阅读说明：本技术 一种电解制备低浓度纳米银抗菌喷雾剂的方法 (Method for preparing low-concentration nano-silver antibacterial spray through electrolysis ) 是由 田军 于 2020-11-28 设计创作，主要内容包括：本发明提供一种电解制备低浓度纳米银抗菌喷雾剂的方法,包括以下步骤：将含有稳定剂的流动相反应水溶液持续不断注入至电解银反应装置；进行低电流密度条件下缓慢流动电解,间隔交换依次电解银反应装置的电流方向,获得具有纳米银的纳米银水溶液,不达到浓度的溶液直至老化结束后,纳米银水溶液分装避光保存,增强其稳定性,得到低浓度纳米银抗菌喷雾剂。通过本发明提供的方法改变电解电压及电流、流动相通过速率和搅拌速率,可获得不同粒径大小、表面电荷的纳米银的纳米银水溶液作为抗菌喷雾剂,采用柠檬酸钠作为稳定剂以及使用纯银电极,避免使用硝酸银作为起始原料制备纳米银水溶液,可以更好提高纳米银水溶液的生物兼容性。(The invention provides a method for preparing a low-concentration nano-silver antibacterial spray by electrolysis, which comprises the following steps: continuously injecting a flowing phase reaction aqueous solution containing a stabilizer into an electrolytic silver reaction device; and (3) carrying out slow flowing electrolysis under the condition of low current density, and exchanging the current directions of the successive silver electrolysis reaction devices at intervals to obtain a nano silver aqueous solution with nano silver, wherein the nano silver aqueous solution is subpackaged and stored in a dark place until the aging is finished, so that the stability of the nano silver aqueous solution is enhanced, and the low-concentration nano silver antibacterial spray is obtained. By changing the electrolytic voltage and current, the flow rate of the mobile phase and the stirring rate, the method can obtain nano-silver aqueous solutions of nano-silver with different particle sizes and surface charges as an antibacterial spray, adopts sodium citrate as a stabilizer and a pure silver electrode, avoids using silver nitrate as an initial raw material to prepare the nano-silver aqueous solution, and can better improve the biocompatibility of the nano-silver aqueous solution.)

1. A method for preparing a low-concentration nano-silver antibacterial spray through electrolysis is characterized by comprising the following steps:

1) continuously injecting a mobile phase reaction aqueous solution containing a stabilizer with the concentration of 10 ppm-200 ppm into a mobile electrolytic cell (3) of an electrolytic silver reaction device;

2) opening a switch of the electrolytic silver reaction device, leading the mobile phase reaction aqueous solution into the reactor at a flow rate of 5-10 mL/min, slowly flowing at a flow rate of 1-10 mL/min under the conditions of a voltage range of 2-5V, a constant current range of 0.001-0.01A and a temperature range of 10-40 ℃ and a low current density, electrolyzing, taking a silver anode of the electrolytic silver reactor as a sacrificial anode to release silver ions, diffusing the silver ions to an cathode and reducing the silver ions into nano silver, redissolving the silver ions into the aqueous solution and continuously flowing along with the electrolyte, and exchanging the current direction of the electrolytic silver reaction device at intervals of 10-60 s;

3) continuously obtaining low-concentration nano-silver aqueous solution from a discharge tank (6) of the electrolytic silver reaction device, sampling every 1-6 h, and detecting the effective concentration of silver ions in the low-concentration nano-silver aqueous solution;

4) if the concentration of the nano-silver aqueous solution collected at the discharging pool (6) is not enough, the nano-silver aqueous solution is reintroduced into the flowing electrolytic cell (3) for re-electrolysis through a recycling pipeline (7) of the electrolytic silver reaction device;

5) and (3) after aging is finished, subpackaging the nano-silver aqueous solution in medicinal amber glass packages for dark storage, and enhancing the stability of the medicinal amber glass packages to obtain the low-concentration nano-silver antibacterial spray.

2. The method for electrolytically preparing the low-concentration nano-silver antibacterial spray according to claim 1, wherein the stabilizer comprises sodium citrate, polyvinylpyrrolidone and polyvinyl alcohol in a mass fraction ratio of 50:30: 20.

