A method for catalyst-assisted DBD plasma to kill biological warfare agents

Abstract

The present invention relates to the technical field of plasma killing biological warfare agents, and discloses a method for catalyst-assisted DBD plasma to kill biological warfare agents. The porous catalyst used in the present invention to assist DBD plasma in killing biological warfare agents includes a porous substrate and core-shell structured active particles dispersed in the porous substrate; the shell layer of the core-shell structured active particles is a porous carbon material, and the core layer is a composite of an active metal oxide and a porous support. The active metal oxide includes MnO2 and / or ZnO and is loaded in the porous support. This porous catalyst can convert O3 and H2O2 formed in DBD into ·OH or ·O with higher activity, and at the same time is conducive to the contact between the generated ·OH or ·O and biological warfare agents, thereby improving the effect of DBD plasma in killing biological warfare agents in drinking water. Moreover, it can still maintain a good effect of assisting DBD in killing biological warfare agents after long-term use, and can avoid potential health hazards caused by long-term drinking.

Description

Technical Field

[0001] The present invention relates to the technical field of plasma killing biological warfare agents, and particularly to a method for killing biological warfare agents by catalyst-assisted DBD plasma. Background Art

[0002] Biological warfare agents refer to microorganisms that can reproduce in the bodies of humans, animals or plants and cause large-scale diseases. Generally, they have the characteristics of high pathogenicity, strong stability in the environment, large-area pollution, and multiple transmission routes. In terms of biological species, they are mainly bacteria and viruses, and also include rickettsia, chlamydia, fungi, toxins, etc. Studying the killing methods of biological warfare agents has important practical significance for preventing and controlling the hazards of biological warfare agents and combating biological terrorist attacks.

[0003] Dielectric barrier discharge (DBD) is a discharge phenomenon formed by inserting an insulating medium into the discharge space. The dielectric barrier discharge used for water treatment often lays a layer of insulating medium on one side or both sides of the two electrodes. The water to be treated passes between the two electrodes in a continuous phase or a dispersed phase. When a sufficiently large alternating voltage is applied to the discharge electrodes, filamentous discharge or glow discharge occurs between the electrodes. When dielectric barrier discharge occurs, low-temperature plasma is generated between the two electrodes, which contains a large number of high-energy electrons, active particles (such as O3, H2O2, ·OH, ·O, ·O2 - etc., among which, ·OH has the strongest oxidizing property) and ultraviolet rays. These high-energy electrons, active particles and ultraviolet rays can damage the nucleic acids, cell nuclei, cell walls, cell membranes and other structures and metabolic activities of biological warfare agents such as bacteria (such as Bacillus anthracis, Yersinia pestis, etc.) and viruses (such as hemorrhagic fever virus, etc.), thereby achieving the killing of biological warfare agents.

[0004] Compared with traditional chemical or physical methods, the dielectric barrier discharge technology has the advantages of fast speed, low temperature, and few by-products, so it has good application prospects in killing biological warfare agents in drinking water. However, this technology has the disadvantages of low energy utilization rate and the inability to fully utilize the light energy and other energies excited by the discharge system. Patent CN111790399B discloses a catalyst for treating wastewater by a synergistic low-temperature plasma technology, its preparation and application, and a method for treating phenol wastewater. The catalyst uses a carbon material as a carrier and loads MnO2, CeO2 and ZnO in it, which can cooperate with the DBD technology to improve the energy utilization rate and the phenol degradation effect. However, the catalyst in this patent will have the phenomenon of metal oxide shedding after long-term use, resulting in a decline in catalytic performance. And when it is used to kill biological warfare agents in drinking water, the shed metal oxides enter the drinking water, and long-term drinking may cause potential health hazards. Summary of the Invention

[0005] To solve the above technical problems, the present invention provides a porous catalyst for assisting DBD plasma to kill biological warfare agents in drinking water. This porous catalyst can effectively improve the effect of DBD plasma in killing biological warfare agents in drinking water and reduce the shedding of active metal oxides, so that the porous catalyst can still better assist DBD in killing biological warfare agents after long-term use and avoid potential health hazards caused by long-term drinking.

[0006] The present invention also provides a preparation method of a porous catalyst for assisting DBD plasma to kill biological warfare agents in drinking water. Through this preparation method, it is beneficial for external O3 and H2O2 to enter the interior of the porous catalyst and contact with the active metal oxides. At the same time, it is also beneficial for the generated ·OH or ·O to contact with the biological warfare agents adsorbed in the porous catalyst, further improving the effect of killing biological warfare agents.

[0007] The specific technical solution of the present invention is as follows:

[0008] In a first aspect, the present invention provides a porous catalyst for assisting DBD plasma to kill biological warfare agents in drinking water, comprising a porous substrate and core-shell structured active particles dispersed in the porous substrate; the core layer of the core-shell structured active particles is a composite of an active metal oxide and a porous carrier, and the active metal oxide is loaded in the porous carrier; the shell layer of the core-shell structured active particles is a porous carbon material; the active metal oxide includes MnO2 and / or ZnO.

