A phenolic resin-based composite photocatalyst, its preparation method and application

Abstract

The present invention provides a phenolic resin-based composite photocatalyst, its preparation method and application, belonging to the technical fields of photocatalyst preparation and environmental protection; the present invention uses phenolic resin micro-nano hollow spheres with characteristics such as a wide light response range, adjustable band gap, and strong adsorption performance as the core, and metal sulfide nanosheets with rich active sites and high carrier separation efficiency as the shell, and constructs a phenolic resin-based composite photocatalyst through an interfacial engineering strategy; the phenolic resin-based composite photocatalyst is a Z-type core-shell heterojunction material linked by interfacial hydrogen bonds; the phenolic resin-based composite photocatalyst has the advantages of low cost, wide light response range, rich active sites, high efficiency, good antibiotic tolerance, etc., and can achieve efficient antibiotic degradation under full solar spectrum excitation, and has good practicability.

Description

Technical Field

[0001] The present invention belongs to the technical fields of photocatalyst preparation and environmental protection, and particularly relates to a phenolic resin-based composite photocatalyst, a preparation method thereof, and an application thereof. Background Art

[0002] Antibiotics are a class of antibacterial drugs, mainly including β-lactams (penicillin), tetracyclines (tetracycline hydrochloride), aminoglycosides (neomycin), macrolides (erythromycin), etc., which can effectively inhibit the growth and reproduction of bacteria, and thus are widely used in the medical, health, and food fields. However, antibiotic pollution has become a serious environmental problem. Antibiotic residues can contaminate soil and water bodies, causing serious environmental pollution. In addition, antibiotic residues can also inhibit the growth of beneficial bacteria, thereby affecting the immune function of the human body and further harming human health. Therefore, there is an urgent need to find a low-cost, efficient, and green method for treating antibiotic pollutants.

[0003] In recent years, photocatalytic degradation has developed rapidly and has become one of the effective means for treating antibiotic pollution. Photocatalytic degradation is a process in which highly active free radicals generated by light radiation and photocatalysts in the reaction system degrade pollutants into inorganic substances through processes such as addition, substitution, and electron transfer between free radicals and organic pollutants. However, it has been found in practice that traditional photocatalysts such as metal oxides, metal sulfides, carbon nitrides, MOFs, etc. have problems such as a narrow solar light response range, high cost, poor stability, and lack of active sites in the practical application of sewage purification treatment, resulting in low photocatalytic degradation efficiency. Therefore, we need to find a catalyst with low cost, high efficiency, stability, and non-toxicity. Summary of the Invention

[0004] Aiming at the deficiencies in the prior art, the present invention provides a phenolic resin-based composite photocatalyst, a preparation method thereof, and an application thereof; the present invention uses phenolic resin micro-nano hollow spheres with characteristics such as a wide light response range, adjustable band gap, and strong adsorption performance as the core, and metal sulfide nanosheets with rich active sites and high carrier separation efficiency as the shell, and constructs a phenolic resin-based composite photocatalyst through an interface engineering strategy; the phenolic resin-based composite photocatalyst is a Z-type core-shell heterojunction material connected by interfacial hydrogen bonds; the phenolic resin-based composite photocatalyst has the advantages of low cost, wide light response range, rich active sites, high efficiency, good antibiotic tolerance, etc., and can achieve efficient antibiotic degradation under full solar spectrum excitation, and has good practicability.

[0005] In order to achieve the above technical objectives, the present invention adopts the following technical means:

[0006] The present invention first provides a phenolic resin-based composite photocatalyst, which is a Z-type core-shell heterojunction material obtained by bonding a phenolic resin micro-nano hollow sphere as the core and a metal sulfide nanosheet as the shell through interfacial hydrogen bonds.

[0007] Preferably, the phenolic resin includes any one of resorcinol-formaldehyde resin, catechol-formaldehyde resin, hydroquinone-formaldehyde resin, phenol-formaldehyde resin, chlorophenol-formaldehyde resin, or nitrophenol-formaldehyde resin;

[0008] The metal sulfide nanosheet includes any one of cadmium sulfide, zinc sulfide, copper sulfide, iron sulfide, indium zinc sulfide, or zinc cadmium sulfide.

[0009] Preferably, in the phenolic resin-based composite photocatalyst, the mass ratio of the phenolic resin to the metal sulfide nanosheet is 5-50:5-50.