3. The method for electrolytically preparing a low-concentration nano-silver antibacterial spray according to claim 1, wherein the concentration of the stabilizer in the aqueous solution of the mobile phase reaction is 10ppm to 100 ppm.

4. The method for electrolytically producing a low-concentration nano-silver antibacterial spray according to claim 1, wherein the ultrapure water of the mobile phase solution is ultrapure water having a resistivity of 18M Ω · cm at 25 ℃.

5. The method for electrolytically preparing the low-concentration nano-silver antibacterial spray according to claim 1, wherein the larger the voltage of the electrolytic silver reaction device is, the larger the particle size of the nano-silver in the obtained antibacterial spray is, and the particle size of the nano-silver in the antibacterial spray is 10nm to 50 nm.

6. The method for preparing the low-concentration nano silver antibacterial spray through electrolysis according to claim 1, characterized in that the electrolytic silver reaction device comprises a feeding pool (1), a flowing electrolytic pool (3), a direct current power supply (4), a discharging pool (6) and a recirculation pipeline (7), wherein the feeding pool (1) is communicated with a feeding port (3-1) of the flowing electrolytic pool (3) through a feeding pipe (1-1), a discharging port (3-2) of the flowing electrolytic pool is communicated with the discharging pool through a discharging pipe (6-1), the feeding pipe (1-1) is provided with a flow pump (2), and the recirculation pipeline (7) is used for communicating the discharging pool (6) with the flow pump (2);

a silver cathode (3-3) and a silver anode (3-4) are arranged in the flow electrolytic cell (3), a plurality of labyrinth partition plates (3-5) are oppositely arranged on the silver cathode (3-3) and the silver anode (3-4) to form labyrinth stacking channels (3-6) which are mutually inserted, the labyrinth stacking channels (3-6) prolong the area of microfluid electrolysis in the flow electrolytic cell (3), and the silver anode (3-4) and the silver cathode (3-3) are respectively connected with the anode and the cathode of the direct current power supply (4); the direct current direction is exchanged by the direct current power supply (4) at intervals so as to ensure that the electrode plates of the silver cathode (3-3) and the silver anode (3-4) uniformly participate in the electrolysis process.

7. The method for electrolytically producing a low concentration nano silver antibiotic spray according to claim 6, wherein each labyrinth plate (3-5) is formed of polytetrafluoroethylene processed into a semi-cylindrical body having a semi-circular cross-section, thereby forming a circular groove for fixing.

8. The method for electrolytically preparing a low concentration nano silver antibiotic spray according to claim 6, wherein the labyrinth plate has a length of 50mm, a width of 50mm and a thickness of 1.0mm, and each labyrinth plate (3-5) has a semicircular sectional diameter of 4.0 mm.

9. The method for electrolytically preparing the low-concentration nano-silver antibacterial spray according to claim 6, characterized in that a group of labyrinth separator channels (3-61) is formed between a labyrinth separator on the silver cathode (3-3) and a labyrinth separator on the silver anode (3-4), and a plurality of groups of labyrinth separator channels (3-61) form a serpentine-shaped distribution labyrinth stacked channel (3-6); the length of the labyrinth partition plate pore canal (3-61) is 200mm, and the width is 4.0 mm.

10. The method for electrolytically preparing the low-concentration nano-silver antibacterial spray according to claim 6, characterized in that silver electrodes with the purity of 99.99% -99.999% and the diameter of 2 mm-5 mm are adopted as the silver cathode (3-3) and the silver anode (3-4), the distance between the silver cathode (3-3) and the silver anode (3-4) is 2 mm-10 mm, and the volume of the electrolytic silver reaction device is 1L-10L.

Technical Field

The invention belongs to the technical field of precious metal nano material aqueous solution electrolytic preparation methods, and particularly relates to a method for preparing a low-concentration nano silver antibacterial spray through electrolysis.

