Molybdenum disulfide / zirconium dioxide composite acoustic catalyst as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of acoustic catalysis composite materials, and particularly relates to a molybdenum disulfide / zirconium dioxide composite acoustic catalyst and a preparation method and application thereof. According to the preparation method disclosed by the invention, through a two-step method, zirconium dioxide is firstly prepared, and then MoS2 / ZrO2 is synthesized through a solvothermal synthesis method. According to the method, the influence on the ofloxacin degradation effect is researched from factors such as different compound proportions and addition amounts of MoS2 / ZrO2, the initial concentration and pH value of an ofloxacin solution, ultrasonic time and the like, the feasibility of the technology is comprehensively verified, and the degradation rate of the finally synthesized MoS2 / ZrO2 catalyst on ofloxacin under the ultrasonic condition can reach 80% or above.

Description

Technical Field

[0001] The present invention belongs to the technical field of sono-catalytic composite materials, and particularly relates to a molybdenum disulfide / zirconium dioxide composite sono-catalyst and a preparation method and application thereof. Background Art

[0002] With the rapid development of modern industry and urbanization, antibacterial drugs have received wide attention because they can destroy or slow down the growth of bacteria. With the extensive use and even abuse of antibacterial drugs, bacteria will develop multiple drug resistances, causing serious harm to agriculture, aquaculture, humans and livestock. Ofloxacin is an antibacterial drug with the advantages of broad spectrum, high efficiency, reasonable price, etc., and is widely used in human and animal treatments. Due to the overuse of ofloxacin by humans and veterinarians and its weak environmental degradation ability, it poses a threat to drinking water and irrigation water. It is crucial to solve the negative impact of ofloxacin on the environment.

[0003] There are processes such as adsorption, electrolysis, photocatalysis, chemical oxidation, etc. for the removal of ofloxacin wastewater. However, these methods have disadvantages such as high cost, low efficiency, and secondary pollution. As one of the advanced oxidation methods, ultrasonic degradation technology is gradually replacing traditional treatment methods. The ultrasonic removal technology has attracted extensive attention due to its simple equipment requirements, high efficiency, and convenient operation. During the ultrasonic process, cavitation forms bubbles and then collapses, generating sonoluminescence (SL) and high temperature and high pressure, and then generating a large number of active free radicals to mineralize organic matter. Adding a sono-catalyst can improve the sono-catalytic removal efficiency by generating more electron-hole pairs. Summary of the Invention

[0004] The present invention provides a MoS2 / ZrO2 composite sono-catalyst and a preparation method thereof, which use the formation of a composite of MoS2 and ZrO2 to improve the separation efficiency of electron-hole pairs, thereby improving the sono-catalytic removal efficiency.

[0005] The present invention is achieved by the following technical solutions:

[0006] A molybdenum disulfide / zirconium dioxide composite sono-catalyst, by molar ratio, MoS2:ZrO2 = 5% - 50%.

[0007] The preparation method of the above-mentioned molybdenum disulfide / zirconium dioxide composite sono-catalyst includes the following steps:

[0008] 1) Dissolve ZrO2, Na2MoO2·2H2O, and H2NCSNH2 powders in ethylene glycol, and ultrasonically dissolve them completely to obtain a mixed solution;

[0009] 2) Pour the mixed solution into a reaction kettle with a polytetrafluoroethylene lining and carry out a hydrothermal reaction;

[0010] 3) The product is naturally cooled, and the precipitate is collected by centrifugation, washed with distilled water and absolute ethanol, dried, and ground to obtain the MoS2 / ZrO2 composite acoustic catalyst.

[0011] Furthermore, in the above preparation method, the preparation method of the ZrO2 powder includes the following steps: Dissolve ZrOCl2·8H2O in deionized water, stir magnetically for 30 min to obtain a clear solution, then dropwise add NaOH to adjust the solution pH to 10.5, stir for 4 h, pour the mixed solution into a reaction kettle with a polytetrafluoroethylene inner lining, and carry out hydrothermal reaction at 200 °C for 6 h; the product is naturally cooled, the precipitate is collected by suction filtration, washed with distilled water and absolute ethanol, dried at 120 °C, and ground to obtain the ZrO2 powder.

[0012] Furthermore, in the above preparation method, in step 1), in terms of molar ratio, ZrO2:Na2MoO2·2H2O:H2NCSNH2 = 1:0.05 - 0.5:0.25 - 2.5.