[0010] The present invention also provides a preparation method of the above-mentioned phenolic resin-based composite photocatalyst, which specifically includes the following steps:

[0011] (1) Preparation of phenolic resin micro-nano hollow spheres:

[0012] Tetraethyl orthosilicate, absolute ethanol, deionized water, and ammonia water are stirred and mixed evenly, then a phenolic precursor and a formaldehyde solution are added thereto for stirring reaction. After the reaction ends, the reaction solution is subjected to a hydrothermal reaction at 80-300 °C. After the reaction ends, it is centrifuged, washed, and dried to obtain phenolic resin micro-nano hollow spheres;

[0013] (2) Preparation of phenolic resin-based composite photocatalyst:

[0014] By the in-situ growth method, a resin / sulfide Z-type core-shell heterojunction composite material, that is, a phenolic resin-based composite photocatalyst, is prepared, in which the two-phase interface is bonded in the form of hydrogen bonds through the amino group of thioacetamide (TAA) and the hydroxyl group on the resin surface. The preparation process is as follows:

[0015] Adjusted deionized water and glycerol are mixed and stirred evenly, then a metal precursor, thioacetamide (TAA), and phenolic resin micro-nano hollow spheres are added, and they are mixed evenly under ultrasonic treatment. After mixing evenly, an oil bath heating reaction is carried out. After the reaction ends, it is washed and dried to obtain the phenolic resin-based composite photocatalyst, denoted as RF / Z-100%;

[0016] The metal in the metal precursor includes any one of cadmium, zinc, copper, or iron, as well as combinations of indium zinc and zinc cadmium.

[0017] Preferably, in step (1), the volume ratio of tetraethyl orthosilicate, absolute ethanol, deionized water and ammonia water is (2-5):70:10:(2-4); the concentration of the ammonia water is 28 wt%.

[0018] Preferably, in step (1), the dosage ratio of tetraethyl orthosilicate, phenolic precursor and formaldehyde solution is (1 ml - 5 ml):(2.4 mmol - 4.8 mmol):(4.8 mmol - 9.6 mmol); the concentration of the formaldehyde solution is 33 wt%.

[0019] Preferably, in step (1), the phenolic precursor includes any one of resorcinol, catechol, hydroquinone, m-aminophenol, phenol, chlorophenol or nitrophenol.

[0020] Preferably, in step (1), the conditions for the stirring reaction are stirring for 12 - 24 h;

[0021] The time for the hydrothermal reaction is 12 - 48 h.

[0022] Preferably, in step (2), the metal precursor includes a metal chloride salt.

[0023] Preferably, in step (2), the pH value of the deionized water is 2; the dosage ratio of the deionized water, glycerol, metal precursor, thioacetamide and phenolic resin micro-nano hollow spheres is (20 ml - 40 ml):(4 ml - 12 ml):(1 mmol - 4 mmol):(1 mmol - 8 mmol):(10 mg - 100 mg).

[0024] Preferably, in step (2), the conditions for the oil bath heating reaction are at 60 - 100 °C for 2 h.

[0025] The present invention also provides the application of the above phenolic resin-based composite photocatalyst in the photocatalytic degradation of antibiotics.

[0026] Preferably, the antibiotics include one or more of tetracycline hydrochloride, penicillin, neomycin or erythromycin.

[0027] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0028] (1) The present invention constructs a core-shell material with interfacial hydrogen-bonding through an interfacial engineering strategy. A phenolic resin micro-nano hollow sphere with characteristics such as a wide light response range, adjustable bandgap, and strong adsorption performance is used as the core, and a metal sulfide nanosheet with rich active sites and high carrier separation efficiency is used as the shell to form a core-shell heterojunction composite photocatalyst. The core-shell structural characteristics of the composite photocatalyst endow it with spatially separated oxidation and reduction sites; on the one hand, the interfacial hydrogen bond can act as a bridge for charge transfer to kinetically promote the separation of carriers, and on the other hand, it can improve the structural stability of the composite photocatalyst; in addition, the construction of the Z-scheme heterojunction is beneficial to the separation of carriers and the expansion of the light absorption range, inhibiting the photocorrosion of sulfides.

