A CuO-loaded titanium silicon molecular sieve CuO / TS-1 composite photocatalyst and its application

Abstract

The invention discloses a kind of CuO nanoparticle-loaded titanium silicon molecular sieve CuO / TS-1 composite photocatalyst and its application, the Cu of load is carried on the lattice and surface of TS-1 in the form of CuO, is made by following preparation method: a certain amount of CuSO4 is dissolved in 10ml deionized water and stirred, and a certain amount of ammonia solution (1:1) is added until precipitation is completely dissolved to obtain copper ammonia complex; TS-1 powder is dissolved in deionized water, stirred, ultrasonicated, and uniformly distributed; Then copper ammonia complex is added dropwise to TS-1, stirred, CTAB is added and stirred, and hydrothermal reaction, washing, drying, grinding are carried out to obtain. Composite catalyst of the present invention can be excited by visible light, utilizes the synergy of the adsorption of TS-1 and the photocatalytic action of the composite and the photo-Fenton action of copper dopant, and achieves the purpose of efficiently degrading tetracycline antibiotic wastewater.

Description

Technical Field

[0001] The present invention relates to the technical field of heterogeneous catalysis, and in particular to a CuO-loaded titanium silicon molecular sieve CuO / TS-1 composite photocatalyst and applications thereof. Background Art

[0002] Fenton technology uses hydrogen peroxide to react with ferrous ions to produce hydroxyl radicals (·OH) with enhanced ability, and ferrous ions are oxidized to ferric ions (Fe 3+ ), and iron ions have a coagulation effect and can be used to remove some organic matter. However, existing Fenton technology has problems such as strict reaction pH value restrictions, large H2O2 dosage, low active species production, low metal ion utilization, and large chemical sludge production.

[0003] Copper and iron are metal elements in the same main group in the periodic table and have great similarities in chemical properties. 2+ The solubility (10-5M) is higher than that of Fe 3+ The solubility (10 -10 M), and Cu + Reaction coefficient with H2O2 (4×10 5 M -1 s -1 ) is much higher than Fe 2+ Reaction coefficient (63~76M -1 s -1 ), therefore, the advantages of copper-based Fenton over traditional iron-Fenton are that it has a wider range of reaction pH, trace efficiency, low chemical sludge production and less harm to the environment. Therefore, using copper to replace iron as a Fenton reaction reagent has great prospects. TS-1 is a heteroatom molecular sieve belonging to the ZSM-5 series of zeolites. It has an MFI topological structure and a rich pore system, which provides more catalytic sites. This pore structure also makes it easy to combine with other components to enrich the function of the photocatalyst. However, the disadvantage of TS-1 is that it can only absorb ultraviolet light, has poor charge separation, and has limited photoactivity.

[0004] To date, there has been no report on the use of copper-ammonia complexes as precursors to introduce copper-containing compounds into TS-1 to prepare CuO-loaded titanium silicalite CuO / TS-1 composite photocatalysts, and the use of photo-Fenton reaction, adsorption and photocatalysis as photocatalysts to efficiently degrade tetracycline antibiotic wastewater. Summary of the Invention

[0005] The present invention provides a CuO-loaded titanium silicon molecular sieve CuO / TS-1 composite photocatalyst and its application. The composite catalyst can be excited by visible light and utilizes the synergistic effect of TS-1 adsorption and composite photocatalysis and the photo-Fenton effect of copper dopants to achieve the purpose of efficiently degrading tetracycline antibiotic wastewater.

[0006] In order to achieve the above technical purpose, the technical solution of the present invention is:

[0007] A CuO-loaded titanium silicon molecular sieve CuO / TS-1 composite photocatalyst, wherein the loaded Cu is loaded on the lattice and surface of TS-1 in the form of CuO, is prepared by the following preparation method:

[0008] (1) Dissolve CuSO4 in 10 ml of deionized water and stir evenly, then add ammonia solution (1:1) until the precipitate is completely dissolved to obtain a copper-ammonia complex;

[0009] (2) Dissolve TS-1 powder in deionized water, stir and ultrasonicate to make it evenly distributed; then add the cuprammonium complex dropwise into TS-1, stir evenly, add CTAB and stir, perform hydrothermal reaction, wash, dry and grind to obtain the product.

[0010] Among them, the mass ratio of Cu to TS-1 in CuSO4 is 0.05-0.30.

[0011] Wherein, in step (1), the amount of ammonia water used is such that the amount of ammonia water added dropwise is sufficient to dissolve the Cu(OH)2 precipitate into a cuprammonium complex.

[0012] Wherein, in step (2), after TS-1 powder is dissolved in deionized water, the stirring time is 0.5-1.5h, and the ultrasonic time is 0.5-1.5h; the hydrothermal reaction temperature is 80-120°C, and the time is 6-10h.

[0013] Wherein, in step (2), 100 mg of CTAB is added to the reaction solution; deionized water is used for washing; the drying time is 10-14 h, and the drying temperature is 50-70°C.

[0014] The application of CuO-loaded titanium silicalite CuO / TS-1 composite photocatalyst in the degradation of tetracycline antibiotics in wastewater is as follows: the composite photocatalyst CuO / TS-1 and H2O2 are added to the tetracycline wastewater and stirred, and the photodegradation reaction is carried out by irradiation with a 420nm filter for 60 minutes.

