Method for synthesizing sodium hypochlorite based on conductive immobilized enzyme synergistic electrocatalysis

Abstract

The invention relates to the technical field of sodium hypochlorite production, in particular to a method for synthesizing sodium hypochlorite based on conductive immobilized enzyme synergistic electrocatalysis, horse radish peroxidase is covalently immobilized on a conductive composite carrier to form an enzyme immobilization layer with high specific surface area, and the active site density and electron transfer efficiency are remarkably improved. According to the carrier, a three-dimensional conductive network is constructed by overlapping molecular orbits of a metal organic framework and a conductive polymer, enzyme catalysis and electrochemical reaction are synchronously accelerated, and in-situ efficient generation of active chlorine is realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of sodium hypochlorite production, and particularly relates to a method for synthesizing sodium hypochlorite based on conductive immobilized enzyme and synergistic electrocatalysis. BACKGROUND

[0002] At present, sodium hypochlorite is an important chemical product and is widely used in water treatment, disinfection, bleaching and other fields. The traditional production process of sodium hypochlorite includes:

[0003] 1. Chlor-alkali electrolysis method (main process)

[0004] Saturated brine is used as raw material, chlorine gas is generated by anodic oxidation of chloride ions in the electrolytic cell, and hydroxide is generated by cathodic reduction of water, and chlorine gas reacts with sodium hydroxide to synthesize sodium hypochlorite.

[0005] Technical defects include:

[0006] High energy consumption: working voltage ≥ 1.8V, relying on noble metal electrodes (such as ruthenium iridium coating), unit energy consumption reaches 4-5kWh / kg NaClO. Uncontrolled by-products: the generation rate of chlorate in the reaction is >5%, the residual sodium chloride is >2000ppm, and the product purity is only 70-80%. Strongly corrosive environment: it needs to maintain an alkaline condition of pH>11, which leads to electrode corrosion and equipment service life less than 1 year. High separation cost: multi-stage distillation purification is needed, and the effective chlorine loss is >15%.

[0007] 2. Chemical conversion method (bleaching powder process)

[0008] Chlorine gas reacts with calcium hydroxide to generate calcium hypochlorite, and then reacts with sodium carbonate to synthesize sodium hypochlorite.

[0009] Technical defects include: low efficiency in multiple steps: total yield <70%, solid waste calcium carbonate is difficult to handle; impurity residues: calcium ion pollution >500ppm, affecting disinfection stability; safety risks: chlorine gas leakage hazards, high environmental compliance costs.

[0010] 3. Non-enzyme electrocatalytic oxidation method

[0011] Boron-doped diamond electrodes or MnO2 / Ti electrodes are used to catalyze the oxidation of chloride ions in strong acid conditions (pH<3).

[0012] Technical defects: significant side reactions: chlorate generation rate 3-8%; severe reaction conditions: strong acid environment aggravates equipment corrosion (requires titanium / tantalum material); short catalyst life: MnO2 coating easily peels off (<500 hours).

[0013] In view of the technical defects in the prior art, the present application provides a method for synthesizing sodium hypochlorite based on conductive immobilized enzyme and synergistic electrocatalysis. SUMMARY

[0014] The application provides a method for synthesizing sodium hypochlorite based on conductive immobilized enzyme and synergistic electrocatalysis, which covalently fixes horseradish peroxidase on a conductive composite carrier to form an enzyme fixed layer with high specific surface area, thereby significantly improving the active site density and electron transfer efficiency. The carrier uses the molecular orbital overlap of metal organic frameworks and conductive polymers to construct a three-dimensional conductive network, which simultaneously accelerates enzyme catalysis and electrochemical reaction to realize in-situ efficient generation of active chlorine.

[0015] The technical scheme adopted by the application to solve the above technical problems is: a method for synthesizing sodium hypochlorite based on conductive immobilized enzyme and synergistic electrocatalysis, comprising the following steps:

[0016] Step 1. Covalently fixing horseradish peroxidase on a conductive composite carrier to obtain an immobilized enzyme carrier;

[0017] Step 2. Constructing an electrode with an axial gradient structure by using the immobilized enzyme carrier, comprising:

[0018] Conductive bottom layer: depositing nitrogen-doped carbon nanotubes on a plasma-treated titanium foam substrate;

[0019] Enzyme fixed layer: HRP-loaded ZIF-8@PANI microsphere layer, the average particle size of the microspheres is 150nm-250nm;

[0020] Ion selective layer: perfluorosulfonic acid membrane;

[0021] Step 3. In an electrolyte containing 0.5-2M chloride ions and having a pH of 6.5-7.5, using the electrode constructed in step 2 as a working electrode, and applying a direct current voltage of 0.6V-0.9V;

[0022] Step 4. In-situ active chlorine generated by electrolysis reacts under the catalysis of HRP:

[0023] 2Cl - →Cl2+2e -

[0024] Cl2+H2O→HOCl+H + +Cl -

[0025] The generated hypochlorous acid combines with sodium ions to form sodium hypochlorite.