[0029] (2) The phenolic resin used in the present invention is a cross-linked polymer formed by the polycondensation reaction of phenols and formaldehyde and other substances under alkaline conditions. Under the conditions of high-temperature hydrothermal reaction, a D–A coupling with a low HOMO–LUMO gap is generated, endowing it with characteristics such as a narrow bandgap and high conductivity, thereby broadening the light response range of the resin material and achieving a wide spectral response. At the same time, the resin material also has characteristics such as adjustable morphology, large specific surface area, good adsorption performance, good stability, and adjustable energy band.

[0030] (3) The morphology and structure of the phenolic resin-based composite photocatalyst prepared in the present invention are controllable, and the resin micro-nano hollow sphere core has the characteristic of adjustable particle size. The phenolic resin-based composite photocatalyst has high photocatalytic activity, has strong performance in degrading antibiotics under sunlight irradiation, and has the characteristic of wide spectral response, and can promote the degradation reaction under near-infrared light. The composite photocatalyst can photocatalytically degrade a variety of antibiotics including β-lactams (penicillin), tetracyclines (tetracycline hydrochloride), aminoglycosides (neomycin), and macrolides (erythromycin).

[0031] (4) The phenolic resin-based composite photocatalyst prepared in the present invention has the advantages of low cost, wide light response range, rich active sites, high efficiency, good antibiotic tolerance, etc., and can achieve efficient antibiotic degradation under full solar spectrum excitation. In addition, after 30 days of cyclic reaction, the degradation efficiency can still be maintained above 90%. In addition, the preparation process method of the phenolic resin-based composite photocatalyst of the present invention is simple, with low energy consumption. Only by using the hydrothermal-oil bath in-situ synthesis method can samples be prepared, with simple operation, good reaction selectivity, large yield, and low energy consumption. During the preparation process of the phenolic resin-based composite photocatalyst, it is non-toxic, pollution-free, green and environmentally friendly, and has good industrial practicability. Brief Description of the Drawings

[0032] Figure 1 X-ray diffraction patterns of phenolic resin micro-nano hollow spheres (a), metal sulfides (b), and phenolic resin-based composite photocatalysts (c).

[0033] Figure 2 SEM image of phenolic resin micro-nano hollow spheres. Specific implementation mode

[0034] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments, but the protection scope of the present invention is not limited thereto.

[0035] Example 1:

[0036] In this example, a phenolic resin-based composite photocatalyst was prepared by an in-situ growth method. ZnIn2S4 was selected as the metal sulfide in the phenolic resin-based composite photocatalyst, and the amino group of thioacetamide (TAA) and the hydroxyl group on the resin surface were bonded in the form of hydrogen bonds at the two-phase interface of the metal sulfide.

[0037] (1) Preparation of phenolic resin hollow spheres:

[0038] Add 3.46 mL of tetraethyl orthosilicate, 70 mL of absolute ethanol, 10 mL of H2O, and 3 mL of 28 wt% ammonia water into a 100 mL beaker, stir for 15 min to mix evenly; then add 3.6 mmol of phenolic precursor resorcinol and 7.2 mmol of 33 wt% formaldehyde solution thereto, and stir and react for 24 h.

[0039] After the reaction, transfer the reaction solution to a 100 mL autoclave, carry out hydrothermal reaction at 250 °C for 24 h. After the reaction, centrifuge, wash, and vacuum dry overnight at 60 °C to obtain the phenolic resin hollow spheres.

[0040] (2) Preparation of phenolic resin-based composite photocatalyst:

[0041] Add 32 mL of deionized water adjusted to pH = 2 with 0.5 M hydrochloric acid into a 100 mL round-bottom flask, add 8 mL of glycerol thereto and stir to mix evenly, then add 272 mg of ZnCl2, 586 mg of InCl3·4H2O, 300 mg of TAA, and 50 mg of phenolic resin hollow spheres into the round-bottom flask to obtain a mixture.

[0042] Ultrasonically treat the mixture for 0.5 h, then heat it to 80 °C in an oil bath and react for 2 h. After the reaction, centrifuge and wash three times with water and ethanol respectively, and finally dry overnight at 60 °C in a vacuum oven to obtain the phenolic resin-based composite photocatalyst, denoted as sample 1.

[0043] Figure 1X-ray diffraction patterns of phenolic resin micro-nano hollow spheres, metal sulfides and phenolic resin-based composite photocatalysts. From the figure, characteristic peaks of metal sulfides and phenolic resin can be observed, indicating the successful preparation of the composite photocatalyst.

