. When the membrane electrolysis system was started in the constant current mode, the current was 0.18 A and the voltage was 15.5 V.

[0046] An electrolysis system without a diaphragm was set as the control group, and the experimental conditions were exactly the same as those of the membrane electrolysis system. By comparing the differences in the energy efficiency of humic acid removal between the membrane electrolysis system and the traditional electrolysis system under the conditions of constant current, constant voltage, and the same energy consumption.

[0047] The test results are as follows:

[0048] Table 1 Differences in the energy efficiency of humic acid removal between the membrane electrolysis system and the traditional electrolysis system

[0049]

[0050] As shown in Table 1, whether under constant current / constant voltage / the same energy consumption, the relative efficiency (3.00) of the membrane electrolysis system is better than that of the traditional electrolysis system (constant current: 1.64; constant voltage: 0.14; same energy consumption: 1.42). After adding the cationic surfactant CTAB, the relative efficiency of the membrane electrolysis system still remains the highest (8.87), which is better than that of the traditional electrolysis system (constant current: 3.75; constant voltage: 0.82; same energy consumption: 4.17). This can be attributed to the regulation of pH from 7.1 to 2.23 during the electrolysis process in the membrane electrolysis system, while in the traditional electrolysis system, due to the occurrence of H + and OH -For the neutralization reaction, the pH after treatment basically remains between 7 and 9. At the same time, the bubbles in membrane electrolysis are relatively single. Single bubbles can exhibit stronger positive charges under acidic conditions, with stronger bubble stability, and can adhere to more humic acids through electrostatic interactions. At the same time, acidification can cause the aggregation of humic acids, enabling the bubbles to carry more humic acids at one time. The humic acids adhered to the bubble surface can form a natural barrier to maintain the stability of the bubbles. Therefore, when no surfactant is added, the relative efficiency of the membrane electrolysis system is superior to that of the traditional electrolysis system. After adding CTAB, the positive charge of the bubbles is enhanced, which can increase the adhesion amount of the bubbles and further enhance the stability of the bubbles. Therefore, after adding the surfactant, the relative efficiency of the membrane electrolysis system is still the highest.

[0051] As Figure 2 shown, during the treatment of humic acid by membrane electrolysis coupled with the cationic surfactant CTAB, the upper layer liquid can enrich high-concentration humic acids (963 - 1054%), and the organic matter content in the lower part of the liquid is greatly removed, leaving only (11.7 - 13.7%). By adding alkali to completely mix the upper and lower layer liquids, the oxidation rate of the organic matter after mixing recovery is tested to be 2.9 - 3.7%. This shows that the removal of humic acid mainly relies on the enhanced adhesion of electrolysis bubbles.

[0052] As Figure 3 shown, it is feasible to separate the cationic surfactant CTAB by foam fractionation, that is, by short-term aeration. 61% of CTAB can be recovered after 10 minutes of aeration at an aeration intensity of 150 mL / min, and 80% of CTAB can be recovered after 10 minutes of aeration at an aeration intensity of 600 mL / min.

[0053] As Figure 4 shown, after adding the surfactant to the membrane electrolysis system, in addition to 6.6% of the humic acid being complexed with the surfactant and 7.1% remaining in the lower layer liquid of the membrane electrolysis, the content in the upper layer liquid of the membrane electrolysis reaches 62.1%, and the residue on the electrodes and components reaches 24.2%. The expected recovery rate of humic acid is between 62.1% and 86.3%.

[0054] As Figure 5 shown, in the first cycle, the removal rate of humic acid by membrane electrolysis coupled with the surfactant reaches 88.4%, and the surfactant is collected by foam fractionation. With a short-term aeration flow rate of 600 mL / min for 10 minutes, the surfactant collected by the skimmer and added in the second cycle can still make the humic acid removal rate reach 88.9%.

[0055] Therefore, in the actual application process, using enhanced charged bubbles as a treatment method for removing humic acid can not only reduce energy consumption, but also efficiently recover humic acid and additives. Moreover, this method effectively reduces the requirement for the high oxidation potential of the electrodes used in electrolysis and saves the investment cost.