[0013] Furthermore, in the above preparation method, in step 2), the conditions of the hydrothermal reaction are that the reaction temperature is 180 °C and the reaction time is 24 h.

[0014] The above application of the molybdenum disulfide / zirconium dioxide composite acoustic catalyst in the catalytic degradation of organic pollutant wastewater.

[0015] Furthermore, in the above application, the organic pollutant is ofloxacin.

[0016] Furthermore, in the above application, the method is as follows: Add the molybdenum disulfide / zirconium dioxide composite acoustic catalyst to the wastewater containing ofloxacin, and ultrasonicate at a power of 200 - 500 W for 120 min.

[0017] Furthermore, in the above application, the addition amount of the molybdenum disulfide / zirconium dioxide composite acoustic catalyst is 0 - 2 g / L, and the initial concentration of ofloxacin is 5 - 25 mg / L.

[0018] Furthermore, in the above application, the initial pH of the wastewater containing ofloxacin is 5.0 - 9.0.

[0019] The beneficial effects of the present invention are:

[0020] 1. The present invention combines the acoustic catalyst material with ultrasonic technology to treat organic pollutant wastewater, and can degrade the organic pollutants into CO2, H2O and other environmentally harmless inorganic salts, playing an important role in the field of water pollution treatment.

[0021] 2. The method of the present invention has the advantages of simple process, easy operation, good degradation effect and low energy consumption.

[0022] 3. The present invention uses a two-step method to prepare the MoS2 / ZrO2 composite. Compared with the single ZrO2 semiconductor material, its degradation effect on organic pollutant wastewater has been improved, and it has good application value. Description of the Drawings

[0023] Figure 1 XRD patterns of MoS2 / ZrO2 with different composite ratios.

[0024] Figure 2 XPS pattern of MoS2 / ZrO2 with a molar ratio of 10%.

[0025] Figure 3 EDS pattern of MoS2 / ZrO2 with a molar ratio of 10%.

[0026] Figure 4 Effect of the composite ratio of MoS2 / ZrO2 on the catalytic ultrasonic degradation of ofloxacin.

[0027] Figure 5 Effect of the addition amount of MoS2 / ZrO2 with a molar ratio of 10% on the degradation rate of ofloxacin.

[0028] Figure 6 Effect of the initial concentration of ofloxacin on the activity of the MoS2 / ZrO2 catalyst.

[0029] Figure 7 Effect of the initial pH of the ofloxacin solution on the activity of the MoS2 / ZrO2 catalyst.

[0030] Figure 8 Effect of the ultrasonic time on the degradation rate of ofloxacin. Detailed Embodiments

[0031] To better understand the technical solution of the present invention, specific embodiments are used for further detailed description, but the solution is not limited thereto.

[0032] Example 1 MoS2 / ZrO2 Composite Acoustic Catalyst

[0033] (I) Preparation of ZrO2

[0034] Dissolve 1.61 g of ZrOCl2·8H2O in deionized water. After magnetic stirring for 30 min, a clear solution is obtained. Dropwise add NaOH solution to make the pH = 10.5. After stirring for 4 h, transfer the solution to a 100 mL stainless steel autoclave lined with polytetrafluoroethylene, and react at 200 °C in a forced air drying oven for 6 h. After the reaction, filter by suction and wash 3 times with deionized water and absolute ethanol. Then place the obtained product in a vacuum drying oven at 120 °C for 4 h to completely remove moisture, and grind the obtained sample into fine powder to obtain ZrO2 powder.

[0035] (2) Preparation of MoS2 / ZrO2 Composite Acoustic Catalyst

[0036] Synthesis of MZ-5: Using ethylene glycol as the solvent, MoS2 / ZrO2 was synthesized by solvothermal method. Dissolve Na2MoO4·2H2O (60.5 mg, 0.25 mmol), H2NCSNH2 (95.2 mg, 1.25 mmol) and ZrO2 (615 mg, 5 mmol) in 50 mL of ethylene glycol, and ultrasonically treat for 30 min to completely dissolve it. Then transfer the mixed solution to a 100 mL stainless steel autoclave lined with polytetrafluoroethylene, and react at 180 °C in a forced-air drying oven for 24 h. After cooling to room temperature, centrifuge and wash to remove the liquid. Put the obtained product into a vacuum drying oven for drying, and grind it to obtain the MoS2 / ZrO2 (MZ-5) composite acoustic catalyst powder.