[0015] During degradation, the dosage of the composite photocatalyst CuO / TS-1 is 25-75 mg / L, the dosage of H2O2 is 0-15 ml / L, the concentration of tetracycline antibiotics in the wastewater is 10-70 mg / L, and the initial pH value of the wastewater is 2-11.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] The present invention uses copper ammonia complex as a precursor to prepare CuO / TS-1 composite materials, uses CuSO4 as a copper source, and spherical TS-1 as a carrier to synthesize CuO / TS-1 composite catalysts with different Cu and TS-1 mass ratios.

[0018] The present invention prepares a CuO-loaded titanium silicon molecular sieve CuO / TS-1 composite photocatalyst that can be excited by visible light and has high catalytic activity. TS-1 acts as an adsorbent, adsorbing organic matter in nanoscale micropores, creating a local high-concentration pollutant environment. OH generated on the catalyst surface preferentially reacts with organic matter in the micropores, achieving a cycle of "adsorption-degradation-activation". The CuO-loaded TS-1 has an -O-Ti-O-semiconductor chain that is excited by visible light, generating electrons and holes. The electrons are transported to the loaded Cu 2+ Capture, inhibit electron-hole recombination, and improve light energy utilization; Cu on the catalyst surface 2+ It can be reduced by visible light, which accelerates the rate of the Fenton reaction and improves the oxidation capacity of the entire system. The present invention utilizes the synergistic effect of the adsorption and photocatalytic effect of TS-1 and the photo-Fenton effect of the copper load to efficiently degrade high-concentration tetracycline antibiotic wastewater.

[0019] The composite catalyst of the present invention is applicable to the degradation of tetracycline antibiotics in wastewater in a wide pH range of 2-11; part of the CuO enters the lattice of TS-1, reducing the amount of CuO in the reaction. 2+ The advantages of copper-based Fenton over traditional iron-Fenton are that it has a wider range of reaction pH, high efficiency in trace amounts, less chemical sludge production and less harm to the environment; the use of H2O2 is reduced, saving resources; the CuO loaded on the surface of TS-1 changes the band structure of TS-1, allowing it to absorb visible light to produce photocatalytic reactions. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 XRD spectra and FT-IR spectra of TS-1 and composite catalyst;

[0021] Figure 2 SEM, TEM images of TS-1 and SEM, TEM, and HRTEM images of CuO / TS-1, and the corresponding element mapping images of CuO / TS-1;

[0022] Figure 3 Nitrogen adsorption-desorption isotherms and pore size distribution curves of TS-1 and xCuO / TS-1;

[0023] Figure 4XPS measurement spectra of TS-1 and CuO / TS-1 samples;

[0024] Figure 5 The relationship diagram of UV-visible spectra (x = 0.05, 0.1, 0.2, 0.3) and band energy (hv) of TS-1 and xCuO / TS-1;

[0025] Figure 6 It curves, electrochemical impedance spectroscopy (EIS) Nyquist plots, and Mott-Schottky plots of TS-1 and 0.2CuO / TS-1 under visible light;

[0026] Figure 7 are the degradation results of different reaction systems;

[0027] Figure 8 The effect of different CuO loadings on TC (tetracycline) degradation;

[0028] Figure 9 is the effect of different tetracycline concentrations on TC (tetracycline) degradation;

[0029] Figure 10 is the effect of H2O2 volume concentration on TC (tetracycline) degradation;

[0030] Figure 11 is the effect of pH on TC degradation;

[0031] Figure 12 is the effect of catalyst dosage on TC degradation;

[0032] Figure 13 The results of the cyclic experiment of TC degradation by CuO / TS-1;

[0033] Figure 14 This is the pseudo-first-order reaction kinetics diagram of CuO / TS-1 photo-Fenton degradation of TC;

[0034] Figure 15 The results of the free radical shielding experiment on TC degradation in the photo-Fenton system are shown;

[0035] Figure 16 The experimental results of the effects of different atmospheres on TC degradation performance are shown in Figure 2.

[0036] Figure 17 To test the effect of different hydrothermal temperatures and times on TC degradation;

[0037] Figure 18 Schematic diagram of the degradation of tetracycline by CuO / TS-1. DETAILED DESCRIPTION

[0038] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0039] Example 1

[0040] This embodiment provides a CuO-loaded titanium silicalite CuO / TS-1 composite photocatalyst, in which the loaded Cu is loaded on the lattice and surface of TS-1 in the form of CuO, and is prepared by the following preparation method:

[0041] (1) Anhydrous CuSO4 is added to deionized water under stirring to dissolve, and then ammonia water is added. The amount of ammonia water is such that the Cu(OH)2 precipitate is just dissolved into a cuprammonium complex, thereby preparing a cuprammonium complex solution;

[0042] (2) Dissolve TS-1 powder in deionized water, stir for 0.5 h, and ultrasonicate for 1.5 h to make it evenly distributed; then add the cuprammonium complex dropwise to TS-1, stir evenly, add CTAB to make the CTAB mass concentration in the reaction solution 30 mg / L, stir, and undergo hydrothermal reaction at a temperature of 100 ° C for 8 h, then wash with deionized water, dry for 10 h at a drying temperature of 70 ° C, and grind to obtain.

[0043] Among them, the mass ratio of Cu to TS-1 in CuSO4 is 0.05:1.