[0009] During the process of dielectric barrier discharge (DBD), ultraviolet light, as well as active particles such as O3, H2O2, ·OH, ·O, and ·O2 can be generated. - ZnO can catalyze the conversion of O3 and H2O2 into ·OH with stronger oxidizing ability. In addition, it can also generate ·OH using ultraviolet light; MnO2 can also activate O3 and decompose O3 into highly active ·O. Therefore, using MnO2 and / or ZnO to assist DBD plasma in killing biological warfare agents in drinking water can improve the energy utilization rate of the system and achieve a better effect of killing biological warfare agents.

[0010] When the active metal oxides (MnO2 and / or ZnO) are loaded onto the porous substrate by conventional methods (such as the impregnation sintering method), the active metal oxides are likely to fall off during use, resulting in a decline in the catalytic performance of the porous catalyst after long-term use. Moreover, when used to kill biological warfare agents in drinking water, the fallen active metal oxides enter the drinking water and may cause potential health hazards during long-term drinking.

[0011] To solve the above problems, the present invention loads active metal oxides in a porous carrier, and sets a loose carbon material shell layer on the outer layer to form core-shell structured active particles, and then disperses them in a porous substrate. When in use, the porous substrate can adsorb biological warfare agents such as bacteria and viruses through its larger pores. At the same time, O3 and H2O2 are adsorbed into the core-shell structured active particles and come into contact with the active metal oxides to generate more active ·OH or ·O. These reactive oxygen species diffuse outside the core-shell structured active particles and come into contact with the biological warfare agents adsorbed in the porous substrate, killing them to prevent their reproduction or desorption into drinking water in the porous substrate. In addition, some ·OH or ·O will also diffuse outside the porous catalyst and come into contact with the biological warfare agents that are not adsorbed, achieving the killing of these biological warfare agents.

[0012] Through the above method, the energy of the DBD system can be fully utilized, and it is beneficial for ·OH or ·O to come into contact with biological warfare agents, thereby improving the effect of DBD in killing biological warfare agents. Moreover, using a loose carbon material shell layer to coat the porous carrier loaded with active metal oxides can prevent the active metal oxides from falling off and entering drinking water, avoiding the decline of the catalytic performance of the porous catalyst and potential health hazards after long-term use. At the same time, using the pores in the loose carbon material is beneficial for O3 and H2O2 to enter the core layer and for ·OH or ·O to be released outside the core layer, thereby reducing the influence of the shell layer coating on the catalytic effect of the active metal oxides.

[0013] Preferably, the porous catalyst includes the following components: core-shell structured active particles, montmorillonite, kaolin.

[0014] In a second aspect, the present invention provides a method for preparing the porous catalyst, including the following steps:

[0015] (1) Using the impregnation sintering method, load active metal oxides on a porous carrier to obtain active metal oxide / porous carrier composite particles;

[0016] (2) Coat chitosan on the surface of the active metal oxide / porous carrier composite particles to obtain active metal oxide / porous carrier@chitosan particles;

[0017] (3) Mix the active metal oxide / porous carrier@chitosan particles, montmorillonite, kaolin, paraffin and water evenly, granulate and form, and then calcine to volatilize the paraffin and carbonize the chitosan to obtain the porous catalyst.

[0018] In the above process, by first mixing and granulating the active metal oxide / porous support@chitosan particles with other raw materials, and then carbonizing the chitosan to form a porous carbon material, the gas released during the carbonization of chitosan is used to form pores in the porous catalyst. These pores can connect the core-shell structured active particles with the outside of the porous catalyst and the pores formed by the volatilization of paraffin, which is beneficial for the entry of external O3 and H2O2 into the core-shell structured active particles. At the same time, it is also beneficial for the generated ·OH or ·O to contact the biological warfare agents adsorbed in the porous catalyst, thereby improving the effect of killing biological warfare agents such as bacteria and viruses.

[0019] Preferably, step (2) specifically includes the following steps: adding the active metal oxide / porous support composite particles to the chitosan solution, dispersing evenly, drying and grinding to obtain the active metal oxide / porous support@chitosan particles.

[0020] Further, in step (2), the mass ratio of the active metal oxide / porous support composite particles to chitosan is 1:0.15 - 0.35.

[0021] When the coating amount of chitosan on the surface of the active metal oxide / porous support composite particles is too small, the shell layer formed after its carbonization is difficult to effectively prevent the active metal oxide from falling off from the porous catalyst, resulting in poor catalytic effect of the porous catalyst after long-term use; while when the coating amount of chitosan is too large, it will cause a great hindrance to the entry of O3 and H2O2 and the release of ·OH or ·O, thereby affecting the effect of killing biological warfare agents.

[0022] Further, in step (2), the concentration of the chitosan solution is 0.07 - 0.12 g / mL.

[0023] Preferably, step (1) specifically includes the following steps: adding the porous support to the soluble metal salt solution, where the soluble metal salt is soluble Mn(II) salt and / or soluble Zn(II) salt. After sufficient impregnation, adding an alkali to carry out a precipitation reaction. After the reaction is completed, take out and calcine in an inert gas atmosphere to obtain the active metal oxide / porous support composite particles.

[0024] By impregnation, the metal ions Mn 2+ and / or Zn 2+ are loaded into the porous support. Then, by reacting the metal ions with the alkali, they are converted into metal hydroxide precipitates Mn(OH)2 and / or Zn(OH)2. Subsequently, through calcination in an inert gas atmosphere, the metal hydroxides can be in-situ decomposed into metal oxides MnO2 and / or ZnO. In this way, active metal oxides can be loaded on the surface and in the pores of the porous support.

