CN114804209B - Burr microsphere type MnO 2 Preparation method of material and sterilization and disinfection application - Google Patents

Abstract

The invention belongs to the technical field of electrode active materials, and in particular relates to a burr microsphere type MnO ₂ A preparation method of the material and sterilization and disinfection application. The invention adds urea in the reaction process, controls the hydrothermal reaction time, and can prepare the burr microsphere MnO ₂ A material having a regular stable microstructure and a higher specific surface area; further microsphere MnO with burrs ₂ The material is deposited on the electrode, the water to be treated is firstly electrified by voltage to change the permeability of the cell membrane, and then is aerated by ozone, so that substances such as protein, nucleic acid and the like in cells can be directly decomposed through the cell membrane more easily, irreversible fatal damage is caused to the cells, and the remarkable sterilization effect is achieved.

Description

Preparation method of burr microsphere MnO2 material and its sterilization and disinfection application

Technical field

The invention belongs to the technical field of electrode active materials. More specifically, it relates to a preparation method of burr microsphere MnO ₂ material and its sterilization and disinfection application.

Background technique

With the growth of the world's population and the pollution of existing water resources, water scarcity has gradually become a global challenge threatening human survival. The use of recycled water can effectively alleviate the problem of water scarcity. However, the presence of pathogenic microorganisms in water bodies is a major problem that needs to be faced in the efficient use of recycled water.

For the above problems, ozone is currently mainly used in drinking water and wastewater treatment to inactivate pathogens in the water. However, it has been found in practical applications that ozone disinfection has certain limitations: when the dosage of ozone or the contact time is insufficient, the bacteria may repair themselves because intracellular substances such as enzymes and DNA within the bacteria are not fully oxidized and destroyed. Causes the risk of secondary pollution of water quality; in order to ensure the ozone disinfection effect, a higher ozone dosage and contact time must be ensured to further oxidize the cell contents. However, at the same time, excessive ozone will interact with bromine and nitrogen in the water. Compounds and organic matter generate toxic and harmful by-products such as bromate and N-nitrosodimethylamine (NDMA), resulting in higher operating costs and more disinfection by-products. In order to solve this problem, ozone treatment is usually used in combination with other disinfection processes. For example, a Chinese patent application discloses a water sterilization treatment system. This system cannot completely sterilize water quality by using ozone alone. It needs to be combined with silver ions and diamine. Oxidizing chlorine can improve the sterilization effect of water quality; however, other disinfection processes introduced will also introduce other harmful by-products, such as heavy metal ions, etc., which are less safe.

Therefore, there is an urgent need to provide a safe and efficient water sterilization and disinfection method.

Contents of the invention

The technical problem to be solved by the present invention is to overcome the defects and deficiencies of the existing ozone disinfection and sterilization method alone, including dosage, long processing time, low safety, and limited sterilization and disinfection effects, and provide a safe and efficient water quality sterilization and disinfection method.

The object of the present invention is to provide a burr microsphere type MnO ₂ material.

Another object of the present invention is to provide a method for preparing the burr microsphere type MnO ₂ material.

Another object of the present invention is to provide the application of the burr microsphere type MnO ₂ material.

The above objects of the present invention are achieved through the following technical solutions:

A method for preparing burr microsphere MnO ₂ material, which is characterized by including the following steps:

S1. Place the manganese salt and urea under acidic conditions to form a homogeneous solution, heat to reflux at 70-90°C, and stir to complete the reaction to obtain a reaction solution containing solid _MnO2 . Preferably, the heating and refluxing temperature is 80°C.

S2. Complete the hydrothermal reaction of the reaction solution obtained in step S1 at 110 to 130°C, wash the solid obtained until neutral, and dry. Preferably, the temperature of the hydrothermal reaction is 120°C. The present invention uses urea to prepare burr microsphere-type MnO ₂ materials. During the preparation process, urea is unstable and will decompose into NH ₃ and CO ₂ under high temperature and acidic conditions. The decomposition product NH ₃ serves as an alkaline catalyst to accelerate MnO ₂ The formation of seed crystals helps to form hollow microspheres of manganese dioxide.

Further, in step S1, the stirring reaction time is 10 to 30 minutes. Preferably, the stirring reaction time is 20 minutes.

