Sodium hypochlorite generating device

Abstract

The application belongs to the field of drinking water treatment and particularly relates to a sodium hypochlorite generating device, which comprises a brine tank, a sodium hypochlorite tank and an electrolytic cell in communication with the brine tank and the sodium hypochlorite tank respectively. An anode plate, a first partition plate, a selective ion exchange membrane, a second partition plate and a cathode plate are sequentially arranged in the electrolytic cell. A porous layer is arranged on the surface of the anode plate, and a high-crystalline nanoporous material obtained by reacting a metal salt with tetra(4-(aminopyrazol-3-yl)phenyl)ethylene is loaded in the porous layer. The selective ion exchange membrane is a sulfonated polyphenyl ether membrane containing sodium polystyrene sulfonate and polytriphenylphosphonium. A positively charged membrane is arranged on the surface of the cathode plate, and the positively charged membrane comprises a base membrane and a polyallylamine hydrochloride layer arranged on the surface of the base membrane. Through the synergistic effect of the anode antifouling, the cathode scale prevention and the high-selectivity ion exchange membrane, the current efficiency is significantly improved, the salt consumption and the energy consumption are reduced, and the efficient and stable preparation of sodium hypochlorite disinfectant is realized.

Description

Technical Field

[0001] This invention relates to the field of drinking water treatment technology, and more specifically to a sodium hypochlorite generating device. Background Technology

[0002] Drinking water treatment is a crucial aspect of safeguarding public health, and disinfection, as a key component of the water treatment process, aims to effectively inactivate pathogenic microorganisms such as bacteria and viruses in water, preventing the spread of waterborne infectious diseases. Currently, mainstream drinking water disinfection technologies include chlorination, ultraviolet disinfection, and ozone disinfection. Among these, chlorination has become the most widely used disinfection method globally due to its reliable and sustained disinfection effect and relatively low cost.

[0003] In chlorination disinfection systems, commonly used disinfectants include liquid chlorine, calcium hypochlorite, and sodium hypochlorite. Sodium hypochlorite solution is miscible with water in any proportion. Sodium hypochlorite hydrolyzes in water to produce hypochlorous acid, a highly oxidizing acid that can effectively penetrate the interior of bacteria and viruses, reacting with proteins, nucleic acids, and enzymes to inactivate them. Furthermore, the effective chlorine content of sodium hypochlorite is easy to measure and control, facilitating precise dosing.

[0004] Currently, sodium hypochlorite is mostly prepared on-site by electrolyzing sodium chloride solution to avoid safety risks caused by decomposition, corrosion, or leakage during transportation and storage. However, in actual operation, existing sodium hypochlorite generators suffer from problems such as easy scaling on the electrode plates, low current efficiency, and high salt and energy consumption. Although diaphragm-type sodium hypochlorite generators have been gradually promoted in recent years to improve their electrolysis efficiency and operational stability, the problems of significantly reduced current efficiency, high salt and energy consumption, and sensitivity to brine quality and operating environment, resulting in unstable operation, remain largely unresolved.

[0005] Therefore, there is a need to provide a sodium hypochlorite generator with higher current efficiency, lower salt and energy consumption, and stable operation. Summary of the Invention

[0006] (a) Technical problems to be solved

[0007] In view of the above-mentioned technical problems, the present invention provides a sodium hypochlorite generating device that can improve current efficiency, reduce salt consumption and energy consumption, and has good operational stability.

[0008] (II) Technical Solution

[0009] To achieve the above objectives, the main technical solutions adopted by the present invention include:

[0010] The present invention provides a sodium hypochlorite generating device, comprising a brine tank, a sodium hypochlorite water tank, and an electrolytic cell respectively connected to the brine tank and the sodium hypochlorite water tank;

[0011] The electrolytic cell is internally arranged with an anode plate, a first partition plate, a selective ion exchange membrane, a second partition plate, and a cathode plate in sequence.

[0012] The surface of the anode plate is provided with a porous layer, in which a highly crystalline nanoporous material obtained by reacting a metal salt with tetrakis(4-(aminopyrazole-3-yl)phenyl)ethylene is loaded.

[0013] The selective ion exchange membrane is a sulfonated polyphenylene ether membrane containing sodium polystyrene sulfonate and poly(terphenylpiperidine);

[0014] The cathode plate is provided with a positively charged membrane on its surface, the positively charged membrane comprising a base membrane and a polyallylamine hydrochloride layer disposed on the surface of the base membrane.

[0015] In the sodium hypochlorite generating apparatus described above, preferably, the electrolytic cell is connected to the brine tank and the sodium hypochlorite water tank via pipes and a water pump, respectively.

[0016] The anode plate is a titanium-coated ruthenium-iridium plate;

[0017] The first partition and the second partition are made of polytetrafluoroethylene, polyvinylidene fluoride, or chlorinated polyvinyl chloride.

[0018] The cathode plate is a titanium plate or a nickel plate.

[0019] In the sodium hypochlorite generating apparatus described above, preferably, the porous layer is a polyolefin porous layer; the polyolefin porous layer is a polyethylene porous layer, a polypropylene porous layer, or a polyethylene-polypropylene porous layer.

[0020] In the sodium hypochlorite generating apparatus described above, the preferred method for preparing the highly crystalline nanoporous material is as follows:

[0021] Metal salt and tetra(4-(aminopyrazole-3-yl)phenyl)ethylene are added to an organic solvent, ultrasonically treated for 15-30 min, and then reacted at 120-140℃ for 50-80 h to obtain highly crystalline nanoporous material.

