CN113929079A

CN113929079A - Preparation method and application of biomass charcoal electrode

Info

Publication number: CN113929079A
Application number: CN202111374268.8A
Authority: CN
Inventors: 王海波; 孙威; 石宝友
Original assignee: Research Center for Eco Environmental Sciences of CAS
Current assignee: Research Center for Eco Environmental Sciences of CAS
Priority date: 2021-11-19
Filing date: 2021-11-19
Publication date: 2022-01-14
Anticipated expiration: 2041-11-19
Also published as: CN113929079B

Abstract

The present disclosure provides a preparation method and an application of a biomass charcoal electrode, wherein the preparation method comprises: step S1: placing the orange peel into an oven for drying; step S2: the dried orange peel is put into a quartz boat and placed in a tube furnace, and is carbonized under inert gas, comprising: step S2.1: setting a first heating rate for heating, and preheating at a first preset temperature for a first preset time when the temperature is raised to the first preset temperature; step S2.2: and heating at a first heating rate to raise the temperature from a first preset temperature to a second preset temperature, and pyrolyzing at the second preset temperature for a second period of preset time to obtain the orange peel biomass charcoal electrode.

Description

Preparation method and application of biomass charcoal electrode

Technical Field

The disclosure belongs to the technical field of biomass charcoal electrode preparation and electrochemical disinfection, and particularly relates to a preparation method and application of a biomass charcoal electrode.

Background

In recent years, with the rapid development of economy in China, the problem of water pollution is increasingly serious, water quality is in a worsening trend, and further higher requirements are put forward on a water treatment process, particularly a disinfection link. In the face of the problem of disinfection by-products generated by the current disinfection mode and the limitation of control of microbial pathogens, safe disinfection becomes an important research content for ensuring human life health, and is also an objective requirement for ensuring safe drinking of water.

Chlorine gas has long been used as a disinfectant for most drinking water treatments due to its low transportation cost and good sterilizing effect, but chlorine gas itself is harmful to the human body, and chlorine disinfection generates disinfection by-products. Ozone disinfection and sterilization has the characteristics of good effect, small using amount, quick action, few disinfection byproducts and simple production conditions, but the application of ozone is limited because the ozone cannot be transported for a long distance and stored for a long time and the ozone has no continuous disinfection effect. Ultraviolet rays are mainly disinfected through a physical process, and the disinfection effect of the ultraviolet rays is gradually weakened along with the increase of the turbidity of water and does not have a continuous disinfection effect.

The electrochemical disinfection method has the characteristics of environmental friendliness, safety, high efficiency and low treatment cost, and is widely concerned in recent years, but at present, the research level of electrochemical disinfection still stays in the experimental exploration or demonstration engineering stage, the application of water treatment is influenced by various factors, the disinfection mechanism and the application condition are not very clear, and the regulation and control rule of key disinfection species still needs to be deeply researched. Currently, the anode for mainstream, efficient and stable electrochemical water treatment application is still a noble metal coating titanium electrode, but the treatment method has high one-time investment cost. Biomass materials can be used not only to form biomass-derived carbon materials, but can also be used to achieve doping of heteroatoms into the carbon network, particularly N-doping, which can improve the performance of the intended electrochemical device. As an inexpensive and abundant carbon source, biomass has been used as a potential and successful raw material for the production of carbon and its composite material base materials to achieve desirable performance lithium/sodium ion batteries. However, the existing biomass material preparation method is complex and high in cost, and is rarely applied to water treatment disinfection and sterilization, so that a simple and low-cost method capable of being prepared in a large scale is needed, and the biomass material is widely applied to environmental treatment.

Disclosure of Invention

In view of the above technical problems, the present disclosure provides a method for preparing a biomass charcoal electrode and an application thereof, so as to at least partially solve the above technical problems.

In order to solve the technical problem, an aspect of the present disclosure provides a method for preparing a biomass charcoal electrode, including:

step S1: placing the orange peel into an oven for drying;

step S2: the dried orange peel is put into a quartz boat and placed in a tube furnace, and is carbonized under inert gas, comprising the following steps:

step S2.1: setting a first heating rate for heating, and preheating at a first preset temperature for a first preset time when the temperature is raised to the first preset temperature;

step S2.2: and heating at the first heating rate to raise the temperature from the first preset temperature to a second preset temperature, and pyrolyzing at the second preset temperature for a second period of preset time to obtain the orange peel biomass charcoal electrode.