Furthermore, in step S2, the hydrothermal reaction time is 2 to 12 hours. Preferably, the hydrothermal reaction time is 6 hours. In the present invention, by changing the time of the hydrothermal reaction, the length of the nanorods on the manganese dioxide microspheres can be controlled. The hydrothermal reaction time is preferably 6 hours. This is because the R-MnO ₂ microspheres prepared by hydrothermal treatment for 6 hours have a regular and stable microstructure and a higher specific surface area. The length of the nanorods on the surface of the spheres is approximately 0.1 μm, which helps to adhere to and puncture the bacterial cell membrane. No MnO ₂ nanorods grew on the surface of R-MnO ₂ -0h without hydrothermal heating. After the hydrothermal time was extended to 12h, the growth of nanorods on the surface of R-MnO ₂ -12h microspheres began to become messy and irregular, and some The microsphere structure begins to collapse and fragment, resulting in a loss of reactive surface area.

Furthermore, the burr microsphere type MnO ₂ material is also doped with non-ferrous metals, and the non-ferrous metals include gold, silver, platinum and copper.

Furthermore, the non-ferrous metal-doped burr microsphere MnO ₂ material loads non-ferrous metal nanoparticles onto the surface of the burr microsphere MnO ₂ through a chemical reduction method.

Preferably, in the non-ferrous metal-doped burr microsphere type MnO ₂ material, the mass fraction of non-ferrous metal is 0.1% to 5.0%.

Specifically, the method of loading non-ferrous metal nanoparticles onto the surface of the burr microsphere MnO ₂ through chemical reduction method includes the following steps:

Through light excitation or reducing agents, metal ions undergo a reduction reaction to generate metal nanoparticles on the surface of MnO ₂ .

Further, the added amount of urea is 0.2-0.6 mol/L. Preferably, the added amount of urea is 0.4 mol/L.

Furthermore, the acidic condition is pH<2. An acidic environment can be created by directly adding inorganic acids. Preferably, an oxidizing agent, such as KClO ₃ , etc., can also be added to the reaction.

In addition, the present invention also provides a burr microsphere MnO ₂ material prepared by the preparation method.

Further, the burr microsphere type MnO ₂ material is used in electrode materials, sterilization and disinfection, and capacitive desalination.

In addition, the present invention also provides a method for sterilizing and disinfecting water, which is characterized in that the burr microsphere type MnO ₂ material is deposited on an electrode, and the electrode is connected to a direct current and placed in the water to form a loop, and 1.2 to 1.8 is applied. After V voltage treatment for 1 to 5 minutes, use ozone aeration for 2 to 10 minutes.

The burr microsphere type MnO ₂ material prepared by the special process of the present invention is deposited on the electrode. The water quality to be treated is first subjected to voltage electrification treatment. The bacteria will be adsorbed to the electrode that stores a large amount of charge. The charge released by the electrode directly destroys the bacteria. The membrane potential increases the permeability of the membrane and destroys the integrity of the cell membrane. The concentration of ROSs in the bacterial cell increases and the bacteria are in a more fragile state. At this time, ozone aeration treatment can more easily decompose intracellular ROS directly through the cell membrane. Substances such as proteins and nucleic acids can cause irreversible fatal damage to cells and ultimately achieve significant sterilization and disinfection effects.

Further, the dosage of ozone is 0.2-0.6 mg/L.

Furthermore, the air intake flow rate of the ozone is 0.2-0.8L/min.

The water sterilization and disinfection method of the present invention is suitable for the sterilization and disinfection of various bacteria in various water qualities, including but not limited to Escherichia coli (E.coli K-12), Staphylococcus aureus (S.aureus), Salmonella ( Salmonella) and Enterococcus faecalis (E.faecalis); especially suitable for disinfection of salt wastewater, ballast water and other water quality.

The invention has the following beneficial effects:

The present invention is a burr microsphere type MnO ₂ material. By adding urea during the reaction process and then controlling the hydrothermal reaction time, a burr microsphere type MnO ₂ material with hollow interior and nanorods on the surface can be prepared, which has regular and stable properties. Microstructure and higher specific surface area; further deposit the burr microsphere type MnO ₂ material on the electrode, first apply voltage to the water to be treated, change the permeability of the cell membrane, and then use ozone aeration to make it easier to pass through The cell membrane directly decomposes proteins, nucleic acids and other substances in the cells, causing irreversible fatal damage to the cells and achieving significant sterilization and disinfection effects. Moreover, this method can reduce the dosage and contact time of ozone, thereby reducing treatment costs and disinfection by-products. It does not require the addition of any chemical reagents, is clean and pollution-free, and can be widely used for various bacteria in water quality, especially for salt-containing water. Disinfection of waste water, ballast water and other water quality.