[0022] The mass ratio of the metal salt to tetra(4-(aminopyrazol-3-yl)phenyl)ethylene is 1.5:1-3:1;

[0023] The metal salt is zinc nitrate or aluminum nitrate;

[0024] The organic solvent is N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, or dimethyl sulfoxide.

[0025] In the sodium hypochlorite generating apparatus described above, preferably, the selective ion exchange membrane is prepared as follows:

[0026] A selective ion exchange membrane was obtained by repeatedly coating a sulfonated polyphenylene ether membrane with a mixed solution of sodium polystyrene sulfonate and poly(terphenylpiperidine) and drying it.

[0027] In the mixed solution, the concentration of sodium polystyrene sulfonate is 10-30 g / L, and the concentration of poly(terphenylpiperidine) is 2-6 g / L.

[0028] In the sodium hypochlorite generating apparatus described above, preferably, the polyallylamine hydrochloride layer is fixed to the base film by crosslinking with an aldehyde crosslinking agent.

[0029] In the sodium hypochlorite generating apparatus described above, preferably, the positively charged diaphragm is prepared by the following method:

[0030] Under pH conditions of 3-5, a 5-15 g / L polyallylamine hydrochloride solution is coated onto the base membrane. After drying, the base membrane is immersed in a 0.05-0.25 wt% hexamethylenetetramine solution for 15-30 min, then removed, cleaned, and dried to obtain a positively charged membrane.

[0031] In the sodium hypochlorite generating apparatus described above, preferably, the base membrane is a polysulfone membrane, a polyethersulfone membrane, or a polyvinylidene fluoride membrane.

[0032] In the sodium hypochlorite generating apparatus described above, preferably, in the electrolytic cell, the anode plate, the first partition plate, and the selective ion exchange membrane form the anode chamber, and the cathode plate, the second partition plate, and the selective ion exchange membrane form the cathode chamber;

[0033] The brine tank is used to supply the anode chamber and the cathode chamber with sodium chloride solution prepared from tap water or concentrated water obtained from seawater desalination. The anolyte generated in the anode chamber and the catholyte generated in the cathode chamber enter the sodium hypochlorite tank and generate sodium hypochlorite solution in the sodium hypochlorite tank.

[0034] The sodium hypochlorite generating apparatus described above, preferably, operates at 300-1500 A / m. 2 Operating at a current density, the residence time of sodium chloride solution prepared from tap water or concentrated water obtained from seawater desalination in the electrolyzer is 2-6 minutes.

[0035] (III) Beneficial Effects

[0036] The sodium hypochlorite generator of this invention effectively inhibits the deposition of calcium and magnesium ions and organic contaminants in the brine solution on the electrode surface by loading a highly crystalline nanoporous material and setting a positively charged membrane with a polyallylamine hydrochloride layer on the cathode plate. The highly crystalline nanoporous material adsorbs and degrades organic contaminants, reducing anode contamination, while the positively charged membrane prevents calcium and magnesium ions in the brine solution from precipitating and forming scale on the cathode plate. The synergistic effect of the highly crystalline nanoporous material and the positively charged membrane significantly reduces electrode surface fouling and activity loss, effectively preventing a decrease in device current efficiency due to scaling and contamination, thereby ensuring long-term stable operation of the device and helping to reduce salt and energy consumption.

[0037] The selective ion exchange membrane of this invention can preferentially adsorb polyvalent cations such as calcium and magnesium through electrostatic interaction, shielding the interaction with sodium ions. At the same time, it can effectively increase the negative charge density, providing a low-resistance and fast transport channel for sodium ions, thereby improving current efficiency and operational stability, as well as reducing salt consumption and power consumption. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of the overall structure of the sodium hypochlorite generating device in this invention.

[0039] [Explanation of Labels in the Attached Image]

[0040] 1: Brine tank; 2: Sodium hypochlorite tank; 3: Electrolytic cell; 4: Anode plate; 5: First partition; 6: Selective ion exchange membrane; 7: Second partition; 8: Cathode plate; 9: Pipeline; 10: Water pump; 11: Exhaust port; 12: Chlorine absorption device. Detailed Implementation

[0041] To better explain and facilitate understanding of the present invention, the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0042] like Figure 1 As shown, this invention provides a sodium hypochlorite generating device, including a brine tank 1, a sodium hypochlorite water tank 2, and an electrolytic cell 3 connected to both the brine tank 1 and the sodium hypochlorite water tank 2. Inside the electrolytic cell 3, an anode plate 4, a first partition plate 5, a selective ion exchange membrane 6, a second partition plate 7, and a cathode plate 8 are sequentially arranged. A porous layer is formed on the surface of the anode plate 4, and a highly crystalline nanoporous material obtained by reacting a metal salt with tetrakis(4-(aminopyrazole-3-yl)phenyl)ethylene is loaded in the porous layer. The selective ion exchange membrane 6 is a sulfonated polyphenylene ether membrane containing sodium polystyrene sulfonate and poly(terphenylpiperidine). A positively charged membrane is formed on the surface of the cathode plate 8, comprising a base membrane and a polyallylamine hydrochloride layer disposed on the surface of the base membrane.

[0043] In the aforementioned electrolytic cell 3, the anode plate 4, the first partition 5, and the selective ion exchange membrane 6 together form the anode chamber, and the cathode plate 8, the second partition 7, and the selective ion exchange membrane 6 together form the cathode chamber. The brine tank 1 is used to supply the anode chamber and cathode chamber with a sodium chloride solution prepared from tap water or concentrated water obtained from seawater desalination. After the reaction, the anolyte produced in the anode chamber and the catholyte produced in the cathode chamber enter the sodium hypochlorite tank 2, where a sodium hypochlorite solution is generated.