[0044] Example 2

[0045] This embodiment provides a CuO-loaded titanium silicalite CuO / TS-1 composite photocatalyst, in which the loaded Cu is loaded on the lattice and surface of TS-1 in the form of CuO, and is prepared by the following preparation method:

[0046] (1) Anhydrous CuSO4 is added to deionized water under stirring to dissolve, and then ammonia water is added. The amount of ammonia water is such that the Cu(OH)2 precipitate is just dissolved into a cuprammonium complex, thereby preparing a cuprammonium complex solution;

[0047] (2) Dissolve TS-1 powder in deionized water, stir for 1.5 h, and ultrasonicate for 0.5 h to make it evenly distributed; then add the cuprammonium complex dropwise to TS-1, stir evenly, add CTAB to make the CTAB mass concentration in the reaction solution 70 mg / L, stir, and undergo hydrothermal reaction at a temperature of 80°C for 10 h, then wash with deionized water, dry for 14 h at a temperature of 50°C, and grind to obtain.

[0048] Among them, the mass ratio of Cu to TS-1 in CuSO4 is 0.10:1.

[0049] Example 3

[0050] This embodiment provides a CuO-loaded titanium silicalite CuO / TS-1 composite photocatalyst, in which the loaded Cu is loaded on the lattice and surface of TS-1 in the form of CuO, and is prepared by the following preparation method:

[0051] (1) Anhydrous CuSO4 is added to deionized water under stirring to dissolve, and then ammonia water is added. The amount of ammonia water is such that the Cu(OH)2 precipitate is just dissolved into a cuprammonium complex, thereby preparing a cuprammonium complex solution;

[0052] (2) Dissolve TS-1 powder in deionized water, stir for 1 hour, and ultrasonicate for 1 hour to make it evenly distributed; then add the cuprammonium complex dropwise to TS-1, stir evenly, add CTAB to make the CTAB mass concentration in the reaction solution 50 mg / L, stir, and undergo hydrothermal reaction at a temperature of 120°C for 6 hours, then wash with deionized water, dry for 12 hours at a drying temperature of 60°C, and grind to obtain.

[0053] Among them, the mass ratio of Cu to TS-1 in CuSO4 is 0.20:1.

[0054] Example 4

[0055] This embodiment provides a CuO-loaded titanium silicalite CuO / TS-1 composite photocatalyst, in which the loaded Cu is loaded on the lattice and surface of TS-1 in the form of CuO, and is prepared by the following preparation method:

[0056] (1) Dissolve a certain amount of CuSO4 in 10 ml of deionized water and stir evenly, then add a certain amount of ammonia solution (1:1) until the precipitate is completely dissolved to obtain a copper-ammonia complex;

[0057] (2) Dissolve TS-1 powder in deionized water, stir for 1 hour, and ultrasonicate for 1 hour to make it evenly distributed; then add the cuprammonium complex dropwise into TS-1, stir evenly, add CTAB to make the CTAB mass concentration in the reaction solution 60 mg / L, stir, and undergo hydrothermal reaction at a temperature of 90°C for 8 hours, then wash with deionized water, dry for 12 hours at a drying temperature of 60°C, and grind to obtain.

[0058] Among them, the mass ratio of Cu to TS-1 in CuSO4 is 0.30:1.

[0059] Example 5

[0060] This embodiment provides a CuO-loaded titanium silicalite CuO / TS-1 composite photocatalyst, in which the loaded Cu is loaded on the lattice and surface of TS-1 in the form of CuO, and is prepared by the following preparation method:

[0061] (1) Dissolve a certain amount of CuSO4 in 10 ml of deionized water and stir evenly, then add a certain amount of ammonia solution (1:1) until the precipitate is completely dissolved to obtain a copper-ammonia complex;

[0062] (2) TS-1 powder was dissolved in deionized water, stirred for 1.5 h, and ultrasonicated for 1 h to make it evenly distributed; then the cuprammonium complex was added dropwise to TS-1, stirred evenly, and CTAB was added to make the CTAB mass concentration in the reaction solution 60 mg / L, stirred, and subjected to hydrothermal reaction at a temperature of 110 ° C for 7 h, and then washed with deionized water and dried for 12 h at a drying temperature of 60 ° C, and ground to obtain the product.

[0063] Among them, the mass ratio of Cu to TS-1 in CuSO4 is 0.15:1.

[0064] Application Example 1

[0065] The composite photocatalyst CuO / TS-1 prepared in Example 1 and H2O2 were added to the tetracycline wastewater and stirred, and the mixture was irradiated with a 420 nm filter to perform a photodegradation reaction. The tetracycline in the reaction solution was quantitatively analyzed using a UV-visible spectrophotometer.

[0066] During degradation, the dosage of the composite photocatalyst CuO / TS-1 was 50 mg, the dosage of H2O2 was 10 ml / L, the tetracycline concentration in the tetracycline wastewater was 50 mg / L, and the initial pH value of the wastewater was 6.

[0067] The principle diagram of TC degradation by CuO / TS-1 is shown in the figure Figure 18 shown.