Description of the drawings

Figure 1 is a scanning electron microscope SEM image of R-MnO ₂ (a), R-MnO ₂ -0h (b), R-MnO ₂ -12h (c), and U-MnO ₂ (d) materials prepared by the present invention.

Figure 2 is an X-ray diffraction (XRD) pattern of the R-MnO ₂ material prepared in Example 1 of the present invention.

Figure 3 is a scanning electron microscope SEM image of bacteria at different stages in application examples of the present invention.

Detailed ways

The invention will be further described below with reference to the accompanying drawings and specific examples, but the examples do not limit the invention in any way. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in this technical field.

Among them, commercially available MnO ₂ (CAS: 1313-13-9, AR, 85%) was purchased from Aladdin.

Unless otherwise stated, the reagents and materials used in the following examples were all commercially available. In the present invention, if the temperature is not specified, it means that it is carried out at room temperature.

Example 1 Preparation of Burr Microsphere MnO ₂ Material

The preparation method of the burr microsphere type _MnO material includes the following steps:

S1. Add 0.01 mol MnSO ₄ and 0.015 mol KClO ₃ into an Erlenmeyer flask containing 60 mL of concentrated nitric acid to form a homogeneous solution. Then add 0.024 mol urea and stir vigorously for 20 minutes in an 80°C water bath. At the upper end of the Erlenmeyer flask Set up a condensation reflux device; black solid MnO ₂ is continuously generated during the stirring process;

S2. Move the reaction solution obtained in step S1 to a 100 mL Teflon-lined high-pressure hydrothermal reaction kettle, place it in an oven for hydrothermal reaction at 120°C for 6 hours; after the reaction is completed, naturally cool to room temperature, filter, and use ultrapure water and The obtained solid was washed repeatedly with absolute ethanol until the filtrate was neutral, and dried at 60°C for 12 hours to obtain three-dimensional rambutan-like hollow microsphere manganese dioxide (R-MnO ₂ -6h, hereinafter abbreviated as R-MnO ₂ ). .

The obtained R-MnO ₂ was subjected to scanning electron microscopy SEM examination, and the results are shown in Figure 1a. It can be seen from the figure that the R-MnO ₂ prepared after 6 hours of hydrothermal preparation has a regular 3D microsphere shape. Many regular MnO ₂ nanorods grow on the surface of the R-MnO ₂ sphere. The center of the sphere has a hollow structure, and the whole forms a Three-dimensional hollow rambutan-like microsphere structure, with particle diameter between 600 and 800nm. It has a more regular and stable microstructure and a higher specific surface area.

The obtained R- _MnO2 was subjected to X-ray diffraction (XRD) testing, and the results are shown in Figure 2. It can be seen from the figure that the prepared RMnO ₂ material matches PDF 44-0141, and the corresponding diffraction peaks are (110), (200), (220), (310), (400), (2111), (330) ), (301), (411), (600), (521), (002), (541) and (631), corresponding to each crystal face of α-MnO ₂ , and no other ones appear in the figure. Impurity peaks and diffraction peaks have good peak shapes, indicating that the prepared R-MnO ₂ has an α-MnO ₂ crystal phase and is pure in phase without impurities.

Example 2 Preparation of Burr Microsphere MnO ₂ Material

The preparation method of the burr microsphere type _MnO material includes the following steps:

S1. Add 0.01 mol MnSO ₄ and 0.015 mol KClO ₃ into an Erlenmeyer flask containing 60 mL of concentrated nitric acid to form a homogeneous solution. Then add 0.024 mol urea and stir vigorously for 20 minutes in an 80°C water bath. At the upper end of the Erlenmeyer flask Set up a condensation reflux device; black solid MnO ₂ is continuously generated during the stirring process;

S2. Move the reaction solution obtained in step S1 to a 100 mL Teflon-lined high-pressure hydrothermal reaction kettle, place it in an oven for hydrothermal reaction at 120°C for 12 hours; after the reaction is completed, naturally cool to room temperature, filter, and use ultrapure water and The obtained solid was washed repeatedly with absolute ethanol until the filtrate was neutral, and dried at 60°C for 12 hours to obtain three-dimensional rambutan-like hollow microsphere manganese dioxide (R-MnO ₂ -12h).