[0037] Synthesis of MZ-10: Using ethylene glycol as the solvent, MoS2 / ZrO2 was synthesized by solvothermal method. Dissolve Na2MoO4·2H2O (121 mg, 0.5 mmol), H2NCSNH2 (190.3 mg, 2.5 mmol) and ZrO2 (615 mg, 5 mmol) in 50 mL of ethylene glycol, and ultrasonically treat for 30 min to completely dissolve it. Then transfer the mixed solution to a 100 mL stainless steel autoclave lined with polytetrafluoroethylene, and react at 180 °C in a forced-air drying oven for 24 h. After cooling to room temperature, centrifuge and wash to remove the liquid. Put the obtained product into a vacuum drying oven for drying, and grind it to obtain the MoS2 / ZrO2 (MZ-10) composite acoustic catalyst powder.

[0038] Synthesis of MZ-20: Using ethylene glycol as the solvent, MoS2 / ZrO2 was synthesized by solvothermal method. Dissolve Na2MoO4·2H2O (242 mg, 1 mmol), H2NCSNH2 (380.6 mg, 5 mmol) and ZrO2 (615 mg, 5 mmol) in 50 mL of ethylene glycol, and ultrasonically treat for 30 min to completely dissolve it. Then transfer the mixed solution to a 100 mL stainless steel autoclave lined with polytetrafluoroethylene, and react at 180 °C in a forced-air drying oven for 24 h. After cooling to room temperature, centrifuge and wash to remove the liquid. Put the obtained product into a vacuum drying oven for drying, and grind it to obtain the MoS2 / ZrO2 (MZ-20) composite acoustic catalyst powder.

[0039] Synthesis of MZ-30: MoS2 / ZrO2 was synthesized by solvothermal method using ethylene glycol as the solvent. Na2MoO4·2H2O (363 mg, 1.5 mmol), H2NCSNH2 (570.9 mg, 7.5 mmol) and ZrO2 (615 mg, 5 mmol) were dissolved in 50 mL of ethylene glycol and ultrasonicated for 30 min to completely dissolve them. Then the mixed solution was transferred to a 100 mL stainless steel autoclave lined with polytetrafluoroethylene and reacted at 180 °C for 24 h in a forced air drying oven. After cooling to room temperature, the liquid was removed by centrifugation and washing, and the obtained product was placed in a vacuum drying oven for drying. After grinding, the MoS2 / ZrO2 (MZ-30) composite acoustic catalyst powder was obtained.

[0040] Synthesis of MZ-50: MoS2 / ZrO2 was synthesized by solvothermal method using ethylene glycol as the solvent. Na2MoO4·2H2O (605 mg, 2.5 mmol), H2NCSNH2 (951.5 mg, 12.5 mmol) and ZrO2 (615 mg, 5 mmol) were dissolved in 50 mL of ethylene glycol and ultrasonicated for 30 min to completely dissolve them. Then the mixed solution was transferred to a 100 mL stainless steel autoclave lined with polytetrafluoroethylene and reacted at 180 °C for 24 h in a forced air drying oven. After cooling to room temperature, the liquid was removed by centrifugation and washing, and the obtained product was placed in a vacuum drying oven for drying. After grinding, the MoS2 / ZrO2 (MZ-50) composite acoustic catalyst powder was obtained.

[0041] (III) Characterization

[0042] The phase purity and structure of the synthesized MoS2 / ZrO2 composite material were analyzed by X-ray powder diffraction (XRD) technology, and the obtained pattern is as Figure 1 shown. The XRD pattern of the neat continuous wave sample shows high crystallinity because of the presence of sharp, narrow and strong diffraction peaks, which conforms to the standard structure (JCPDS 01-088-1007), indicating the successful synthesis of the MoS2 / ZrO2 composite.

[0043] Figure 2 The XPS spectra of MoS2, ZrO2 and the MoS2 / ZrO2 composite acoustic catalyst are shown. The spectrum of MoS2 indicates the presence of Mo and S elements in the MoS2 sample, the spectrum of ZrO2 indicates the presence of Zr and O elements in the ZrO2 sample, and the elements Mo, S, Zr, O are observed in the spectrum of MoS2 / ZrO2, indicating the successful preparation of the MoS2 / ZrO2 composite material.

[0044] Figure 3EDS spectrum of MoS2 / ZrO2, showing the distribution of four elements. The mappings of Mo, S, Zr, and O show a uniform elemental distribution throughout the sample. The elemental distribution based on EDS confirmed the successful synthesis of the composite material.