[0025] Further, in step (1), in the soluble metal salt solution, the content of metal ions is 0.2 - 0.5 mol / L.

[0026] Further, in step (1), the mass - volume ratio of the porous carrier to the soluble metal salt solution is 1 g: 10 - 20 mL.

[0027] Further, in step (1), the base is sodium hydroxide, and the molar ratio of metal ions in the soluble metal salt solution to the base is 1: 2 - 5.

[0028] Further, in step (1), the calcination temperature is 400 - 500 °C, and the time is 3 - 4 h.

[0029] Preferably, in step (3), the calcination specifically includes the following steps: in an inert gas, heating to 700 - 1000 °C at a rate of 1 - 15 °C / min, and maintaining the temperature for 1 - 2 h.

[0030] Preferably, in step (3), the mass ratio of the catalyst / porous carrier@chitosan particles, montmorillonite, kaolin, paraffin, and water is 1: 0.7 - 1.0: 0.2 - 0.3: 0.05 - 0.15: 0.4 - 0.6.

[0031] Preferably, in step (3), when mixing the active metal oxide / porous carrier@chitosan particles, montmorillonite, kaolin, paraffin, and water, first pass the paraffin through a 50 - 60 - mesh sieve.

[0032] In the third aspect, the present invention provides the application of the porous catalyst in killing biological warfare agents in drinking water by DBD plasma.

[0033] When the porous catalyst of the present invention is used for killing biological warfare agents in drinking water by DBD plasma, it can improve the effect of killing biological warfare agents, and can still maintain a good role in assisting DBD to kill biological warfare agents after long - term use, and can avoid potential health hazards caused by long - term drinking.

[0034] Preferably, the application includes the following steps: setting the porous catalyst between the water inlet and the water outlet in the DBD plasma reactor, passing the contaminated drinking water into the DBD plasma reactor from the water inlet, performing DBD plasma treatment to kill biological warfare agents, and discharging the drinking water after killing the biological warfare agents from the water outlet.

[0035] Compared with the prior art, the present invention has the following advantages:

[0036] (1) The porous catalyst of the present invention can convert O3 and H2O2 formed in DBD into more active ·OH or ·O, and at the same time can adsorb biological warfare agents such as bacteria and viruses, which is conducive to the contact between the generated ·OH or ·O and the biological warfare agents, thereby improving the effect of DBD plasma in killing biological warfare agents in drinking water;

[0037] (2) The porous catalyst of the present invention can use the loose carbon material shell to prevent the shedding of active metal oxides, and can still maintain a good role in assisting DBD plasma to kill biological warfare agents in drinking water after long-term use, and can avoid potential health hazards caused by long-term drinking. At the same time, it can also reduce the influence of the coating of the shell layer on the catalytic effect of active metal oxides;

[0038] (3) By using the preparation method of the porous catalyst in the present invention, a connected structure can be formed between the core-shell structured active particles and the outside of the porous catalyst and the pores formed by the volatilization of paraffin, which is conducive to the entry of external O3 and H2O2 into the core-shell structured active particles, and at the same time is conducive to the contact between the generated ·OH or ·O and the biological warfare agents adsorbed in the porous catalyst, thereby achieving a better biological warfare agent killing effect.

[0039] In summary, the present invention can produce the following unexpected effects: by using the porous catalyst in the present invention, the effect of DBD plasma in killing biological warfare agents in drinking water can be improved, and it can still maintain a good role in assisting DBD to kill biological warfare agents after long-term use, and can avoid potential health hazards caused by long-term drinking. Detailed Embodiments

[0040] The present invention will be further described below in conjunction with embodiments.

[0041] General Embodiment

[0042] A porous catalyst for assisting DBD plasma to kill biological warfare agents in drinking water, comprising a porous substrate and core-shell structured active particles dispersed in the porous substrate; the core layer of the core-shell structured active particles is a composite of active metal oxides and a porous carrier, and the active metal oxides are loaded in the porous carrier; the shell layer of the core-shell structured active particles is a loose carbon material; the active metal oxides include MnO2 and / or ZnO.

[0043] As a specific embodiment, the porous catalyst comprises the following components: core-shell structured active particles, montmorillonite, kaolin.

[0044] A method for preparing the porous catalyst, comprising the following steps:

[0045] (1) Using the impregnation sintering method, load active metal oxides on a porous carrier to obtain active metal oxide / porous carrier composite particles;

[0046] (2) Coating chitosan on the surface of the active metal oxide / porous support composite particles to obtain active metal oxide / porous support@chitosan particles;

[0047] (3) Mixing the active metal oxide / porous support@chitosan particles, montmorillonite, kaolin, paraffin and water evenly, granulating and forming, and then calcining to volatilize the paraffin and carbonize the chitosan to obtain a porous catalyst.