The obtained R-MnO ₂ -12h material was subjected to scanning electron microscopy SEM examination. The results are shown in Figure 1c. It can be seen from the figure that the growth of nanorods on the surface of R-MnO ₂ -12h material microspheres begins to become messy and irregular, and part of the microsphere structure begins to collapse and break.

Example 3 Preparation of Burr Microsphere MnO ₂ Material

The preparation method of the burr microsphere type _MnO material includes the following steps:

S1. Add 0.01 mol MnSO ₄ and 0.015 mol KClO ₃ into an Erlenmeyer flask containing 60 mL of concentrated nitric acid to form a homogeneous solution. Then add 0.024 mol urea and stir vigorously for 20 minutes in an 80°C water bath. At the upper end of the Erlenmeyer flask Set up a condensation reflux device; black solid MnO ₂ is continuously generated during the stirring process;

S2. Move the reaction solution obtained in step S1 to a 100 mL Teflon-lined high-pressure hydrothermal reaction kettle, place it in an oven for hydrothermal reaction at 120°C for 6 hours; after the reaction is completed, naturally cool to room temperature, filter, and use ultrapure water and Wash the obtained solid repeatedly with absolute ethanol until the filtrate becomes neutral, and dry it at 60°C for 12 hours to obtain three-dimensional rambutan-like hollow microsphere manganese dioxide (R-MnO ₂ );

S3. Add 0.1g R-MnO ₂ obtained in step S2 into a beaker containing a mixture of 50mL ultrapure water and 50mL isopropyl alcohol. Shake and stir thoroughly to form a uniform suspension. Use a 300W xenon lamp to illuminate for 1 hour. Turn off the xenon lamp and add 50 μL of 20 mM silver nitrate solution, stir continuously for 10 minutes; filter, wash and dry to obtain rambutan manganese dioxide (0.17% Ag/R-MnO ₂ ) with a theoretical silver content of 0.17%.

Example 4 Preparation of Burr Microsphere MnO ₂ Material

The preparation method of the burr microsphere type _MnO material includes the following steps:

S1. Add 0.01 mol MnSO ₄ and 0.015 mol KClO ₃ into an Erlenmeyer flask containing 60 mL of concentrated nitric acid to form a homogeneous solution. Then add 0.024 mol urea and stir vigorously for 20 minutes in an 80°C water bath. At the upper end of the Erlenmeyer flask Set up a condensation reflux device; black solid MnO ₂ is continuously generated during the stirring process;

S2. Move the reaction solution obtained in step S1 to a 100 mL Teflon-lined high-pressure hydrothermal reaction kettle, place it in an oven for hydrothermal reaction at 120°C for 6 hours; after the reaction is completed, naturally cool to room temperature, filter, and use ultrapure water and Wash the obtained solid repeatedly with absolute ethanol until the filtrate becomes neutral, and dry it at 60°C for 12 hours to obtain three-dimensional rambutan-like hollow microsphere manganese dioxide (R-MnO ₂ );

S3. Add 0.1g R-MnO ₂ obtained in step S2 into a beaker containing a mixture of 50mL ultrapure water and 50mL isopropyl alcohol. Shake and stir thoroughly to form a uniform suspension. Use a 300W xenon lamp to illuminate for 1 hour. Turn off the xenon lamp and add 150 μL of 20 mM silver nitrate solution, stir continuously for 10 minutes; filter, wash and dry to obtain rambutan manganese dioxide (0.51% Ag/R-MnO ₂ ) with a theoretical silver content of 0.51%.