In one embodiment, in step S1, the size of the orange peel includes a square small block with a side length of 1-3 cm.

In one embodiment, in step S1, the temperature of the orange peel dried in the oven includes: 60-100 ℃, and the drying time comprises: 24-36 h.

In one embodiment, in step S2, the inert gas includes: nitrogen or argon.

In one embodiment, in step S2.1, the first temperature rise rate includes: 5-20 ℃/min.

In one embodiment, in step S2.1, the range of the first preset temperature includes: 80-100 ℃, and the first preset period of time comprises: 10-30 min.

In one embodiment, in step S2.2, the range of the second preset temperature includes: 600-800 ℃, and the second-stage preset time comprises the following steps: 1-3 h.

In another aspect of the present disclosure, there is provided a use of a biomass charcoal electrode, comprising: the biomass charcoal electrode prepared by the preparation method in the embodiment treats bacteria in water through electrochemical reaction.

In another embodiment, the electrolyte solution in the electrochemical reaction includes at least one of: sodium chloride solution, sodium sulfate solution and phosphate buffer solution.

In another embodiment, the bacteria comprise at least one of: pseudomonas aeruginosa, Pseudomonas stutzeri and Escherichia coli.

According to the technical scheme, the preparation method and the application of the biomass charcoal electrode disclosed by the invention have the following beneficial effects:

(1) according to the preparation method disclosed by the embodiment of the disclosure, the orange peel is put into an oven to be dried to remove moisture in the orange peel; then, the dried orange peels are placed into a tubular furnace, and are preheated at a first preset temperature for a first preset time to stabilize the temperature in the tubular furnace and prevent the tubular furnace from being cracked due to too fast subsequent temperature rise; and then, raising the temperature in the tube furnace from the first preset temperature to a second preset temperature, and pyrolyzing the orange peel at the second preset temperature for a second period of preset time to carbonize the orange peel in the tube furnace, so that a small hole structure is formed in the orange peel, and a durability freedom is formed in the orange peel.

(2) The biomass charcoal electrode is prepared by using the orange peel in the embodiment disclosed by the invention, and the method has the advantages of simple preparation method, easiness in obtaining and operating raw material orange peel, no special equipment requirement, good reproducibility and capability of large-scale preparation.

(3) The biomass charcoal electrode prepared by the method in the embodiment of the disclosure contains a lot of persistent free radicals; when the biomass charcoal electrode is used as a cathode, more superoxide radicals can be generated, and the anode can be promoted to generate more chlorine radicals.

Drawings

FIG. 1 is a macroscopic view of the front and back sides of an orange peel biomass charcoal piece in example 2 of the disclosure;

fig. 2A to 2D are SEM images of orange peel biomass charcoal electrode obtained in example 2 of the present disclosure at different magnifications;

FIGS. 3A-3D are SEM images of commercial graphite electrodes at different magnifications in the examples of the disclosure;

FIG. 4 is an X-ray diffraction pattern of an orange peel biomass carbon electrode obtained in example 2 of the present disclosure;

FIG. 5 shows CuO/Cu contained in the orange peel biomass charcoal electrode obtained in example 2 of the present disclosure₂Photoelectron spectrum of O component on Cu2p orbit;

FIG. 6 shows CuO/Cu contained in the orange peel biomass charcoal electrode obtained in example 2 of the present disclosure₂Photoelectron spectrum of O component on Cu2p3 orbit;

FIG. 7 is a graph of the infrared spectrum characterization of orange peel biomass charcoal electrode and graphite electrode obtained in example 2 of the present disclosure;

fig. 8 to 9 are graphs showing the effect of sterilization by using orange peel biomass charcoal electrode and graphite electrode in examples 5 to 10 of the present disclosure;

FIG. 10 is a mechanism diagram of persistent radical generation in example 2 of the present disclosure;

FIG. 11 is a graph showing the results of persistent radical characterization on the surfaces of orange peel biomass charcoal electrode and graphite electrode obtained in example 2 of the present disclosure;

FIG. 12 is a graph of superoxide radical characterization results of orange peel biomass charcoal and graphite electrodes obtained in example 2 of the present disclosure;

fig. 13 is a graph of results of chlorine radical characterization of orange peel biomass charcoal electrode and graphite electrode obtained in example 2 of the present disclosure.

Detailed Description

In order that the objects, technical solutions and advantages of the present invention will become more apparent, the present invention will be further described in detail with reference to the accompanying drawings in conjunction with the following specific embodiments.