[0048] As a specific embodiment, step (1) specifically includes the following steps: adding a porous support to a soluble metal salt solution, the soluble metal salt being a soluble Mn(II) salt and / or a soluble Zn(II) salt. After sufficient impregnation, adding an alkali to carry out a precipitation reaction. After the reaction is completed, taking it out and calcining it in an inert gas atmosphere to obtain the active metal oxide / porous support composite particles. Optionally, in the soluble metal salt solution, the content of metal ions is 0.2 - 0.5 mol / L; the mass-volume ratio of the porous support to the soluble metal salt solution is 1 g:10 - 20 mL; the alkali is sodium hydroxide, and the molar ratio of the metal ions in the soluble metal salt solution to the alkali is 1:2 - 5. Optionally, the temperature of the calcination is 400 - 500 °C and the time is 3 - 4 h.

[0049] As a specific embodiment, step (2) specifically includes the following steps: adding the active metal oxide / porous support composite particles to a chitosan solution, dispersing evenly, drying and grinding to obtain the active metal oxide / porous support@chitosan particles. Optionally, the mass ratio of the active metal oxide / porous support composite particles to chitosan is 1:0.15 - 0.35, and the concentration of the chitosan solution is 0.07 - 0.12 g / mL.

[0050] As a specific embodiment, in step (3), the mass ratio of the catalyst / porous support@chitosan particles, montmorillonite, kaolin, paraffin and water is 1:0.7 - 1.0:0.2 - 0.3:0.05 - 0.15:0.4 - 0.6.

[0051] As a specific embodiment, in step (3), when mixing the active metal oxide / porous support@chitosan particles, montmorillonite, kaolin, paraffin and water, first pass the paraffin through a 50 - 60 mesh sieve.

[0052] As a specific embodiment, in step (3), the calcination specifically includes the following steps: in an inert gas, heating from room temperature to 700 - 1000 °C at a rate of 1 - 15 °C / min, and keeping the temperature constant for 1 - 2 h.

[0053] Application of the porous catalyst in killing biological warfare agents in drinking water by DBD plasma.

[0054] As a specific embodiment, the application includes the following steps: setting the porous catalyst between the water inlet and the water outlet in a DBD plasma reactor, introducing the contaminated drinking water into the DBD plasma reactor from the water inlet, performing DBD plasma treatment to kill biological warfare agents, and discharging the drinking water after killing the biological warfare agents from the water outlet.

[0055] Example 1

[0056] A porous catalyst for assisting DBD plasma to kill biological warfare agents in drinking water is prepared through the following steps:

[0057] (1) Mn(NO3)2 and Zn(NO3)2 are added to water, stirred and dissolved to prepare a precursor solution containing 0.1 mol / L Mn(NO3)2 and 0.4 mol / L Zn(NO3)2. Then, diatomite is added thereto at an addition amount of 0.1 g / mL, stirred for 30 min, and then sodium hydroxide is added at an addition amount of 1 mol / L, and stirring is continued for 1.5 h. After the solid is separated by suction filtration, it is washed with water three times, dried in an oven at 105 °C, and then heated to 400 °C at a rate of 20 °C / min under nitrogen protection and kept at a constant temperature for 4 h to obtain MnO2-ZnO / diatomite composite particles.

[0058] (2) Chitosan is added to a 5 wt% acetic acid solution, stirred and dissolved to prepare a chitosan solution with a concentration of 0.1 g / mL. Then, MnO2-ZnO / diatomite composite particles are added thereto at an addition amount of 0.5 g / mL, stirred for 1 h, dried in an oven at 105 °C, ground, and passed through a 50-mesh sieve to obtain MnO2-ZnO / diatomite@chitosan particles.

[0059] (3) After passing paraffin through a 50-mesh sieve, MnO2-ZnO / diatomite@chitosan particles, montmorillonite, kaolin, paraffin and water are weighed according to a mass ratio of 1:0.7:0.2:0.1:0.5; MnO2-ZnO / diatomite@chitosan particles, montmorillonite, kaolin and paraffin are mixed and stirred for 15 min, water is added, and stirring is continued for 30 min to obtain a mixed slurry. The mixed slurry is granulated and formed into spherical blanks with a diameter of 3 mm, dried in an oven at 105 °C, and then heated to 800 °C at a rate of 10 °C / min under nitrogen protection and kept at a constant temperature for 1.5 h to obtain a porous catalyst.

[0060] Example 2

[0061] A porous catalyst for assisting DBD plasma to kill biological warfare agents in drinking water is prepared through the following steps:

[0062] (1) Add Zn(NO3)2 to water, stir to dissolve it, and make a Zn(NO3)2 solution with a concentration of 0.2 mol / L. Then add diatomite to it at an addition amount of 0.05 g / mL, stir for 1 h, and then add sodium hydroxide at an addition amount of 1 mol / L, and continue to stir for 1 h. After filtering and separating the solid, wash it 3 times with water, dry it in an oven at 105 °C, and then under nitrogen protection, heat it to 500 °C at a rate of 20 °C / min, and keep it at a constant temperature for 3 h to obtain ZnO / diatomite composite particles.

[0063] (2) Add chitosan to a 5 wt% acetic acid solution, stir to dissolve it, and make a chitosan solution with a concentration of 0.07 g / mL. Then add ZnO / diatomite composite particles to it at an addition amount of 0.2 g / mL, stir for 1 h, dry it in an oven at 105 °C, grind it, and pass it through a 50-mesh sieve to obtain ZnO / diatomite@chitosan particles.