Example 5 Preparation of Burr Microsphere MnO ₂ Material

The preparation method of the burr microsphere type _MnO material includes the following steps:

S1. Add 0.01 mol MnSO ₄ and 0.015 mol KClO ₃ into an Erlenmeyer flask containing 60 mL of concentrated nitric acid to form a homogeneous solution. Then add 0.024 mol urea and stir vigorously for 20 minutes in an 80°C water bath. At the upper end of the Erlenmeyer flask Set up a condensation reflux device; black solid MnO ₂ is continuously generated during the stirring process;

S2. Move the reaction solution obtained in step S1 to a 100 mL Teflon-lined high-pressure hydrothermal reaction kettle, place it in an oven for hydrothermal reaction at 120°C for 6 hours; after the reaction is completed, naturally cool to room temperature, filter, and use ultrapure water and Wash the obtained solid repeatedly with absolute ethanol until the filtrate becomes neutral, and dry it at 60°C for 12 hours to obtain three-dimensional rambutan-like hollow microsphere manganese dioxide (R-MnO ₂ );

S3. Add 0.1g R-MnO ₂ obtained in step S2 into a beaker containing a mixture of 50mL ultrapure water and 50mL isopropyl alcohol. Shake and stir thoroughly to form a uniform suspension. Use a 300W xenon lamp to illuminate for 1 hour. Turn off the xenon lamp and add 250 μL of 20 mM silver nitrate solution, stir continuously for 10 minutes; filter, wash and dry to obtain rambutan manganese dioxide (0.85% Ag/R-MnO ₂ ) with a theoretical silver content of 0.85%.

Example 6 Preparation of Burr Microsphere MnO ₂ Material

The preparation method of the burr microsphere type _MnO material includes the following steps:

S1. Add 0.01 mol MnSO ₄ and 0.015 mol KClO ₃ into an Erlenmeyer flask containing 60 mL of concentrated nitric acid to form a homogeneous solution. Then add 0.024 mol urea and stir vigorously for 20 minutes in an 80°C water bath. At the upper end of the Erlenmeyer flask Set up a condensation reflux device; black solid MnO ₂ is continuously generated during the stirring process;

S2. Move the reaction solution obtained in step S1 to a 100 mL Teflon-lined high-pressure hydrothermal reaction kettle, place it in an oven for hydrothermal reaction at 120°C for 6 hours; after the reaction is completed, naturally cool to room temperature, filter, and use ultrapure water and Wash the obtained solid repeatedly with absolute ethanol until the filtrate becomes neutral, and dry it at 60°C for 12 hours to obtain three-dimensional rambutan-like hollow microsphere manganese dioxide (R-MnO ₂ );

S3. Add 0.1g R-MnO ₂ obtained in step S2 to 10mL HAuCl ₄ (2.5×10 ^-4 M) solution, stir at room temperature for 3 hours, add 600 μL NaBH ₄ solution (6mM) under ice bath conditions, and stir in ice bath for 1 hours, gold ions are reduced to gold nanoparticles; filter, wash and dry, wash with water, centrifuge and vacuum dry for 12 hours to obtain rambutan manganese dioxide (Au/R-MnO ₂ ) doped with gold nanoparticles.

Example 7 Preparation of Burr Microsphere MnO ₂ Material

The preparation method of the burr microsphere type _MnO material includes the following steps:

S1. Dissolve 2.8mmol KMnO ₄ in 75mL of ultrapure water, stir for 10min, add 1mL of 37% hydrochloric acid dropwise during the stirring process, then add 0.024mol of urea, and continue stirring for 20min;

S2. Move the reaction solution obtained in step S1 to a 100 mL Teflon-lined high-pressure hydrothermal reaction kettle, place it in an oven for hydrothermal reaction at 110°C for 12 hours; after the reaction is completed, naturally cool to room temperature, filter, and use ultrapure water and The obtained solid was washed repeatedly with absolute ethanol until the filtrate was neutral, and dried at 60°C for 12 hours to obtain three-dimensional sea urchin-like hollow microspheres of U-MnO ₂ .

The obtained U-MnO ₂ material was subjected to scanning electron microscopy SEM examination, and the results are shown in Figure 1d. It can be seen from the figure that the U-MnO ₂ particles are hollow spherical in shape, with many spikes growing on the surface. The particle diameter is about 4 μm, forming a hollow structure of sea urchin-like manganese dioxide as a whole.

Compared with U-MnO ₂ , R-MnO ₂ particles have smaller sizes and larger specific surface areas. Capacitive materials with larger specific surface areas can provide more abundant active reaction sites, which is beneficial to capturing ions in the solution, thereby Improve the electrochemical properties and specific capacitance; in addition, the tip burr structure of appropriate size on the surface of the material is more conducive to the adhesion of bacteria.

