Supported photocatalyst, method for preparing the same, and use thereof

Abstract

The application relates to the field of photocatalysts and microbial contaminated water treatment, and particularly discloses a supported photocatalyst and a preparation method and application thereof, the supported photocatalyst comprising a carrier and an active component loaded on the carrier; the carrier is g-C3N4 nanotubes, and the active component is Pd nanoparticles and Pd monatomic atoms. The supported photocatalyst contains trace Pd elements, reduces the amount of noble metals, and reduces the cost. Meanwhile, the supported photocatalyst has stable sterilization effect and can be recycled. Furthermore, the preparation method of the supported photocatalyst is simple and convenient, low in cost, green and environment-friendly, and has wide application prospect.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of photocatalysts and microbial contaminated water treatment, in particular, to a supported photocatalyst and a preparation method and application thereof. BACKGROUND

[0002] At present, the traditional industrial water disinfection methods mainly include chlorine disinfection and ultraviolet disinfection. Although chlorine disinfection and ultraviolet disinfection can effectively kill pathogenic microorganisms, there are some unavoidable shortcomings. For example, chlorine or chlorine-containing oxidants will react with trace organic matter in water during disinfection, producing chlorinated disinfection by-products. These disinfection by-products are carcinogenic, teratogenic, mutagenic and genotoxic, and have certain harmfulness to human health and receiving water bodies. Although the ultraviolet disinfection process overcomes the disadvantages of producing harmful by-products due to the addition of chemical reagents, it also has many problems in practical application. For example, high energy consumption, generation of ozone during sterilization process, etc. Hydrogen peroxide (H2O2) disinfection or Fenton system disinfection composed of H2O2 is a clean disinfection technology. During the disinfection process, H2O2 is decomposed into water and oxygen, without secondary pollution. However, the H2O2-based disinfection technology also has many challenges, such as the difficulty of cracking the highly symmetrical H2O2 molecule to produce active species, the high production of Fe sludge in the Fenton system, and the difficulty of storage and transportation of liquid H2O2. Therefore, developing new H2O2 disinfection technology to treat microbial contaminated water is an urgent problem to be solved at present.

[0003] Photocatalytic disinfection technology as a new, efficient, low-cost and environmentally friendly advanced oxidation technology has attracted widespread attention. In 1985, Matsunaga et al. first used a UVA band light source to kill microorganisms under TiO2 catalysis. Since then, various heterogeneous photocatalysts such as TiO2, WO3, CdS, g-C3N4 (CN) have been applied in water disinfection field, among which TiO2 and CN are the most common. CN has great potential in the development of energy-saving and environment-friendly materials due to its suitable visible light energy band, morphology plasticity and other characteristics. Although these photocatalytic materials have their own unique advantages, they also have the shortcomings of general photocatalytic disinfection materials, such as low visible light utilization efficiency, short active species life, slow speed, etc. Recently reported, the bimetallic Pd-Au supported on TiO2 as catalyst, in situ activation of H2 and O2 chemical reaction to inactivate bacteria in water, the disinfection efficiency is high and there is no chemical residue. The main mechanism of disinfection and sterilization of this technology is to form more mobile radical intermediates (HO·, HOO· / O2· -), the large amount of free radicals generated can be used for killing bacteria. In this process, the rate of direct formation of free radicals by H2 / O2 is much higher than the rate of decomposition of H2O2 to form free radicals. Therefore, the disinfection effect of in-situ catalysis of H2 / O2 is better than that of H2O2. Recent studies have initially explored the feasibility of efficient photocatalytic disinfection, but there are also deficiencies in the specific implementation process. For example, the in-situ activation of H2 chemical reaction uses exogenous H2 input, which has low utilization rate, high energy consumption and great safety hazards.

[0004] Photocatalytic in-situ generation and activation of H2O2 for treating microbial contaminated water has good application prospects, mainly because: on the one hand, there is no introduction of exogenous H2O2, overcoming the difficulties of storage and transportation, on the other hand, in-situ activation avoids the low efficiency caused by the migration process. After searching, Chinese patent No. ZL 201710636545.5, the patent name is: a preparation method and application of a visible light catalyst; the application prepared a visible light catalyst Au / Ag / g-C3N4 by modifying g-C3N4 with Au and Ag nanoparticles, and applied it to sterilization under visible light irradiation. Through the loading of Au and Ag nanoparticles on the surface of g-C3N4, the ability to absorb visible light is improved, so that the catalyst can produce good catalytic effect under the irradiation of sunlight, thereby reducing the consumption of energy and achieving good sterilization effect. However, the Au and Ag nanoparticles used in the application are expensive, resulting in high cost of photocatalytic sterilization.