As a novel technology, the electrochemical disinfection and sterilization water treatment technology has the characteristics of safety, high efficiency, convenience, flexibility, environmental friendliness and the like, and is receiving more and more attention.

The biomass charcoal electrode is simple in preparation method, easy to operate, free of special equipment requirements, green, safe, environment-friendly and good in reproducibility. Compared with other commonly used electrodes, the biomass charcoal electrode prepared by the method is used for disinfection and sterilization in water treatment, and the method is expected to provide an electrode material with low disposable investment, low treatment cost and good sterilization effect so as to provide a new application possibility for the electrochemical disinfection technology in the scenes of demands such as safe terminal drinking water supply, small-scale emergency disinfection treatment, water reuse in ecological facilities and the like in regions without centralized water supply.

The method takes orange peel as a raw material, charcoals the orange peel into biomass derived carbon by using high temperature, and utilizes CuO/Cu contained in the orange peel in the pyrolysis process₂And reacting the O with organic functional groups on the surface of the orange peel to generate persistent free radicals. The biomass charcoal piece is used as an electrode of an electrochemical reaction device, and in the reaction process, the persistent free radicals can induce oxygen and chloride ions in a solution to generate superoxide radicals and chlorine radicals, so that the sterilization of salt-containing water is realized.

The embodiment of the disclosure provides a preparation method of a biomass charcoal electrode, which comprises the following steps:

step S1: placing the orange peel into an oven for drying;

step S2: the dried orange peel is put into a quartz boat and placed in a tube furnace, and is carbonized under inert gas, comprising:

step S2.2: and heating at a first heating rate to raise the temperature from a first preset temperature to a second preset temperature, and pyrolyzing at the second preset temperature for a second period of preset time to obtain the orange peel biomass charcoal electrode.

According to the preparation method disclosed by the embodiment of the disclosure, the orange peel is put into an oven to be dried to remove moisture in the orange peel; then, the dried orange peels are placed into a tubular furnace, and are preheated at a first preset temperature for a first preset time to stabilize the temperature in the tubular furnace and prevent the tubular furnace from being cracked due to too fast subsequent temperature rise; and then, raising the temperature in the tube furnace from the first preset temperature to a second preset temperature, and pyrolyzing the orange peel at the second preset temperature for a second period of preset time to carbonize the orange peel in the tube furnace, so that a small hole structure is formed in the orange peel, and a durability freedom is formed in the orange peel.

The biomass charcoal electrode prepared by the preparation method in the embodiment of the disclosure can generate more superoxide radicals and promote the anode to generate more chlorine radicals when an electrochemical reaction is used as a cathode, and can inactivate bacteria when electrochemical disinfection and sterilization are carried out by utilizing rich and persistent radicals contained in orange peel, so that the biomass charcoal electrode has a better disinfection and sterilization effect.

According to the embodiment of the disclosure, in step S1, the size of the orange peel includes a square small block with a side length of 1-3 cm, and the side length of the orange peel can be selected to be 1, 1.5, 2, 2.5, 3cm and the like.

According to the embodiment of the disclosure, the orange peels cut into different sizes are cleaned by ultrapure water, and are pressed to be flat by an iron block; and then, putting the cleaned orange peel into an oven for drying.

According to the embodiment of the present disclosure, in step S1, the temperature at which the orange peel is dried in the oven includes: 60-100 ℃, 60, 70, 80, 90 and 100 ℃ can be selected, wherein 100 ℃ is preferred.

According to the embodiment of the present disclosure, the orange peel drying time includes: 24-36 h, and 24, 26, 28, 30, 32, 34 and 36h can be selected, wherein 24h is preferred.

Through this disclosed embodiment, utilize the oven to dry preliminarily with the moisture in the tangerine peel, can reduce the moisture residue in the tangerine peel.

According to an embodiment of the present disclosure, in step S2, the inert gas includes: nitrogen, or argon, with nitrogen being preferred.

Through this disclosed embodiment, utilize inert gas as the protective gas, can prevent that the orange peel from taking place the oxidation when the carbonization in the tubular furnace, choose for use nitrogen gas also more economical as the protective gas.

According to an embodiment of the present disclosure, in step S2.1, the first ramp rate comprises: 5-20 ℃/min, optionally 5, 10, 15 and 20 ℃/min, wherein 10 ℃/min is preferred.