[0064] (3) After passing paraffin through a 50-mesh sieve, weigh ZnO / diatomite@chitosan particles, montmorillonite, kaolin, paraffin, and water according to a mass ratio of 1:0.8:0.3:0.05:0.6; mix and stir ZnO / diatomite@chitosan particles, montmorillonite, kaolin, and paraffin for 15 min, add water, and continue to stir for 30 min to obtain a mixed slurry. Granulate and mold the mixed slurry to make spherical blanks with a diameter of 3 mm, dry them in an oven at 105 °C, and then under nitrogen protection, heat them to 700 °C at a rate of 5 °C / min, and keep it at a constant temperature for 2 h to obtain a porous catalyst.

[0065] Example 3

[0066] A porous catalyst for assisting DBD plasma to kill biological warfare agents in drinking water is prepared through the following steps:

[0067] (1) Add Mn(NO3)2 to water, stir to dissolve it, and make a Mn(NO3)2 solution with a concentration of 0.4 mol / L. Then add diatomite to it at an addition amount of 0.1 g / mL, stir for 30 min, and then add sodium hydroxide at an addition amount of 1 mol / L, and continue to stir for 30 min. After filtering and separating the solid, wash it 3 times with water, dry it in an oven at 105 °C, and then under nitrogen protection, heat it to 450 °C at a rate of 20 °C / min, and keep it at a constant temperature for 3.5 h to obtain MnO2 / diatomite composite particles.

[0068] (2) Chitosan was added to a 5 wt% acetic acid solution. After stirring and dissolving, a chitosan solution with a concentration of 0.12 g / mL was prepared. Then, MnO2 / diatomite composite particles were added thereto at an addition amount of 0.8 g / mL. After stirring for 1 h, it was dried in an oven at 105 °C, ground, and passed through a 50-mesh sieve to obtain MnO2 / diatomite@chitosan particles.

[0069] (3) After passing paraffin through a 50-mesh sieve, MnO2 / diatomite@chitosan particles, montmorillonite, kaolin, paraffin, and water were weighed according to a mass ratio of 1:1.0:0.3:0.15:0.4; MnO2 / diatomite@chitosan particles, montmorillonite, kaolin, and paraffin were mixed and stirred for 15 min, then water was added, and stirring was continued for 30 min to obtain a mixed slurry. The mixed slurry was granulated and formed into spherical green bodies with a diameter of 3 mm. After drying in an oven at 105 °C, it was heated to 1000 °C at a rate of 15 °C / min under nitrogen protection and held at a constant temperature for 1 h to obtain a porous catalyst.

[0070] Comparative Example 1

[0071] A porous catalyst for assisting DBD plasma to kill biological warfare agents in drinking water was prepared through the following steps:

[0072] (1) Mn(NO3)2 and Zn(NO3)2 were added to water, stirred and dissolved to prepare a precursor solution containing 0.1 mol / L Mn(NO3)2 and 0.4 mol / L Zn(NO3)2. Then, diatomite was added thereto at an addition amount of 0.1 g / mL. After stirring for 30 min, sodium hydroxide was added at an addition amount of 1 mol / L, and stirring was continued for 1.5 h. After filtering and separating the solid, it was washed three times with water, dried in an oven at 105 °C, and then heated to 400 °C at a rate of 20 °C / min under nitrogen protection and held at a constant temperature for 4 h to obtain MnO2-ZnO / diatomite composite particles.

[0073] (2) After passing paraffin through a 50-mesh sieve, MnO2-ZnO / diatomite composite particles, montmorillonite, kaolin, paraffin, and water were weighed according to a mass ratio of 0.83:0.7:0.2:0.1:0.5; MnO2-ZnO / diatomite composite particles, montmorillonite, kaolin, and paraffin were mixed and stirred for 15 min, then water was added, and stirring was continued for 30 min to obtain a mixed slurry. The mixed slurry was granulated and formed into spherical green bodies with a diameter of 3 mm. After drying in an oven at 105 °C, it was heated to 800 °C at a rate of 10 °C / min under nitrogen protection and held at a constant temperature for 1.5 h to obtain a porous catalyst.

[0074] Comparative Example 2

[0075] A porous catalyst for assisting DBD plasma to kill biological warfare agents in drinking water is prepared through the following steps:

[0076] (1) Add Mn(NO3)2 and Zn(NO3)2 into water, stir to dissolve, and prepare a precursor solution containing 0.1 mol / L Mn(NO3)2 and 0.4 mol / L Zn(NO3)2. Then add diatomite into it at an addition amount of 0.1 g / mL, stir for 30 min, and then add sodium hydroxide at an addition amount of 1 mol / L, and continue to stir for 1.5 h. After filtering and separating the solid, wash it 3 times with water, dry it in an oven at 105 °C, and then under nitrogen protection, heat it to 400 °C at a rate of 20 °C / min and keep it at a constant temperature for 4 h to obtain MnO2-ZnO / diatomite composite particles.