[0005] Therefore, there is an urgent need for a new photocatalyst to solve the above problems of photocatalytic sterilization. SUMMARY

[0006] The purpose of the present application is to solve the problems of traditional disinfection technology, such as the generation of disinfection by-products causing secondary pollution, high energy consumption, high treatment cost, low photon utilization rate of photocatalyst, and poor effect, thereby providing a supported photocatalyst, a preparation method and application thereof. The supported photocatalyst contains a small amount of Pd element, which reduces the amount of noble metal and reduces the cost. At the same time, the sterilization effect of the supported photocatalyst is stable and can be recycled. Furthermore, the preparation method of the supported photocatalyst is simple, convenient, low-cost, green and environmentally friendly, and has a wide application prospect.

[0007] In order to achieve the above purpose, the present application provides a supported photocatalyst, which comprises a carrier and an active component loaded on the carrier.

[0008] The carrier is g-C3N4 nanotube, and the active component is Pd nanoparticle and Pd monatomic atom. The present application also provides a preparation method of a supported photocatalyst, which comprises:

[0009] (1) melamine aqueous solution is subjected to hydrothermal reaction to obtain g-C3N4, and the g-C3N4 is calcined to obtain g-C3N4 nanotubes;

[0010] (2) the g-C3N4 nanotubes, a Pd precursor solution and polyvinylpyrrolidone are mixed first, and ascorbic acid is added to react.

[0011] The application further provides a supported photocatalyst prepared by the preparation method.

[0012] The application further provides an application of the supported photocatalyst in water sterilization.

[0013] The application further provides a water sterilization method, which comprises the following steps: mixing the supported photocatalyst with water containing bacteria, adsorbing in the dark, and irradiating under visible light.

[0014] The supported photocatalyst is the supported photocatalyst described above.

[0015] In the technical scheme, the supported photocatalyst of the application is loaded with trace Pd elements (0.031-0.228wt%), which reduces the amount of noble metal and lowers the cost; the introduction of Pd nanoparticles increases the in-situ hydrogen peroxide generation amount, avoids the addition of exogenous hydrogen peroxide, loads Pd nanoparticles and Pd single atoms on the surface of g-C3N4 nanotubes (CNT), and improves the utilization rate of graphite-type carbon nitride g-C3N4 (CN) for visible light; and the Pd atoms in-situ efficiently activate hydrogen peroxide to generate free radicals and efficiently sterilize.

[0016] Meanwhile, the preparation method of the supported photocatalyst has simple reaction conditions, simple steps, low cost, simple operation and environmental protection.

[0017] Further, the supported photocatalyst prepared by the application has excellent broad-spectrum sterilization performance, stable sterilization effect, recyclability, and wide application prospect.

[0018] Other features and advantages of the application will be described in detail in the following specific embodiment part. BRIEF DESCRIPTION OF DRAWINGS

[0019] The accompanying drawings are included to provide a further understanding of the application, and constitute a part of the specification, and are used together with the following specific embodiments to explain the application, but do not constitute a limitation on the application. In the drawings:

[0020] Figure 1a is a TEM image of product B1 prepared in Example 1, b is a dark field TEM image of product B1 prepared in Example 1, c is a crystal plane spacing image of a single Pd particle of product B1 prepared in Example 1;

[0021] Figure 2 is a spherical aberration analysis image of product B1 prepared in Example 1 of the present application;

[0022] Figure 3 a is a TEM image of product B1 prepared in Example 1, b is an EDS layer image of C element in product B1 prepared in Example 1, c is an EDS layer image of N element in product B1 prepared in Example 1, d is an EDS layer image of Pd element in product B1 prepared in Example 1;

[0023] Figure 4 is an X-ray diffraction image of product B1 prepared in Example 1 of the present application, product D1 prepared in Comparative Example 1 and product D2 prepared in Comparative Example 2;

[0024] Figure 5 is a UV-vis analysis image of product B1 prepared in Example 1 of the present application, product D1 prepared in Comparative Example 1 and product D2 prepared in Comparative Example 2;

[0025] Figure 6 is a O2 generation condition of product B1 prepared in Example 1 of the present application, product D1 prepared in Comparative Example 1 and product D2 prepared in Comparative Example 2 under light condition; 1 ;

[0026] Figure 7 is a O2· generation condition of product B1 prepared in Example 1 of the present application, product D1 prepared in Comparative Example 1 and product D2 prepared in Comparative Example 2 under light condition; - ;

[0027] Figure 8 is a HO· generation condition of product B1 prepared in Example 1 of the present application, product D1 prepared in Comparative Example 1 and product D2 prepared in Comparative Example 2 under light condition;

[0028] Figure 9 is a H2O2 generation condition of product B1 prepared in Example 1 of the present application and product D2 prepared in Comparative Example 2 in a sterilization reaction under light condition;

[0029] Figure 10 is a sterilization effect image of product B1 prepared in Example 1 of the present application, product D1 prepared in Comparative Example 1 and product D2 prepared in Comparative Example 2 on Escherichia coli;

[0030] Figure 11 is a cycle sterilization effect image of product B1 prepared in Example 1 of the present application;

[0031] Figure 12 The diagram shows the bactericidal effect of products B1-B4 obtained in Examples 1-4 of this invention on Escherichia coli.