Background

Since the roman times, people have noticed the sterilization property of silverware and no disinfection by-products, and gradually combined the silverware with a ceramic filter to be applied to drinking water systems, the application and development of silver in the sterilization field have been greatly developed.

The research team Robert E.Geertsma of the national institute of public health and Environment, the Netherlands reviewed that nanosilver has a series of broad-spectrum antibacterial properties against gram-negative bacteria (Acinetobacter, Escherichia coli, Pseudomonas, Salmonella and Vibrio) and gram-positive bacteria (Bacillus, Clostridium, enterococcus, Listeria, Staphylococcus aureus, Streptococcus) ("Wijnhoven, S.W.P., et al, Nano-silver-a review of available data and knowledge gates in human and environmental strain Nanotoxicolology, 2009.3(2):109 and 138").

Massimiliano Galdiero research team, Experimental medicine department, second university of Neilas, Italy, also demonstrated that nanosilver is resistant to a variety of viruses, including human immunodeficiency virus, hepatitis B virus, herpes simplex virus, respiratory syncytial virus, and monkeypox virus, and has a lower Potential to develop resistance compared to conventional antivirals because metals may attack multiple targets in the virus ("Galdiero Stefania, et al., Silver Nanoparticles Potential Antiviral Agents, 2011.16(10): 8894 @").

The research team Eric m.v. hoek, institute of nanosystems, university of los angeles, california, reviews the antibacterial effect of silver nanomaterials, and it is believed that although the antibacterial mechanism of nano-silver has not been fully elucidated, the three most common antibacterial toxicity mechanisms proposed to date are: (1) releases free silver ions, and then destroys a series of intracellular reactions such as ATP generation and DNA replication after being absorbed by cells; (2) nano-silver and ROS (reactive Oxygen species) generated by silver ions, which generate oxidative stress, resulting in membrane lipid and DNA damage; (3) silver nanoparticles directly damage the viral cell membrane ("Eric M.V. Hoek et al, A review of the antibacterial effects of silver nanoparticles for human health and the environment. journal of nanopartical Research,2010.12(5): 1531-1551").

The research team Akihide Ryo of the microbiology department of the medical college of Japan, Binsheng, university of medicine finds that the nano-silver can effectively inhibit the activity of the novel coronavirus of the extracellular SARS-CoV-2 within the concentration range of 1-10 ppm. Through luciferase-based pseudovirus entry experiments, it is shown that nanosilver interacts with structural proteins on the surface of extracellular viruses, prevents viruses from attaching to or entering the surfaces, or effectively inhibits virus invasion by destroying the integrity of new coronaviruses, while protecting target cells from infection at an early stage. The authors speculate that nanosilver exerts an antiviral effect on SARS-CoV-2 by disrupting the disulfide bond on spike protein and ACE2 receptor, and this study indicated that nanosilver is a highly effective germicide useful against new coronavirus ("Akihide Ryo et al, Point anti viral effect of silver nanoparticles on SARS-CoV-2.Biochemical and biological research communications,2020.533(1): 195-.

Due to the excellent antibacterial ability and catalytic performance of nano-silver, nano-silver is widely applied to the fields of antibacterial disinfection, industrial catalysis, electronic components, pollutant treatment and the like at present, and plays an important role in industrial production and life of people.

The broad spectrum antimicrobial properties of silver encourage its use in biomedical applications, water and air purification, food production, cosmetics, clothing, and many household products. With the rapid development of nanotechnology, the application range of nanotechnology is further expanded, and now silver becomes the most common engineering nanomaterial in consumer products.

Roberto vazzez-Munoz, the national center for emerging infections, texas, san antonio university, texas, usa, proposed the use of nanosilver-based disinfecting products in personal protective gear, surface coatings, etc., that can be used for protection against new corona viruses and that have better resistance ("Roberto vazzez-Munoz et al, Nanotechnology as an Alternative to Reduce the Spread of COVID-19. changees, 2020.11(2): 15").