According to the embodiment of the disclosure, the temperature in the tube furnace is raised to the first preset temperature by using a programmed heating mode. The speed of the temperature programming is preferably 10 ℃/min, on one hand, the temperature in the tube furnace is favorably and slowly increased, and the tube furnace is not damaged and cracked; on the other hand, the method is favorable for the formation of a small pore structure inside the orange peel and the utilization of the CuO/Cu existing in the orange peel per se when the orange peel is sintered at the second preset temperature₂The O component reacts with organic functional groups in orange peel to generate persistent free radicals.

According to an embodiment of the disclosure, in step S2.1, the range of the first preset temperature includes: 80-100 ℃, and can be selected from 80, 90 and 100 ℃, wherein 100 ℃ is preferred.

According to an embodiment of the present disclosure, in step S2.1, the first preset period of time includes: 10-30 min, optionally 10, 15, 20, 25, 30min, preferably 20 min.

According to the embodiment of the disclosure, the orange peel is dried in the oven at 100 ℃ for 20min, the furnace tube is preheated, the working environment of the tube furnace is kept stable, and the cracking of the furnace tube caused by the fact that the furnace tube of the tube furnace is heated from low temperature to high temperature is prevented.

According to an embodiment of the present disclosure, in step S2.2, the range of the second preset temperature includes: 600-800 ℃, optionally 600, 650, 700, 750 and 800 ℃, wherein 700 ℃ is preferred.

According to an embodiment of the present disclosure, in step S2.2, the second preset time period includes: 1-3 h, optionally 1, 1.5, 2, 2.5 and 3h, wherein 2h is preferred.

By the embodiments of the present disclosureThe orange peel is sintered at a second preset temperature, so that on one hand, the surface of the orange peel can be carbonized, and a small-hole structure is formed inside the orange peel; on the other hand, the CuO/Cu is favorable for the existence of the orange peel₂The O reacts with organic functional groups in the orange peel to generate persistent free radicals.

In order to make the objects, technical solutions and advantages of the present disclosure more clearly understood, the following detailed description of the disclosed method for preparing biomass charcoal electrode is provided in conjunction with specific examples.

Example 1

Orange peel obtained from the market is cut into small pieces with a side length of 2 x 2cm, washed clean with ultrapure water and flattened with iron pieces. Then, the orange peel is placed in an oven at 80 ℃ to be dried for 36 h. Then, taking out and putting the quartz boat into a tubular graphite furnace, heating the quartz boat in the tubular graphite furnace at a first heating rate of 10 ℃/min to a first preset temperature of 100 ℃, and maintaining the temperature at the first preset temperature for 20 min. And then, heating to a second preset temperature of 700 ℃ at a heating rate of 10 ℃/min, and maintaining at the temperature for 2 hours to finally obtain the formed biomass charcoal electrode slice.

The specific surface area of the orange peel measured by a specific surface analyzer is 3.80m²The pore size of the orange peel is about 20 μm as measured by scanning electron microscopy.

Example 2

Orange peel obtained from the market is cut into small pieces having a side length of 2.5 × 2.5cm, washed clean with ultrapure water, and then flattened with iron pieces. Then, the orange peel was placed in an oven at 100 ℃ and baked for 24 hours. Then, taking out and putting the quartz boat into a tubular graphite furnace, heating the quartz boat in the tubular graphite furnace at a first heating rate of 10 ℃/min to a first preset temperature of 100 ℃, and maintaining the temperature at the first preset temperature for 20 min. Then, the temperature is increased to 700 ℃ at the heating rate of 10 ℃/min, and the temperature is maintained for 2h, and finally the formed biomass charcoal electrode slice (figure 1) is obtained.

The specific surface area of the orange peel measured by a specific surface analyzer is 3.80m²(g) orange peel measured by scanning Electron microscopyHas a pore size of about 20 μm.

Fig. 1 is a macroscopic view of the front and back sides of an orange peel biomass charcoal piece in example 2 of the present disclosure.

As shown in FIG. 1, fine pores are formed on the surface of the obtained orange peel biomass charcoal tablets.