[0068] Application Example 2

[0069] The content of this embodiment is basically the same as that of Application Example 1, except that the degradation reaction systems are different. The reaction systems are ① no irradiation (dark), ② only light irradiation, ③ H2O2, ④ TS-1, ⑤ TS-1 / H2O2, and ⑥ CuO / TS-1 / H2O2. The degradation results of different reaction systems are shown in Figure 2. Figure 7 As shown, the results show that: the adsorption capacity of TS-1 for tetracycline was tested in a dark adsorption system. The tetracycline solution reached adsorption and desorption equilibrium on the TS-1 surface in about 20 minutes. After equilibrium, the concentration of tetracycline remained basically unchanged. Since there was no light source to provide visible light energy during the dark adsorption process, tetracycline did not undergo photodegradation. Tetracycline showed almost no change under visible light irradiation, indicating that the molecular structure of tetracycline was relatively stable and would not self-degrade under visible light conditions. At the same time, the effect of H2O2 on the degradation of tetracycline was verified. A tetracycline explanation experiment was carried out by adding 10ml / L of 30% H2O2 without adding a catalyst. Figure 7 As can be seen in the figure, even after adding H2O2, the TC degradation rate was only 13% after 60 minutes of catalysis. This is likely due to the decomposition of ·OH by some H2O2 under light. Experiments investigating the simultaneous addition of TS-1 and H2O2 showed that the TS-1 / H2O2 system achieved a tetracycline degradation efficiency of 40% after 60 minutes, compared to the TS-1 system. This demonstrates that TS-1 can effectively catalyze the degradation of tetracycline by hydrogen peroxide. For CuO-loaded TS-1, the photo-Fenton efficiency of tetracycline reached 86% when combined with H2O2, demonstrating that CuO loading can indeed enhance the photo-Fenton efficiency of TS-1.

[0070] Application Example 3

[0071] The content of this embodiment is basically the same as that of Application Example 1, except that the CuO loading of the catalyst is different, and the CuO loading is respectively: 0.10, 0.15, 0.20, 0.25, 0.30, and TS-1 is used alone as the catalyst. The effect of different CuO loadings on the degradation of TC (tetracycline) is shown in FIG. Figure 8The results show that compared to pure TS-1, the xCuO / TS-1 composite catalyst exhibits faster catalytic efficiency and better TC degradation performance under the same conditions. After 60 minutes of reaction, the TC removal rates for 0.05CuO / TS-1, 0.10CuO / TS-1, 0.15CuO / TS-1, 0.20CuO / TS-1, 0.25CuO / TS-1, and 0.30CuO / TS-1 were 40%, 65%, 84%, 86%, 83%, and 82%, respectively. This indicates that the TC degradation rate initially increases with increasing CuO loading, but decreases slightly when the CuO loading exceeds 20%. This is likely due to the optimal Vis absorption intensity of CuO / TS-1, which is consistent with the DRS characterization results.

[0072] Application Example 4

[0073] The content of this embodiment is basically the same as that of Application Example 1, except that the concentration of tetracycline in the tetracycline wastewater is different, and the tetracycline concentrations are: 10 mg / L, 20 mg / L, 30 mg / L, and 70 mg / L. The effects of different tetracycline concentrations on its degradation are shown in Figure 2. Figure 9 The results show that when the tetracycline concentration increases from 10 mg / L to 50 mg / L, the degradation rate of CuO / TS-1 is almost the same: 88.9%, 86.8%, 86.1%, and 86%, respectively. When the tetracycline concentration rises to 70 mg / L, the degradation rate drops to only 66.3%. This is because as the TC concentration increases, the catalyst's adsorption of TC increases, competing with hydrogen peroxide for active sites on the catalyst surface. This reduces the number of hydroxyl radicals produced, leading to a decrease in the TC degradation rate. Furthermore, the intermediates of TC degradation accumulate on the catalyst surface, hindering contact between the catalyst and hydrogen peroxide, causing the degradation rate to decrease with increasing tetracycline concentration. In this case, the catalyst dosage and hydrogen peroxide concentration become limiting factors.

[0074] Application Example 5

[0075] The content of this embodiment is basically the same as that of Application Example 1. The difference is that the H2O2 concentration in the system is different. The H2O2 concentration in the system is: 0ml / L, 5ml / L, 15ml / L. The effect of H2O2 volume concentration on TC degradation is shown in the following figure. Figure 10As shown in the results, when the volume concentration of H2O2 increases from 0ml / L to 15ml / L, the degradation rate of TC increases from 51% to 86% within 60 minutes of reaction, indicating that the degradation rate of TC increases with the increase of the volume concentration of H2O2. However, when the H2O2 concentration is further increased to 15ml / L, the degradation rate of TC decreases slightly, and the degradation rate after 60 minutes of reaction is 82%. This phenomenon can be explained as follows: (1) When the H2O2 concentration in the solution is lower than the critical value, as the H2O2 concentration increases, the catalyst contacts the hydrogen peroxide molecules more fully, and the number of ·OH radicals produced by the catalysis also increases.

[96] (2) When the H2O2 concentration is higher than the critical value (10ml / L), the excess ·OH radicals produced by catalysis will react with hydrogen peroxide to generate less active ·HO2 radicals, which will lead to a slight decrease in the degradation rate of tetracycline and a decrease in the utilization rate of H2O2. This shows that the addition of H2O2 should not be too much. Too much not only increases economic costs but also does not improve the degradation efficiency of tetracycline.