The university of Italy Tuolingian applied the scientific and technological system Cristina Balagna research team, which found that the anti-new coronavirus effect could be effectively improved by compositely sputtering silver nanoparticles onto the filtration system of air conditioning system and medical respirator. Compared with a blank control group which is not treated by nano silver, the SARS-CoV-2 new coronavirus infectivity of the mask with the surface treated by the nano silver is reduced by an order of magnitude, and the authors think that the nano silver can have certain efficacy for surface disinfection of crowded areas (such as supermarkets, production places, schools, hospitals and the like) which are exposed to contact with human bodies ("Cristina Balagna et al, Virucdal effect obtained from coronavirus SARS-CoV-2of a silver nano cluster/silicon composite infected.

Disclosure of Invention

Aiming at the defects, the invention provides a method for obtaining a nano-silver aqueous solution with the particle size of 10 nm-50 nm by changing the process parameters such as electrolytic voltage (2V-10V), current (0.001A-0.01A), mobile phase passing rate (1 mL/min-10 mL/min) and the like, wherein the nano-silver aqueous solution can be used as an antibacterial spray.

The invention provides a method for preparing a low-concentration nano-silver antibacterial spray by electrolysis, which comprises the following steps:

1) continuously injecting a mobile phase reaction aqueous solution containing a stabilizer with the concentration of 10 ppm-200 ppm into a mobile electrolytic cell of an electrolytic silver reaction device;

2) opening a switch of the electrolytic silver reaction device, leading the mobile phase reaction aqueous solution into the reactor at a flow rate of 5-10 mL/min, slowly flowing at a flow rate of 1-10 mL/min under the conditions of a voltage range of 2-5V, a constant current range of 0.001-0.01A and a temperature range of 10-40 ℃ and a low current density, electrolyzing, taking a silver anode of the electrolytic silver reactor as a sacrificial anode to release silver ions, diffusing the silver ions to an cathode and reducing the silver ions into nano silver, redissolving the silver ions into the aqueous solution and continuously flowing along with the electrolyte, and exchanging the current direction of the electrolytic silver reaction device at intervals of 10-60 s;

3) continuously obtaining low-concentration nano-silver aqueous solution from a discharge tank of the electrolytic silver reaction device, sampling every 1-6 h, and detecting the effective concentration of silver ions in the low-concentration nano-silver aqueous solution;

4) if the concentration of the nano-silver aqueous solution collected at the discharge tank is not enough, the nano-silver aqueous solution is reintroduced into the flow electrolytic cell for re-electrolysis through a recirculation pipeline of the electrolytic silver reaction device;

5) and (3) after aging is finished, subpackaging the nano-silver aqueous solution in medicinal amber glass packages for dark storage, and enhancing the stability of the medicinal amber glass packages to obtain the low-concentration nano-silver antibacterial spray.

Further, the stabilizer comprises sodium citrate, polyvinylpyrrolidone and polyvinyl alcohol in a mass ratio of 50:30: 20.

Further, the concentration of the stabilizer in the aqueous fluid phase reaction solution is from 10ppm to 100 ppm.

Further, the ultrapure water of the mobile phase solution was ultrapure water having a resistivity of 18M Ω · cm at 25 ℃.

Further, the method for electrolytically preparing the low-concentration nano-silver antibacterial spray according to claim 1, wherein the larger the voltage of the electrolytic silver reaction device is, the larger the particle size of the nano-silver in the obtained antibacterial spray is, and the particle size of the nano-silver in the antibacterial spray is 10nm to 50 nm.

Furthermore, the electrolytic silver reaction device comprises a feeding pool, a flowing electrolytic pool, a direct current power supply, a discharging pool and a recirculation pipeline, wherein the feeding pool is communicated with a feeding hole of the flowing electrolytic pool through a feeding pipe;

a silver cathode and a silver anode are arranged in the flowing electrolytic cell, a plurality of labyrinth clapboards are oppositely arranged on the silver cathode and the silver anode to form labyrinth stacking channels which are mutually inserted, the labyrinth stacking channels prolong the area of microfluid electrolysis in the flowing electrolytic cell, and the silver anode and the silver cathode are respectively connected with the positive electrode and the negative electrode of a direct current power supply; the direct current direction is exchanged by the direct current power supply at intervals so as to ensure that the electrode plates of the silver cathode and the silver anode uniformly participate in the electrolysis process.

