A kind of ZnO-MoO3 material loaded oxygen vacancy and its preparation method and the application of activated ferrate in degrading water pollutants

Abstract

The application discloses a kind of ZnO-MoO3 material of loading oxygen vacancy and its preparation method and the application of activated high ferrate degradation water pollutants, the preparation method of ZnO-MoO3 material of loading oxygen vacancy is as follows: the mass ratio 10:1~80:1 of ZnO and MoO3 is weighed, first using oscillator initial mixing, then be placed in ball mill jar, again put into ball mill and carry out ball milling to depth mixing, again the mixed powder is placed in tube furnace and calcined under inert atmosphere, calcination temperature is 300~900 DEG C, calcination time is 2~10 hours, collect sample after calcination, after cooling to room temperature, the ZnO-MoO3 material of loading oxygen vacancy is prepared.The application uses ZnO-MoO3 material of loading oxygen vacancy and activates high ferrate (Fe (VI)) to strengthen degradation typical drug pollutants, and the material significantly improves the degradation ability of high ferrate to drug pollutants, widens the application scene of high ferrate and realizes the effective removal of water drug pollutants.

Description

Technical Field

[0001] The invention belongs to the field of water treatment, and in particular relates to a ZnO-MoO3 material loaded with oxygen vacancies, a preparation method thereof, and application of activated ferrate in degrading water pollutants. Background Art

[0002] Ferrate (Fe(VI)) is a multifunctional water purifier with oxidation, flocculation, and adsorption properties, and is widely used in water treatment. However, Fe(VI) is easily affected by water environmental factors such as pH, coexisting substances in the water, and temperature, causing it to self-decompose, resulting in its inability to fully degrade pollutants. In addition, Fe(VI) has the defect of selective oxidation, which makes it unable to effectively remove some pollutants. Therefore, there is an urgent need to develop Fe(VI) activation technology to overcome these shortcomings and achieve the goal of enhanced degradation of water pollutants.

[0003] With the widespread use of various pharmaceuticals, refractory drugs are increasingly accumulating in natural water bodies, negatively impacting both the ecology and human health. However, current conventional water treatment processes are unable to effectively remove these drugs from water.

[0004] The present invention uses ZnO-MoO3 material loaded with oxygen vacancies to activate Fe(VI) to enhance the degradation of typical pharmaceutical pollutants. After calcination, the surface of the ZnO-MoO3 material contains a large number of oxygen vacancies. The localized electrons contained in the oxygen vacancies help activate Fe(VI) to form an intermediate valence iron oxide compound (Fe(V) / Fe(IV)) with strong reactivity, thereby improving the oxidation performance of Fe(VI). At the same time, oxygen vacancies are easy to combine with dissolved oxygen, and thus have the potential to form active oxygen free radicals, which helps to compensate for the selective oxidation of high-valent iron species. In addition, compared with single ZnO (159.33m 2 / g) or MoO3(171.29m 2 / g) has a larger specific surface area (195.37m 2 / g) and Brønsted acid sites, which help to improve the adsorption capacity of the reaction system. Summary of the Invention

[0005] In view of the above-mentioned technical problems existing in the prior art, the purpose of this application is to provide a ZnO-MoO3 material loaded with oxygen vacancies, a preparation method thereof, and the application of activated ferrate (Fe(VI)) to degrade water pollutants. In order to make up for the defects of Fe(VI) in the application of water treatment and to achieve effective removal of pharmaceutical pollution in water bodies, the present invention uses ZnO-MoO3 material loaded with oxygen vacancies to activate Fe(VI) to enhance the degradation of typical pharmaceutical pollutants. This material significantly improves the degradation ability of Fe(VI) on pharmaceutical pollutants, broadens the application scenarios of Fe(VI), and achieves effective removal of pharmaceutical pollutants in water bodies.

[0006] The present invention provides a method for preparing a ZnO-MoO3 material loaded with oxygen vacancies, as well as a method for activating Fe(VI), improving the pollutant degradation performance of Fe(VI), and expanding the application scenarios of Fe(VI). The preparation method of the ZnO-MoO3 material is optimized by regulating the mass ratio of ZnO and MoO3, calcination temperature, and other conditions during the material preparation process. By adding the ZnO-MoO3 material and Fe(VI) in a specific ratio to contaminated water, the conversion of Fe(VI) into more reactive Fe(V) and Fe(IV) is promoted, and reactive oxygen species (ROS) are simultaneously generated, thereby enhancing the degradation and removal of pollutants.

[0007] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0008] A method for preparing a ZnO-MoO3 material loaded with oxygen vacancies comprises the following steps:

[0009] 1) Weigh ZnO and MoO3 in a mass ratio of 10:1 to 80:1 and initially mix using an oscillator;

[0010] 2) The primary mixture of ZnO and MoO3 is placed in a ball mill jar, and then placed in a ball mill for ball milling to achieve deep mixing. The mixed powder is then placed in a tube furnace and calcined under an inert atmosphere at a temperature of 300 to 900° C. for 2 to 10 hours. The calcined sample is collected and cooled to room temperature to obtain the oxygen vacancy-loaded ZnO-MoO3 material.

[0011] Furthermore, the mass ratio of ZnO to MoO3 in step 1) is 25 to 35:1, more preferably 30:1.

[0012] Furthermore, in step 2), the inert atmosphere is nitrogen, the calcination temperature is 580-620° C., and the calcination time is 4-7 hours.