Comparative Example 1 Preparation of Microsphere MnO ₂ Material

The preparation method of the microspherical _MnO material includes the following steps:

S1. Add 0.01 mol MnSO ₄ and 0.015 mol KClO ₃ into an Erlenmeyer flask containing 60 mL of concentrated nitric acid to form a homogeneous solution. Then add 0.024 mol urea and stir vigorously for 20 minutes in an 80°C water bath. At the upper end of the Erlenmeyer flask Set up a condensation reflux device; black solid MnO ₂ is continuously generated during the stirring process;

S2. Transfer the reaction liquid obtained in step S1 to naturally cool to room temperature, filter, and wash the obtained solid repeatedly with ultrapure water and absolute ethanol until the filtrate becomes neutral, and dry it at 60°C for 12 hours to obtain a three-dimensional rambutan-like hollow Microsphere manganese dioxide (R-MnO ₂ -0h).

The obtained R-MnO ₂ -0h material was subjected to scanning electron microscopy SEM examination. The results are shown in Figure 1b. It can be seen from the figure that the R-MnO ₂ -0h material obtained without hydrothermal reaction formed a rough spherical structure, and no MnO ₂ nanorods grew on the surface.

Application example 1 Capacitor-ozone synergistic sterilization method

The MnO ₂ materials prepared in Examples 1 to 7 and Comparative Example 1 are used for capacitor-ozone synergistic sterilization, which specifically includes the following steps:

SI. Grind and mix the MnO ₂ materials prepared in Examples 1 to 8 with acetylene black and polyvinylidene fluoride (PVDF) at a mass ratio of 8:1:1. After mixing, add 1-methane dropwise. Base-2-pyrrolidone (C ₅ H ₉ NO, NMP) and stir to form a uniform color slurry, then evenly apply it on the 6×3cm ² graphite sheet base, with an area of 3×3cm ² to deposit on the graphite The mass of the active material on the sheet is 20 mg. After coating the electrode sheet, place it in a vacuum drying oven to be vacuum dried at 60°C for 12 hours;

SII, place the graphite electrode deposited with MnO ₂ material obtained in step SII in a capacitive reaction cell, form a closed loop with the DC voltage circuit, and apply a voltage of 1.5V to the electrode;

SIII. Use a peristaltic pump to circulate physiological saline containing bacteria (E.coli) with a concentration of 10 ⁶ to 10 ⁸ CFU/mL in the capacitive reaction cell. The flow rate of the solution is 1 to 100 mL/min, and the capacitor energization time is 5min;

SIV. Sampling the aqueous solution after capacitive treatment and adding it to the Erlenmeyer flask. Ozone is continuously blown into the Erlenmeyer flask containing the water sample through the micro aerator. The inlet concentration of ozone is 0.6mg/L and the inlet flow rate is 0.5 L/min, the ozone and aqueous solution are fully mixed under magnetic stirring, and the ozone treatment time is 10 minutes.

Determination of sterilization and disinfection effects:

After sterilization and disinfection, take a 50 μL sample, spread it evenly on the LB-agar medium, place it in a constant temperature incubator at 37°C for 12 hours, use 50 μL of sterile saline-coated LB-agar medium as a blank control, and record The number of colonies on the culture medium was used to calculate the concentration of viable E. coli in the sample taken. The results are shown in Table 1.

Table 1 Measurement results of sterilization and disinfection effects

It can be seen from the table that after the MnO ₂ material prepared in the present invention is made into an electrode, the bacteria are first treated with a smaller voltage, and then combined with ozone aeration, significant sterilization and disinfection effects can be achieved, with a sterilization rate of more than 99%.

Comparing Examples 1 to 2 and 7 with Comparative Example 1, it can be seen that the surface burr microstructure of the electrode materials (R-MnO ₂ -6h, R-MnO ₂ -12h and U-MnO ₂ ) makes the capacitor system have better bactericidal performance. Among R-MnO ₂ materials, R-MnO ₂ -6h has the best effect. This is due to the fact that the R-MnO ₂ microspheres prepared by hydrothermal treatment for 6 hours have a regular and stable microstructure and a higher specific surface area, which illustrates the performance of the capacitor material. The microscopic three-dimensional structure and the appropriately sized burr tips on the particle surface are beneficial to increasing the charge storage capacity and surface charge density of the electrode, while also enhancing its adhesion interaction with bacteria, thus improving the bactericidal performance of the capacitive system.