[0077] (2) Add chitosan into 5 wt% acetic acid solution, stir to dissolve, and prepare a chitosan solution with a concentration of 0.1 g / mL. Then add MnO2-ZnO / diatomite composite particles into it at an addition amount of 0.5 g / mL, stir for 1 h, dry it in an oven at 105 °C, grind it, pass it through a 50-mesh sieve, and then under nitrogen protection, heat it to 800 °C at a rate of 10 °C / min and keep it at a constant temperature for 1.5 h to obtain MnO2-ZnO / diatomite@carbon material shell particles.

[0078] (3) After passing paraffin through a 50-mesh sieve, weigh montmorillonite, kaolin, paraffin and water according to a mass ratio of 0.7:0.2:0.05:0.25; mix montmorillonite, kaolin and paraffin and stir for 15 min, then add water and continue to stir for 30 min to obtain a mixed slurry. Granulate and mold the mixed slurry to make spherical blanks with a diameter of 3 mm, dry them in an oven at 105 °C, and then under nitrogen protection, heat them to 800 °C at a rate of 10 °C / min and keep them at a constant temperature for 1.5 h. Then mix them with MnO2-ZnO / diatomite@carbon material shell particles according to a mass ratio of 0.9:1 to obtain a porous catalyst.

[0079] Comparative Example 3

[0080] A porous catalyst for assisting DBD plasma to kill biological warfare agents in drinking water is prepared through the following steps:

[0081] (1) Mn(NO3)2 and Zn(NO3)2 were added to water and stirred until dissolved to prepare a precursor solution containing 0.1 mol / L Mn(NO3)2 and 0.4 mol / L Zn(NO3)2. Then, diatomite was added thereto at an addition amount of 0.1 g / mL, and after stirring for 30 min, sodium hydroxide was added at an addition amount of 1 mol / L, and stirring was continued for 1.5 h. After the solid was separated by suction filtration, it was washed with water three times, dried in an oven at 105 °C, and then heated to 400 °C at a rate of 20 °C / min under nitrogen protection and held at a constant temperature for 4 h to obtain MnO2-ZnO / diatomite composite particles.

[0082] (2) Chitosan was added to a 5 wt% acetic acid solution and stirred until dissolved to prepare a chitosan solution with a concentration of 0.1 g / mL. Then, MnO2-ZnO / diatomite composite particles were added thereto at an addition amount of 0.5 g / mL, and after stirring for 1 h, it was dried in an oven at 105 °C, ground, passed through a 50-mesh sieve, and then heated to 800 °C at a rate of 10 °C / min under nitrogen protection and held at a constant temperature for 1.5 h to obtain MnO2-ZnO / diatomite@carbon material shell particles.

[0083] (3) After passing paraffin through a 50-mesh sieve, MnO2-ZnO / diatomite@carbon material shell, chitosan, montmorillonite, kaolin, paraffin, and water were weighed according to a mass ratio of 1:0.2:0.7:0.2:0.1:0.5; the MnO2-ZnO / diatomite@carbon material shell particles, montmorillonite, kaolin, and paraffin were mixed and stirred for 15 min, water was added, and stirring was continued for 30 min to obtain a mixed slurry. The mixed slurry was granulated and formed into spherical green bodies with a diameter of 3 mm, dried in an oven at 105 °C, and then heated to 800 °C at a rate of 10 °C / min under nitrogen protection and held at a constant temperature for 1.5 h to obtain a porous catalyst.

[0084] Comparative Example 4

[0085] A porous catalyst for assisting DBD plasma to kill biological warfare agents in drinking water was prepared through the following steps:

[0086] (1) Mn(NO3)2 was added to water and stirred until dissolved to prepare a Mn(NO3)2 solution with a concentration of 0.4 mol / L. Then, diatomite was added thereto at an addition amount of 0.1 g / mL, and after stirring for 30 min, sodium hydroxide was added at an addition amount of 1 mol / L, and stirring was continued for 30 min. After the solid was separated by suction filtration, it was washed with water three times, dried in an oven at 105 °C, and then heated to 450 °C at a rate of 20 °C / min under nitrogen protection and held at a constant temperature for 3.5 h to obtain MnO2 / diatomite composite particles.

[0087] (2) Chitosan was added to a 5 wt% acetic acid solution and stirred until dissolved to prepare a chitosan solution with a concentration of 0.05 g / mL. Then, MnO2 / diatomite composite particles were added thereto at an addition amount of 0.8 g / mL, and after stirring for 1 h, it was dried in an oven at 105 °C, ground, and passed through a 50-mesh sieve to obtain MnO2 / diatomite@chitosan particles.

[0088] (3) After passing paraffin through a 50-mesh sieve, MnO2 / diatomite@chitosan particles, montmorillonite, kaolin, paraffin, and water were weighed according to a mass ratio of 1:1.0:0.3:0.15:0.4; the MnO2 / diatomite@chitosan particles, montmorillonite, kaolin, and paraffin were mixed and stirred for 15 min, then water was added, and stirring was continued for 30 min to obtain a mixed slurry. The mixed slurry was granulated and formed into spherical green bodies with a diameter of 3 mm, dried in an oven at 105 °C, and then heated to 1000 °C at a rate of 15 °C / min under nitrogen protection and held at a constant temperature for 1 h to obtain a porous catalyst.