[0044] Figure 2 SEM image of phenolic resin micro-nano hollow spheres. It can be seen from the figure that the diameter of the phenolic resin micro-nano hollow spheres is about 1.5 - 2 microns.

[0045] The above-prepared phenolic resin-based composite photocatalyst was tested for antibiotic degradation under sunlight. The specific steps are as follows:

[0046] 10 mg of the sample was added to 50 mL of an antibiotic aqueous solution with a concentration of 10 mg / L. The reaction vessel was wrapped with tin foil to achieve a light-shielding effect. This process lasted for 30 min to exclude the interference of catalyst adsorption on the experimental results. Then, using sunlight as the light source, a photocatalytic experiment for removing antibiotics was carried out. After 1 h of illumination, about 2 mL of the solution was extracted with a syringe and filtered through an organic filter head. Finally, the liquid product was detected with a UV-visible diffuse reflectance spectrophotometer (UV-2600), and the change in its absorbance was used to represent the change in antibiotic concentration, and the data was recorded.

[0047] Example 2:

[0048] In this example, phenolic resin-based composite photocatalysts were prepared based on different phenolic precursors, and the efficiency of phenolic resin-based composite photocatalysts prepared from different phenolic precursors for degrading antibiotics under sunlight was investigated. The specific preparation process was basically the same as that in Example 1, with only the following differences: The phenolic precursor resorcinol in step (1) of Example 1 was replaced with catechol, m-aminophenol, hydroquinone, chlorophenol, nitrophenol, and phenol respectively to prepare phenolic resin-based composite photocatalysts with different phenolic precursors, denoted as samples 2 - 7.

[0049] Samples 2 - 7 were tested for antibiotic degradation under sunlight using the method described in Example 1. The test results are shown in Table 1.

[0050] Table 1. Efficiency of different samples for degrading antibiotics under sunlight

[0051]

[0052] It can be seen from Table 1 that among all the different phenolic samples, the resorcinol resin has the best performance. The best sample has excellent degradation performance for all antibiotics under sunlight, and the degradation efficiency can reach over 90%.

[0053] Example 3:

[0054] In this example, phenolic resin-based composite photocatalysts were prepared using different amounts of tetraethyl orthosilicate, and the degradation efficiency of the phenolic resin-based composite photocatalysts prepared with different amounts of tetraethyl orthosilicate for antibiotics under sunlight was investigated. The specific preparation process was basically the same as that of Example 1, with only the following differences: the amount of tetraethyl orthosilicate in step (1) of Example 1 was changed to 1 mL, 2 mL, 4 mL, and 5 mL, and phenolic resin-based composite photocatalysts with different amounts of tetraethyl orthosilicate were prepared, denoted as Samples 8 - 11.

[0055] Samples 8 - 11 were tested for antibiotic degradation under sunlight using the method described in Example 1. The test results are shown in Table 2.

[0056] Table 2. Degradation efficiency of different samples for antibiotics under sunlight

[0057]

[0058]

[0059] As can be seen from Table 2, the phenolic resin-based composite photocatalysts with different amounts of tetraethyl orthosilicate have excellent degradation performance for all antibiotics, and among them, the performance of Sample 1 is better.

[0060] Example 4:

[0061] In this example, phenolic resin-based composite photocatalysts were prepared based on different phenolic precursors and amounts of formaldehyde, and the degradation efficiency of the prepared phenolic resin-based composite photocatalysts for antibiotics under sunlight was investigated. The specific preparation process was basically the same as that of Example 1, with only the following differences: the amounts of phenolic precursors in step (1) of Example 1 were changed to 2.4 mmol and 4.8 mmol respectively, and the corresponding amounts of formaldehyde were changed to 4.8 mmol and 9.6 mmol, and phenolic resin-based composite photocatalysts under different conditions were prepared, denoted as Samples 12 and 13.

[0062] Samples 12 and 13 were tested for antibiotic degradation under sunlight using the method described in Example 1. The test results are shown in Table 3.

[0063] Table 3. Degradation efficiency of different samples for antibiotics under sunlight

[0064]

[0065] As can be seen from Table 3, the optimal ratio of phenolics to aldehydes in the resin sample is 3.6:7.2 (mmol), and it has degradation performance for all antibiotics under sunlight.

