CN118383385B

CN118383385B - A doped activated carbon-nickel oxide composite antibacterial agent and its preparation method and application

Info

Publication number: CN118383385B
Application number: CN202410721480.4A
Authority: CN
Inventors: 聂艳丽; 张彬; 杨正芳; 王琪盛; 郭倩倩; 王清; 文官彬; 李翠萍; 李月
Original assignee: Yunnan Forestry And Grassland Technology Extension Station; Kunming University of Science and Technology
Current assignee: Yunnan Forestry And Grassland Technology Extension Station; Kunming University of Science and Technology
Priority date: 2024-06-05
Filing date: 2024-06-05
Publication date: 2024-11-22
Anticipated expiration: 2044-06-05
Also published as: CN118383385A

Abstract

The present invention discloses a doped activated carbon-nickel oxide composite antibacterial agent and a preparation method and application thereof, and belongs to the technical field of antibacterial material preparation. The present invention includes a doped activated carbon-nickel oxide composite antibacterial agent, the composite antibacterial agent is doped with bismuth element, and the activated carbon is loaded with nickel oxide in the form of nanoparticles. The aforementioned composite antibacterial agent is prepared by the preparation method of the present invention, and the composite antibacterial agent is used as an antibacterial agent for Gram-positive bacteria and Gram-negative bacteria in a water environment, which can safely and efficiently kill bacteria in a water environment and remove dye pollutants, so that the water body is purified, while reducing the comprehensive cost of water environment management.

Description

Doped active carbon-nickel oxide composite antibacterial agent and preparation method and application thereof

Technical Field

The invention belongs to the technical field of antibacterial material preparation, and particularly relates to a doped Activated Carbon (AC) -nickel oxide (NiO) composite antibacterial agent, and a preparation method and application thereof.

Background

The aquatic environment contains a large number of bacteria that can potentially infect individuals directly or indirectly through aquatic plants, animals, or water sources, and water borne pathogens cause over 200 tens of thousands of deaths each year, with most victims being children under five years of age. With advances in industrialization, particularly in emerging industrialized countries, biohazard pollution is becoming more and more common and serious. Therefore, even today, in which medical conditions are increasingly different, inhibition and elimination of growth and reproduction of harmful bacteria in water remain an important task concerning human health.

Traditional water bacterial disinfection methods include chlorination, ozone disinfection, ultraviolet (UV) disinfection, filtration, heat sterilization, and the like. The methods have long use history, mature development and simple and convenient operation, and can effectively inactivate pathogenic microorganisms. However, there are inherent limitations in that chemical residues are easily generated, destroyed pathogenic microorganisms are easily revived, and the energy consumption is large. So that the antibacterial performance thereof is limited.

Considering the original ecological balance in the water body environment, the water body environment is sterilized and disinfected, and materials for inhibiting the growth and propagation of water body bacteria in a safe and environment-friendly mode are needed.

In recent years, inorganic antibacterial materials are widely applied to inhibiting the growth and propagation of bacteria in water due to stable properties, good heat resistance, high safety and difficult generation of drug resistance. Among them, inorganic antibacterial materials sterilized by a photocatalytic technique have been a hot spot of research. The method mainly comprises the step of generating Reactive Oxygen Species (ROS) such as superoxide radical (O ^2-), hydroxyl radical (OH-) and hydrogen peroxide (H ₂O₂) in situ by light or a catalyst to kill bacteria. When ROS enter cells, oxidative stress occurs, resulting in inactivation of pathogens by cellular components, protein oxidation, reduced enzymatic activity, DNA damage, and the like. The method has the advantages of mild reaction conditions, no need of additional oxidant, simple operation process and the like. However, the photocatalytic antibacterial agent needs to efficiently utilize excitation of visible light, near infrared light or ultraviolet light, and in a water environment, the water body can generate certain reflection, refraction and other effects on the light, so that the antibacterial effect of the photocatalytic antibacterial agent in the water environment is limited. Meanwhile, the recycling of the antibacterial agent forms a great barrier to the specificity of the water environment, so that the antibacterial agent in the water environment is difficult to recycle, and the cost is relatively high.