[0089] Comparative Example 5

[0090] A porous catalyst for assisting DBD plasma to kill biological warfare agents in drinking water was prepared through the following steps:

[0091] (1) Zn(NO3)2 was added to water and stirred until dissolved to prepare a Zn(NO3)2 solution with a concentration of 0.2 mol / L. Then, diatomite was added thereto at an addition amount of 0.05 g / mL, and after stirring for 1 h, sodium hydroxide was added at an addition amount of 1 mol / L, and stirring was continued for 1 h. After filtering and separating the solid, it was washed three times with water, dried in an oven at 105 °C, and then heated to 500 °C at a rate of 20 °C / min under nitrogen protection and held at a constant temperature for 3 h to obtain ZnO / diatomite composite particles.

[0092] (2) Chitosan was added to a 5 wt% acetic acid solution and stirred until dissolved to prepare a chitosan solution with a concentration of 0.15 g / mL. Then, ZnO / diatomite composite particles were added thereto at an addition amount of 0.2 g / mL, and after stirring for 1 h, it was dried in an oven at 105 °C, ground, and passed through a 50-mesh sieve to obtain ZnO / diatomite@chitosan particles.

[0093] (3) After passing paraffin through a 50-mesh sieve, ZnO / diatomite@chitosan particles, montmorillonite, kaolin, paraffin, and water were weighed according to a mass ratio of 1:0.8:0.3:0.05:0.6. The ZnO / diatomite@chitosan particles, montmorillonite, kaolin, and paraffin were mixed and stirred for 15 min, then water was added, and stirring continued for 30 min to obtain a mixed slurry. The mixed slurry was granulated and formed into spherical green bodies with a diameter of 3 mm. After drying in an oven at 105 °C, under nitrogen protection, the temperature was raised to 700 °C at a rate of 5 °C / min and held constant for 2 h to obtain porous catalysts.

[0094] Application Example

[0095] The porous catalysts prepared in Examples 1 to 3 and Comparative Examples 1 to 5 were taken, and a DBD coaxial dual dielectric barrier discharge low-temperature plasma reactor with the same specifications was used to perform catalyst-assisted DBD plasma to kill H1N1 virus in water. The specific steps were as follows: 50 g of the porous catalyst was loaded into the coaxial dielectric barrier discharge low-temperature plasma reactor (the porous catalyst was filled between the water inlet and the water outlet), water containing H1N1 virus was continuously introduced into the reactor, and DBD plasma treatment was carried out. The flow rate of water in the reactor was controlled at 0.5 m / s, the discharge voltage was 5 kV, the current was 85 mA, and the discharge distance was 18 mm. The H1N1 virus titer in water before and after DBD plasma treatment was detected, and the H1N1 virus removal rate was calculated accordingly. The results are shown in Table 1.

[0096] Table 1

[0097]

[0098] Note: " / " indicates not detected.

[0099] Using the above method, 10 water treatments were carried out, and the porous catalyst was washed with water after every 5 treatments, and then the 11th water treatment was carried out. The H1N1 virus titer in water before and after the 11th treatment was detected, and the H1N1 virus removal rate was calculated accordingly. The results are shown in Table 2.

[0100] Table 2

[0101]

[0102] Note: " / " indicates not detected.

[0103] It can be seen from Table 1 and Table 2 that:

[0104] (1) In the porous catalyst of Example 1, the MnO2-ZnO / diatomite composite particles are coated with a carbon material shell layer, while in Comparative Example 1, there is no such coating. When used for DBD plasma to kill H1N1 virus in water, both the porous catalysts of Example 1 and Comparative Example 1 can thoroughly kill the virus during the first use. However, when used for the 11th time, the virus removal rate of Example 1 is significantly higher than that of Comparative Example 1. It is speculated that in Comparative Example 1, MnO2 and ZnO are prone to fall off during use, resulting in a decrease in the effect of the porous catalyst assisting DBD in killing the virus after multiple uses. While in Example 1, by coating the carbon material shell layer on the MnO2-ZnO / diatomite composite particles, it can prevent MnO2 and ZnO from falling off from the porous catalyst, so it can still play a good role after multiple uses.

[0105] (2) In the porous catalyst of Example 1, the MnO2-ZnO / diatomite@carbon material shell layer is dispersed in the porous substrate, while in Comparative Example 2, the MnO2-ZnO / diatomite@carbon material shell layer and the porous substrate are dispersed and used separately. When used for DBD plasma to kill H1N1 virus in water, the virus removal rate of the porous catalyst of Example 1 is significantly higher than that of Comparative Example 2. It is speculated that when the porous catalyst of Example 1 is used, the porous substrate can adsorb the virus using its larger pores. At the same time, the MnO2-ZnO / diatomite@carbon material shell layer converts O3 and H2O2 into more active ·OH or ·O. By dispersing the MnO2-ZnO / diatomite@carbon material shell layer in the porous substrate, it is beneficial for ·OH or ·O to contact the virus, thus improving the effect of the porous catalyst assisting DBD in killing the virus. While in Comparative Example 2, when the two are dispersed and used separately, it cannot play a role in promoting the contact between ·OH or ·O and the virus.