[0076] Application Example 6

[0077] The content of this embodiment is basically the same as that of Application Example 1, except that the initial pH values ​​of the wastewater are different, namely: 2.2, 4, 7, 8, 9.7, and 11. The effect of the initial pH value of the solution on the degradation of TC is shown in the following figure. Figure 11 The results show that when the initial pH value of the reaction solution is 2.2, 4, 6, 9.7, 8, 7 and 11, the degradation rate of TC after 60 minutes of reaction is 38%, 76%, 79%, 81%, 85%, 86% and 88%, respectively. When the pH value is 2.2, the solution is acidic, and the degradation rate of TC decreases significantly, and the degradation rate after 60 minutes of reaction is only 38%. This is because under acidic conditions, hydrogen peroxide is more easily decomposed into H2O and O 2 , rather than ·OH radicals. When the solution was alkaline at pH 11, the TC degradation rate actually increased, reaching 88% after 60 minutes of reaction. This is likely due to the precipitation of Cu(OH)2 in the alkaline environment to form a copper-ammonium complex, which promoted the Fenton reaction. When the initial pH was between 6 and 11, the TC degradation rate reached over 80% after 60 minutes of catalytic reaction. This indicates that the 0.20CuO / TS-1 catalyst can effectively catalyze hydrogen peroxide to generate ·OH radicals under both acidic and neutral conditions, demonstrating its strong pH adaptability. Compared to the traditional Fenton reaction's strict pH requirements, which require a pH of 3.0 to 4.0 for optimal catalytic performance, the 0.20CuO / TS-1 catalyst has greater application prospects and a wider range of applicability.

[0078] Application Example 7

[0079] The content of this embodiment is basically the same as that of Application Example 1, except that the catalyst dosage is different. The catalyst dosages are 10 mg, 20 mg, 30 mg, 50 mg and 70 mg respectively. The effect of catalyst dosage on TC degradation is shown in the figure. Figure 12 As shown, the results show that for the heterogeneous photo-Fenton system, with the increase of the amount of catalyst CuO / TS-1, the TC degradation rate gradually increases. When the catalyst dosage increases from 10 mg to 50 mg, the TC degradation rate within 60 minutes can reach 56.6%, 64.2%, 74.9% and 85.5%, respectively. The degradation rate increases significantly with the addition of catalyst, while when the catalyst dosage continues to increase from 50 mg to 70 mg, the degradation rate does not increase significantly, and the degradation rates after 60 minutes of reaction are 85.5% and 85.7%, respectively. This is because for the heterogeneous reaction system, the hole h + ,OH,O 2- and 1O free radicals are mainly generated on the catalyst surface. As the catalyst concentration in the reaction system increases, the number of reactive sites on its surface will also increase, making it easier to contact with hydrogen peroxide and TC molecules, and the generated H + As the number of free radicals increases, the degradation rate of TC increases accordingly. However, when the catalyst dosage increases to above 50 mg, the TC degradation rate increases only slightly. Considering the economic adaptability of the catalyst, the catalyst dosage was not further increased.

[0080] Application Example 8

[0081] The content of Application Example 1 was used to conduct 4 degradation cycle tests. The results of the cycle test of CuO / TS-1 degradation of TC are as follows: Figure 13 (a) and the XRD comparison diagram before and after degradation is shown in 13 (b). The pseudo-first-order reaction kinetics of CuO / TS-1 photo-Fenton degradation of TC is shown in Figure 14 shown.

[0082] Application Example 9

[0083] In the free radical shielding experiment of TC degradation in the light-Fenton system, a free radical scavenger was added before the reaction started, and the other procedures were the same as those in Application Example 1.

[0084] The results are as follows Figure 15 The results show that in the presence of IPA and BQ, the degradation rate of TC decreased by 17% and 14%, respectively. Compared with IPA and BQ, EDTA-2Na has the greatest effect on the degradation of TC. After 60 minutes of catalytic reaction, the TC degradation rate decreased from 86% to 45%. However, EDTA-2Na did not completely inhibit the degradation of TC in the photo-Fenton system, indicating that h + Participate in the catalytic degradation process and play a leading role in the oxidation reaction of organic molecules, OH and O2- It plays an auxiliary role in the system and promotes the catalytic degradation reaction.

[0085] Application Example 10

[0086] The test results of the effect of different atmospheres on TC degradation performance are as follows: Figure 16 The results show that compared with air, the degradation rate of TC in N2 atmosphere is reduced by 4%, which may be due to the fact that dissolved oxygen can accept photogenerated electrons on the surface of the catalyst to generate O 2- , after multiple steps of reaction, ·OH is generated, OH and ·O 2- Both are oxidizing and can decompose TC.

[0087] Should Example 11

[0088] This is a test on the effect of different hydrothermal temperatures and times on TC degradation.