Furthermore, each labyrinth partition plate is a semi-cylindrical body with a semicircular section and is prepared by processing polytetrafluoroethylene, and then a circular groove is formed for fixing.

Furthermore, the labyrinth partition plates are 50mm long, 50mm wide and 1.0mm thick, and the diameter of the semicircular section of each labyrinth partition plate is 4.0 mm.

Furthermore, a group of labyrinth partition plate channels are formed between one labyrinth partition plate on the silver cathode and one labyrinth partition plate on the silver anode, and a plurality of groups of labyrinth partition plate channels form a snake-shaped distribution labyrinth stacking channel; the length of the duct of the labyrinth partition board is 200mm, and the width is 4.0 mm.

Furthermore, the silver cathode and the silver anode adopt silver sheets with the purity of 99.99-99.999 percent and the diameter of 2-5 mm, the distance between the silver cathode and the silver anode is 2-10 mm, and the volume of the electrolytic silver reaction device is 1-10L.

The invention has the beneficial effects that:

1. according to the method for preparing the low-concentration nano-silver antibacterial spraying agent by electrolysis, the low-concentration nano-silver aqueous solution prepared by the method is used as the antibacterial spraying agent and is subpackaged in medicinal amber glass packages at room temperature, and the medicinal amber glass packages can be stored in a dark place for more than one year and still do not agglomerate and precipitate. Compared with the performance that the aqueous solution of the nano-silver prepared by the traditional method is usually stable only for a plurality of weeks at room temperature and is easy to accumulate precipitates to generate black precipitates, the aqueous solution of the nano-silver has poor colloidal stability, and the product has better stability.

2. The low-concentration nano-silver aqueous solution obtained by the method for preparing the low-concentration nano-silver antibacterial spraying agent by electrolysis can be used as the antibacterial spraying agent, the sterilization utilization rate of nano-silver can be effectively improved, and the heavy metal exceeding is avoided.

3. The method for preparing the low-concentration nano-silver antibacterial spraying agent by electrolysis can obtain the nano-silver with different particle sizes and surface charges by changing the technological parameters such as electrolysis voltage and current, the flow rate of a mobile phase, the stirring rate and the like.

4. The device used in the method for preparing the low-concentration nano-silver antibacterial spray by electrolysis provided by the invention is operated by adopting continuous flowing electrolysis equipment, and the method is simple and is beneficial to continuous production.

5. The method for preparing the low-concentration nano-silver antibacterial spray through electrolysis avoids using silver nitrate as an initial raw material to prepare a nano-silver aqueous solution, uses sodium citrate and other stabilizing agents and a pure silver electrode, realizes an oxidation-reduction process through an external circuit electrified direct current, avoids introducing nitrate radicals into a final nano-silver aqueous solution, and can better improve the biocompatibility of the nano-silver aqueous solution.

6. Compared with the traditional one-dimensional flow channel design, the device used by the method introduces the low-current mobile phase with the extended channel length to prepare the colloidal nano silver electrolytic cell device, and changes the appearance of the cathode and the anode to ensure that the flow channels are distributed in a snake shape on a two-dimensional plane. On one hand, the geometrical morphology of the positive and negative electrodes is changed to make the positive and negative electrodes compactly arranged, so that i in the electrolyte can be effectively reduced_solThe R resistance enables the electrolytic bath to operate at a lower voltage. On the other hand, on the basis of keeping the space compact design, under the condition of the same electrolyte flow rate and impressed current, the 'electrode surface area/retention volume' is larger, the current density on the unit electrode area is smaller, the polarization degree is lower, and higher electrolytic conversion selectivity and conversion rate are easier to realize on an electrolyte flow channel. Different channel lengths of the flow electrolysis equipment are related to the conversion rate of primary electrolytic conversion, and the longer the channel length is, the higher the conversion rate of the primary electrolytic conversion is under the same electrolyte flow rate and voltage.