Therefore, it is necessary to provide a doped type AC-NiO composite antibacterial agent, a preparation method and application thereof, and a NiO composite antibacterial agent with the morphology of Bi doped AC load nano particles is successfully prepared, and is applied to a water body environment to mainly kill gram positive bacteria and gram negative bacteria. The negative influence of the water environment on the antibacterial effect of the composite antibacterial agent is reduced. Meanwhile, the separation and recovery difficulty of the composite antibacterial agent after the composite antibacterial agent is used in the water environment is reduced, the actual application cost of the composite antibacterial agent is reduced, and the environmental protection safety of the composite antibacterial agent for water treatment is improved.

Disclosure of Invention

In order to overcome the problems in the background art, the invention provides the doped AC-NiO composite antibacterial agent and the preparation method and application thereof, and nickel oxide in the shape of nano particles is loaded on activated carbon, so that the problem of high separation and recovery difficulty caused by the fact that the nickel oxide in the form of powder directly enters a water body is solved, on the one hand, the activated carbon has certain adsorption performance, the adsorption effect of the composite antibacterial agent can be enhanced, the improvement of the antibacterial effect of the composite antibacterial agent is facilitated, but the nickel oxide is loaded on the activated carbon, the antibacterial effect of the nickel oxide can be greatly influenced, the overall antibacterial effect of the AC-NiO composite antibacterial agent is greatly reduced, and therefore, the composite of electrons and holes is hindered by doping Bi, so that the antibacterial effect of the AC-NiO composite antibacterial agent is improved, and meanwhile, the magnetism of the composite antibacterial agent can be enhanced by doping Bi, and the separation and recovery effects of the composite antibacterial agent are improved.

In order to achieve the above purpose, the present invention is realized by the following technical scheme:

The invention provides a doped AC-NiO composite antibacterial agent, wherein the composite antibacterial agent is doped with bismuth element, and the activated carbon is loaded with nickel oxide in the shape of nano particles.

The invention further provides a preparation method of the doped AC-NiO composite antibacterial agent, which comprises the following steps:

S1: 0.24g of NiCl ₂·6H₂ O is weighed and dissolved in 25ml of ethanol to form a green transparent solution, 1.46g of sodium acetate is weighed and dissolved in 10ml of distilled water, and 0.59g of trisodium citrate is weighed and dissolved in 15ml of distilled water;

S2: mixing and stirring the three solutions obtained in the step S2 to obtain a transparent solution, and adding 0.5g of activated carbon powder and 0.2gBi (NO ₃)₃·5H₂ O to the transparent solution to obtain a mixed solution;

S3: performing sealed hydrothermal reaction treatment on the mixed solution obtained in the step S3, and naturally cooling to room temperature to obtain a blue-green product;

S4: washing the blue-green product obtained in the step S3 with deionized water for 5 times, washing the blue-green product obtained in the step S4 with ethanol for 5 times, drying the product, and calcining to obtain the bismuth-doped active carbon-nickel oxide composite antibacterial agent.

Preferably, the activated carbon is prepared by the following steps:

(1) Cleaning shell of Australian nut, drying, pulverizing, mixing 3g shell powder with 10ml activator, and soaking for a certain time;

(2) Carrying out vacuum suction filtration on the shell powder immersed in the step (1), and carrying out high-temperature calcination on the shell powder after pumping;

(3) And (3) cleaning the calcined substance in the step (2) by using a dilute hydrochloric acid solution, repeatedly washing by using distilled water, drying the substance to constant weight after the washing liquid is neutral, quickly grinding and sieving to obtain the activated carbon.

Preferably, in the step S2, the stirring speed is 500r/min and the stirring time is 30min.

Preferably, in the step S3, the hydrothermal reaction temperature is 140 ℃ and the hydrothermal reaction time is 18 hours.

Preferably, in the step S4, the drying temperature is 60 ℃ and the drying time is 4 hours.

Preferably, in the step S4, the calcination temperature is 500 ℃ and the calcination time is 2 hours.

Preferably, in the step (1), the activator is one of H ₃PO₄、ZnCl₂ and KOH, the concentration of the activator is 10% -50%, and the soaking time is 24 hours.