[0106] (3) In the process of preparing the porous catalyst in Example 1, the MnO2-ZnO / diatomite@chitosan particles are first mixed with other raw materials and granulated into spherical green bodies, and then the chitosan is carbonized. While in Comparative Example 3, the chitosan is first carbonized and then mixed and granulated, and chitosan is added as a pore-forming agent during the mixing and granulation process. When used for DBD plasma to kill H1N1 virus in water, the virus removal rate of the porous catalyst of Example 1 is significantly higher than that of Comparative Example 3. It is speculated that by using the method in Example 1, the gas released during the carbonization of chitosan can be utilized to form a connected structure between the core-shell structured active particles and the outside of the porous catalyst, as well as between the core-shell structured active particles and the pores formed by the volatilization of paraffin. This is beneficial for the external O3 and H2O2 to enter the core-shell structured active particles, and at the same time, it is also beneficial for the generated ·OH or ·O to contact the biological warfare agents adsorbed in the porous catalyst, thus improving the effect of killing the virus.

[0107] (4) In the process of preparing the porous catalyst in Example 3 and Comparative Example 4, the mass ratios of the MnO2 / diatomite composite particles to chitosan are 1:0.15 and 1:0.0625, respectively. When used for DBD plasma to kill H1N1 virus in water, at the first use, the porous catalysts of Example 3 and Comparative Example 4 can both kill the virus quite thoroughly. However, at the 11th use, the virus removal rate of Example 3 is higher than that of Comparative Example 4. It is speculated that because the coating amount of chitosan on the surface of the MnO2 / diatomite composite particles in Comparative Example 4 is too small, the shell formed after its carbonization is difficult to effectively prevent the detachment of MnO2 from the porous catalyst.

[0108] (5) In the process of preparing the porous catalyst in Example 2 and Comparative Example 5, the mass ratios of the ZnO / diatomite composite particles to chitosan are 1:0.35 and 1:0.75, respectively. When used for DBD plasma to kill H1N1 virus in water, the virus removal rate of the porous catalyst of Example 2 is significantly higher than that of Comparative Example 5. It is speculated that because the coating amount of chitosan on the surface of the ZnO / diatomite composite particles in Comparative Example 5 is too large, it will cause a great hindrance to the entry of O3 and H2O2 and the release of ·OH or ·O, thus resulting in a poor effect of the porous catalyst assisting DBD to kill the virus.

[0109] The raw materials and equipment used in the present invention are all common raw materials and equipment in the art without special instructions; the methods used in the present invention are all conventional methods in the art without special instructions.

[0110] The above are only the preferred embodiments of the present invention, and do not impose any limitations on the present invention. Any simple modifications, changes and equivalent transformations made to the above embodiments according to the technical essence of the present invention still fall within the protection scope of the technical solution of the present invention.

Claims

1. A method for preparing a porous catalyst for assisting DBD plasma to kill biological warfare agents in drinking water, characterized in that, It includes the following steps: (1) Using the impregnation-sintering method, load active metal oxides on a porous support to obtain active metal oxide / porous support composite particles; (2) Add the active metal oxide / porous support composite particles into a chitosan solution. The mass ratio of the active metal oxide / porous support composite particles to chitosan is 1:0.15 - 0.

35. After uniform dispersion, dry and grind to obtain active metal oxide / porous support@chitosan particles; (3) Mix the active metal oxide / porous support@chitosan particles, montmorillonite, kaolin, paraffin, and water uniformly, granulate and form, and then calcine to volatilize the paraffin and carbonize the chitosan to obtain a porous catalyst; the porous catalyst includes a porous substrate and core-shell structured active particles dispersed in the porous substrate; the core layer of the core-shell structured active particles is a composite of active metal oxides and a porous support, and the active metal oxides are loaded in the porous support; the shell layer of the core-shell structured active particles is a porous carbon material; the active metal oxides include MnO2 and / or ZnO.

2. The method according to claim 1, wherein In step (2), the concentration of the chitosan solution is 0.07 - 0.12 g / mL.

3. The method according to claim 2, characterized in that, In step (2), the concentration of the chitosan solution is 0.1 g / mL.

4. The method according to claim 1, wherein Step (1) specifically includes the following steps: Add the porous support into a soluble metal salt solution. The soluble metal salt is a soluble Mn(II) salt and / or a soluble Zn(II) salt. After sufficient impregnation, add an alkali to carry out a precipitation reaction. After the reaction is completed, take it out and calcine in an inert gas atmosphere to obtain active metal oxide / porous support composite particles.

5. The method according to claim 1, wherein In step (3), the calcination specifically includes the following steps: In an inert gas, heat up to 700 - 1000 °C at a rate of 1 - 15 °C / min, and keep the temperature constant for 1 - 2 h.

6. The method according to claim 5, wherein In step (3), the calcination specifically includes the following steps: In an inert gas, heat up to 800 °C at a rate of 10 °C / min, and keep the temperature constant for 1.5 h.

7. A porous catalyst prepared by the method according to any one of claims 1 - 6.

8. Use of the porous catalyst according to claim 7 in killing biological warfare agents in drinking water by DBD plasma.

9. The application according to claim 8, wherein It includes the following steps: Set the porous catalyst between the water inlet and the water outlet in a DBD plasma reactor, pass the contaminated drinking water into the DBD plasma reactor from the water inlet, carry out DBD plasma treatment to kill biological warfare agents, and discharge the drinking water after killing the biological warfare agents from the water outlet.

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