Comparing Example 1 and Examples 3 to 6, it can be seen that the non-ferrous metal doping reduces the ion and charge transfer impedance, increases the specific capacitance, enables the electrode to store more charges, makes the capacitance treatment effect more thorough, and minimizes the water body Among them, the composite material with the best bactericidal performance is the 0.51% Ag/R-MnO ₂ material of Example 4. The sterilization rate of the 0.51% Ag/R-MnO ₂ capacitor-ozone system is as high as 99.9998%. .

Take 10 mL of bacterial liquid at two time points when the bacteria in Example 1 are untreated and after ozone treatment, add 5 mL of glutaraldehyde solution (concentration: 2.5%), mix well, and refrigerate at 4°C overnight, and then use sterile water Centrifuge and wash it with water three times, then treat it with 30%, 50%, 70%, and 90% ethanol for 10 minutes respectively, and then treat it with absolute ethanol for 20 minutes after centrifugation; put the ethanol-dehydrated bacteria into the refrigerator at -20°C Freeze for 6 hours, then freeze-dry for three days to turn it into a solid powder, and then conduct further SEM characterization. The results are shown in Figure 3.

Application example 2 Capacitor-ozone synergistic sterilization method

The MnO ₂ material prepared in Example 1 is used for capacitor-ozone synergistic sterilization and disinfection. Refer to the conditions of Application Example 1 and adjust the capacitive treatment voltage and time and the dosage and treatment time of ozone treatment. The remaining parameters are the same as Application Example 1. , please refer to Table 2 for specific conditions and bactericidal effects.

Table 2 Results of determination of sterilization and disinfection effects under different conditions

It can be seen from the table that after the MnO ₂ material prepared in the present invention is made into an electrode, the bacteria are first treated with a smaller voltage, and then combined with ozone aeration. By controlling the voltage or ozone-related parameters, significant sterilization and disinfection effects can be achieved. The rate is above 95%.

Among them, combined with the data of Example 1 in Application Example 1, it can be seen from the measurement results of Nos. 1 to 2 that the greater the voltage applied in the capacitor pretreatment, the longer the capacitor treatment time, and the capacitor-ozone synergistic process has better effects on E. coli The better the sterilization performance. When the voltage reaches 1.5V and pretreated for 5 minutes, the overall sterilization performance reaches 99.9861%. In comparison, although at the voltage of 1.8V, the sterilization rate of the R-MnO ₂ capacitor-ozone system can reach 99.9861%. 100.0000%, but too high a voltage may cause water decomposition and increase the energy consumption of the process, so a voltage of 1.5V is optimal.

Combined with the data of Example 1 in Application Example 1, it can be seen from the measurement results of Nos. 5 to 6 that the performance of the capacitor-ozone synergistic process improves with the increase of ozone dosage. When capacitor pretreatment is used, the performance of the synergistic process is equal to Higher than 99%.

Combined with the data of Example 1 in Application Example 1, it can be seen from the measurement results of Nos. 7 to 8 that under the same ozone dosage, the longer the ozone treatment time, the better the sterilization effect, but at the same time, the disinfection by-products will also increase with time. increase.

Comparative Example 2 Single capacitor sterilization and disinfection

The _MnO material prepared in Example 1 is used for capacitor sterilization, which specifically includes the following steps:

SI. Grind and mix the spined microsphere MnO ₂ material prepared in Example 1 with acetylene black and PVDF according to a mass ratio of 8:1:1. After mixing, add NMP drop by drop and stir and mix to form a uniform color. After the slurry is applied, apply it evenly on the 6×3cm ² graphite sheet base with an area of 3×3cm ² so that the mass of the active material deposited on the graphite sheet is 20 mg. After the electrode sheet is coated, place it in a vacuum drying box. Vacuum drying at 60°C for 12 hours;

SII, place the graphite electrode deposited with MnO ₂ material obtained in step SII in a capacitive reaction cell, form a closed loop with the DC voltage circuit, and apply a voltage of 1.5V to the electrode;

SIII. Use a peristaltic pump to circulate physiological saline containing bacteria with a concentration of 10 ⁶ to 10 ⁸ CFU/mL in the capacitive reaction cell. The flow rate of the solution is 1 to 100 mL/min, and the capacitor energization time is 5 minutes.