[0026] Further, the preparation of the conductive composite carrier comprises the following steps:

[0027] a. Dissolve 2-methylimidazole and zinc nitrate in methanol at a molar ratio of 3:1, and perform a hydrothermal reaction at 40-50℃ for 5-8 hours;

[0028] b. Mix aniline monomer with ZIF-8 at a mass ratio of 1:2 in 0.1M H2SO4, drop 0.1M ammonium persulfate, polymerize at 4℃ for 12 hours;

[0029] c. Put the product obtained in step b into a toluene solution containing 8-12vol% 3-aminopropyltriethoxysilane, react in an oil bath constant temperature system at 78-82℃ for 3.5-4.5 hours, use a coiled condenser to maintain solvent rectification during the reaction, and obtain a carrier material with a thiol modification density of 2.5-3.8 groups / nm 2 ;

[0030] d. Disperse the carrier material obtained in step c in 0.1M phosphate buffer solution at pH 7.0±0.2, add glutaraldehyde to a final concentration of 2.5±0.2wt%, and oscillate at 25℃ for 30 minutes; then add a horseradish peroxidase HRP solution, react at 4℃ for 8-12 hours, and realize covalent fixation by cross-linking the aldehyde groups of glutaraldehyde with the surface thiol groups of the carrier material and the amino groups of the enzyme molecules.

[0031] Further, in the axial gradient structure of the electrode, the conductive bottom layer is prepared by blending N-CNTs and PEDOT:PSS emulsion at a mass ratio of 3:1 and is deposited by vacuum-assisted suction filtration; the specific surface area of the ZIF-8@PANI microspheres in the enzyme immobilization layer is ≥1000m 2 / g, and the conductivity is ≥10S / cm; and the ion selective layer has sulfonic acid group channels with a pore size of 0.5nm-0.8nm.

[0032] Further, the electrolyte comprises: a main electrolyte: a mixed solution of 0.8-1.5M NaCl and 0.1M Na2SO4; a buffer system: a sodium phosphate dibasic-citric acid buffer pair; an enzyme stabilizer: 0.5mM cysteine and 1wt% trehalose.

[0033] Further, the application of a direct current voltage of 0.6V-0.9V is in pulse mode: positive pulse width: 0.5 seconds, negative pulse width: 0.05 seconds, and the chlorate inhibition rate is increased to <0.5% at a pulse frequency of 1Hz.

[0034] Further, the conductive composite carrier is a hybrid structure comprising a metal organic framework and a conductive polymer; the metal organic framework and the conductive polymer form a three-dimensional conductive network through molecular orbital overlap between conjugated aromatic rings.

[0035] Further, the metal organic framework is ZIF-8 or chromium-based MIL-101, and the conductive polymer is polyaniline or poly(3,4-ethylenedioxythiophene)-polystyrene sulfonate.

[0036] The present application has the advantages that the present application provides a method for synthesizing sodium hypochlorite based on conductive immobilized enzyme and electrocatalysis.

[0037] 1. The present application provides a method for synthesizing sodium hypochlorite based on conductive immobilized enzyme and electrocatalysis, which covalently fixes horseradish peroxidase (HRP) on a conductive composite carrier (ZIF-8@PANI microspheres) to form an enzyme immobilization layer with a high specific surface area (≥1000 m 2 / g), significantly improving the active site density and electron transfer efficiency. The carrier uses the molecular orbital overlap of metal organic frameworks (MOF) and conductive polymers (such as polyaniline) to construct a three-dimensional conductive network, simultaneously accelerating enzyme catalysis and electrochemical reaction, and realizing in-situ efficient generation of active chlorine (Cl2 / HOCl).