[0056] For any of the technical solutions disclosed in the present utility model as described above, unless otherwise stated, if it discloses a numerical range, the disclosed numerical range is a preferred numerical range. Any person skilled in the art should understand that the preferred numerical range is only the numerical values with relatively obvious technical effects or representativeness among many feasible numerical values. Since there are too many numerical values to enumerate, the present utility model only discloses some numerical values to illustrate the technical solutions of the present utility model. Moreover, the numerical values listed above should not constitute a limitation to the protection scope of the creation of the present utility model.

[0057] If the present utility model discloses or involves components or structural parts that are fixedly connected to each other, then, unless otherwise stated, the fixed connection can be understood as: a detachable fixed connection (such as using bolts or screws for connection), or it can also be understood as: a non-detachable fixed connection (such as riveting or welding). Of course, the components fixedly connected to each other can also be replaced by an integral structure (such as manufactured by an integral casting process) (except when it is obviously impossible to adopt the integral forming process).

[0058] In addition, for the terms used to represent the positional relationship or shape in any of the technical solutions disclosed in the present utility model as described above, unless otherwise stated, their meanings include states or shapes that are approximate, similar, or close to them.

[0059] Any component provided by the present utility model can either be assembled from multiple separate components or be a single component manufactured by an integral forming process.

[0060] The above are only the preferred embodiments of the present utility model and do not limit the present utility model in any other form. Any person skilled in the relevant art may use the technical content disclosed above to make changes or modifications into equivalent embodiments with equivalent changes. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present utility model without departing from the content of the technical solution of the present utility model still fall within the protection scope of the technical solution of the present utility model.

Claims

1. A wastewater organic matter low-oxidation removal device using enhanced electrolytic bubbles, characterized in that: It includes an electrolytic cell, an organic matter collection pool and a surfactant collection pool. A diaphragm is provided in the middle of the electrolytic cell to divide the interior of the electrolytic cell into an anode chamber and a cathode chamber, and either the anode chamber or the cathode chamber is used as a wastewater treatment chamber; an anode electrode plate is provided in the anode chamber, and a cathode electrode plate is provided in the cathode chamber; on one side of the upper opening of the wastewater treatment chamber, there is a discharge trough, and the discharge trough is connected with a first surfactant recovery pipe leading to the surfactant collection pool and a first discharge pipe leading to the organic matter collection pool, and the surfactant collection pool is connected with a surfactant feeding pipe leading to the wastewater treatment chamber.

2. The wastewater organic matter low oxidation removal device using enhanced electrolytic bubbles according to claim 1, characterized in that: Magnetic stirring rotors are respectively provided in the anode chamber and the cathode chamber, and magnetic stirrers are respectively provided on the lower sides of the anode chamber and the cathode chamber.

3. The wastewater organic matter low oxidation removal device using enhanced electrolytic bubbles according to claim 1, characterized in that: An air diffuser A is provided at the bottom inside the organic matter collection pool, and an air diffuser B is provided at the bottom inside the wastewater treatment chamber. The air diffuser A and the air diffuser B are respectively connected with the air outlet of an air pump through an air supply pipe.

4. The device for low-oxidation removal of organic matter in wastewater using enhanced electrolytic bubbles according to claim 1, wherein: A slag scraping machine is provided above the wastewater treatment chamber to scrape the air flotation substances floating on the liquid surface in the wastewater treatment chamber towards the discharge trough.

5. The wastewater organic matter low oxidation removal device using enhanced electrolytic bubbles according to claim 1, characterized in that: A discharge port A is provided on the side of the bottom of the wastewater treatment chamber, and a second discharge pipe is connected to the discharge port A. A discharge port B is provided on the side of the bottom of the organic matter collection pool, and a third discharge pipe communicating with the second discharge pipe is connected to the discharge port B. A pressure pump and a membrane filter are provided on the third discharge pipe.

6. The wastewater organic matter low-oxidation removal device using enhanced electrolytic bubbles according to claim 1, characterized in that: The organic matter collection pool is connected with a second surfactant recovery pipe leading to the surfactant collection pool, and a water pump is provided on the surfactant feeding pipe.

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