[0044] In addition, after the chlorine gas generated at the anode enters the sodium hypochlorite tank 2 along with the anolyte and reacts, any unreacted chlorine gas can be absorbed and treated by a chlorine absorption device 12 connected to the sodium hypochlorite tank 2, thus preventing harm. In a non-sealed environment, the hydrogen gas generated at the cathode can be discharged through the exhaust port 11 located on the cathode chamber. Besides directly introducing the anolyte into the sodium hypochlorite tank via pipes and pumps, a negative pressure device can also be used to directly draw the chlorine gas generated in the anode chamber into the sodium hypochlorite tank, allowing the chlorine gas to react with the alkaline cathode liquid to obtain a sodium hypochlorite solution.

[0045] When the brine tank 1 is filled with sodium chloride solution prepared from tap water or concentrated water obtained from seawater desalination, impurities such as calcium and magnesium ions and organic pollutants will inevitably be introduced.

[0046] The sodium hypochlorite generator of this invention achieves efficient and stable operation of the electrolysis process through the coordinated operation of multiple components. Specifically, a porous layer on the surface of the anode plate 4 is loaded with a highly crystalline nanoporous material prepared by reacting a metal salt with tetrakis(4-(aminopyrazole-3-yl)phenyl)ethylene. This material possesses a highly ordered crystal structure and abundant nitrogen coordination sites, with a pore volume of 0.3-0.5 cm³. 3 / g, can effectively adsorb organic pollutants in brine and promote the mineralization and degradation of organic pollutants by utilizing the coordination effect between its metal nodes and organic matter, thereby reducing the accumulation of organic matter at the anode interface. This characteristic significantly reduces the risk of organic impurities covering the anode active coating, alleviates the problem of increased charge transfer resistance caused by contamination, helps maintain good electrocatalytic activity of the anode, inhibits the occurrence of side reactions such as oxygen evolution, and thus improves the effective current utilization rate and slows down the decline trend of the overall current efficiency of the device.

[0047] The positively charged membrane disposed on the surface of the cathode plate 8 includes a base film and a polyallylamine hydrochloride layer disposed on its surface. The polyallylamine hydrochloride layer can impart a persistent positive charge to the membrane surface. When containing polyvalent cations such as Ca... 2+ Mg 2+When brine flows through the diaphragm, the positive charge on the membrane surface effectively prevents calcium and magnesium ions from approaching and adhering to the surface of the cathode plate 8 through electrostatic repulsion. This mechanism fundamentally prevents the precipitation and accumulation of insoluble scale layers such as calcium hydroxide and magnesium hydroxide on the cathode, thereby ensuring continuous exposure and efficient operation of the cathode reaction interface and solving the problem of decreased current efficiency and unstable operation caused by cathode scaling.

[0048] More preferably, the porous layer is disposed on the surface of the anode plate in contact with the solution, and the positively charged diaphragm is disposed on the surface of the cathode plate in contact with the solution.

[0049] In the selective ion exchange membrane 6, sodium polystyrene sulfonate increases the negative charge density of the membrane, enhancing its selective permeability to cations and providing a low-resistance, rapid transport channel for sodium ions. Meanwhile, poly(terphenylpiperidine) contains multiple aromatic rings and nitrogen atoms in its molecular structure, exhibiting strong cation-binding capacity. It can enrich and retain polyvalent cations such as calcium and magnesium on the membrane surface, weakening their competitive interference with sodium ion migration pathways and forming a shielding effect during sodium ion transport. The synergistic effect of these two components improves current efficiency and operational stability, while reducing salt and power consumption.

[0050] Preferably, the electrolytic cell 3, especially the anode chamber and cathode chamber in the electrolytic cell 3, can be connected to the brine tank 1 and the sodium hypochlorite tank 2 respectively through pipes and water pumps.

[0051] The aforementioned anode plate 4 is preferably a titanium-coated ruthenium-iridium plate. The titanium substrate coated with the ruthenium-iridium coating exhibits excellent electrocatalytic activity and corrosion resistance, especially showing high selectivity for the chlorine evolution reaction. It can effectively promote the oxidation of chloride ions to generate chlorine gas, which is then hydrolyzed to form hypochlorite, increasing the formation rate of the target product. Simultaneously, its good conductivity and structural stability under strong oxidizing environments can reduce the occurrence of side reactions, decrease ineffective current loss, and extend electrode lifespan, thereby ensuring the current efficiency and reliability of the device during long-term operation.

[0052] The first partition 5 and the second partition 7 can be made of polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), or chlorinated polyvinyl chloride (PVC). PTFE, PVDF, and PVC possess excellent chemical stability, corrosion resistance, and mechanical strength, enabling them to be used long-term in electrolytic environments containing chlorine, high salt, and with a wide pH range without swelling or degradation. As internal partition components of the electrolytic cell 3, these materials also effectively support the selective ion exchange membrane 6 and maintain physical isolation between the anode and cathode chambers, preventing gas crosstalk and solution short circuits, and ensuring the safe and stable operation of the electrolysis process.

[0053] The cathode plate 8 can be a titanium plate or a nickel plate. Titanium or nickel plates, as cathode materials, have good electrical conductivity and corrosion resistance in alkaline environments.