[0032] Figure 13 The diagram shows the bactericidal effect of product B1 obtained in Example 1 of the present invention on Escherichia coli under different conditions.

[0033] Figure 14 The image shows the bactericidal effect of product B1 obtained in Example 1 of this invention on Escherichia coli at different initial concentrations.

[0034] Figure 15 The image shows the bactericidal effect of product B1 obtained in Example 1 of this invention on Bacillus subtilis.

[0035] Figure 16 This is a diagram showing the bactericidal effect of product B1 obtained in Example 1 of the present invention on bacteria in actual water.

[0036] Figure 17 The image shows the bactericidal effect of product B1 obtained in Example 1 of the present invention and hydrogen peroxide of the same concentration.

[0037] Figure 18 The image shows the bactericidal effect of various species generated from product B1 obtained in Example 1 of this invention. Detailed Implementation

[0038] The following provides a detailed description of specific embodiments of the present invention. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.

[0039] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0040] This invention provides a supported photocatalyst, which includes a support and an active component supported on the support;

[0041] The carrier is g-C3N4 nanotubes, and the active components are Pd nanoparticles and Pd single atoms.

[0042] The supported photocatalyst of the application is loaded with trace Pd elements, reduces the amount of noble metal, and reduces the cost; the introduction of Pd nanoparticles increases the in-situ hydrogen peroxide generation amount, avoids the exogenous addition of hydrogen peroxide, loads Pd nanoparticles and Pd single atoms on the surface of g-C3N4 nanotubes, and improves the utilization rate of g-C3N4 to visible light; and the Pd atom in-situ efficiently activates hydrogen peroxide to generate free radicals and efficiently sterilizes.

[0043] According to a preferred embodiment of the application, the loading amount of Pd elements in the supported photocatalyst is 0.031-0.228wt%.

[0044] The application further provides a preparation method of the supported photocatalyst, which comprises:

[0045] (1) hydrothermal reaction of a melamine aqueous solution to obtain g-C3N4, and calcination of the g-C3N4 to obtain g-C3N4 nanotubes;

[0046] (2) mixing of the g-C3N4 nanotubes, a Pd precursor solution and polyvinylpyrrolidone, and then adding ascorbic acid for reaction.

[0047] The preparation method provided by the application has simple reaction conditions, simple steps, low cost, and simple and environmentally friendly operation.

[0048] According to a preferred embodiment of the application, in order to make the prepared supported photocatalyst have better photocatalytic sterilization performance, in step (1), the hydrothermal reaction conditions include: temperature of 180-250℃, and time of 10-14h.

[0049] According to a preferred embodiment of the application, in order to make the prepared supported photocatalyst have better photocatalytic sterilization performance, in step (1), the calcination conditions include: temperature of 500-600℃, time of 4-5h, and heating rate of 1-5℃ / min.

[0050] According to a preferred embodiment of the application, in order to make the prepared supported photocatalyst have better photocatalytic sterilization performance, in step (1), the concentration of melamine in the melamine aqueous solution is 20-80g / L.

[0051] According to a preferred embodiment of the application, in order to make the prepared supported photocatalyst have better photocatalytic sterilization performance, in step (1), the concentration of melamine in the melamine aqueous solution is 50g / L.

[0052] According to a preferred embodiment of the application, in step (1), after calcination, the product is further washed and dried.

[0053] The washing and drying are conventional means in the art, for example, washing with deionized water and drying at 60℃.

[0054] According to a preferred embodiment of the present application, in step (2), the mixing conditions are conventional means in the art, for example, at room temperature, for 0.5-2h, with a stirring rate of 500-800rpm.

[0055] According to a preferred embodiment of the present application, in order to make the prepared supported photocatalyst have better photocatalytic sterilization performance, in step (2), the Pd precursor is selected from PdCl2 and / or chloropalladic acid.