Example 3

Orange peel obtained from the market is cut into small pieces having a side length of 2.5 × 2.5cm, washed clean with ultrapure water, and then flattened with iron pieces. Then, the orange peel was placed in an oven at 100 ℃ and baked for 24 hours. Then, taking out and putting the quartz boat into a tubular graphite furnace, heating the quartz boat in the tubular graphite furnace at a first heating rate of 20 ℃/min to a first preset temperature of 100 ℃, and maintaining the temperature at the first preset temperature for 20 min. And then, heating to a second preset temperature of 800 ℃ at a heating rate of 20 ℃/min, and maintaining at the temperature for 2 hours to finally obtain the formed biomass charcoal electrode slice.

The specific surface area of the orange peel measured by a specific surface analyzer is 4.92m²(g), the aperture of the orange peel is about 15 μm as measured by scanning electron microscopy.

Example 4

Orange peel obtained from the market is cut into small pieces having a side length of 2.5 × 2.5cm, washed clean with ultrapure water, and then flattened with iron pieces. Then, the orange peel was placed in an oven at 100 ℃ and baked for 24 hours. Then, taking out and putting the quartz boat into a tubular graphite furnace, heating the quartz boat in the tubular graphite furnace at a first heating rate of 10 ℃/min to a first preset temperature of 100 ℃, and maintaining the temperature at the first preset temperature for 20 min. And then, heating to a second preset temperature of 800 ℃ at a heating rate of 10 ℃/min, and maintaining at the temperature for 2 hours to finally obtain the formed biomass charcoal electrode slice.

The specific surface area of the orange peel measured by a specific surface analyzer is 5.01m²(g), the aperture of the orange peel is about 15 μm as measured by scanning electron microscopy.

Characterization test

The orange peel biomass charcoal electrode formed by firing of example 2 was characterized.

Fig. 2A to 2D are SEM images of the orange peel biomass charcoal electrode obtained in example 2 of the present disclosure at different magnifications.

As shown in FIGS. 2A to 2D, the surface of the orange peel can be observed to contain a large number of continuously distributed small pores by a scanning electron microscope, and the pore diameter of the orange peel is about 20 μm by the scanning electron microscope.

Commercial graphite electrodes are widely used in electrochemical reactions due to their good electrical conductivity.

Fig. 3A-3D are SEM images of commercial graphite electrodes at different magnifications in the examples of the disclosure.

As shown in FIGS. 3A to 3D, the commercial graphite electrode has a dense surface and a small pore size, and the pore size of the commercial graphite electrode is about 5 μm as measured by a scanning electron microscope and the specific surface area of the commercial graphite electrode is 6.9m as measured by a specific surface area measuring instrument²(ii) in terms of/g. Compared with a commercial graphite electrode, the orange peel biomass charcoal electrode prepared by the method in the embodiment 2 has a larger aperture and a smaller specific surface area, and the aperture structure is favorable for electron transmission and has a better disinfection and sterilization effect in the disinfection and sterilization process.

Fig. 4 is an X-ray diffraction pattern of copper oxide crystals of the orange peel biomass carbon electrode obtained in example 2 of the present disclosure.

As shown in FIG. 4, XRD tests prove that the orange peel contains a small amount of Cu, and the Cu exists in a form of CuO/Cu₂Composition of O, JCPDS card number of CuO: no. 00-048-1548.

FIG. 5 shows CuO/Cu contained in orange peel biomass charcoal electrode obtained in example 2 of the present disclosure₂Photoelectron spectrum of O component on Cu2p orbit; FIG. 6 shows CuO/Cu contained in orange peel biomass charcoal electrode obtained in example 2 of the present disclosure₂Photoelectron spectrum of the O component on Cu2p3 orbital.

As shown in fig. 5 to 6, the valence of the Cu-containing component of the orange peel biomass charcoal electrode is analyzed, and it is proved that Cu in the orange peel biomass charcoal electrode is CuO/Cu₂The form of O exists. Because of the CuO/Cu in the orange peel₂O, in the process of firingIn the process, the functional groups with aromatic structures in orange peels, biopolymers and the like react to generate persistent free radicals.

Fig. 7 is a graph of infrared spectral characterization of orange peel biomass charcoal electrodes and graphite electrodes obtained in example 2 of the present disclosure.

As shown in fig. 7, infrared spectroscopy of the orange peel biomass charcoal electrode and the graphite electrode revealed that C-C, N (CH) among aromatic compounds was present in the orange peel₃)₂Structures (aromatic I, aromatic II) and CH in biopolymers₂The structure (biopolymer I and biopolymer II) exists, while the main component in the graphite electrode is biopolymer II such as petroleum coke and needle coke, and the aromatic substances are hardly contained.