[0054] Preferably, the porous layer in this invention is a polyolefin porous layer, specifically a polyethylene porous layer, a polypropylene porous layer, or a polyethylene-polypropylene porous layer, etc. Polyolefin materials possess excellent chemical stability, corrosion resistance, and hydrophilic / hydrophobic compatibility, enabling them to remain stable for extended periods in saline, weakly alkaline, or weakly acidic electrolytic environments without easily swelling, aging, or detaching. As a carrier for highly crystalline nanoporous materials, this porous layer's abundant pore structure facilitates sufficient contact between pollutants and the loaded material, improving adsorption efficiency. Simultaneously, it has minimal impact on water flow resistance, ensuring effective electrolyte circulation.

[0055] The preparation method of the above-mentioned highly crystalline nanoporous material is as follows:

[0056] A metal salt and tetrakis(4-(aminopyrazole-3-yl)phenyl)ethylene are added to N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, or dimethyl sulfoxide, and the mixture is ultrasonically treated for 15-30 min, followed by reaction at 130 °C for 50-80 h to obtain a highly crystalline nanoporous material. The mass ratio of the metal salt to tetrakis(4-(aminopyrazole-3-yl)phenyl)ethylene is 1.5:1-3:1, and the preferred metal salt is zinc nitrate or aluminum nitrate.

[0057] Zinc or aluminum ions in the metal salt act as metal nodes, coordinating with multiple nitrogen atoms on the tetra(4-(aminopyrazol-3-yl)phenyl)ethylene molecule to gradually self-assemble into a metal-organic framework-like highly crystalline nanoporous material with a periodic network structure. A longer reaction time promotes slow crystal growth, improving the material's crystallinity and structural order. A reaction temperature of 120-140℃ is suitable, promoting coordination bond formation while preventing the decomposition of organic ligands, ensuring product stability. Organic solvents such as DMF and DMSO possess strong polarity and good thermal stability, effectively dissolving the metal salt and macromolecular ligands, maintaining system homogeneity at high temperatures, preventing precipitation or aggregation, and contributing to the formation of porous materials with uniform channels and complete structures. Ultrasonic pretreatment accelerates raw material mixing and initial depolymerization, improving the homogeneity of the initial reaction stage.

[0058] The highly crystalline nanoporous material prepared by the above method possesses a highly ordered crystalline structure, large pore volume, and abundant nitrogen active sites. It not only exhibits strong adsorption capacity for organic pollutants in water, but its metal centers can also serve as catalytic active sites, promoting the oxidative degradation of organic matter, thus synergistically achieving a dual purification function of adsorption and degradation. This characteristic enables it to effectively intercept and remove organic impurities in brine after being loaded onto the surface of anode plate 4, significantly reducing their accumulation at the electrode interface, inhibiting anode contamination and side reactions, maintaining stable electrolysis efficiency, and extending the device's operating cycle.

[0059] It should be noted that tetra(4-(aminopyrazole-3-yl)phenyl)ethylene can specifically be tetra(4-(5-aminopyrazole-3-yl)phenyl)ethylene, which can be prepared by introducing an amino group at the 5-position of the pyrazole ring of tetra(4-(5-aminopyrazole-3-yl)phenyl)ethylene.

[0060] The structural formula of tetra(4-(pyrazol-3-yl)phenyl)ethylene is as follows:

[0061] ;

[0062] The structural formula of tetra(4-(5-aminopyrazole-3-yl)phenyl)ethylene is as follows:

[0063] ;

[0064] Preferably, the selective ion exchange membrane 6 is prepared as follows:

[0065] A selective ion exchange membrane 6 is obtained by repeatedly coating a sulfonated polyphenylene ether membrane with a mixed solution of sodium polystyrene sulfonate and poly(terphenylpiperidine), followed by drying. The concentration of sodium polystyrene sulfonate in the mixed solution is 10-30 g / L, and the concentration of poly(terphenylpiperidine) is 2-6 g / L. More preferably, the mixed solution is coated at least twice.

[0066] The above preparation method constructs a functional surface layer with high ion selectivity on the basis of the original sulfonated polyphenylene ether membrane through physical coating and drying. Multiple coatings ensure that the functional layer is uniform and dense, avoids local defects, and improves the overall stability and durability of the membrane. Drying is used to promote solvent evaporation, allowing sodium polystyrene sulfonate and poly(terphenylpiperidine) to adhere firmly to the sulfonated polyphenylene ether membrane.

[0067] Preferably, the base membrane can be a polysulfone membrane, a polyethersulfone membrane, or a polyvinylidene fluoride membrane.

[0068] Preferably, the above-mentioned polyallylamine hydrochloride layer can be fixed on the base film by crosslinking with an aldehyde crosslinking agent. Specifically, the method for preparing the positively charged separator is as follows:

[0069] Under pH conditions of 3-5, a 5-15 g / L polyallylamine hydrochloride solution is coated onto the base membrane. After drying, the base membrane is immersed in a 0.05-0.25 wt% hexamethylenetetramine solution for 15-30 min, then removed, cleaned, and dried to obtain a positively charged membrane.

[0070] The aforementioned crosslinking treatment effectively improves the adhesion stability of the polyallylamine layer in the electrolytic environment, preventing it from dissolving or detaching during operation and ensuring the long-term maintenance of the surface positive charge. A stable positively charged layer continuously repels cations such as calcium and magnesium in the brine, reducing their migration and accumulation towards the cathode, thereby inhibiting the deposition and scaling of hydroxides on the cathode plate 8, ensuring stable operation of the electrolysis process, and reducing maintenance frequency.