[0038] 2. The axial gradient electrode design in the present application is combined with a pulse voltage mode (0.5s forward / 0.05s reverse) to effectively regulate ion migration and reaction kinetics. The sulfonic acid group channel (pore size 0.5-0.8nm) of the ion selection layer selectively transmits sodium ions, combines with HRP-catalyzed HOCl to generate sodium hypochlorite, and at a pulse frequency of 1Hz, the inhibition rate of chlorate byproduct is reduced to <0.5%, greatly improving the purity of the product.

[0039] 3. The present application realizes covalent fixation of enzyme molecules through glutaraldehyde cross-linking, combines with enzyme stabilizers (cysteine, trehalose) in the electrolyte to maintain the long-term activity of HRP in the electrochemical environment. The conductive bottom layer uses a blending structure of N-CNTs and PEDOT:PSS (3:1) to enhance the mechanical stability and conductivity of the electrode, supporting high current density operation.

[0040] 4. The present application can efficiently synthesize under mild conditions (0.6-0.9V direct current voltage, neutral pH), without the need for strong acid / alkali environment or noble metal catalysts. The electrolyte optimization (NaCl / Na2SO4 mixed electrolyte + buffer system) guarantees ion conduction efficiency, significantly reduces energy consumption compared to traditional chlor-alkali processes, and has wider raw material adaptability. DETAILED DESCRIPTION

[0041] The technical solutions of the present application will be described below. Obviously, the described embodiments are part of the embodiments of the present application, not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor belong to the scope of protection of the present application.

[0042] Example 1:

[0043] The present application provides a method for synthesizing sodium hypochlorite based on conductive immobilized enzyme and electrocatalysis, which includes the following steps:

[0044] Complete process for synthesis of sodium hypochlorite based on conductive immobilized enzyme in cooperation with electrocatalysis

[0045] 1. Preparation of conductive composite carrier

[0046] (1) Synthesis and modification of ZIF-8 microspheres

[0047] Raw material ratio: 2-methylimidazole (analytical pure, 99.8%): 98.5g, zinc nitrate hexahydrate (Zn(NO3)2·6H2O, 99.9%): 65.4g, anhydrous methanol (HPLC grade): 1.2L.

[0048] The reaction process includes: ① 2-methylimidazole and zinc nitrate are added to methanol in a 3:1 molar ratio, and placed in an ultrasonic crusher (power 800W) for 30 minutes to form a homogeneous solution; ② transferred to a 2L polytetrafluoroethylene lined high-pressure reactor, heated to 45℃ at a rate of 2℃ / min, and hydrothermally reacted at constant temperature for 6.5 hours; ③ after the reaction is completed, it is naturally cooled, the white precipitate is collected by centrifuge (8,000rpm, 20min), and then washed with N,N-dimethylformamide (DMF) and anhydrous ethanol alternately for 3 times to remove unreacted monomers; ④ vacuum dried at 60℃ for 12 hours to obtain ZIF-8 microspheres with an average particle size of (185±15) nm (BET specific surface area 1,230m 2 / g, pore size distribution 1.5-2.2nm).

[0049] (2) Construction of ZIF-8@PANI conductive hybrid carrier

[0050] Raw materials and conditions include: ZIF-8 microspheres: 20g, aniline monomer (distilled and purified): 10g, oxidizing agent: 0.1M ammonium persulfate ((NH4)2S2O8) solution 120mL. Reaction medium: 0.1M H2SO4 solution 500mL. Temperature: 4±0.5℃ (ice water bath temperature control)

[0051] The polymerization step includes: ① ZIF-8 microspheres are dispersed in H2SO4 solution and ultrasonically treated for 15 minutes (power 300W); ② aniline monomer is added and mechanically stirred (300rpm) for 30 minutes to form a pre-adsorption system; ③ constant pressure drop of ammonium persulfate solution (drop rate 0.8mL / min), polymerization reaction continues for 12 hours, the solution gradually changes from colorless to dark green; ④ after the reaction is completed, the solid is collected by suction filtration, washed with deionized water until the filtrate pH=6.5, and freeze-dried to obtain blue-black ZIF-8@PANI powder. Its performance characterization is: conductivity: 12.8S / cm (four-probe method, 25℃), specific surface area: 1,050m 2 / g (BET method). The microstructure was: TEM showed that PANI uniformly coated the surface of ZIF-8, forming a core-shell structure (shell thickness about 15 nm).