[0056] According to a preferred embodiment of the present application, in order to make the prepared supported photocatalyst have better photocatalytic sterilization performance, in step (2), the weight ratio of the g-C3N4 nanotube to the Pd precursor is 1000:0.5-3, wherein the Pd precursor is calculated based on the element palladium, for example, 1000:1, 1000:2 or 1000:2.5.

[0057] According to a preferred embodiment of the present application, in order to make the prepared supported photocatalyst have better photocatalytic sterilization performance, in step (2), the concentration of the polyvinylpyrrolidone is 50-150g / L, for example, 60g / L, 70g / L, 80g / L, 120g / L or 130g / L, and the concentration of the ascorbic acid is 8-20g / L, for example, 9g / L, 12g / L, 15g / L or 18g / L.

[0058] According to a preferred embodiment of the present application, the concentration of the polyvinylpyrrolidone is 100g / L, and the concentration of the ascorbic acid is 10g / L.

[0059] According to a preferred embodiment of the present application, in step (2), the reaction conditions include a temperature of 80-120℃ and a time of 4-6h.

[0060] According to a preferred embodiment of the present application, in step (2), the reaction conditions include a temperature of 80℃ and a time of 4h.

[0061] According to a preferred embodiment of the present application, in step (2), the reaction conditions further include reflux.

[0062] The present application further provides a supported photocatalyst prepared by the above preparation method.

[0063] The present application further provides an application of the above supported photocatalyst in water sterilization. The present application further provides an application of the above supported photocatalyst in water sterilization.

[0064] The application further provides a method for sterilizing a water body, which comprises: mixing a supported photocatalyst with a water body containing bacteria, adsorbing in the dark, and then irradiating with visible light.

[0065] The supported photocatalyst is the supported photocatalyst as described above.

[0066] The supported photocatalyst prepared by the application has excellent broad-spectrum sterilization performance, stable sterilization effect, and recycling, and has a wide application prospect.

[0067] According to a preferred embodiment of the application, in order to achieve better sterilization effect, the concentration of the supported photocatalyst in the water body is 0.1-1 mg / mL.

[0068] According to a preferred embodiment of the application, the time for adsorbing in the dark can be selected in a wide range, for example, the time for adsorbing in the dark can be 20-40 min, and can also be 25 min, 30 min, 35 min.

[0069] According to a preferred embodiment of the application, in order to achieve better sterilization effect, the irradiation conditions include: time is 2-5 h, light intensity is 80-120 mW / cm 2 ,

[0070] According to a preferred embodiment of the application, the light intensity for irradiation is 100 mW / cm 2 .

[0071] According to a preferred embodiment of the application, in order to achieve sterilization effect close to actual application, the visible light is provided by a xenon lamp with an ultraviolet filter.

[0072] According to a preferred embodiment of the application, the bacteria are selected from Escherichia coli and / or Bacillus subtilis.

[0073] According to a preferred embodiment of the application, in order to achieve better sterilization effect, the concentration of the bacteria is 10 6 -10 9 CFU / mL.

[0074] According to a preferred embodiment of the application, in order to improve the activity of the catalyst, light irradiation and air exposure are required during sterilization.

[0075] The application will be described in detail below through examples. In the following examples, the drugs and reagents are all conventional commercially available products.

[0076] Example 1

[0077] (1) 5 g melamine was dissolved in 100 ml deionized water, stirred and mixed for 2 h, transferred to a reaction kettle, and reacted at 200 °C for 12 h. The obtained product was washed with water and dried at 60 °C to obtain g-C3N4 (CN);

[0078] (2) The CN obtained in step (1) was placed in a muffle furnace, and the furnace temperature was raised to 550 °C at a rate of 2 °C / min, and then the furnace was kept at this temperature for 4 h. Then the furnace temperature was gradually reduced to room temperature, and the high-temperature calcined product g-C3N4 nanotube (CNT) was taken out;

[0079] (3) 10 g polyvinylpyrrolidone, 1 g CNT and 0.835 mL PdCl2 solution in HCl (2 g / L) were dissolved in 100 ml distilled water, stirred and adsorbed for 2 h, 2 g ascorbic acid was added, and refluxed at 80 °C for 4 h. After filtration, washing, drying and sieving, the product Pd NPs+SAs / CNT, denoted as B1, was obtained.

[0080] Example 2

[0081] The method described in Example 1 was followed, except that in step (3), the mass ratio of Pd to CNT was 0.5:1000 (the theoretical Pd loading amount was 0.05 wt%), and the product Pd NPs+SAs / CNT, denoted as B2, was obtained.

[0082] Example 3

[0083] The method described in Example 1 was followed, except that in step (3), the mass ratio of Pd to CNT was 1.5:1000 (the theoretical Pd loading amount was 0.15 wt%), and the product Pd NPs+SAs / CNT, denoted as B3, was obtained.