[0071] The sodium hypochlorite generator of the present invention can operate at 300-1500 A / m 2 The stable and efficient operation over a relatively wide current density range demonstrates the excellent adaptability of its electrode structure and membrane system to different loads. Within this range, the device maintains high current efficiency, avoiding insufficient yield due to excessively low current density or exacerbated side reactions and increased energy consumption due to excessively high current density. Simultaneously, the hydraulic residence time of the sodium chloride solution prepared from tap water or the concentrated water from seawater desalination in electrolyzer 3 is 2-6 minutes, resulting in a short process and rapid reaction, which is conducive to compact design and continuous production. These operating conditions match actual engineering requirements, ensuring both the effective chlorine generation rate and balancing energy efficiency and equipment lifespan, reflecting the device's excellent comprehensive performance and strong on-site operability.

[0072] To further clarify the present invention and its technological advancements, the following description is provided in conjunction with specific embodiments and technical effects.

[0073] Example 1

[0074] This embodiment provides a sodium hypochlorite generating device, including a brine tank, a sodium hypochlorite water tank, and an electrolytic cell connected to the brine tank and the sodium hypochlorite water tank respectively via a water pump and pipelines. Inside the electrolytic cell, an anode plate, a polytetrafluoroethylene (PTFE) plate, a selective ion exchange membrane, another PTFE plate, and a cathode plate are arranged sequentially. In this embodiment, the anode plate is a titanium-coated ruthenium-iridium plate, its surface coated with a porous polyethylene layer, in which a highly crystalline nanoporous material is loaded. The selective ion exchange membrane is a sulfonated polyphenylene ether membrane containing sodium polystyrene sulfonate and poly(terphenylpiperidine). The cathode plate is a titanium plate, its surface having a positively charged membrane, which includes a polysulfone membrane and a polyallylamine hydrochloride layer disposed on the surface of the polysulfone membrane.

[0075] In this embodiment, the preparation method of the highly crystalline nanoporous material is as follows: zinc nitrate and tetrakis(4-(5-aminopyrazole-3-yl)phenyl)ethylene in a mass ratio of 1.5:1 are added to N,N-dimethylformamide, ultrasonically treated for 20 min, and then reacted at 130℃ for 50 h to obtain the highly crystalline nanoporous material.

[0076] The selective ion exchange membrane is prepared as follows: a mixed solution of sodium polystyrene sulfonate and poly(terphenylpiperidine) is coated twice onto a sulfonated polyphenylene ether membrane, and the membrane is dried to obtain the selective ion exchange membrane. In the mixed solution, the concentration of sodium polystyrene sulfonate is 10 g / L, and the concentration of poly(terphenylpiperidine) is 4 g / L.

[0077] The positively charged membrane is prepared as follows: Under pH 3 conditions, a 10 g / L polyallylamine hydrochloride solution is coated on a polysulfone membrane. After drying, the polysulfone membrane is immersed in a 0.25 wt% hexamethylene aldehyde solution for 15 min, then removed, cleaned, and dried to obtain the positively charged membrane.

[0078] In this embodiment, the anode plate and the selective ion exchange membrane together form the anode chamber, and the cathode plate and the selective ion exchange membrane together form the cathode chamber. A brine tank supplies concentrated water obtained from seawater desalination to the anode and cathode chambers. The anolyte produced in the anode chamber and the catholyte produced in the cathode chamber enter the sodium hypochlorite tank and react to generate sodium hypochlorite.

[0079] The sodium hypochlorite generator in this embodiment operates under a current density of 500 A / m. 2 The residence time of the concentrated water obtained from seawater desalination in the electrolyzer is 6 minutes.

[0080] After testing, the sodium hypochlorite generator of this embodiment can operate efficiently and stably for more than 2 months, with a current efficiency of 91.8%, salt consumption of 4.1 kg / kg, and energy consumption of 4.6 kWh / kg.

[0081] Example 2

[0082] This embodiment provides a sodium hypochlorite generating device, including a brine tank, a sodium hypochlorite water tank, and an electrolytic cell connected to the brine tank and the sodium hypochlorite water tank respectively via a water pump and pipelines. Inside the electrolytic cell, an anode plate, a polyvinylidene fluoride (PVDF) plate, a selective ion exchange membrane, another PVDF plate, and a cathode plate are arranged sequentially. In this embodiment, the anode plate is a titanium-coated ruthenium-iridium plate, its surface coated with a porous polypropylene layer, in which a highly crystalline nanoporous material is loaded. The selective ion exchange membrane is a sulfonated polyphenylene ether membrane containing sodium polystyrene sulfonate and poly(terphenylpiperidine). The cathode plate is a nickel plate, its surface disposed of with a positively charged membrane, which includes a polyethersulfone (PES) membrane and a polyallylamine hydrochloride layer disposed on the surface of the PES membrane.

[0083] In this embodiment, the preparation method of the highly crystalline nanoporous material is as follows: aluminum nitrate and tetrakis(4-(5-aminopyrazole-3-yl)phenyl)ethylene in a mass ratio of 2:1 are added to N,N-dimethylacetamide, ultrasonically treated for 15 min, and then reacted at 120℃ for 80 h to obtain the highly crystalline nanoporous material.

[0084] The selective ion exchange membrane is prepared as follows: a mixed solution of sodium polystyrene sulfonate and poly(terphenylpiperidine) is coated twice onto a sulfonated polyphenylene ether membrane, and the membrane is dried to obtain the selective ion exchange membrane. In the mixed solution, the concentration of sodium polystyrene sulfonate is 20 g / L, and the concentration of poly(terphenylpiperidine) is 6 g / L.