Preferably, in the step (2), the calcination temperature is 600 ℃ and the calcination time is 2 hours; in the step (3), the concentration of the dilute hydrochloric acid is 5%, the drying temperature is 100 ℃, and the dilute hydrochloric acid is sieved by a 200-mesh sieve.

The invention also provides application of the bismuth-doped active carbon-nickel oxide composite antibacterial agent as a gram-positive bacteria and gram-negative bacteria antibacterial agent in a water body environment.

The invention has the beneficial effects that:

1. According to the invention, the NiO with the shape of the nano particles is loaded on the activated carbon, so that the composite antibacterial agent is easier to separate and recycle after being used, and meanwhile, the adsorption property of the activated carbon is effectively utilized, so that the composite antibacterial agent has relatively abundant antibacterial modes, and the applicability of the composite antibacterial agent is improved.

2. According to the invention, by doping Bi, the negative influence of the AC load NiO on the NiO antibacterial effect is improved, meanwhile, the magnetism of the composite antibacterial agent is enhanced, the separation and recovery effect of the composite antibacterial agent after use is improved, the actual use cost of the composite antibacterial agent is reduced, and the secondary pollution of chemical residues to water is further avoided.

3. According to the invention, the Australian nut shells are used as raw materials for preparing the activated carbon, so that on one hand, the recycling of the Australian nut shells is realized, the waste caused by direct discarding is avoided, and on the other hand, the sources of the raw materials are wide, the raw materials are easy to obtain, and the cost is relatively low.

4. The composite antibacterial agent prepared by the invention has obvious antibacterial effects on gram-positive bacteria such as escherichia coli and staphylococcus aureus, gram-negative bacteria and the like, has adsorption and degradation effects on organic dyes such as malachite green, methylene blue and methyl orange, and has good comprehensive antibacterial effects.

5. The composite antibacterial agent prepared by the invention can realize better antibacterial performance on complex bacterial environments in water environments.

Drawings

FIG. 1 is an SEM image of an AC prepared by adding different activators according to the invention, wherein FIG. (a) adds ZnCl ₂, FIG. (b) adds KOH, and FIG. (c) adds H ₃PO₄.

FIG. 2 shows BET and BJH pore size distribution diagrams of ACs prepared by adding different activators according to the present invention, wherein FIG. (a) shows a nitrogen adsorption-desorption isothermal curve and FIG. (b) shows a pore size distribution diagram.

Fig. 3 is an SEM image of NiO of different morphologies, wherein fig. (a) is a nanoparticle morphology, fig. (b) is a floc morphology, fig. (c) is a sheet morphology, fig. (d) is a sheet morphology, fig. (e) is a camellia morphology, and fig. (f) is a spherical morphology.

Fig. 4 is a graph showing comparison of antibacterial performance of NiO with different morphologies, wherein fig. (a) is an antibacterial effect graph and fig. (b) is an antibacterial histogram.

Fig. 5 is a graph comparing antibacterial properties of AC, niO, AC-NiO at different concentrations, wherein the upper graph is an antibacterial effect graph and the lower graph is an antibacterial effect histogram.

Fig. 6 is an SEM and EDS diagram of the composite antimicrobial agent of the present invention, wherein fig. (a) is an SEM diagram (magnified 10000 times) of the composite antimicrobial agent of the present invention, fig. (b) is an SEM diagram (magnified 200000 times) of the composite antimicrobial agent of the present invention, fig. (c) is a carbon element EDS diagram, fig. (d) is a nickel element EDS diagram, fig. (e) is an oxygen element EDS diagram, and fig. (f) is a bismuth element EDS diagram.

FIG. 7 shows XPS spectrum of the composite antibacterial agent of the present invention, wherein, the graph (a) is XPS full spectrum, the graph (b) is Ni 2p spectrum, the graph (c) is O1s spectrum, and the graph (d) is Bi 4f spectrum.

FIG. 8 is an EPR spectrum of the AC-NiO and the composite antibacterial agent of the present invention.

FIG. 9 is a graph of the result of diffuse reflection of ultraviolet light for an AC-NiO and the composite antimicrobial agent of the present invention, wherein the left graph is an ultraviolet spectrum, and the right graph is a band gap graph.