[0066] Example 5:

[0067] In this example, phenolic resin-based composite photocatalysts were prepared from phenolic resin hollow spheres with different particle sizes, and the degradation efficiency of the prepared phenolic resin-based composite photocatalysts for antibiotics under sunlight was investigated. The specific preparation process was basically the same as that in Example 1, with only the following differences: the particle sizes of the phenolic resin hollow spheres were adjusted to be 100-200 nm, 500-600 nm, and 800-1000 nm respectively, and phenolic resin-based composite photocatalysts under different conditions were prepared, denoted as Samples 14-16.

[0068] Samples 14-16 were tested for antibiotic degradation under sunlight using the method described in Example 1. The test results are shown in Table 4.

[0069] Table 4. Degradation efficiency of different samples for antibiotics under sunlight

[0070]

[0071]

[0072] As can be seen from Table 4, the optimal size of the resin hollow micro-nano spheres is 1.5-2 microns, and they have degradation performance for all antibiotics under sunlight excitation.

[0073] Example 6:

[0074] In this example, a phenolic resin-based composite photocatalyst was prepared by adjusting the reactants in the hydrothermal reaction in step (1), and the degradation efficiency of the prepared phenolic resin-based composite photocatalyst for antibiotics under sunlight was investigated. The specific preparation process was basically the same as that in Example 1, with only the following differences: the reaction substrate, aqueous formaldehyde solution, in the hydrothermal reaction process in step (1) was replaced with paraformaldehyde, and then a phenolic resin-based composite photocatalyst was prepared, denoted as Sample 17.

[0075] Sample 17 was tested for antibiotic degradation under sunlight using the method described in Example 1. The test results are shown in Table 5.

[0076] Table 5. Degradation efficiency of different samples for antibiotics under sunlight

[0077]

[0078] As can be seen from Table 5, the best aldehyde is aqueous formaldehyde solution. The best sample has degradation performance for all antibiotics under sunlight.

[0079] Example 7:

[0080] In this example, phenolic resin-based composite photocatalysts were prepared based on different hydrothermal reaction temperatures, and the degradation efficiency of the phenolic resin-based composite photocatalysts prepared at different hydrothermal reaction temperatures for antibiotics under sunlight was investigated. The specific preparation process was basically the same as that of Example 1, with only the following differences: the hydrothermal reaction temperature in step (1) of Example 1 was adjusted to 80 °C, 100 °C, 150 °C, 200 °C, and 300 °C, and then phenolic resin-based composite photocatalysts with different hydrothermal reaction temperatures were prepared, denoted as Samples 18-22.

[0081] Samples 18-22 were tested for the degradation of antibiotics under sunlight using the method described in Example 1. The test results are shown in Table 6.

[0082] Table 6. Degradation efficiency of different samples for antibiotics under sunlight

[0083]

[0084]

[0085] As can be seen from Table 6, the optimal hydrothermal temperature of the resin is 250 °C, and the best sample has the degradation performance for all antibiotics under sunlight.

[0086] Example 7:

[0087] In this example, phenolic resin-based composite photocatalysts were prepared based on different hydrothermal reaction times, and the degradation efficiency of the phenolic resin-based composite photocatalysts prepared at different hydrothermal reaction times for antibiotics under sunlight was investigated. The specific preparation process was basically the same as that of Example 1, with only the following differences: the hydrothermal reaction time in step (1) of Example 1 was adjusted to 12 h, 36 h, and 48 h, and then phenolic resin-based composite photocatalysts with different hydrothermal reaction times were prepared, denoted as Samples 23-25.

[0088] Samples 23-25 were tested for the degradation of antibiotics under sunlight using the method described in Example 1. The test results are shown in Table 7.

[0089] Table 7. Degradation efficiency of different samples for antibiotics under sunlight

[0090]

[0091] As can be seen from Table 7, the optimal duration of the hydrothermal reaction of the resin is 24 h, and the best sample has the degradation performance for all antibiotics under sunlight.

[0092] Example 9:

[0093] In this example, phenolic resin-based composite photocatalysts were prepared based on different metal sulfides, and the degradation efficiency of the phenolic resin-based composite photocatalysts prepared with different metal sulfides under sunlight was investigated. The specific preparation process was basically the same as that of Example 1, with only the following differences: The types of metals in the metal precursors were changed, and ZnCl2 and InCl3·4H2O were adjusted to chlorides of Cd, Zn, CdZn, Cu, or Fe, respectively, so that the prepared metal sulfide nanosheets were changed from ZnIn2S4 to CdS, ZnS, CdZnS, CuS, FeS, and then phenolic resin-based composite photocatalysts were prepared respectively, denoted as Samples 26 - 30.