[0085] The positively charged membrane is prepared as follows: Under pH 4 conditions, a 15 g / L polyallylamine hydrochloride solution is coated on a polyethersulfone membrane. After drying, the polyethersulfone membrane is immersed in a 0.1 wt% hexamethylene aldehyde solution for 20 min, then removed, cleaned, and dried to obtain the positively charged membrane.

[0086] In this embodiment, the anode plate and the selective ion exchange membrane together form the anode chamber, and the cathode plate and the selective ion exchange membrane together form the cathode chamber. A brine tank supplies concentrated water obtained from seawater desalination to the anode and cathode chambers. The anolyte produced in the anode chamber and the catholyte produced in the cathode chamber enter the sodium hypochlorite tank and react to generate sodium hypochlorite.

[0087] The sodium hypochlorite generator in this embodiment operates under a current density of 900 A / m. 2 The residence time of the concentrated water obtained from seawater desalination in the electrolyzer is 4 minutes.

[0088] After testing, the sodium hypochlorite generator of this embodiment can operate efficiently and stably for more than 2 months, with a current efficiency of 92.5%, salt consumption of 3.9 kg / kg, and energy consumption of 4.8 kWh / kg.

[0089] Example 3

[0090] This embodiment provides a sodium hypochlorite generating device, including a brine tank, a sodium hypochlorite water tank, and an electrolytic cell connected to the brine tank and the sodium hypochlorite water tank respectively via a water pump and pipelines. Inside the electrolytic cell, an anode plate, a polytetrafluoroethylene (PTFE) plate, a selective ion exchange membrane, another PTFE plate, and a cathode plate are arranged sequentially. In this embodiment, the anode plate is a titanium-coated ruthenium-iridium plate, its surface coated with a polyethylene-polypropylene porous layer, in which a highly crystalline nanoporous material is loaded. The selective ion exchange membrane is a sulfonated polyphenylene ether membrane containing sodium polystyrene sulfonate and poly(terphenylpiperidine). The cathode plate is a titanium plate, its surface disposed of with a positively charged membrane, which includes a polyvinylidene fluoride (PVDF) membrane and a polyallylamine hydrochloride layer disposed on the surface of the PVDF membrane.

[0091] In this embodiment, the preparation method of the highly crystalline nanoporous material is as follows: zinc nitrate and tetrakis(4-(5-aminopyrazole-3-yl)phenyl)ethylene in a mass ratio of 3:1 are added to N-methylpyrrolidone, ultrasonically treated for 30 min, and then reacted at 140℃ for 70 h to obtain the highly crystalline nanoporous material.

[0092] The selective ion exchange membrane is prepared as follows: a mixed solution of sodium polystyrene sulfonate and poly(terphenylpiperidine) is coated twice onto a sulfonated polyphenylene ether membrane, and the membrane is dried to obtain the selective ion exchange membrane. In the mixed solution, the concentration of sodium polystyrene sulfonate is 30 g / L, and the concentration of poly(terphenylpiperidine) is 2 g / L.

[0093] The positively charged membrane is prepared as follows: Under pH 5 conditions, a 5 g / L polyallylamine hydrochloride solution is coated on a polyvinylidene fluoride membrane. After drying, the polyvinylidene fluoride membrane is immersed in a 0.05 wt% hexamethylene aldehyde solution for 25 min. After cleaning and drying, the positively charged membrane is obtained.

[0094] In this embodiment, the anode plate and the selective ion exchange membrane together form the anode chamber, and the cathode plate and the selective ion exchange membrane together form the cathode chamber. A brine tank supplies concentrated water obtained from seawater desalination to the anode and cathode chambers. The anolyte produced in the anode chamber and the catholyte produced in the cathode chamber enter the sodium hypochlorite tank and react to generate sodium hypochlorite.

[0095] The sodium hypochlorite generator in this embodiment operates under a current density of 1500 A / m. 2 The residence time of the concentrated water obtained from seawater desalination in the electrolyzer is 2 minutes.

[0096] After testing, the sodium hypochlorite generator of this embodiment can operate efficiently and stably for more than 2 months, with a current efficiency of 89.9%, salt consumption of 4.4 kg / kg, and energy consumption of 5.1 kWh / kg.

[0097] Example 4

[0098] This embodiment provides a sodium hypochlorite generating device, including a brine tank, a sodium hypochlorite water tank, and an electrolytic cell connected to the brine tank and the sodium hypochlorite water tank respectively via a water pump and pipelines. Inside the electrolytic cell, an anode plate, a polytetrafluoroethylene (PTFE) plate, a selective ion exchange membrane, another PTFE plate, and a cathode plate are arranged sequentially. In this embodiment, the anode plate is a titanium-coated ruthenium-iridium plate, with its surface coated with a porous polyethylene layer, the porous layer containing a highly crystalline nanoporous material. The selective ion exchange membrane is a sulfonated polyphenylene ether membrane containing sodium polystyrene sulfonate and poly(terphenylpiperidine). The cathode plate is a nickel plate, with a positively charged membrane on its surface, the positively charged membrane comprising a polysulfone membrane and a polyallylamine hydrochloride layer disposed on the surface of the polysulfone membrane.

[0099] In this embodiment, the preparation method of the highly crystalline nanoporous material is as follows: zinc nitrate and tetrakis(4-(5-aminopyrazole-3-yl)phenyl)ethylene with a mass ratio of 2.5:1 are added to dimethyl sulfoxide, ultrasonically treated for 25 min, and then reacted at 130℃ for 60 h to obtain the highly crystalline nanoporous material.