FIG. 10 is a graph comparing the antibacterial effects of other antibacterial agents and the composite antibacterial agent of the present invention, wherein FIG. (a) is an E.coli zone of inhibition, FIG. (b) is a Staphylococcus aureus zone of inhibition, the middle graph is an antibacterial effect graph, and the lower graph is an antibacterial effect histogram.

FIG. 11 is a graph showing the results of the cyclic antibacterial test of the composite antibacterial agent of the present invention, wherein the upper graph shows the results of the cyclic antibacterial test of Escherichia coli, and the lower graph shows the results of the antibacterial test of Staphylococcus aureus.

FIG. 12 is a SEM image of the contact of the complex antimicrobial agent of the present invention with bacteria, wherein FIG. (a) is an untreated E.coli SEM image, FIG. (b) is an E.coli SEM image treated with the complex antimicrobial agent of the present invention, FIG. (c) is an untreated Staphylococcus aureus SEM image, and FIG. (d) is an Staphylococcus aureus SEM image treated with the complex antimicrobial agent of the present invention.

Fig. 13 is a graph showing the bacteriostatic effect of the composite antibacterial agent of the present invention on the Dian pond water.

FIG. 14 is a scanning ultraviolet spectrum of the composite antimicrobial of the present invention adsorbed to degrade different dyes, wherein FIG. (a) is malachite green dye, FIG. (b) is methylene blue dye, and FIG. (c) is methyl orange dye.

FIG. 15 is a graph of the magnetic results of AC, AC-NiO and the composite antimicrobial agent of the present invention.

Detailed Description

The present invention will be described in further detail with reference to specific examples.

In the examples of the present invention and the comparative examples, chemical reagents not specifically described were all tested using commercially available analytical techniques. The examples of the present invention and comparative examples used macadamia shells produced from the lincang of Yunnan.

Example 1

In this example, activated carbon was prepared by the following steps:

(1) After the macadamia shell is washed clean, the shell is dried and crushed, and then 3g of shell powder is taken, evenly mixed with 10ml of ZnCl ₂ with the concentration of 10 percent and soaked for 24 hours.

(2) And (3) carrying out vacuum suction filtration on the shell powder immersed in the step (1), and calcining the shell powder for 2 hours at 600 ℃ after pumping.

(3) Washing the calcined substance in the step (2) by using a dilute hydrochloric acid solution with the concentration of 5%, repeatedly washing the calcined substance by using distilled water until the eluate is neutral (pH=6-7), drying the substance to constant weight at 100 ℃, quickly grinding the dried substance, and sieving the ground substance by using a 200-mesh sieve to obtain the activated carbon.

In this example, a composite antimicrobial agent was prepared by the following steps:

S2: mixing the three solutions obtained in the step S2 and stirring at a speed of 500r/min for 30min to obtain a transparent solution, and adding 0.5g of activated carbon powder and 0.2gBi (NO ₃)₃·5H₂ O to the transparent solution to obtain a mixed solution;

s3: carrying out sealed hydrothermal reaction treatment on the mixed solution obtained in the step S3 at 140 ℃, and naturally cooling to room temperature after reacting for 18 hours to obtain a blue-green product;

s4: washing the blue-green product obtained in the step S3 by deionized water for 5 times, washing the blue-green product obtained in the step S4 by ethanol for 5 times, drying the product at 60 ℃ for 4 hours, and calcining the product at 500 ℃ for 2 hours to obtain the bismuth-doped active carbon-nickel oxide composite antibacterial agent.

An SEM image of the Activated Carbon (AC) prepared in this example is shown in fig. 1 (a). The BET and BJH pore size distribution plots for AC are shown in FIG. 2. In the obtained composite antibacterial agent, nickel oxide has a nanoparticle morphology, as shown in fig. 3 (a).

As can be seen from FIG. 1 (a), the ZnCl ₂ activated AC has a larger pore-like structure, the AC surface is smoother, and the ZnCl ₂ activated regulation pore-forming effect is not obvious, but the effect on deep hole formation is obvious.

As can be seen from FIG. 2 (a), the adsorption isotherm of ZnCl ₂ activator is I-type, and has no obvious hysteresis loop, which shows that the activated carbon prepared in the embodiment contains higher micropore structure.