[0094] Taking CdS as an example, the preparation of the phenolic resin-based composite photocatalyst is as follows:

[0095] Add 32 mL of deionized water adjusted to pH = 2 with 0.5 M hydrochloric acid into a 100 mL round-bottom flask, add 8 mL of glycerol and stir to mix evenly, and then add 183 mg of CdCl2, 300 mg of TAA, and 50 mg of phenolic resin hollow spheres into the round-bottom flask to obtain a mixture.

[0096] Ultrasonically treat the mixture for 0.5 h, then heat it to 80 °C in an oil bath and react for 2 h. After the reaction, wash it three times by centrifugation with water and ethanol respectively, and finally dry it overnight at 60 °C in a vacuum oven to obtain the phenolic resin-based composite photocatalyst.

[0097] Samples 26 - 30 were tested for antibiotic degradation under sunlight by the method described in Example 1, and the test results are shown in Table 8.

[0098] Table 8. Degradation efficiency of different samples for antibiotics under sunlight

[0099]

[0100] As can be seen from Table 8, ZnIn2S4 in the metal sulfide nanosheets has the best effect, and the best composite sample has the degradation performance for all antibiotics under sunlight.

[0101] Example 10:

[0102] In this example, phenolic resin hollow spheres and phenolic resin-based composite photocatalysts with different composite ratios of metal sulfides were prepared, and the degradation efficiency of the phenolic resin-based composite photocatalysts prepared under different conditions for antibiotics under sunlight was investigated respectively. The specific preparation process was basically the same as that of Example 1, with only the following differences: the amounts of phenolic resin hollow spheres and metal sulfides were adjusted so that in the prepared phenolic resin-based composite photocatalysts, the phenolic resin hollow spheres were 20%, 40%, 60%, 80%, 120%, 140%, 160%, 180%, and 200% of the mass of the metal sulfide respectively. The prepared phenolic resin-based composite photocatalysts were denoted as Samples 31-39 respectively.

[0103] Samples 31-39 were tested for the degradation of antibiotics under sunlight by the method described in Example 1, and the test results are shown in Table 9.

[0104] Table 9. Degradation efficiency of different samples for antibiotics under sunlight

[0105]

[0106]

[0107] It can be seen from Table 9 that when the mass ratio of phenolic resin hollow micro-nano spheres to metal sulfide nanosheets is 100%, the degradation performance of the catalyst is the best, and the best sample has the degradation performance for all antibiotics under sunlight.

[0108] Example 11:

[0109] In this example, the degradation efficiency of the phenolic resin-based composite photocatalyst prepared in Example 1 for tetracycline was investigated under different conditions. The investigation conditions were basically the same as those described in Example 1, with only the replacements shown in Table 2, and the corresponding investigation results are shown in Table 10.

[0110] Table 10. Degradation efficiency of Sample 1 for tetracycline under different reaction conditions

[0111]

[0112]

[0113] It can be seen from Table 10 that as the concentration of tetracycline increases from 10 mg / L to 50 mg / L, the degradation ability of tetracycline can still maintain a relatively good level. When the concentration reaches 50 mg / L, the degradation efficiency can still be as high as 84%. As the amount of the phenolic resin-based composite photocatalyst increases, the degradation rate of tetracycline gradually increases and reaches the maximum value when 10 mg of the phenolic resin-based composite photocatalyst is used. Moreover, the composite sample has excellent degradation performance for the degradation of all antibiotics in the full spectral range, especially good performance under near-infrared light.

[0114] The phenolic resin-based composite photocatalyst prepared in the present invention has excellent performance under different light conditions, and even has excellent degradation performance (97%) under near-infrared light, which indicates that the phenolic resin-based composite photocatalyst prepared in the present invention has the characteristic of broad-spectrum response. In addition, the phenolic resin-based composite photocatalyst still maintains good performance under slightly acidic pH conditions, but its performance decreases significantly under alkaline conditions. This shows that the phenolic resin-based composite photocatalyst has better activity under acidic conditions.

[0115] Therefore, the phenolic resin-based composite photocatalyst prepared by the method described in Example 1 has better performance. When the phenolic resin-based composite photocatalyst is under sunlight and the pH value is slightly acidic, it has better catalytic effect.