7. The device used by the method provided by the invention is provided with the flowing electrolysis equipment which is formed by a plurality of groups of labyrinth separator pore passages formed by the labyrinth separator and prolongs the channel length, and can accurately regulate and control the contact residence time (momentum transfer) and the reaction heat effect control (heat transfer) between the substrate and the electrode surface by controlling the flow rate (mass transfer) of the electrolyte, and can better regulate a plurality of groups of condition parameters of external voltage, the formula of the electrolyte raw material (reaction control) and the flow rate of the electrolyte. Compared with a tank type electrolytic reaction device, the running output of the electrolytic product of the flowing electrolytic device in unit time is more uniform, the electrolytic product flowing out in each time period can be intuitively collected and represented, and the parameters of the electrolytic reaction condition are easier to accurately control and easier to linearly amplify.

8. Compared with the traditional method in which electrolysis is carried out in a single batch in a beaker or a reaction kettle, the device used in the method can constantly produce the nano-silver aqueous solution with stable quality based on the mobile phase electrolyzer device. The device used by the method effectively improves mass transfer diffusion current and reduces the occurrence of side reaction of electrolytic reaction by lengthening the path length of the electrolyte channel, and the reaction flux is easily amplified in a parallel connection mode by the compact design of the lengthened electrolyte channel path.

Drawings

The invention will be described in more detail hereinafter on the basis of embodiments and with reference to the accompanying drawings. Wherein:

fig. 1 shows the tyndall effect of the nano silver under the irradiation of the light beam by the nano silver aqueous solution prepared by the preparation method provided by the embodiment 1 of the invention;

FIG. 2 is the inductively coupled atomic emission spectrometry (ICP-AES) data of the aqueous solution of nano-silver prepared by the preparation method provided in example 1 of the present invention;

FIG. 3 is a UV-VIS absorption spectrum of the aqueous nano-silver solution prepared by the preparation method provided in example 1 of the present invention;

fig. 4 is an X-ray diffraction spectrum of nano-silver in the nano-silver aqueous solution prepared by the preparation method provided in example 1 of the present invention;

FIG. 5 is a schematic view of the entire electrolytic silver reaction apparatus used in example 1 of the present invention;

FIG. 6 is a schematic structural view of an electrolytic silver reaction device with a side view of a flow electrolytic cell according to example 1 of the present invention;

FIG. 7 is a schematic diagram of the production of nano-silver by a flow electrolytic cell in the electrolytic silver reaction device provided by the invention.

Detailed description of the preferred embodiments

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example 1

A method for preparing a low-concentration nano-silver antibacterial spray through electrolysis is characterized by comprising the following steps:

1) continuously injecting a mobile phase reaction aqueous solution containing a stabilizer with the concentration of 10ppm into a mobile electrolytic cell of an electrolytic silver reaction device;

2) starting a switch of the electrolytic silver reaction device, leading the mobile phase reaction aqueous solution into the reactor at the flow rate of 5mL/min, slowly flowing at the constant current of 0.001A within the voltage range of 3V and at the temperature of 25 ℃ at the flow rate of 1mL/min, electrolyzing for 60min, taking a silver anode of the electrolytic silver reactor as a sacrificial anode to release silver ions, diffusing the silver ions to an cathode and reducing the silver ions into nano silver, dissolving the silver ions again into the aqueous solution, continuously flowing along with the electrolyte, and exchanging the current direction of the electrolytic silver reaction device at intervals of 10 s;

3) continuously obtaining low-concentration nano-silver aqueous solution from a discharge tank (6) of the electrolytic silver reaction device, sampling every 1-6 h, and detecting the effective concentration of silver ions in the low-concentration nano-silver aqueous solution;

4) if the concentration of the nano-silver aqueous solution collected at the discharging pool (6) is not enough, the nano-silver aqueous solution is reintroduced into the flowing electrolytic cell (3) for re-electrolysis through a recycling pipeline (7) of the electrolytic silver reaction device;

5) and (3) after aging is finished, subpackaging the nano-silver aqueous solution in medicinal amber glass packages for dark storage, and enhancing the stability of the medicinal amber glass packages to obtain the low-concentration nano-silver antibacterial spray.