The embodiment of the disclosure also provides a biomass charcoal piece prepared by the preparation method, and the biomass charcoal piece is used as an electrode (cathode or anode) to realize water disinfection and sterilization through electrochemical reaction.

According to an embodiment of the present disclosure, the electrolyte solution of the electrochemically reactive species includes at least one of: sodium chloride solution, sodium sulfate solution, Phosphate Buffer Solution (PBS).

According to an embodiment of the present disclosure, the bacteria comprise at least one of: pseudomonas aeruginosa, Pseudomonas stutzeri and Escherichia coli.

Example 5

The orange peel biomass charcoal electrode prepared by the method of example 2 is used as a cathode, the iridium oxide/ruthenium oxide coating titanium electrode is used as an anode, the two electrodes are inserted into an electrolytic cell containing pseudomonas stutzeri, wherein the electrolyte solution is 0.09% sodium chloride solution, the two electrode plates are connected with an electrochemical workstation by leads, and 10V direct current voltage is introduced for carrying out electrochemical disinfection and sterilization test.

Example 6

The method in example 6 was the same as that in example 5, except that the cathode electrode used in example 6 was a graphite electrode.

Example 7

The process in example 7 is the same as that in example 5, except that the electrolyte solution used in example 7 is a 0.09% sodium sulfate solution.

Example 8

The method in example 8 was the same as that in example 7, except that the cathode electrode used in example 8 was a graphite electrode.

Example 9

The procedure in example 9 was the same as that in example 5, except that the electrolyte solution used in example 9 was a phosphate buffer solution (containing 0.09% sodium chloride).

Example 10

The method in example 10 was the same as that in example 9, except that the cathode electrode used in example 10 was a graphite electrode.

Fig. 8 to 9 are graphs showing the effect of sterilization by using orange peel biomass charcoal electrode and graphite electrode in examples 5 to 10 of the present disclosure.

As shown in fig. 8 to 9, when electrochemical sterilization is performed using the orange peel biomass charcoal electrode as a cathode, the sterilization effect using the sodium chloride electrolyte solution is the best regardless of whether electrochemical sterilization is performed using a phosphate buffer solution (containing 0.09% sodium chloride), a 0.09% sodium chloride solution, or a 0.09% sodium sulfate solution. When 0.09% sodium chloride is used as an electrolyte solution and an orange peel biomass carbon electrode or a graphite electrode is used as a cathode, the disinfection and sterilization effect of the orange peel biomass carbon electrode used as the cathode is better than that of a commercial graphite electrode.

FIG. 10 is a mechanism diagram of persistent radical generation in example 2 of the present disclosure.

As shown in FIG. 10, during the firing of the biomass charcoal electrode, CuO/Cu contained in orange peel₂O component, aromatic molecular precursor containing benzene ring (phenol or chlorobenzene, X in FIG. 10 is halogen atom or-OH) is adsorbed on the surface of copper oxide particle by physical adsorption at high temperature, and then electron is transferred to the surface of copper oxide particle by chemical reaction through dehydration or HX removalCu (II) is reduced into Cu (I), and a large number of persistent free radical species (PFR) which takes carbon as a center and is adjacent to an oxygen atom and is mixed with a semi-quinoid free radical and a methoxybenzene free radical with oxygen as a center structure are generated at the same time^·﹣)。

Fig. 11 is a graph of the results of characterization of persistent free radicals on the surfaces of orange peel biomass charcoal electrode and graphite electrode obtained in example 2 of the present disclosure.

As shown in fig. 11, the characteristic peak intensity of the persistent radical contained in the orange peel biomass charcoal electrode before the reaction was higher than that of the persistent radical contained in the biomass charcoal electrode after the reaction and the graphite electrode, demonstrating that the persistent radical was consumed for killing bacteria. It can also be seen from fig. 11 that the graphite electrode contains few persistent radicals in the disclosed embodiment. Therefore, the result proves that when the orange peel biomass charcoal electrode is used as the cathode, the participating electrochemical disinfection and sterilization effect is stronger than the participating disinfection and sterilization effect of the graphite electrode. Embodiments of the present disclosure employ electron spin resonance spectroscopy (ESR, BRUKER EMX, Germany) for relevant free radical testing.