[0045] Example 2 Degradation of Ofloxacin by MoS2 / ZrO2 Composite Sonocatalyst

[0046] The ofloxacin solution was degraded by ultrasound, and its maximum absorption wavelength was measured. The sono-catalytic activity of the MoS2 / ZrO2 composite material was evaluated by calculating the absorbance. After the ultrasound, the solution was filtered through a 0.22 μm microporous membrane, and the UV-vis spectrum of the obtained filtrate was measured in the range of 200 - 400 nm. The degradation rate of the ofloxacin solution could be calculated using the absorbance of the solution at its λmax = 291 nm.

[0047] The formula is: Degradation rate (%) = [(A0 - A t ) / A0] × 100%

[0048] where A0 is the initial absorbance of ofloxacin, and A t is the absorbance of ofloxacin after ultrasound.

[0049] (I) Influence of the composite ratio of different MoS2 / ZrO2 composite sonocatalysts on the degradation effect

[0050] The method is as follows: MoS2, ZrO2, and MoS2 / ZrO2 composite sonocatalysts (MZ-5, MZ-10, MZ-20, MZ-30, MZ-50) were added to the ofloxacin solution with an initial concentration of 10 mg / L, and the addition amount was 1 g / L for all. The solution was sonicated catalytically for 120 min at an ultrasonic power of 500 W.

[0051] Figure 4 Figure showing the comparison of the stirring adsorption and synergistic ultrasonic degradation effects of MoS2 / ZrO2 composite catalysts with different composite ratios on ofloxacin. From Figure 4 it can be seen that when the molar ratio increased from 5% to 50%, the degradation rate of ofloxacin showed a trend of first increasing and then decreasing. When the molar ratio was 10%, the degradation rate reached 77.15 ± 0.47%. This is because the composite of the materials improved the relationship between the band gap energies of MoS2 and ZrO2, thus inhibiting the recombination of electron-hole pairs, generating more reactive oxygen species, and increasing the degradation rate.

[0052] (II) Influence of the addition amount of MoS2 / ZrO2 on the degradation rate of ofloxacin

[0053] Method: Take 20 mL of ofloxacin solution with a concentration of 10 mg / L, add the MoS2 / ZrO2 composite acoustic catalyst prepared in Example 1 with a molar ratio of 10%, and the addition amounts are 0 mg, 10 mg, 20 mg, 30 mg, and 40 mg respectively. Under an ultrasonic power of 500 W, ultrasonicate for 120 min. The results are as Figure 5 。

[0054] It can be Figure 5 seen that as the addition amount of MoS2 / ZrO2 gradually increases, the degradation rate of ofloxacin continuously increases until it remains stable. When the addition amount is 30 mg, that is, 1.5 g / L, the degradation rate can reach 82.69 ± 0.26%. The increase in the degradation rate can be attributed to the increase in the active sites provided by MoS2 / ZrO2. In addition, it can be found that as the addition amount of the catalyst increases, the adsorption effect also continuously enhances, further indicating that the MoS2 / ZrO2 composite material can adsorb and bind with ofloxacin, thereby achieving a higher degradation rate.

[0055] (III) Influence of the initial concentration of ofloxacin on the degradation rate

[0056] Method: Take 20 mL of ofloxacin solutions with concentrations of 5 mg / L, 10 mg / L, 15 mg / L, 20 mg / L, and 25 mg / L respectively, add the MoS2 / ZrO2 composite acoustic catalyst prepared in Example 1 with a molar ratio of 10% to each, and the addition amount is 1.5 g / L for all. Under an ultrasonic power of 500 W, ultrasonicate for 120 min. The results are as Figure 6 。

[0057] The results show that when the initial concentration of ofloxacin is 10 - 25 mg / L, the degradation rate is negatively correlated with the concentration. This is because as the concentration of the pharmaceutical wastewater increases, the ofloxacin molecules shield each other, and the ofloxacin molecules and the MoS2 / ZrO2 catalyst shield each other, restricting the energy absorption and transfer caused by cavitation. When the initial concentration is 10 mg / L, the degradation rate can reach 82.69 ± 0.26%.

[0058] (IV) Influence of the pH of the ofloxacin solution on the degradation rate

[0059] Method: Take 20 mL of ofloxacin solution with an initial concentration of 10 mg / L, adjust the initial pH of the solution to 5, 6, 7, 8, and 9 respectively, add the MoS2 / ZrO2 composite acoustic catalyst prepared in Example 1 with a molar ratio of 10% to each, and the addition amount is 30 mg. Under an ultrasonic power of 500 W, ultrasonicate for 120 min. The results are as Figure 7 。

[0060] It can be Figure 7It can be seen that within the range of pH = 5 - 9, the pH has little effect on the degradation rate of ofloxacin. Among them, the degradation rate at pH = 9 is slightly higher than that at other pH values, which is 85.88% ± 0.63%. This result indicates that a weakly alkaline environment is conducive to the degradation of ofloxacin. Generally speaking, under ultrasonic conditions, MoS2 / ZrO2 has stable catalytic performance at pH = 5 - 9.