Example 2

This example uses the same method as in example 1 to prepare a composite antimicrobial agent, except that: in this example, the activator was KOH and the activator concentration was 50%.

An SEM image of the Activated Carbon (AC) prepared in this example is shown in fig. 1 (b). The BET and BJH pore size distribution plots for AC are shown in FIG. 2. In the obtained composite antibacterial agent, nickel oxide has a nanoparticle morphology, as shown in fig. 3 (a).

As can be seen from FIG. 1 (b), the KOH-activated AC has relatively dense pores and a uniform distribution.

As can be seen from fig. 2 (a), the adsorption isotherm of KOH as an activator is type I, and there is no obvious hysteresis loop, indicating that the activated carbon contains a higher microporous structure.

Example 3

This example uses the same method as in example 1 to prepare a composite antimicrobial agent, except that: in this example, the activator was H ₃PO₄ and the activator concentration was 35%.

An SEM image of the Activated Carbon (AC) prepared in this example is shown in fig. 1 (c). The BET and BJH pore size distribution plots for AC are shown in FIG. 2. In the obtained composite antibacterial agent, nickel oxide has a nanoparticle morphology, as shown in fig. 3 (a). SEM and EDS images of the AC-NiO/Bi composite antibacterial agent prepared in this example are shown in FIG. 6. The XPS diagram is shown in FIG. 7. The EPR spectrum is shown in FIG. 8. The result of the diffuse reflection of ultraviolet is shown in fig. 9. The antibacterial effect against E.coli and Staphylococcus aureus is shown in FIG. 10. The cyclic antibacterial effect is shown in fig. 11. SEM images of the contact with bacteria are shown in fig. 12. The antibacterial effect on the Dian pond water is shown in figure 13. The adsorption and degradation performance of the dye dirt is shown in figure 14. The magnetic results are shown in FIG. 15.

As can be seen from FIG. 1 (c), H ₃PO₄ activated AC, which exhibited an irregular shape, a loose surface structure, and holes were clearly visible.

As can be seen from fig. 2 (a), the adsorption isotherm of the activated carbon obtained by using H ₃PO₄ as an activator is II-type, which indicates that the adsorption process is mainly macroporous adsorption, and the activated carbon contains a macroporous structure.

As can be seen from fig. 1 and fig. 2 (a), all three activators can activate AC and generate pore structure, but H ₃PO₄ is the activated carbon activated by the activator with specific surface area of maximum 1039.32m ²/g, and total pore volume of 1.43cm ²/g; secondly, activated carbon activated by ZnCl ₂, wherein the specific surface area is 315.12m ²/g, and the total pore volume is 0.33cm ²/g; KOH-activated carbon has the lowest surface area and total pore volume of 162.57m ²/g,0.19cm²/g, respectively. By means of the specific surface area and the total pore volume of the AC activated by fig. 2 (b) and three different activators, H ₃PO₄,ZnCl₂ can be obtained, with average pore diameters of 2.8nm,1.9nm,2.3nm, respectively, for the KOH activated carbon. Among the three activators, H ₃PO₄ has obvious advantages in terms of specific surface area, total volume and average pore diameter compared with the other two, and is beneficial to improving the antibacterial effect. Meanwhile, the AC prepared by taking H ₃PO₄ as an activator has the highest yield and low price. Considering the comprehensive factors of the construction of antibacterial materials, H ₃PO₄ is the optimal choice for the preparation of Australian nut shell activated carbon as an activator.

As can be seen from fig. 6 (a) and (b), a plurality of metal particles are dispersed in the random dispersed pore structure of the activated carbon, and the metal particles are NiO, which indicates that AC and NiO are successfully combined, and as can be seen from fig. 6 (c-f), C, ni, O, bi elements are well dispersed on the surface of the material, and the successful incorporation of Bi is verified.