In the electrochemical disinfection and sterilization process of the orange peel biomass charcoal electrode, persistent free radicals can induce the generation of superoxide radical, and the reactions involved in the reaction process are as follows:

O₂+PFR^·﹣→O₂ ^·﹣+PFR(1)

fig. 12 is a graph of superoxide radical characterization results of orange peel biomass charcoal electrodes and graphite electrodes obtained in example 2 of the present disclosure.

As shown in fig. 12, in the process of selecting the orange peel biomass charcoal electrode for sterilization, the persistent radical induces the most amount of superoxide radical, and the superoxide radical has stronger oxidizing property, so the sterilization effect of the orange peel biomass charcoal electrode is stronger than that of the graphite electrode, and the sodium sulfate solution is selected for testing to reduce the interference of the sodium chloride solution and the phosphate solution (containing sodium chloride solution) on the detection of the superoxide radical.

In the electrochemical disinfection and sterilization process of the orange peel biomass carbon electrode, compared with a graphite electrode, the orange peel biomass carbon electrode is more beneficial to the generation of chlorine free radicals and free chlorine induced by a ruthenium iridium coating titanium anode, and the reactions involved in the reaction process are as follows:

MO_X+Cl^﹣+hv→Cl^· (2)

Cl^·+Cl^﹣→Cl₂+e^- (3)

Cl^·+Cl^﹣→Cl₂ (4)

Cl₂+H₂O→HOCl+H⁺+Cl^﹣ (5)

wherein MO is_XRefers to a metal oxide anode and is referred to herein as an iridium oxide/ruthenium oxide coated titanium electrode.

As shown in fig. 13, the orange peel biomass charcoal electrode generates more chlorine radicals than the graphite electrode; and the electronegativity of the orange peel biomass carbon electrode is stronger than that of the graphite electrode, so that bacteria can be combined with the surface of the anode through a larger repulsive force, and the inactivation of the bacteria by chlorine free radicals is realized, so that the orange peel biomass carbon electrode has a higher sterilization effect.

In the embodiment of the disclosure, the orange peel biomass carbon electrode generates a large amount of persistent free radicals, and the persistent free radicals can induce the generation of superoxide radicals and chlorine radicals in a large amount. Free radical species (superoxide radical and chlorine radical) contain unpaired electrons, which can rob other electrons, oxidize biological cells (bacteria) near the electrode to lose electrons, destroy double-chain or single-chain structures of DNA in the bacterial cells, inactivate the bacteria and finally cause cell damage and apoptosis. The graphite electrode does not contain persistent free radicals, and the graphite electrode cannot induce the generation of superoxide radicals and chlorine radicals in a large amount, so that the disinfection and sterilization effect is lower than that of an orange peel biomass charcoal electrode when the graphite electrode is used as a cathode.

The above-mentioned embodiments are intended to illustrate the objects, aspects and advantages of the present disclosure in further detail, and it should be understood that the above-mentioned embodiments are only illustrative of the present disclosure and are not intended to limit the present disclosure, and any modifications, equivalents, improvements and the like made within the spirit and principle of the present disclosure should be included in the scope of the present disclosure.

Claims

1. A preparation method of a biomass charcoal electrode comprises the following steps:

step S1: placing the orange peel into an oven for drying;

2. The preparation method according to claim 1, wherein in step S1, the size of the orange peel comprises square small blocks with 1-3 cm side length.

3. The preparation method of claim 1, wherein in step S1, the temperature of the orange peel dried in the oven comprises: 60-100 ℃, and the drying time comprises: 24-36 h.

4. The production method according to claim 1, wherein, in step S2, the inert gas includes: nitrogen or argon.

5. The production method according to claim 1, wherein in step S2.1, the first temperature rise rate includes: 5-20 ℃/min.

6. The preparation method according to claim 1, wherein in step S2.1, the first preset temperature range comprises: 80-100 ℃, and the first preset period of time comprises: 10-30 min.

7. The preparation method according to claim 1, wherein in step S2.2, the second preset temperature range comprises: 600-800 ℃, and the second-stage preset time comprises the following steps: 1-3 h.

8. Use of a disinfectant for sterilization, comprising: the biomass charcoal electrode prepared by the method of any one of claims 1 to 7 is used for treating bacteria in water through electrochemical reaction.

9. Use according to claim 8, wherein the electrolyte solution in the electrochemical reaction comprises at least one of: sodium chloride solution, sodium sulfate solution and phosphate buffer solution.

10. The use of claim 8, wherein the bacteria comprise at least one of: pseudomonas aeruginosa, Pseudomonas stutzeri and Escherichia coli.