[0061] (V) Influence of ultrasonic time on degradation effect

[0062] The method is as follows: Add MoS2, ZrO2 and MoS2 / ZrO2 composite acoustic catalysts to the ofloxacin solution with an initial concentration of 10 mg / L. The catalyst addition amount is 1.5 g / L, the MoS2 / ZrO2 composite ratio is 10%, the ultrasonic power is 500 W, and the ultrasonic time is 30, 60, 90, 120 min.

[0063] Figure 8 It is a comparison chart of the degradation effects of ofloxacin solutions by MoS2, ZrO2 and MoS2 / ZrO2 composite acoustic catalysts at different times. "US" represents the degradation of ofloxacin by only ultrasonic without catalyst; "US + ZrO2" represents the degradation of ofloxacin under the combined action of ultrasonic and ZrO2 catalyst; "US + MoS2" represents the degradation of ofloxacin under the combined action of ultrasonic and MoS2 catalyst; "US + MoS2 / ZrO2" represents the degradation of ofloxacin under the combined action of ultrasonic and MZ-10 catalyst. It can be seen from the figure that MoS2 / ZrO2 significantly improves the degradation rate of ofloxacin, further confirming that MoS2 / ZrO2 has excellent ultrasonic catalytic activity and can significantly improve the ultrasonic degradation effect of ofloxacin.

Claims

1. A molybdenum disulfide / zirconium dioxide composite acoustic catalyst, characterized in that, In terms of molar ratio, MoS2:ZrO2 = 5% - 50%.

2. The preparation method of a molybdenum disulfide / zirconium dioxide composite acoustic catalyst according to claim 1, characterized in that It includes the following steps: 1) Dissolve ZrO2, Na2MoO2·2H2O, and H2NCSNH2 powders in ethylene glycol, and ultrasonically dissolve them completely to obtain a mixed solution; 2) Pour the mixed solution into a reaction kettle with a polytetrafluoroethylene liner and conduct a hydrothermal reaction; 3) Let the product cool naturally, centrifuge to collect the precipitate, wash it with distilled water and absolute ethanol, dry it, grind it, and prepare the MoS2 / ZrO2 composite acoustic catalyst.

3. The preparation method according to claim 2, wherein The preparation method of the ZrO2 powder includes the following steps: Dissolve ZrOCl2·8H2O in deionized water, stir magnetically for 30 min to obtain a clear solution, then add NaOH dropwise to adjust the solution pH = 10.5, stir magnetically for 4 h, and then pour the mixed solution into a reaction kettle with a polytetrafluoroethylene liner and conduct a hydrothermal reaction at 200 °C for 6 h; Let the product cool naturally, filter by suction to collect the precipitate, wash it with distilled water and absolute ethanol, dry it at 120 °C, and grind it to prepare the ZrO2 powder.

4. The preparation method according to claim 2, characterized in that, In step 1), in terms of molar ratio, ZrO2:Na2MoO2·2H2O:H2NCSNH2 = 1:0.05 - 0.5:0.25 - 2.

5.

5. The preparation method according to claim 2, wherein In step 2), the conditions of the hydrothermal reaction are that the reaction temperature is 180 °C and the reaction time is 24 h.

6. The application of the molybdenum disulfide / zirconium dioxide composite acoustic catalyst according to claim 1 in catalytic degradation of organic pollutant wastewater.

7. The application according to claim 6, wherein The organic pollutant is ofloxacin.

8. The application according to claim 7, wherein The method is as follows: Add the molybdenum disulfide / zirconium dioxide composite acoustic catalyst to the wastewater containing ofloxacin and ultrasonically treat it for 120 min at a power of 200 - 500 W.

9. The application according to claim 8, characterized in that, The addition amount of the molybdenum disulfide / zirconium dioxide composite acoustic catalyst is 0 - 2 g / L, and the initial concentration of ofloxacin is 5 - 25 mg / L.

10. The application according to claim 8, characterized in that, The initial pH of the wastewater containing ofloxacin is 5.0 - 9.0.

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