[0116] The described embodiments are the preferred embodiments of the present invention, but the present invention is not limited to the above embodiments. Without departing from the essential content of the present invention, any obvious improvements, substitutions or modifications that those skilled in the art can make all belong to the protection scope of the present invention.

Claims

1. A preparation method of a phenolic resin-based composite photocatalyst, characterized in that, Comprising: (1) Preparation of phenolic resin micro-nano hollow spheres: Tetraethyl orthosilicate, absolute ethanol, deionized water and ammonia water are stirred and mixed evenly, then a phenolic precursor and formaldehyde solution are added thereto and stirred for reaction. After the reaction, the reaction solution is subjected to hydrothermal reaction at 80-300 °C. After the reaction, it is centrifuged, washed and dried to obtain phenolic resin micro-nano hollow spheres; (2) Preparation of phenolic resin-based composite photocatalyst: Deionized water with adjusted pH value and glycerol are mixed and stirred evenly, then a metal precursor, thioacetamide TAA and phenolic resin micro-nano hollow spheres are added, and they are mixed evenly under ultrasonic treatment. After mixing evenly, an oil bath heating reaction is carried out. After the reaction, it is washed and dried to obtain the phenolic resin-based composite photocatalyst; The metal in the metal precursor includes any one of cadmium, zinc, copper or ferrous, as well as combinations of indium zinc and zinc cadmium.

2. The preparation method of the phenolic resin-based composite photocatalyst according to claim 1, wherein, In step (1), the volume ratio of tetraethyl orthosilicate, absolute ethanol, deionized water and ammonia water is (2-5):70:10:(2-4); the concentration of the ammonia water is 28 wt%; The dosage ratio of tetraethyl orthosilicate, phenolic precursor and formaldehyde solution is (1 ml-5 ml):(2.4 mmol-4.8 mmol):(4.8 mmol-9.6 mmol); the concentration of the formaldehyde solution is 33 wt%.

3. The preparation method of the phenolic resin-based composite photocatalyst according to claim 1, characterized in that In step (1), the phenolic precursor includes any one of resorcinol, catechol, hydroquinone, m-aminophenol, phenol, chlorophenol or nitrophenol; The conditions for the stirring reaction are stirring for 12-24 h; The time of the hydrothermal reaction is 12-48 h.

4. The preparation method of the phenolic resin-based composite photocatalyst according to claim 1, characterized in that, In step (2), the metal precursor includes a metal chloride salt.

5. The preparation method of the phenolic resin-based composite photocatalyst according to claim 1, characterized in that, In step (2), the pH value of the deionized water is adjusted to 2; the dosage ratio of the deionized water, glycerol, metal precursor, thioacetamide and phenolic resin micro-nano hollow spheres is (20 ml-40 ml):(4 ml-12 ml):(1 mmol-4 mmol):(1 mmol-8 mmol):(10 mg-100 mg).

6. The preparation method of the phenolic resin-based composite photocatalyst according to claim 1, characterized in that In step (2), the conditions for the oil bath heating reaction are to continue for 2 h at 60-100 °C.

7. The phenolic resin-based composite photocatalyst prepared by the method according to any one of claims 1 to 6, characterized in that, The phenolic resin-based composite photocatalyst is a Z-type core-shell heterojunction material with phenolic resin micro-nano hollow spheres as the core and metal sulfide nanosheets as the shell, which are linked by interfacial hydrogen bonds.

8. The phenolic resin-based composite photocatalyst according to claim 7, wherein The types of phenolic resin include any one of resorcinol-formaldehyde resin, catechol-formaldehyde resin, hydroquinone-formaldehyde resin, m-aminophenol-formaldehyde resin, phenol-formaldehyde resin, chlorophenol-formaldehyde resin or nitrophenol-formaldehyde resin; The metal sulfide nanosheets include any one of cadmium sulfide, zinc sulfide, copper sulfide, ferrous sulfide, indium zinc sulfide or zinc cadmium sulfide; In the phenolic resin-based composite photocatalyst, the mass ratio of phenolic resin to metal sulfide nanosheets is 5-50:5-50.

9. Application of the phenolic resin-based composite photocatalyst according to claim 7 in photocatalytic degradation of antibiotics.

10. The application according to claim 9, characterized in that, The antibiotics include one or more of tetracycline hydrochloride, penicillin, neomycin or erythromycin.

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