[0100] The selective ion exchange membrane is prepared as follows: a mixed solution of sodium polystyrene sulfonate and poly(terphenylpiperidine) is coated twice onto a sulfonated polyphenylene ether membrane, and the membrane is dried to obtain the selective ion exchange membrane. In the mixed solution, the concentration of sodium polystyrene sulfonate is 25 g / L, and the concentration of poly(terphenylpiperidine) is 5 g / L.

[0101] The positively charged membrane is prepared as follows: Under pH 4 conditions, a 10 g / L polyallylamine hydrochloride solution is coated on a polysulfone membrane. After drying, the polysulfone membrane is immersed in a 0.15 wt% hexamethylene aldehyde solution for 30 min. After cleaning and drying, the positively charged membrane is obtained.

[0102] In this embodiment, the anode plate and the selective ion exchange membrane together form the anode chamber, and the cathode plate and the selective ion exchange membrane together form the cathode chamber. A brine tank supplies concentrated water obtained from seawater desalination to the anode and cathode chambers. The anolyte produced in the anode chamber and the catholyte produced in the cathode chamber enter the sodium hypochlorite tank and react to generate sodium hypochlorite.

[0103] The sodium hypochlorite generator in this embodiment operates under a current density of 300 A / m. 2 The residence time of the concentrated water obtained from seawater desalination in the electrolyzer is 5 minutes.

[0104] After testing, the sodium hypochlorite generator of this embodiment can operate efficiently and stably for more than 2 months, with a current efficiency of 91.5%, salt consumption of 4.3 kg / kg, and energy consumption of 4.5 kWh / kg.

[0105] Example 5

[0106] This embodiment provides a sodium hypochlorite generating device, including a brine tank, a sodium hypochlorite water tank, and an electrolytic cell connected to the brine tank and the sodium hypochlorite water tank respectively via a water pump and pipelines. Inside the electrolytic cell, an anode plate, a polytetrafluoroethylene (PTFE) plate, a selective ion exchange membrane, another PTFE plate, and a cathode plate are arranged sequentially. In this embodiment, the anode plate is a titanium-coated ruthenium-iridium plate, its surface coated with a porous polyethylene layer, in which a highly crystalline nanoporous material is loaded. The selective ion exchange membrane is a sulfonated polyphenylene ether membrane containing sodium polystyrene sulfonate and poly(terphenylpiperidine). The cathode plate is a titanium plate, its surface having a positively charged membrane, which includes a polysulfone membrane and a polyallylamine hydrochloride layer disposed on the surface of the polysulfone membrane.

[0107] In this embodiment, the preparation method of the highly crystalline nanoporous material is as follows: aluminum nitrate and tetrakis(4-(5-aminopyrazole-3-yl)phenyl)ethylene in a mass ratio of 2:1 are added to N,N-dimethylformamide, ultrasonically treated for 20 min, and then reacted at 130℃ for 70 h to obtain the highly crystalline nanoporous material.

[0108] The selective ion exchange membrane is prepared as follows: a mixed solution of sodium polystyrene sulfonate and poly(terphenylpiperidine) is coated twice onto a sulfonated polyphenylene ether membrane, and the membrane is dried to obtain the selective ion exchange membrane. In the mixed solution, the concentration of sodium polystyrene sulfonate is 15 g / L, and the concentration of poly(terphenylpiperidine) is 3 g / L.

[0109] The positively charged membrane is prepared as follows: Under pH 3 conditions, an 8 g / L polyallylamine hydrochloride solution is coated on a polysulfone membrane. After drying, the polysulfone membrane is immersed in a 0.2 wt% hexamethylene aldehyde solution for 20 min, then removed, cleaned, and dried to obtain the positively charged membrane.

[0110] In this embodiment, the anode plate and the selective ion exchange membrane together form the anode chamber, and the cathode plate and the selective ion exchange membrane together form the cathode chamber. A brine tank supplies a sodium chloride solution prepared from tap water to the anode and cathode chambers. The anolyte produced in the anode chamber and the catholyte produced in the cathode chamber enter the sodium hypochlorite tank and react to form sodium hypochlorite.

[0111] The sodium hypochlorite generator in this embodiment operates under a current density of 1200 A / m. 2 The residence time of the concentrated water obtained from seawater desalination in the electrolyzer is 3.5 min.

[0112] After testing, the sodium hypochlorite generator of this embodiment can operate efficiently and stably for more than 2 months, with a current efficiency of 90.7%, salt consumption of 4.5 kg / kg, and energy consumption of 5.0 kWh / kg.

[0113] Comparative Example 1

[0114] This comparative example provides a sodium hypochlorite generating device, which differs from Example 1 in that the anode plate surface does not have a porous layer, and no highly crystalline nanoporous material is loaded on the anode plate.

[0115] After testing, the sodium hypochlorite generator in this comparative example could not operate efficiently and stably during operation due to contamination of the electrode plates. The continuous operation time was less than one month, the current efficiency of the device was 82.3%, the salt consumption was 6.6 kg / kg, and the energy consumption was 8.7 kWh / kg.

[0116] Comparative Example 2

[0117] This comparative example provides a sodium hypochlorite generator, which differs from Example 1 in that a positively charged diaphragm is not installed on the cathode plate. Testing revealed that the sodium hypochlorite generator in this comparative example could not operate efficiently and stably during operation due to scaling of calcium and magnesium polyvalent ions on the electrode plates. With a continuous operating time of less than one month, the device's current efficiency was 76.4%, salt consumption was 7.9 kg / kg, and energy consumption was 10.6 kWh / kg.