As can be seen from FIG. 7 (a), bi 4f, bi 4d and O1s states exist in the AC-NiO/Bi composite antibacterial agent prepared by the present invention; as can be seen from fig. 7 (b), 5 peaks appear in fig. 7 (b), wherein peaks at 853.6eV and 872.4eV are assigned to surface Ni ²⁺ species, and further three satellite peaks (Sat 1 and Sat 2) are also determined at 855.4, 861.8eV and 879.3eV, which are assigned to paramagnetic Ni ²⁺ compounds formed by multiple electron transitions. After adding Bi, the binding energy is slightly changed, and the existence of Bi weakens the Ni-O bond, thereby being beneficial to the formation of surface oxygen vacancies. FIG. 7 (c) shows 3 peaks in O1s, wherein 529.2eV belongs to lattice oxygen of Ni-O, 531.2eV belongs to oxygen vacancies adsorbed on the surface of the material, and the binding energy in O1s is basically unchanged after doping Bi. Binding energies 163.9eV and 158.6eV in FIG. 7 (d) are consistent with the two sets of peaks Bi 4f7/2 and Bi 4f5/2, respectively, indicating that Bi exists in trivalent form. From a combination of FIGS. 7 (a-b), it is evident that Bi was successfully doped, and that the change in binding energy caused by Bi doping is favorable for the formation of surface oxygen vacancies, thereby improving antibacterial properties.

As can be seen from FIG. 11, after four cycles, the antibacterial rate of the composite antibacterial agent of the present invention was reduced to 74.89% for Escherichia coli, 24.61% for Escherichia coli, only about 6% for Staphylococcus aureus on average, and about 69.84% for Staphylococcus aureus on average, 28.6% for Staphylococcus aureus on average, and only about 7% for Escherichia coli on average. Although the antibacterial rate of the composite antibacterial agent is reduced to a certain extent in the circulating process, the reduction range is smaller, which proves that the composite antibacterial agent has better stability and better recycling property.

As can be seen from FIG. 12, the composite antibacterial agent of the present invention can effectively destroy the bacterial cell structure, thereby achieving the antibacterial purpose.

In fig. 13, an antibacterial experiment is performed on a Yunnan pond water body in Kunming, yunnan province, and after a plurality of miscellaneous bacteria appear in a culture medium after 24h culture (as shown in the left graph of fig. 13), more than 99% of bacteria in the water body can be removed after the composite antibacterial agent is added into the culture medium for treatment (as shown in the right graph of fig. 13), which shows that the composite antibacterial agent has excellent antibacterial performance on escherichia coli and staphylococcus aureus, and can achieve excellent antibacterial effect when more complex bacterial types exist in the water body environment.

As can be seen from FIG. 14, the composite antibacterial agent prepared by the invention also has remarkable adsorption and degradation performances on dye pollutants such as malachite green, methylene blue, methyl orange and the like.

Comparative example 1

This comparative example was prepared with nickel oxide in a flocculent morphology (as shown in fig. 3 (b)) and the antibacterial performance of the nickel oxide was tested and the results are shown in fig. 4.

Comparative example 2

The comparative example was prepared as nickel oxide in a flake form (as shown in fig. 3 (c)), and the antibacterial performance of the nickel oxide was tested, and the result is shown in fig. 4.

Comparative example 3

The comparative example was prepared as shown in fig. 3 (d) and the antibacterial performance of nickel oxide was tested as shown in fig. 4.

Comparative example 4

The comparative example was prepared with a teaflower-like morphology of nickel oxide (as shown in fig. 3 (e)), and the antibacterial performance of the nickel oxide was tested, and the results are shown in fig. 4.

Comparative example 5

The comparative example was prepared with nickel oxide having a spherical morphology (as shown in fig. 3 (f)), and the antibacterial performance of the nickel oxide was tested, and the results are shown in fig. 4.

As can be seen from FIG. 4, the NiO with the nanoparticle morphology has higher antibacterial activity compared with other morphologies, and the inactivation rate of the NiO with the nanoparticle morphology to Escherichia coli can reach 99.73%. Therefore, the nickel oxide with the nanometer morphology is beneficial to improving the antibacterial effect of the composite antibacterial agent prepared by the invention.

Comparative example 6

This comparative example was prepared by the same method as in example 1, except that: bi was not doped in this comparative example.