[0084] Example 4

[0085] The method described in Example 1 was followed, except that in step (3), the mass ratio of Pd to CNT was 3:1000 (the theoretical Pd loading amount was 0.3 wt%), and the product Pd NPs+SAs / CNT, denoted as B4, was obtained.

[0086] Comparative Example 1

[0087] The method described in Example 1 was followed, except that in step (3),

[0088] Step (3) 34 mg of KI and 100 mg of polyvinylpyrrolidone were weighed and dissolved in 10 mL of formamide, the solution was heated at 120°C, then 59 mg of H2PdCl4 powder was added and stirred for 10 min; after the mixture was cooled to room temperature, 120 mL of acetone was added, the product was collected by centrifugation to obtain Pd nanoparticles; the obtained Pd nanoparticles were mixed with the CNT obtained in step (2) according to a mass ratio of 1:1000, and methanol was added, vacuum drying was stirred for 1 h, then the obtained mixture was heated at 400°C for 2 h, and the composite product Pd / CNT, denoted as D1, was obtained after cleaning, drying and sieving. NPs / CNT, denoted as D1.

[0089] Comparative Example 2

[0090] The method described in Example 1 was followed, except that step (3) was not performed, and CNT, denoted as D2, was obtained.

[0091] Test Example 1

[0092] The product B1 obtained in Example 1 was subjected to transmission electron microscope analysis and high-angle dark field spherical aberration electron microscope analysis, respectively, and the results are shown in Figure 1 and Figure 2 .

[0093] Figure 1 a is a transmission electron microscope image of the product B1 obtained in Example 1, and from Figure 1 a, the CNT with a tubular structure and the uniformly distributed Pd nanoparticles can be observed;

[0094] Figure 1 b is a dark field transmission electron microscope image of the product B1 obtained in Example 1, and from Figure 1 b, the obvious bright spots, i.e. Pd nanoparticles, can be observed;

[0095] Figure 1 c is a crystal face spacing diagram of a single Pd particle of the product B1 obtained in Example 1, and from Figure 1 c, the crystal lattice spacing of 0.22 nm, i.e. the crystal face spacing of the Pd nanoparticles, can be observed, and from the above analysis and observation, it can be determined that the Pd nanoparticles are uniformly dispersed on the surface of the carrier.

[0096] Figure 2 is a spherical aberration analysis diagram of the product B1 obtained in Example 1, and from Figure 2 it can be seen that the white bright spots distributed on the surface of the CNT are Pd atoms.

[0097] It can be determined in combination with Figure 1 and Figure 2 that the product B1 obtained in Example 1 is a composite material of Pd nanoparticles and single-atom-loaded CNT, i.e. Pd / CNT, denoted as D1. NPs+SAs / CNT.

[0098] Detection Example 2

[0099] To further determine the distribution of each element, the product B1 prepared in Example 1 was taken as a sample to perform energy spectrum analysis (EDS), and the specific results are shown in Figure 3 .

[0100] Figure 3 a is a TEM image of the product B1 prepared in Example 1, and the area in the image is an area selected for analysis, Figure 3 b is an EDS layered image of the C element in the product B1 prepared in Example 1; Figure 3 c is an EDS layered image of the N element in the product B1 prepared in Example 1; the distribution profiles of both are completely consistent with Figure 3 a, indicating that the profile is the structure of CN.

[0101] Figure 3 d is an EDS layered image of the Pd element in the product B1 prepared in Example 1, and it is observed that the sizes and brightness levels of the bright spots of the Pd element are different, indicating that Pd with different particle sizes exists, that is, Pd nanoparticles and Pd single atoms coexist.

[0102] From the above data, it can be found that C, N and Pd are uniformly distributed in the product B1 prepared in Example 1.

[0103] Detection Example 3

[0104] The product B1 prepared in Example 1, the product D1 prepared in Comparative Example 1 and the product D2 prepared in Comparative Example 2 were subjected to X-ray diffraction, and the specific results are shown in Figure 4 .