The sterilization and disinfection effect measurement method refers to Application Example 1, and the sterilization rate is 80.6329%.

Comparative Example 3 Ozone sterilization alone

Take a sample of the aqueous solution containing E. coli with a concentration of 10 ⁶ to 10 ⁸ CFU/mL and add it to the Erlenmeyer flask. Ozone is continuously blown into the Erlenmeyer flask containing the water sample through a micro aerator. The inlet concentration of ozone is 0.6 mg. /L, the air inlet flow rate is 0.5L/min, the ozone and aqueous solution are fully mixed under magnetic stirring, and the ozone treatment time is 10 minutes.

The method for measuring the sterilization and disinfection effect refers to Application Example 1, and the sterilization rate is 90.7759%.

After ozone treatment, take 10 mL of bacterial solution, add 5 mL of glutaraldehyde solution (concentration: 2.5%), mix well and refrigerate at 4°C overnight, then centrifuge and wash it 3 times with sterile water, and then wash it with 30 %, 50%, 70%, 90% ethanol for 10 minutes, centrifuged and then treated with absolute ethanol for 20 minutes; put the ethanol-dehydrated bacteria into the refrigerator at -20°C for 6 hours, and then freeze-dry for three days to make them The solid powder was further characterized by scanning electron microscopy (SEM). The results are shown in Figure 3.

As can be seen from the picture, the untreated E. coli cells are full rod-shaped and the bacterial envelope is intact; in Comparative Example 3, after ozone treatment alone, the bacterial surface appears distorted and wrinkled to varying degrees, and filaments are formed, and part of the bacterial membrane is Cavities and holes appeared, but the damage was not particularly serious, and there was still the possibility of suspended animation and resurrection of the bacteria. In Application Example 1, after capacitor-ozone collaborative treatment, the bacteria showed severe shrinkage and cracking, accompanied by cytoplasmic leakage.

Comparative Example 4 Capacitor-Ozone Collaborative Sterilization and Disinfection Method

The MnO ₂ material in Application Example 1 was replaced with commercially available MnO ₂ for capacitor-ozone synergistic sterilization and disinfection, and the remaining parameters were the same as Application Example 1.

The method for measuring the sterilization and disinfection effect refers to Application Example 1, and the sterilization rate is 91.8966%.

The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, etc. may be made without departing from the spirit and principles of the present invention. All simplifications should be equivalent substitutions, and are all included in the protection scope of the present invention.

Claims (8)

1. Burr microsphere type MnO ₂ The preparation method of the material is characterized by comprising the following steps:

s1, putting manganese salt and urea under an acidic condition to prepare a homogeneous solution, heating and refluxing at 70-90 ℃ and stirring for reaction for 10-30 min to obtain a solid MnO-containing solution ₂ Is a reaction solution of (a);

s2, carrying out hydrothermal reaction on the reaction solution obtained in the step S1 at the temperature of 110-130 ℃ for 2-12 hours, washing the obtained solid to be neutral, and drying to obtain the catalyst;

wherein the burr microsphere type MnO ₂ The material is doped with nonferrous metals including gold, silver, platinum and copper; the non-ferrous metal doped burr microsphere MnO ₂ The material loads nonferrous metal nano particles to the burr microsphere MnO by a chemical reduction method ₂ A surface; the non-ferrous metal doped burr microsphere MnO ₂ In the material, the mass fraction of the nonferrous metal is 0.1-5.0%.

2. The method according to claim 1, wherein the urea is added in an amount of 0.2 to 0.6mol/L.

3. The method of claim 1, wherein the acidic condition is a pH <2.

4. A burr microsphere type MnO prepared by the preparation method of any one of claims 1 to 3 ₂ A material.

5. The burr microsphere type MnO of claim 4 ₂ The material is applied to electrode materials, sterilization and disinfection and capacitance desalination.

6. A method for sterilizing water, characterized in that the burr microsphere type MnO according to claim 4 is used ₂ The material is deposited on the electrode, the electrode is connected with direct current and then placed in water to form a loop, and after 1.2-1.8V voltage is applied for 1-5 min, ozone aeration treatment is carried out for 2-10 min.

7. The method according to claim 6, wherein the ozone is added in an amount of 0.2 to 0.6mg/L.

8. The method of claim 6, wherein the ozone intake flow rate is 0.2 to 0.8L/min.