[0118] Comparative Example 3

[0119] This comparative example provides a sodium hypochlorite generating device, which differs from Example 1 in that the selective ion exchange membrane is only a sulfonated polyphenylene ether membrane and is not coated with a mixed solution of sodium polystyrene sulfonate and poly(terphenylpiperidine).

[0120] After testing, it was found that the sodium hypochlorite generator in this comparative example could not operate efficiently and stably during operation because the ion exchange membrane failed to effectively retain polyvalent cations such as calcium and magnesium. The current efficiency of the device was 83.0% and the salt consumption was 7.3 kg / kg, while the energy consumption was 8.2 kWh / kg, with a continuous operating time of less than one month.

[0121] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A sodium hypochlorite generating apparatus, characterized in that, It includes a brine tank (1), a sodium hypochlorite tank (2), and an electrolytic cell (3) that is connected to the brine tank (1) and the sodium hypochlorite tank (2) respectively. The electrolytic cell (3) is provided with an anode plate (4), a first partition plate (5), a selective ion exchange membrane (6), a second partition plate (7), and a cathode plate (8) in sequence inside. A porous layer is provided on the surface of the anode plate (4), and a highly crystalline nanoporous material obtained by reacting a metal salt with tetrakis(4-(aminopyrazole-3-yl)phenyl)ethylene is loaded in the porous layer; The selective ion exchange membrane (6) is a sulfonated polyphenylene ether membrane containing sodium polystyrene sulfonate and poly(terphenylpiperidine); The surface of the cathode plate (8) is provided with a positively charged membrane, which includes a base film and a polyallylamine hydrochloride layer disposed on the surface of the base film; The preparation method of highly crystalline nanoporous materials is as follows: Metal salt and tetra(4-(aminopyrazole-3-yl)phenyl)ethylene are added to an organic solvent, ultrasonically treated for 15-30 min, and then reacted at 120-140℃ for 50-80 h to obtain highly crystalline nanoporous material. The mass ratio of the metal salt to tetra(4-(aminopyrazol-3-yl)phenyl)ethylene is 1.5:1-3:1; The metal salt is zinc nitrate or aluminum nitrate; The organic solvent is N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, or dimethyl sulfoxide.

2. The sodium hypochlorite generating apparatus according to claim 1, characterized in that, The electrolytic cell (3) is connected to the brine tank (1) and the sodium hypochlorite tank (2) respectively through pipes and water pumps; The anode plate (4) is a titanium-coated ruthenium-iridium plate; The first partition (5) and the second partition (7) are polytetrafluoroethylene (PTFE) sheets, polyvinylidene fluoride (PVDF) sheets, or chlorinated polyvinyl chloride (PVC) sheets; The cathode plate (8) is a titanium plate or a nickel plate.

3. The sodium hypochlorite generating apparatus according to claim 1, characterized in that, The porous layer is a polyolefin porous layer; the polyolefin porous layer is a polyethylene porous layer, a polypropylene porous layer, or a polyethylene-polypropylene porous layer.

4. The sodium hypochlorite generating apparatus according to claim 1, characterized in that, The selective ion exchange membrane (6) is prepared as follows: A mixed solution of sodium polystyrene sulfonate and poly(terphenylpiperidine) was coated multiple times on a sulfonated polyphenylene ether membrane and dried to obtain a selective ion exchange membrane (6). In the mixed solution, the concentration of sodium polystyrene sulfonate is 10-30 g / L, and the concentration of poly(terphenylpiperidine) is 2-6 g / L.

5. The sodium hypochlorite generating apparatus according to claim 1, characterized in that, The polyallylamine hydrochloride layer is fixed to the base film by crosslinking with an aldehyde crosslinking agent.

6. The sodium hypochlorite generating apparatus according to claim 5, characterized in that, The preparation method of the positively charged diaphragm is as follows: Under pH conditions of 3-5, a 5-15 g / L polyallylamine hydrochloride solution is coated onto the base membrane. After drying, the base membrane is immersed in a 0.05-0.25 wt% hexamethylenetetramine solution for 15-30 min, then removed, cleaned, and dried to obtain a positively charged membrane.

7. The sodium hypochlorite generating apparatus according to claim 1, characterized in that, The base membrane is a polysulfone membrane, a polyethersulfone membrane, or a polyvinylidene fluoride membrane.

8. The sodium hypochlorite generating apparatus according to claim 1, characterized in that, In the electrolytic cell (3), the anode plate (4), the first partition plate (5) and the selective ion exchange membrane (6) form the anode chamber, and the cathode plate (8), the second partition plate (7) and the selective ion exchange membrane (6) form the cathode chamber; The brine tank (1) is used to supply the anode chamber and the cathode chamber with sodium chloride solution prepared from tap water or concentrated water obtained from seawater desalination. The anolyte generated in the anode chamber and the catholyte generated in the cathode chamber enter the sodium hypochlorite tank (2) and generate sodium hypochlorite solution in the sodium hypochlorite tank (2).

9. The sodium hypochlorite generating apparatus according to claim 8, characterized in that, The sodium hypochlorite generator operates at 300-1500 A / m 2 The sodium chloride solution prepared from tap water or the concentrated water obtained from seawater desalination is kept in the electrolyzer (3) for 2-6 minutes at the current density.

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