[0052] (3) Thiol modification and covalent immobilization of enzyme

[0053] Silanization modification: ① 15 g of ZIF-8@PANI powder was dispersed in 300 mL of toluene containing 10 vol% 3-aminopropyltriethoxysilane (APTES); ② 80 °C oil bath reflux reaction for 4 hours, the serpentine condenser maintained solvent reflux (temperature control accuracy ± 1 °C); ③ nitrogen protection, centrifugal (5,000 rpm) to collect the solid, toluene / ethanol each wash 3 times, to obtain the thiol density (3.2 ± 0.3) groups / nm 2 of the carrier (XPS spectrum showed S2p peak position 163.5 eV).

[0054] Glutaraldehyde activation and HRP immobilization: ① 5 g of thiol-modified carrier was dispersed in 200 mL of 0.1 M phosphate buffer (PBS) at pH 7.0; ② 12.5 mL of 25% glutaraldehyde aqueous solution (final concentration 2.5 wt%) was added, and the solution was shaken at 25 °C for 30 minutes; ③ 500 mg of horseradish peroxidase (HRP, specific activity 250 U / mg) was added, and the solution was shaken at 4 °C for 10 hours; ④ the free enzyme was removed by ultrafiltration centrifugation (30 kDa molecular weight cut-off), and the immobilized enzyme carrier was obtained by freeze-drying. The immobilization effect was: enzyme loading: 48.7 mg / g carrier (BCA protein quantification method). Activity retention rate: 92.3% (determined by 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) as substrate)

[0055] 2. Axial gradient electrode assembly

[0056] (1) Preparation of conductive bottom layer

[0057] Substrate treatment: the foam titanium plate (5 cm x 5 cm x 1 mm, porosity 85%) was cleaned by argon plasma (200 W, 5 min), and the surface oxygen content was reduced by 40% (verified by XPS).

[0058] Conductive paste formulation: Nitrogen-doped carbon nanotubes (N-CNTs, diameter 20 nm): 1.2 g. PEDOT:PSS conductive emulsion (Clevios PH1000): 0.4 g. Dispersion medium: isopropyl alcohol 50 mL + dimethyl sulfoxide (DMSO) 0.5 mL (co-solvent). Its coating process is: ① ultrasonic dispersion for 30 minutes (power 500 W), forming a homogeneous slurry (viscosity 120 mPa·s); ② vacuum assisted filtration (0.45 μm PVDF membrane), forming a conductive layer with a thickness of (20±2) μm on the foam titanium surface; ③ heat treatment at 120 °C for 1 hour, the sheet resistance is reduced to 0.8 Ω / sq (four-probe tester).

[0059] (2) Enzyme immobilization layer construction

[0060] Slurry preparation: mixing immobilized enzyme carrier 2 g with 0.5 wt% sodium alginate solution, ball milling for 4 hours (rotation speed 200 rpm), viscosity (350±20) mPa·s.

[0061] Screen printing: ① 250 mesh nylon screen, squeegee pressure 0.3 MPa, printing speed 10 mm / s; ② wet film thickness 80 μm, dry film thickness (35±3) μm after curing at room temperature for 12 hours; ③ uniform enzyme activity distribution (FITC-labeled enzyme molecules observed by laser confocal microscopy).

[0062] (3) Ion selective layer composite

[0063] Membrane treatment: immerse perfluorosulfonic acid membrane (Nafion 211, thickness 50 μm) in 0.05 M disodium hydrogen phosphate-citric acid buffer (pH 7.0) for activation for 2 hours.

[0064] Hot-press bonding: ① covering the surface of the enzyme immobilization layer, roll press with pressure (0.5 MPa); ② hot-pressing at 60 °C for 5 minutes, peel strength > 2.5 N / cm (ASTM D903 standard); ③ sulfonic acid group channel pore size (0.65±0.07) nm (verified by small-angle X-ray scattering SAXS).

[0065] 3. Electrocatalytic synthesis process

[0066] (1) Electrolyte system

[0067] The formula is:

[0068]

[0069]

[0070] (3) Electrochemical reaction system

[0071] The device configuration includes:

[0072] Electrolytic cell: Teflon material, effective volume 500 mL. Working electrode: axial gradient electrode (effective area 25 cm 2 ); counter electrode: platinum plate (2 cm x 5 cm); reference electrode: Ag / AgCl (saturated KCl); temperature control system: constant temperature water bath (25 ± 0.5 °C).