Fig. 1 shows the tyndall effect of the nano silver in the aqueous solution of nano silver prepared in this example under the irradiation of the light beam.

Fig. 2 shows inductively coupled atomic emission spectroscopy (ICP-AES) data of the nano-silver aqueous solution prepared by the preparation method provided in this example.

Fig. 3 shows the ultraviolet-visible absorption spectrum of the nano-silver aqueous solution prepared by the preparation method provided in this example.

Fig. 4 shows an X-ray diffraction spectrum of nano-silver in the nano-silver aqueous solution prepared by the preparation method provided by the embodiment of the invention.

The electrolytic silver reaction device adopted by the invention is shown in figures 5-6 and comprises a feeding pool 1, a flowing electrolytic pool 3, a direct current power supply 4, a discharging pool 6 and a recirculation pipeline 7, wherein the feeding pool 1 is communicated with a feeding port 3-1 of the flowing electrolytic pool 3 through a feeding pipe 1-1, a discharging port 3-2 of the flowing electrolytic pool is communicated with the discharging pool through a discharging pipe 6-1, the feeding pipe 1-1 is provided with a flowing pump 2, and the recirculation pipeline 7 is used for communicating the discharging pool 6 with the flowing pump 2;

a silver cathode 3-3 and a silver anode 3-4 are arranged in the flow electrolytic cell 3, a plurality of labyrinth partition plates 3-5 are oppositely arranged on the silver cathode 3-3 and the silver anode 3-4 to form labyrinth stacking channels 3-6 which are mutually inserted, the labyrinth stacking channels 3-6 prolong the micro-fluid electrolysis area in the flow electrolytic cell 3, and the silver anode 3-4 and the silver cathode 3-3 are respectively connected with the positive electrode and the negative electrode of the direct-current power supply 4; the direct current direction is exchanged by the direct current power supply 4 at intervals so as to ensure that the electrode plates of the silver cathode 3-3 and the silver anode 3-4 uniformly participate in the electrolysis process.

Each labyrinth partition plate 3-5 is a semi-cylindrical body with a semicircular section and is prepared by processing polytetrafluoroethylene, and then a circular groove is formed for fixing. The labyrinth partition plate is 50mm long, 50mm wide and 1.0mm thick, and the diameter of the semicircular section of each labyrinth partition plate 3-5 is 4.0 mm.

A group of labyrinth separator pore passages 3-61 are formed between one labyrinth separator on the silver cathode 3-3 and one labyrinth separator on the silver anode 3-4, and a plurality of groups of labyrinth separator pore passages 3-61 form a snake-shaped distribution labyrinth stacking channel 3-6; the length of the labyrinth partition plate pore canal 3-61 is 200mm, and the width is 4.0 mm. The silver electrodes with the purity of 99.99-99.999% and the diameter of 5mm are adopted by the silver cathodes 3-3 and the silver anodes 3-4, the length of the electrodes is 10cm, the distance between the silver cathodes 3-3 and the silver anodes 3-4 is 6mm, and the volume of the electrolytic silver reaction device is 10L.

As shown in FIG. 7, the principle of preparing the nano-silver aqueous solution by the electrolytic method using the electrolytic silver reaction device is that silver is usedThe electrode is used as a sacrificial anode, and the oxidation reaction Ag (bulk) → Ag occurs at the anode⁺+e^-Thereby releasing silver ions Ag into the solution⁺Silver ion Ag⁺Then the silver ions are diffused to the surface of a cathode to be reduced to generate nano silver stabilized by ligand into solution nAg⁺+ne^-→Ag_n. It is noted that a possible side reaction of the anode is 2Ag⁺+H₂O→Ag₂O↓+2H⁺The cathode may have a side reaction in which silver ions are largely reduced on the cathode to form bulk silver deposited on the surface thereof, thereby reducing the yield of nano silver. In all electrolytic cells, the oxidation-reduction reaction with the same quantity of electrons on the working electrode and the counter electrode occurs, and ideally, the silver ions Ag after anodic oxidation⁺Reducing the silver into nano silver in a cathode in a sufficient equal amount, and dissolving the silver in an aqueous solution under the protection of a ligand. The two side reactions are related to substrate mass transfer diffusion between the cathode and the anode in the solution, for example, the S-shaped bent flow electrolytic pipeline design is beneficial to the electrolyte to be in full contact with the cathode and the anode successively in the process of fluid mass transfer turning. And the direct current direction is exchanged within a certain time in the electrolytic process, so that the silver electrodes at two ends are uniformly oxidized, the silver electrodes at two ends are prevented from being unbalanced, and the silver electrodes are uniformly reduced into soluble nano silver to enter the aqueous solution.