After the composite antibacterial agent in the comparative example is prepared into antibacterial solutions with different concentrations, an antibacterial effect experiment is carried out, for example, the antibacterial solution with the concentration of 50 mug/ml is prepared by adding 50 mug of the antibacterial agent in the comparative example into 1ml of water. The antibacterial effect of the composite antibacterial agent prepared in this comparative example is shown in fig. 5, the EPR spectrum is shown in fig. 8, the diffuse reflection result of ultraviolet rays is shown in fig. 9, the antibacterial effect on e.coli (escherichia coli) and s.aureus (staphylococcus aureus) is shown in fig. 10, and the magnetic experiment result is shown in fig. 15.

The oxygen vacancies not only can provide enough adsorption sites to adsorb O ₂ and act as active sites to activate O ₂ to produce more O ² _–, but also facilitate the separation of photogenerated carriers, thereby producing more ROS to enhance the antimicrobial properties of the material. As can be seen from fig. 8, both AC-NiO and AC-NiO/Bi have paramagnetic resonance signals at g=2.003, indicating the presence of oxygen vacancies for both antimicrobial agents. Meanwhile, compared with the AC-NiO, the signal of the oxygen vacancies of the AC-NiO/Bi sample is enhanced, which shows that the doping of Bi promotes the generation of more surface oxygen vacancies, thereby further improving the antibacterial property of the material.

As can be seen from fig. 9, after doping Bi, the band gap of the composite antibacterial agent of the present invention is significantly reduced, and the recombination rate of the photo-generated carriers is slowed down, which is beneficial to improving the antibacterial performance of the composite antibacterial agent of the present invention.

Comparative example 7

The comparative example adopts AC as an antibacterial agent to prepare antibacterial solutions with different concentrations for antibacterial effect experiments.

The antibacterial effect of the antibacterial agent in this comparative example is shown in fig. 5, the antibacterial effect on e.coli (escherichia coli) and s.aureus (staphylococcus aureus) is shown in fig. 10, and the magnetic test result is shown in fig. 15.

As can be seen from fig. 10, the AC antimicrobial agent does not show a zone of inhibition for both bacteria, indicating that AC has no ion elution and has poor antimicrobial properties. The composite antibacterial agent has a remarkable inhibition area on two bacteria, the antibacterial width of the AC-NiO is maximum, the antibacterial circle widths of E.coli and S.aureus are 15.31mm and 18.43mm respectively, the AC-NiO/Bi is slightly reduced compared with the AC-NiO, and the antibacterial circle widths of E.coli and S.aureus are 13.24mm and 14.71mm respectively, so that after Bi doping, the ion dissolution of the antibacterial agent is reduced, the specific gravity of the ion sterilizing part is reduced, and the safety of the material is enhanced. Meanwhile, as can be seen from fig. 10, under the condition that the concentration of the antibacterial solution is the same (300 μg), the antibacterial rate of the AC-NiO to e.coli and s.aureus is 66.87% and 44.22%, respectively, while the antibacterial rate of the composite antibacterial agent of the present invention reaches 98.77% and 78.90%, and meanwhile, after the combination of NiO and AC, the antibacterial rate of the AC-NiO is reduced more than that of NiO, and after the doping of Bi, the antibacterial rate of the composite antibacterial agent is significantly improved and higher than that of NiO, which means that the doping of Bi can not only compensate for the reduction of the antibacterial rate caused by the combination of NiO and AC, but also promote the further improvement of the antibacterial rate of the composite antibacterial agent.

As can be seen from FIG. 15, the composite antibacterial agent of the present invention has an optimal magnetic property, which is advantageous for recycling the composite antibacterial agent of the present invention.

Comparative example 8

The comparative example adopts NiO as an antibacterial agent to prepare antibacterial solutions with different concentrations for antibacterial effect experiments.

The antibacterial effect of the antibacterial agent in this comparative example is shown in fig. 5.