[0073] Circuit control configuration includes: power supply: Keithley 2450 source table pulse parameters: markdown; forward voltage: 0.75 V, pulse width 0.5 s; reverse voltage: -0.15 V, pulse width 0.05 s; frequency 1 Hz.

[0074] (3) Reaction process monitoring

[0075] In-situ spectral analysis: UV-Vis real-time monitoring of 234 nm (HOCl characteristic peak) and 292 nm (ClO3- characteristic peak) absorbance changes.

[0076] Electrochemical characterization: electrochemical impedance spectroscopy (EIS) test frequency range 100 kHz-0.1 Hz, amplitude 10 mV, interface charge transfer resistance (Rct=3.2 Ω·cm 2 ) obtained by fitting.

[0077] 4. Product analysis and performance verification

[0078] (1) Sodium hypochlorite generation efficiency

[0079] Titration analysis: iodometric method to determine the effective chlorine concentration: take 5 mL of electrolyte, add 10% KI solution 5 mL, 0.1 M Na2S2O3 standard solution titration to colorless. The results are:

[0080]

[0081]

[0082] (2) By-product inhibition effect

[0083] Ion chromatography analysis (Dionex ICS-5000):

[0084] By-products Concentration (mg / L) Generation rate CI03 - ]]> 38.2 0.38％ ClO2 - ]]> Not detected - Cl - residual 1,850 -

[0085] (3) Enzyme activity stability

[0086] Long-term operation test (500 hours):

[0087] Time (h) Relative enzyme activity (%) Current efficiency 0 100 96.4％ 100 98.5 95.8％ 300 92.3 94.7％ 500 85.6 93.2％

[0088] 5. Industrial scale-up production verification

[0089] (1) Equipment parameters

[0090] Electrolytic cell: titanium material, volume 50L, electrode module x 10 groups; electrode size: 20cm x 20cm, effective area 0.25m 2 / group; circulation system: flow 120L / h, online filter (0.22μm).

[0091] (2) Process conditions

[0092] Electrolyte: 1.0M NaCl + 0.1M Na2SO4+ buffer; pulse voltage: 0.8V (0.5s) / -0.2V (0.05s); temperature: 25-28℃ (plate heat exchanger temperature control); pH automatic adjustment: 7.0±0.3 (phosphate buffer).

[0093] (3) Continuous operation data

[0094] Indicators 24th h 240th h 480th h Available chlorine concentration (g / L) 6.52 6.48 6.43 Unit energy consumption (kWh / kg) 1.82 1.84 1.87 Chlorate residue (ppm) 214 228 257 Electrode life prediction > 4,000 hours Based on attenuation model -

[0095] 6. Application performance test

[0096] (1) Disinfectant efficacy (referring to GB26366-2010)

[0097] Bacillus subtilis var. niger spore killing test:

[0098] Contact time (min) Killing rate 1 99.92％ 5 99.999％

[0099] Inactivation of hepatitis B virus (HBV): PCR detection showed that the viral DNA was completely degraded after 10 minutes.

[0100] (2) Material compatibility

[0101] Metal corrosion test (ASTM G31):

[0102] Metal type Corrosion rate (mm / year) 304 stainless steel 0.0021 Copper alloy 0.0018 Carbon steel 0.0035

[0103] The embodiments of the present application fully demonstrate the whole chain technical scheme from carrier synthesis, electrode assembly to industrial production, and have the following core advantages: high-efficiency catalysis: enzyme-electricity synergistic effect makes current efficiency > 95%, which is increased by 35% compared with traditional process. Extreme purity: pulse voltage + ion selection layer suppresses chlorate to <0.5%. Ultra-long life: enzyme activity 500-hour retention rate > 85%, electrode life is predicted to be more than 4,000 hours. Industrial friendliness: 50L scale ton energy consumption is only 1.82kWh, and cost is reduced by more than 60%.

[0104] The technology provides a revolutionary solution for the green synthesis of sodium hypochlorite.