[0105] From the X-ray diffraction patterns of the product B1 prepared in Example 1, the product D1 prepared in Comparative Example 1 and the product D2 prepared in Comparative Example 2, it can be seen that two diffraction peaks appear at 13.28 and 27.39 in the three materials, which correspond to the (100) and (002) crystal planes of g-C3N4 respectively. However, the characteristic peaks of Pd do not appear in the three materials, mainly because the content of Pd is extremely low, which is lower than the detection limit of XRD, and at the same time it also indicates that Pd is highly dispersed. Figure 4 Detection Example 4

[0106] The product B1 prepared in Example 1, the product D1 prepared in Comparative Example 1 and the product D2 prepared in Comparative Example 2 were subjected to UV-vis to understand the light capture ability of different materials, and the specific results are shown in

[0107] . Figure 5 From the UV-vis results of the product B1 prepared in Example 1, the product D1 prepared in Comparative Example 1 and the product D2 prepared in Comparative Example 2, it can be seen that the light capture ability of the product B1 prepared in Example 1 is the best, and the light capture ability of the product D2 prepared in Comparative Example 2 is the worst.

[0108] Figure 5 ​The UV-vis analysis graphs of the product B1 prepared in Example 1, the product D1 prepared in Comparative Example 1 and the product D2 prepared in Comparative Example 2 show that both B1 and D1 have red shift, indicating that the visible light capturing ability of both is superior to that of D2.

[0109] Test Example 5

[0110] ICP-MS analysis was performed on the samples of the product B1 prepared in Example 1, the product B2 prepared in Example 2, the product B4 prepared in Example 4 and the product D1 prepared in Comparative Example 1 to understand the actual content of Pd loaded.

[0111] It was found that the Pd content in the product B1 prepared in Example 1 was 0.074%, the Pd content in the product B2 prepared in Example 2 was 0.031%, the Pd content in the product B4 prepared in Example 4 was 0.228%, and the Pd content in the product D1 prepared in Comparative Example 1 was 0.065%.

[0112] It can be seen that the actual content of Pd loaded in B1 and D1 is comparable.

[0113] Test Example 6

[0114] The samples of the product B1 prepared in Example 1, the product D1 prepared in Comparative Example 1 and the product D2 prepared in Comparative Example 2 were respectively determined for the type of active species generated under light and air exposure conditions, and the specific results are shown in Table 2. Figures 6-8

[0115] From Table 2, it can be seen that the product B1 prepared in Example 1, the product D1 prepared in Comparative Example 1 and the product D2 prepared in Comparative Example 2 can all generate O2 under light conditions. 1 1 Figure 6 From Table 3, it can be seen that the product B1 prepared in Example 1, the product D1 prepared in Comparative Example 1 and the product D2 prepared in Comparative Example 2 can all generate O2· under light conditions. - - -

[0116] From Table 4, it can be seen that the product B1 prepared in Example 1, the product D1 prepared in Comparative Example 1 and the product D2 prepared in Comparative Example 2 can all generate HO· under light conditions. Figure 7

[0117] From Table 5, it can be seen that the product B1 prepared in Example 1, the product D1 prepared in Comparative Example 1 and the product D2 prepared in Comparative Example 2 can all generate HO· under light conditions. Figure 8 ​​​​​​​​

[0118] These results indicate that O2· - It may play a major role in the highly effective sterilization of B1.

[0119] Case 7

[0120] Using product B1 prepared in Example 1 and product D2 prepared in Comparative Example 2 as samples, the generation of H2O2 during the sterilization reactions under light and air exposure was determined. The specific results are as follows: Figure 9 As shown.

[0121] Depend on Figure 9 The H2O2 production of product B1 obtained in Example 1 and product D2 obtained in Comparative Example 2 during the bactericidal reaction under light irradiation shows that B1 has a higher H2O2 production capacity than D2, and the accumulated amount of H2O2 can reach 2 ppm.

[0122] Application Example 1

[0123] Using a 300W xenon lamp as the light source, ultraviolet light was filtered out, and the light intensity was adjusted to 100mW / cm². 2 The initial concentration of the cultured E. coli was adjusted to approximately 10% with sterile water. 9 CFU (Chemical Fuel Infusion Units) were weighed and dissolved in 20 mL of sterile water. The solution was allowed to adsorb in the dark for 30 min. Then, the light source was turned on, and the solution was aerated. Every 30 min, 100 μL of the mixture was taken out, diluted a certain factor, and evenly spread onto LB solid medium. The culture dishes were then incubated at 37°C for 24 h. Colony counts were calculated, and the number of colonies in the culture dishes after each sterilization reaction was recorded. Specific results are shown below. Figure 10 As shown,

[0124] The photocatalysts are product B1 prepared in Example 1, product D1 prepared in Comparative Example 1, and product D2 prepared in Comparative Example 2, respectively.

[0125] Depend on Figure 10 The bactericidal effects of product B1 obtained in Example 1, product D1 obtained in Comparative Example 1, and product D2 obtained in Comparative Example 2 on Escherichia coli can be seen from the graphs. Pure CNT material D2 cannot effectively kill Escherichia coli. Compared with D2, the bactericidal effect of D1 is improved, but it is still not ideal. B1 can effectively remove Escherichia coli from the water. The bactericidal effect of B1 is significantly better than that of D1, indicating that single-atom Pd makes an outstanding contribution to the improvement of bactericidal efficiency.