[0089] Figure 17 a is the degradation efficiency diagram of TC by samples CuO / TS-1 (x=80℃, y=8h), CuO / TS-1 (x=100℃, y=8h), and CuO / TS-1 (x=120℃, y=8h) under the same reaction conditions. Figure 17 It can be seen from a that after 60 min of visible light irradiation, the degradation rates of TC by CuO / TS-1 (x = 80 °C), CuO / TS-1 (x = 100 °C), and CuO / TS-1 (x = 120 °C) are 73.75%, 85.54%, and 66.27%, respectively. Figure 17 b is the degradation efficiency diagram of TC by samples CuO / TS-1 (x=100℃, y=6h), CuO / TS-1 (x=100℃, y=8h), and CuO / TS-1 (x=100℃, y=10h) under the same conditions. Figure 17 As shown in Figure 1, after 60 minutes of visible light irradiation, the degradation rates of TC by CuO / TS-1 (x = 6 hours), CuO / TS-1 (y = 8 hours), and CuO / TS-1 (y = 10 hours) were 70.81%, 85.54%, and 73.99%, respectively. Therefore, we can conclude that CuO / TS-1 (x = 100°C, y = 8 hours) exhibits the best degradation performance, i.e., the hydrothermal temperature is 100°C and the hydrothermal time is 8 hours. All subsequent photo-Fenton degradation tests used the photocatalyst CuO / TS-1 (x = 100°C, y = 8 hours).

[0090] Related tests:

[0091] Figure 1(a) XRD spectra of TS-1 and the xCu-TS-1 composite catalyst from Example 1. (b) FT-IR spectra of TS-1 and the xCu-TS-1 composite catalyst from Example 1. XRD characterizes the phase composition of the samples. After crystal structure treatment, the structure of TS-1 remains intact, and the skeletal structure is not destroyed. FT-IR further demonstrates that the structure of the TS-1 microspheres remains unchanged.

[0092] The phase composition and crystal structure of TS-1 and xCuO / TS-1 samples were characterized by XRD. Figure 1 As shown in (a), compared with TS-1 molecular sieve, xCuO / TS-1 (x = 0.05, 0.10, 0.20, 0.30) shows the characteristic diffraction peaks of TS-1 at 7.8, 8.8, 23.2, 23.8 and 24.3, respectively, corresponding to the (101), (200), (501), (151) and (313) lattice planes of TS-1, respectively. No impurity peaks appear, indicating that the structure of TS-1 does not collapse after alkali treatment and the skeleton structure is not destroyed. The FT-IR spectra of TS-1 and xCu-TS-1 (x = 0.05, 0.10, 0.20, 0.30) are shown in Figure 1. Figure 1 (b) The sample has the peaks at 456, 550, 808, 1093 and 1230 cm -1 The characteristic absorption peaks of TS-1 skeleton appeared near the surface of the sample, indicating that the TS-1 skeleton structure was not destroyed after treatment with the copper ammonium complex, which is consistent with the XRD data. -1 The peak appears at 970 cm-1, which is consistent with the topological structure of the MFI of TS-1 molecular sieve. -1 The peak at 970 cm-1 is attributed to the stretching vibration of Si-O-Ti bonds or the perturbation of Si-O bonds by the presence of Ti atoms in the framework, and the peak at 970 cm-1 is attributed to the stretching vibration of Si-O-Ti bonds or the perturbation of Si-O bonds by the presence of Ti atoms in the framework. -1 The absorption peak at 970 cm is related to the relative content of framework titanium. -1 and 550cm -1 The peak intensity ratio I970 / I550 can generally reflect the relative concentration of framework titanium. Figure 1 (b) It can be seen that the I970 / I550 value of 0.20CuO / TS-1 is 0.493, and the I970 / I550 value of untreated TS-1 is 0.445, indicating that more active framework titanium appears in the composite after CuO nanoparticles loading.

[0093] Figure 2(a) SEM of TS-1, (b) TEM image, (c) SEM, (d) TEM of CuO / TS-1, (e) HRTEM image, (fi) corresponding element mapping image of CuO / TS-1. Both TS-1 and CuO / TS-1 are elliptical. CuO / TS-1 inherits the porous quasi-spherical morphology of TS-1, with a size between 200 and 400 nm. Ti, O, Si and Cu exist in CuO / TS-1, and TS-1 is uniformly modified with monodispersed CuO, which greatly improves the photocatalytic activity. Both TS-1 and CuO / TS-1 are elliptical. CuO / TS-1 inherits the porous quasi-spherical morphology of TS-1, with a size between 200 and 400 nm. From Figure 2 (d) It can be seen that after treatment with the copper-ammonia complex, some small pores are connected to form larger pores, which significantly enriches the pore structure of CuO / TS-1 and is conducive to enhancing the photocatalytic activity. Figure 2 (e) It can be seen that CuO nanoparticles are uniformly attached to the surface of TS-1, with a size of about 3 to 5 nm. Elemental mapping ( Figure 2 (f)-(i)) show that Ti, O, Si, and Cu exist in CuO / TS-1, and TS-1 is uniformly modified by CuO nanoparticles. Figure 3 (a) Nitrogen adsorption-desorption isotherms of TS-1 and xCuO / TS-1 of Examples 1 to 4, (b) Pore size distribution curves of TS-1 and xCuO / TS-1 of Examples 1 to 4. The specific surface areas and pore volumes of TS-1 and xCuO / TS-1 are shown in Table 1. Figure 2 (a) As can be seen, at high relative partial pressures, the N adsorption and desorption isotherms of the CuO / TS-1 molecular sieve exhibit a distinct hysteresis loop. This indicates that hydrothermal synthesis of CuO / TS-1 under alkaline conditions forms a certain amount of mesopores, increasing the mesopore volume, thereby effectively reducing mass transfer resistance, optimizing diffusion performance, and increasing the accessibility of active sites. The sample treated under alkaline hydrothermal conditions exhibits a large mesopore surface area, providing a large number of active sites for the simultaneous and uniform loading of CuO. This facilitates light absorption and exposes more active CuO sites for catalytic reactions.