As can be seen from FIG. 5, when the concentration of the antibacterial solution is increased from 50 to 400. Mu.g/ml, the antibacterial ratio of NiO to the antibacterial solution is 14.12%, 30.45%, 34.75%, 94.10% and 94.38% in sequence; the antibacterial rate of AC-NiO was 20.30%, 21.15%, 40.13%, 61.04% and 69.83% in this order. When the concentration of the NiO antibacterial solution is increased from 200 mug/ml to 300 mug/ml, the antibacterial rate is greatly improved, and then the concentration is increased to 400 mug/ml, the antibacterial rate is not greatly improved, which indicates that the suitable concentration of the NiO antibacterial solution is 300 mug/ml, and when the concentration of the NiO is 300 mug/ml, the antibacterial rate of the NiO is obviously reduced after the NiO is combined with AC, so that the comprehensive performance of the antibacterial agent is poor.

In conclusion, the AC-NiO/Bi composite antibacterial agent has excellent antibacterial performance, also has excellent adsorption and degradation performance on dye dirt, also has good recovery and safety, the composite antibacterial agent is used for water environment treatment, can effectively remove pollutants and harmful substances in the water environment, and has high removal safety and low comprehensive cost.

Finally, it is noted that the above-mentioned preferred embodiments illustrate rather than limit the invention, and that, although the invention has been described in detail with reference to the above-mentioned preferred embodiments, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the invention as defined by the appended claims.

Claims

1. A preparation method of a doped active carbon-nickel oxide composite antibacterial agent is characterized by comprising the following steps: the composite antibacterial agent is doped with bismuth element, the active carbon is loaded with nickel oxide with nano particle morphology, the preparation method comprises the following steps:

S1: 0.24g of NiCl ₂·6H₂ O is weighed and dissolved in 25ml of ethanol to form a green transparent solution, 1.46 g sodium acetate is weighed and dissolved in 10ml of distilled water, and 0.59g of trisodium citrate is weighed and dissolved in 15ml of distilled water;

S2: mixing and stirring the three solutions obtained in the step S1 to obtain a transparent solution, and adding 0.5g of activated carbon powder and 0.2gBi (NO ₃)₃·5H₂ O to the transparent solution to obtain a mixed solution;

S3: performing sealed hydrothermal reaction treatment on the mixed solution obtained in the step S2, and naturally cooling to room temperature to obtain a blue-green product;

S4: washing the blue-green product obtained in the step S3 with deionized water for 5 times, washing the blue-green product obtained in the step S3 with ethanol for 5 times, drying the product, and calcining to obtain the bismuth-doped active carbon-nickel oxide composite antibacterial agent.

2. The method for preparing the doped activated carbon-nickel oxide composite antibacterial agent according to claim 1, which is characterized in that: the activated carbon is prepared by the following steps:

3. The method for preparing the doped activated carbon-nickel oxide composite antibacterial agent according to claim 1, which is characterized in that: in the step S2, the stirring rotating speed is 500r/min, and the stirring time is 30min.

4. The method for preparing the doped activated carbon-nickel oxide composite antibacterial agent according to claim 1, which is characterized in that: in the step S3, the hydrothermal reaction temperature is 140 ℃, and the hydrothermal reaction time is 18 hours.

5. The method for preparing the doped activated carbon-nickel oxide composite antibacterial agent according to claim 1, which is characterized in that: in the step S4, the drying temperature is 60 ℃ and the drying time is 4 hours.

6. The method for preparing the doped activated carbon-nickel oxide composite antibacterial agent according to claim 1, which is characterized in that: in the step S4, the calcination temperature is 500 ℃ and the calcination time is 2 hours.

7. The method for preparing the doped activated carbon-nickel oxide composite antibacterial agent according to claim 2, which is characterized in that: in the step (1), the activator is one of H ₃PO₄、ZnCl₂ and KOH, the concentration of the activator is 10-50%, and the soaking time is 24 hours.

8. The method for preparing the doped activated carbon-nickel oxide composite antibacterial agent according to claim 2, which is characterized in that: in the step (2), the calcination temperature is 600 ℃, and the calcination time is 2 hours; in the step (3), the concentration of the dilute hydrochloric acid is 5%, the drying temperature is 100 ℃, and the dilute hydrochloric acid is sieved by a 200-mesh sieve.

9. The use of the bismuth-doped activated carbon-nickel oxide composite antibacterial agent prepared by the preparation method of any one of claims 1-8 as a gram-positive bacteria and gram-negative bacteria bacteriostatic agent in a water environment.