[0126] Application Example 2

[0127] The method described in Application Example 1 was followed, except that product B1 prepared in Example 1 was subjected to three cycles, and the killing effect of the cycled material on Escherichia coli was tested. The specific results are as follows: Figure 11 As shown.

[0128] By Figure 11 The cycle sterilization effect diagram of the product B1 prepared in Example 1 shows that the sterilization performance of B1 after three cycles of regeneration remains basically unchanged, which indicates that the Pd NPs+SAs / CNT composite material has good stability.

[0129] Application Example 3

[0130] According to the method described in Application Example 1, the implementation is carried out, which is different from the implementation, and the sterilization effect test is carried out on the products B1-B4 prepared in Examples 1-4, and the test results are shown in Table 2. Figure 12

[0131] By Figure 12 The sterilization effect diagram of the products B1-B4 prepared in Examples 1-4 on Escherichia coli shows that among the photocatalysts with different Pd loadings, the Pd NPs+SAs / CNT with a mass ratio of Pd to CNT of 1:1000 has the best sterilization effect, and the main reason is that too low Pd loading cannot make good use of photons, and too high loading excessively covers the surface of g-C3N4, reducing photosensitivity.

[0132] Application Example 4

[0133] According to the method described in Application Example 1, the implementation is carried out, which is different from the implementation, and the product B1 prepared in Example 1 is tested, and the sterilization reaction is carried out under the condition of only air exposure and no light, and the specific results are shown in Table 3. Figure 13

[0134] Application Example 5

[0135] According to the method described in Application Example 1, the implementation is carried out, which is different from the implementation, and the product B1 prepared in Example 1 is tested, and the sterilization reaction is carried out under the condition of only light and no air exposure, and the specific results are shown in Table 4. Figure 13

[0136] By Figure 13 The sterilization effect diagram of the product B1 prepared in Example 1 on Escherichia coli under different conditions shows that under the condition of only air exposure and no visible light, the sterilization effect of B1 is very poor; under the condition of only light and no air exposure, the sterilization effect of B1 is greatly improved; under the condition of visible light and air exposure, the sterilization effect of B1 is the best, and it can be seen that light and air exposure are the necessary conditions for the activity of the catalyst to be improved.

[0137] Application Example 6

[0138] According to the method described in Application Example 1, the implementation is carried out, which is different from the implementation, and the product B1 prepared in Example 1 is tested, and the initial concentration of Escherichia coli is 10 6 CFU, 10​​​7 CFU and 10 8 CFU, test results as follows Figure 14 As shown.

[0139] Depend on Figure 14 As shown in the bactericidal effect diagram of product B1 obtained in Example 1 against different initial concentrations of Escherichia coli, product B1 obtained in Example 1 can achieve a good bactericidal effect in water environments with different initial concentrations of Escherichia coli, and the lower the initial bacterial concentration, the shorter the required bactericidal time.

[0140] Application Example 7

[0141] The method described in Application Example 1 was followed, except that the product B1 obtained in Example 1 was tested, and the bacteria used were at an initial concentration of 10. 9 CFU of Bacillus subtilis, test results as follows Figure 15 As shown.

[0142] Depend on Figure 15 As shown in the bactericidal effect diagram of product B1 obtained in Example 1 against Bacillus subtilis, product B1 obtained in Example 1 also has a good bactericidal effect against Bacillus subtilis, demonstrating that the Pd of the present invention... NPs+SAs / CNT materials have a broad spectrum of applications.

[0143] Application Example 8

[0144] The method described in Application Example 1 was implemented, except that the product B1 obtained in Example 1 was tested, and the water used was actual water from different sampling points. The test results are as follows. Figure 16 As shown.

[0145] Depend on Figure 16 As shown in the diagram of the bactericidal effect of product B1 obtained in Example 1 on bacteria in actual water bodies, product B1 obtained in Example 1 can also exert its highly efficient bactericidal effect in actual water bodies, indicating that the Pd of the present invention... NPs+SAs / CNT materials have practical applications.

[0146] Application Example 9

[0147] The method described in Application Example 1 was followed, except that 1 mM H₂O· quencher isopropanol and 1 mM O₂· quencher were added before photocatalytic induced sterilization. - Quenching agent TEMPO, 1mM H + Quenching agent Na2C2O4 and added 5mM 1 O2 quencher histidine, test results are as follows Figure 18 As shown.