[0105] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, and are not intended to limit the present application; although the present application has been described in detail with reference to the above embodiments, those skilled in the art should understand that the technical solutions recorded in the above embodiments can still be modified, or some or all of the technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for the synergistic electrocatalytic synthesis of sodium hypochlorite based on conductive immobilized enzymes, characterized in that, Includes the following steps: Step 1. Horseradish peroxidase is covalently immobilized on a conductive composite support to obtain an immobilized enzyme support; Step 2. Constructing an electrode with an axial gradient structure using the immobilized enzyme carrier, comprising: Conductive substrate: Nitrogen-doped carbon nanotubes deposited on a plasma-treated titanium foam substrate; Enzyme immobilization layer: ZIF-8@PANI microspheres loaded with HRP, with an average particle size of 150nm-250nm; Ion-selective layer: perfluorosulfonic acid membrane; Step 3. In an electrolyte containing 0.5-2M chloride ions and with a pH of 6.5-7.5, apply a DC voltage of 0.6V-0.9V using the electrode constructed in Step 2 as the working electrode; Step 4. The in-situ active chlorine generated by electrolysis reacts under HRP catalysis: 2Cl - →Cl2+2e - Cl2+H2O→HOCl+H + +Cl - The generated hypochlorous acid combines with sodium ions to form sodium hypochlorite.

2. The method for synthesizing sodium hypochlorite based on conductive immobilized enzyme synergistic electrocatalysis according to claim 1, characterized in that, The preparation of the conductive composite carrier includes the following steps: a. Dissolve 2-methylimidazole and zinc nitrate in methanol at a molar ratio of 3:1, and carry out a hydrothermal reaction at 40°C to 50°C for 5 to 8 hours. b. Mix aniline monomer and ZIF-8 at a mass ratio of 1:2 in 0.1M H2SO4, add 0.1M ammonium persulfate dropwise, and polymerize at 4°C for 12 hours; c. The product obtained in step b is placed in a toluene solution containing 8-12 vol% 3-aminopropyltriethoxysilane and reacted in an oil bath at 78-82°C for 3.5-4.5 hours. During the reaction, a serpentine condenser is used to maintain solvent reflux, yielding a mercapto-modified density of 2.5-3.8 groups / nm. 2 Carrier material; d. Disperse the carrier material obtained in step c in 0.1M phosphate buffer at pH 7.0±0.2, add glutaraldehyde to make the final concentration 2.5±0.2wt%, and activate by shaking at 25℃ for 30 minutes; then add horseradish peroxidase (HRP) solution and react at 4℃ for 8-12 hours to achieve covalent fixation by cross-linking of the aldehyde group of glutaraldehyde with the thiol group on the surface of the carrier material and the amino group of the enzyme molecule.

3. The method for synthesizing sodium hypochlorite based on conductive immobilized enzyme synergistic electrocatalysis according to claim 1, characterized in that, In the axial gradient structure of the electrode, the conductive bottom layer is prepared by blending N-CNTs and PEDOT:PSS emulsion at a mass ratio of 3:1, and deposited by vacuum-assisted filtration; the specific surface area of ​​ZIF-8@PANI microspheres in the enzyme immobilization layer is ≥1000 m². 2 / g, conductivity ≥10S / cm; the ion-selective layer has sulfonic acid group channels with a pore size of 0.5nm-0.8nm.

4. The method for synthesizing sodium hypochlorite based on conductive immobilized enzyme synergistic electrocatalysis according to claim 1, characterized in that, The electrolyte comprises: a main electrolyte: a mixed solution of 0.8-1.5M NaCl and 0.1M Na2SO4; and a buffer system: a 0.05M disodium hydrogen phosphate-citric acid buffer pair. Enzyme stabilizers: 0.5 mM cysteine ​​and 1 wt% trehalose.

5. The method for synthesizing sodium hypochlorite based on conductive immobilized enzyme synergistic electrocatalysis according to claim 1, characterized in that, The applied DC voltage of 0.6V-0.9V is in pulse mode: positive pulse width: 0.5 seconds, reverse pulse width: 0.05 seconds, and the chlorate suppression rate is improved to <0.5% at a pulse frequency of 1Hz.

6. The method for synthesizing sodium hypochlorite based on conductive immobilized enzyme synergistic electrocatalysis according to claim 1, characterized in that, The conductive composite carrier is a hybrid structure comprising a metal-organic framework and a conductive polymer; the metal-organic framework and the conductive polymer form a three-dimensional conductive network through the overlapping of molecular orbitals between conjugated aromatic rings.

7. The method for synthesizing sodium hypochlorite based on conductive immobilized enzyme synergistic electrocatalysis according to claim 6, characterized in that, The metal-organic framework is ZIF-8 or chromium-based MIL-101, and the conductive polymer is polyaniline or poly(3,4-ethylenedioxythiophene-polystyrene sulfonate).

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