[0094] From the data in Table 1, it can be seen that after hydrothermal treatment and simultaneous loading of CuO, more mesoporous structures can be formed in TS-1, and the mesoporous surface area and mesopore diameter are increased compared with the original TS-1, which is more conducive to the attachment of CuO nanoparticles to the TS-1 surface. The decrease in BET specific surface area may be due to the alkaline environment etching part of the Si, destroying a certain microporous structure, or it may be that the copper oxide nanoparticles blocked part of the microporous structure.

[0095] Table 1 Specific surface area and pore volume of TS-1 and xCuO / TS-1

[0096]

[0097] Figure 4 XPS spectra of TS-1 (a) and CuO / TS-1 (b); high-resolution C1s, Si 2p, Ti 2p, and O1s spectra of TS-1 (c), (e), (g), and (i), and CuO / TS-1 (d), (f), (h), and (j); (k) XPS spectrum of Cu 2p. The atomic ratios of C, O, Ti, Si, and Cu measured by XPS of TS-1 and 0.20CuO / TS-1 are shown in Figure 2:

[0098] The surface chemical state and elemental composition of representative samples TS-1 and 0.20CuO / TS-1 were studied by XPS spectroscopy. Figure 4 As shown in (a) and (b), the full spectra of TS-1 and CuO / TS-1 contain signals of C, O, Ti and Si elements, and there is an additional Cu signal peak in CuO / TS-1. The high-resolution XPS spectra of TS-1 and CuO / TS-1 are shown in Figure 4 (c)-(k) are shown. C was detected in all samples, and its high-resolution spectrum can be decomposed into three peaks ( Figure 4 (c) and (d)), the peak at 284.8eV is considered to be the indefinite carbon adsorbed on the sample surface, which may be caused by the residual CTAB during the preparation process. The peaks at 286.8eV and 287.7eV are considered to be the residual raw material signals during the preparation of TS-1. The peak at the binding energy of 103.6eV in the Si 2p spectrum is attributed to the silica compound (Fig. 4(e)-(f)), and the peaks at 459.5eV and 465.3eV correspond to Ti 2p3 / 2 and Ti2p1 / 2, respectively, confirming the Si-O-Ti bond in TS-1 ( Figure 4 (g)-(h)). O1s spectrum of CuO / TS-1 ( Figure 4 (i) and (j)) can be fitted with two peaks at 531.8eV and 533.1eV, and the peak at 533.1eV is the lattice oxygen of TS-1. Figure 4 In (k)), the satellite peaks at 935.01 eV and 954.94 eV and the satellite peaks at 943.11 eV and 962.88 eV indicate that copper exists in the oxidation state of +2.

[0099] Table 2 Atomic ratios of C, O, Ti, Si, and Cu measured by XPS on TS-1 and 0.20CuO / TS-1

[0100]

[0101] At the same time, XPS analysis revealed the surface elemental content of TS-1 and 0.20CuO / TS-1 (Table 2). Compared to the Ti / Si molar ratio of 12.5% ​​for TS-1, the Ti / Si molar ratio for 0.20CuO / TS-1 was 73.9%, indicating that 0.20CuO / TS-1 contained more anatase-type TiO2 after alkalization. This is likely due to the copper ammonia complex treatment dissolving some of the framework silicon, with little effect on the framework titanium, leading to an increase in the Ti / Si molar ratio and, consequently, an increase in the relative content of active phase-coordinated framework titanium. This is consistent with the aforementioned FT-IR results. As shown in Table 3.2, a copper content of 6.75% was detected on the surface of 0.20CuO / TS-1 compared to TS-1, indicating that CuO nanoparticles were successfully loaded and modified on TS-1.

[0102] Figure 5 (a) UV-visible spectra of TS-1 and xCuO / TS-1 of Examples 1 to 4 (x = 0.05, 0.1, 0.2, 0.3); (b) Relationship diagram of (αhv)2 and band energy (hv) of TS-1 and xCuO / TS-1 of Examples 1 to 4 (x = 0.05, 0.1, 0.2, 0.3). Figure 5 (a) is the UV-visible diffuse reflectance spectra of TS-1 and xCuO / TS-1. xCuO / TS-1 shows stronger light absorption than TS-1, especially in the range of 400-800nm. Figure 5 The absorption peak of TS-1 near 330nm in (a) is due to the presence of anatase TiO2 in the molecular sieve. [109-110] After the TS-1 molecular sieve was treated with copper-ammonia complex, the absorption peak at 330nm gradually weakened with the increase of CuO loading, indicating that the anatase TiO2 decreased after TS-1 was loaded with CuO nanoparticles. It may be that the copper-ammonia complex treatment dissolved part of the skeleton silicon and also had a great impact on the skeleton titanium. The skeleton titanium connected to silicon would fall off as the silicon dissolved.