[0148] Depend on Figure 18The bactericidal effect of each species generated by product B1 prepared in Example 1 is shown in the figure Figure 8 The HO· generation of product B1 prepared in Example 1, product D1 prepared in Comparative Example 1 and product D2 prepared in Comparative Example 2 under light condition can be known from the following table 1 O2 and O2· - Species play an important role in the photocatalytic bactericidal effect of Pd NPs+SAs / CNT.

[0149] Comparative Example 3

[0150] The test was performed according to the method described in Application Example 1, except that no photocatalyst was added, and 2 ppm of commercial hydrogen peroxide was added, and the test results are shown in the following table Figure 17

[0151] The bactericidal effect of product B1 prepared in Example 1 and hydrogen peroxide of the same concentration is shown in the figure Figure 17 It can be known from the figure that the bactericidal effect of product B1 prepared in Example 1 is significantly better than that of commercial hydrogen peroxide under the condition of generating the same concentration of effective H2O2 content (2 ppm).

[0152] The preferred embodiments of the present application are described in detail above, but the present application is not limited to the specific details in the above-described embodiments, and various simple modifications can be made to the technical solutions of the present application within the technical concept of the present application, and these simple modifications all belong to the protection scope of the present application.

[0153] In addition, it should be noted that each specific technical feature described in the above-described specific embodiments can be combined in any appropriate manner without contradiction, and in order to avoid unnecessary repetition, the present application will not further describe various possible combination manners.

[0154] In addition, various different embodiments of the present application can also be combined in any manner, as long as it does not deviate from the technical concept of the present application, and it should also be considered as disclosed content of the present application.​

Claims

1. A method for preparing a supported photocatalyst for water disinfection, characterized in that, The supported photocatalyst includes a support and an active component supported on the support; The carrier is g-C3N4 nanotubes, and the active components are Pd nanoparticles and Pd single atoms; The loading of Pd element in the supported photocatalyst is 0.031-0.228 wt%; The preparation method includes: (1) Melamine aqueous solution was subjected to hydrothermal reaction to obtain g-C3N4, and the g-C3N4 was calcined to obtain g-C3N4 nanotubes; (2) First, mix the g-C3N4 nanotubes, Pd precursor solution and polyvinylpyrrolidone, and then add ascorbic acid to carry out the reaction; In step (1), the conditions for the hydrothermal reaction include: a temperature of 180-250℃ and a time of 10-14h; The calcination conditions include: a temperature of 500-600℃, a time of 4-5h, and a heating rate of 1-5℃ / min. The concentration of melamine in the melamine aqueous solution is 20-80 g / L.

2. The preparation method according to claim 1, characterized in that, The concentration of melamine in the melamine aqueous solution is 50 g / L.

3. The preparation method according to claim 1 or 2, characterized in that, In step (2), the mixing conditions include: time of 0.5-2h and stirring speed of 500-800rpm.

4. The preparation method according to claim 1, characterized in that, In step (2), the Pd precursor is selected from PdCl2 and / or chloropalladium acid; The weight ratio of the g-C3N4 nanotubes to the Pd precursor is 1000:0.5-3, wherein the Pd precursor is calculated as palladium. The concentration of the polyvinylpyrrolidone is 50-150 g / L; The concentration of ascorbic acid is 8-20 g / L.

5. The preparation method according to claim 1, characterized in that, In step (2), the concentration of polyvinylpyrrolidone is 100 g / L; The concentration of ascorbic acid is 10 g / L.

6. The preparation method according to claim 1, characterized in that, In step (2), the reaction conditions include: a temperature of 80-120℃ and a time of 4-6h.

7. The preparation method according to claim 1, characterized in that, In step (2), the reaction conditions include: a temperature of 80°C and a time of 4 hours.

8. A supported photocatalyst prepared by the preparation method according to any one of claims 1-7.

9. The application of the supported photocatalyst according to claim 8 in water disinfection.

10. A method for sterilizing water, characterized in that, The method includes: mixing a supported photocatalyst with water containing bacteria, adsorbing it in the dark, and then irradiating it with visible light; The supported photocatalyst is the supported photocatalyst according to claim 8; The concentration of the supported photocatalyst in the water body is 0.1-1 mg / mL; The time for light-shielded adsorption is 20-40 minutes; The irradiation conditions include: a duration of 2-5 hours and a light intensity of 80-120 mW / cm². 2 ; The visible light is provided by a xenon lamp with an ultraviolet filter; The concentration of the bacteria is 10. 6 -10 9 CFU / mL.

11. The method according to claim 10, characterized in that, The light-shielded adsorption time is 30 minutes; The light intensity is 100 mW / cm² 2 .

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