The silver cathode 3-3 and the silver anode 3-4 in the embodiment are both 50mm in length, 50.0 mm in width and 1.0mm in thickness. The feeding tank 1, the feeding pipe 1-1, the discharging pipe 6-1 and the discharging tank 6 are all made of borosilicate glass materials.

The stabilizer in the embodiment comprises sodium citrate, polyvinylpyrrolidone and polyvinyl alcohol in a mass fraction ratio of 50:30:20, and the concentration of the adopted sodium citrate is 30 ppm.

The ultrapure water of the mobile phase solution in this example was ultrapure water having a resistivity of 18M Ω · cm at 25 ℃.

The larger the voltage of the electrolytic silver reaction device is, the larger the particle size of the nano silver in the obtained antibacterial spraying agent is, and the particle size distribution in the obtained nano silver aqueous solution is 10-50 nm.

The above parameters can be selected from the process parameters according to the actual application.

Example 2

1) Continuously injecting a mobile phase reaction aqueous solution containing a stabilizer with the concentration of 20ppm into a mobile electrolytic cell of an electrolytic silver reaction device;

2) opening a switch of the electrolytic silver reaction device, leading the mobile phase reaction aqueous solution into the reactor at the flow rate of 10mL/min, slowly flowing at the constant current of 0.005A and the temperature of 25 ℃ at the flow rate of 10mL/min and electrolyzing for 30min, taking a silver anode of the electrolytic silver reactor as a sacrificial anode to release silver ions, diffusing the silver ions to an cathode and reducing the silver ions into nano silver, dissolving the silver ions again into the aqueous solution and continuously flowing along with the electrolyte, and exchanging the current directions of the electrolytic silver reaction device at intervals of 20 s;

3) continuously obtaining low-concentration nano-silver aqueous solution from a discharge tank (6) of the electrolytic silver reaction device, sampling every 1-6 h, and detecting the effective concentration of silver ions in the low-concentration nano-silver aqueous solution;

4) if the concentration of the nano-silver aqueous solution collected at the discharging pool (6) is not enough, the nano-silver aqueous solution is reintroduced into the flowing electrolytic cell (3) for re-electrolysis through a recycling pipeline (7) of the electrolytic silver reaction device;

5) and (3) after aging is finished, subpackaging the nano-silver aqueous solution in medicinal amber glass packages for dark storage, and enhancing the stability of the medicinal amber glass packages to obtain the low-concentration nano-silver antibacterial spray.

The flow rate of the flowing phase reaction aqueous solution in the electrolytic silver reaction device in the step 2) of the invention, the electrolytic voltage range, the constant current range, the electrolytic temperature, the flow rate of the flowing phase reaction aqueous solution in the reactor, the current direction exchange interval time, the concentration of the stabilizer in the flowing phase reaction aqueous solution, the diameter of the silver electrode, the distance between the silver anode 3-3 and the silver cathode 3-4, the container of the electrolytic silver reaction device and the sampling interval time in the step 3) can be set according to the requirements of different particle sizes of the nano silver in the nano silver aqueous solution which can be used as an antibacterial spray and the conditions required by the reaction.

The above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.

Furthermore, those skilled in the art will appreciate that while some embodiments herein include some features included in other embodiments, rather than other features, combinations of features of different embodiments are meant to be within the scope of the invention and form different embodiments. For example, in the claims above, any of the claimed embodiments may be used in any combination. The information disclosed in this background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.