[111] . Figure 5 (b) Relationship between the square root of the Kubelka-Munk function and photon energy

[112] The band gap values ​​of TS-1 and xCuO / TS-1 (x = 0.05, 0.1, 0.2, 0.3) can be estimated from the intercept of the tangent. Compared with the band gap of TS-1 (3.30 eV), the band gap of xCuO / TS-1 (x = 0.05, 0.1, 0.2, 0.3) (3.20 eV, 2.60 eV, 2.3 0 eV, 2.29 eV) is reduced after loading CuO nanoparticles.

[0103] Figure 6(a) It curves of TS-1 and 0.2CuO / TS-1 under visible light. (b) Nyquist plots of electrochemical impedance spectroscopy (EIS) of TS-1 and xCuO / TS-1. (c) Mott-Schottky plots of TS-1 and (d) 0.2CuO / TS-1 at selected frequencies of 500 and 1000 kHz. The separation and migration information of photoinduced electron-hole pairs of the samples were studied by transient photocurrent and electrochemical impedance spectroscopy (EIS). Figure 6 As shown in (a), TS-1 and 0.2CuO / TS-1 exhibit rapid and reproducible photocurrent responses under visible light irradiation, with 0.2CuO / TS-1 exhibiting a stronger photocurrent intensity than TS-1. This is attributed to the enhanced electron-hole transfer capability of the composite catalyst after CuO loading, which effectively prevents the recombination of photogenerated carriers. Generally, the radius of the arc in the EIS Nyquist plot reflects the electron transfer resistance, with the smaller the EIS semicircle radius, the higher the photogenerated carrier transfer efficiency. Compared with TS-1, 0.05CuO / TS-1, 0.10CuO / TS-1, and 0.30CuO / TS-1, 0.20CuO / TS-1 has the smallest semicircle radius and the lowest electron-hole transfer resistance. The photocurrent and electrical impedance results are generally consistent, further confirming that CuO loading promotes the spatial separation of electron-hole pairs in TS-1, enhancing the photocatalytic degradation activity. To explore the photocatalytic mechanism, the flat band potentials of TS-1 and 0.2CuO / TS-1 were measured using Mott-Schottky plots (6c and d). The positive slopes of the curves indicate that both TS-1 and CuO / TS-1 are n-type semiconductors. The cross-intercepts indicate that the flat band potentials of TS-1 and 0.2CuO / TS-1 are -1.0 V and -0.50 V, respectively (vs Ag / AgCl, pH = 7). The flat band potentials of TS-1 and 0.2CuO / TS-1 relative to the standard hydrogen electrode (SHE) were calculated using the Nernst equation (Evs.NHE = Evs.Ag / AgCl + 0.22) to be -0.78 eV and -0.28 eV, respectively. Based on the band gap energy and conduction band potential, the valence band (VB) potentials of TS-1 and CuO / TS-1 are 2.50 eV and 2.0 eV, respectively.

[0104] Although the embodiments of the present invention have been described above, it will be apparent to those skilled in the art that modifications and substitutions made without departing from the principles and spirit of the present invention are intended to fall within the scope of protection claimed by the present invention.

Claims

1. A CuO-supported titanium silicon molecular sieve CuO / TS-1 composite photocatalyst, characterized by: The loaded Cu is loaded on the lattice and surface of TS-1 in the form of CuO and is prepared by the following method: (1) Dissolve CuSO4 in 10 ml of deionized water and stir evenly, then add ammonia solution until the precipitate is completely dissolved to obtain a copper-ammonia complex; (2) Dissolve TS-1 powder in deionized water, stir and ultrasonicate to make it evenly distributed; then add copper ammonia complex dropwise into TS-1, stir evenly, add CTAB and stir, perform hydrothermal reaction, wash, dry and grind to obtain; The mass ratio of Cu to TS-1 in CuSO4 is (0.05-0.30):1; In step (1), the amount of ammonia water used is such that the Cu(OH)2 precipitate is just dissolved into a cuprammonium complex by adding ammonia water dropwise.

2. The CuO-supported titanium silicon molecular sieve CuO / TS-1 composite photocatalyst according to claim 1, characterized in that: In step (2), after the TS-1 powder is dissolved in deionized water, the stirring time is 0.5-1.5 h, and the ultrasonic time is 0.5-1.5 h; the hydrothermal reaction temperature is 80-120 ° C, and the time is 6-10 h.

3. The CuO-supported titanium silicon molecular sieve CuO / TS-1 composite photocatalyst according to claim 1, characterized in that: In step (2), the CTAB mass concentration in the reaction solution is 50 mg / L; deionized water is used for washing; the drying time is 10-14 h, and the drying temperature is 50-70°C.

4. Use of the CuO-supported titanium silicon molecular sieve CuO / TS-1 composite photocatalyst according to any one of claims 1 to 3 in the degradation of tetracycline antibiotics in wastewater, characterized in that: Composite photocatalyst CuO / TS-1 and H2O2 were added to tetracycline antibiotic wastewater and stirred, and photodegradation reaction was carried out by irradiation with a 420nm filter for 60 minutes.

5. The use of a CuO-supported titanium silicon molecular sieve CuO / TS-1 composite photocatalyst for the degradation of tetracycline antibiotics in wastewater according to claim 4, characterized in that: During degradation, the dosage of the composite photocatalyst CuO / TS-1 is 10-75 mg, the dosage of H2O2 is 0-15 ml / L, the concentration of tetracycline antibiotics in the wastewater is 25-75 mg / L, and the initial pH value of the wastewater is 2-11.

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