[0013] Further, the ball milling speed in step 2) is 500-700 r / min, and the ball milling time is 1-4 hours, which aims to mix ZnO and MoO3 sufficiently and reduce the particle size of the mixture.

[0014] The ZnO-MoO3 material loaded with oxygen vacancies can be well applied to activate high ferrate to degrade water pollutants.

[0015] The ZnO-MoO3 material loaded with oxygen vacancies is applied to activate Fe(VI) to intensify the degradation of water drug pollution, and further, the method for activating the material to intensify Fe(VI) can be applied to the field of drinking water treatment and sewage advanced treatment.

[0016] The application method of the ZnO-MoO3 material to intensify Fe(VI) to remove water pollutants comprises the following steps:

[0017] 1) According to the approximate concentration of pollutants in the water sample to be treated, a certain amount of ZnO-MoO3 material and Fe(VI) are prepared, and the pH of the water sample to be treated is adjusted to obtain the water sample to be treated;

[0018] 2) The ZnO-MoO3 material and Fe(VI) are mixed and added into the water body containing drug pollution in proportion, and the mixed reagent is fully mixed and reacted with the water body pollutants under stirring;

[0019] 3) The change of the concentration of pollutants in the water body, the change of total organic carbon (TOC) and the change of precipitated metal ions are measured to evaluate the degradation degree of pollutants in the water body and the leaching of the catalyst.

[0020] Further, the pH of the pretreated water body in step 1) is adjusted to 5-9.

[0021] Further, the molar ratio of Fe(VI) to pollutants prepared in step 1) is 3:1-20:1, and the mass ratio of ZnO-MoO3 material to Fe(VI) is 1:2-2:1.

[0022] Further, the molar ratio of Fe(VI) to organic pollutants in the water body is 5-6:1, and the mass ratio of the loaded ZnO-MoO3 material to high Fe(VI) is controlled in the range of 0.8-1.2:1.

[0023] The beneficial effects obtained by the present application are as follows:

[0024] (1) Compared with the oxidation degradation of water pollutants by single Fe(VI), the surface oxygen vacancies generated by calcination during the preparation of the ZnO-MoO3 material of the present invention contain localized electrons, which can confine the activation of Fe(VI) to convert it into Fe(IV) and Fe(V), thereby improving the efficiency of Fe(VI) oxidation degradation of pollutants;

[0025] (2) ZnO in the ZnO-MoO3 material, as an amphoteric oxide, can buffer the pH to a certain extent, preventing the stability of Fe(VI) from being affected by large changes in pH, thereby ensuring the effectiveness of Fe(VI) in treating water pollutants;

[0026] (3) The surface oxygen vacancies in the ZnO-MoO3 material have a strong binding ability with dissolved oxygen in water, and the localized electrons contained in the material have the potential to generate reactive oxygen species (ROS) after combining with dissolved oxygen, which can make up for the selective oxidation defect of Fe(V) / Fe(IV);

[0027] (4) ZnO-MoO3 material has a larger specific surface area (compared to single ZnO (159.33m 2 / g) or MoO3(171.29m 2 / g, the composite material has a larger specific surface area (195.37m 2 / g), has a certain adsorption capacity and can enrich pollutants. In addition, the MoO3 in the material has Brønsted acid sites, which can further enhance the adsorption performance of the material. This increases the probability of contact reaction between Fe(VI) and pollutants, and improves the efficiency of Fe(VI) oxidation degradation of pollutants.

[0028] (5) The flocculation of Fe(VI) can greatly reduce the precipitation of Zn in the activated material. 2+ 、Mo 6+ Secondary pollution caused by dissolving into water, thereby reducing the impact of the precipitation of metal ions in the activated material on the concentration of heavy metal ions in the water to be treated;

[0029] (6) The enhanced Fe(VI) degradation method for water pollutants described in the present invention is simple to operate, low-cost, and integrates multiple water treatment process flows, and has certain economic and engineering application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 shows the microscopic morphology of the materials; (a) ZnO micromorphology and (b) MoO3 doped with ZnO micromorphology (i.e., 1:30 calcined ZnO-MoO3 material).

[0031] Figure 2Material property characteristics (XRD, TPD-O2); (a) XRD comparison diagram of ZnO-MoO3 material before and after calcination and (b) TPD-O2 diagram of calcined ZnO-MoO3 material before and after reaction.

[0032] Figure 3 Graphs showing the removal rate of trimethoprim (TMP) and the effect of inorganic mineralization in Example 1 and Comparative Examples 1 and 2; (a) graph showing the removal rate of trimethoprim (TMP) and (b) graph showing the removal rate of inorganic mineralization.

[0033] Figure 4 The removal rate of trimethoprim (TMP) in Example 1 and Comparative Examples 3 and 4 is shown in FIG.

[0034] Figure 5 The removal rates of pollutants and the pH change curves of the reaction solutions in Examples 2 and 3 are shown. (a), (b) The removal rates of pollutants in Examples 2 and 3 and (c) the pH change curves. DETAILED DESCRIPTION

[0035] The present invention will be further described below with reference to specific embodiments, but the protection scope of the present invention is not limited thereto.

[0036] The ferrate used in the embodiment of the present invention is potassium ferrate.

[0037] Blank example 1:

[0038] A method for preparing a ZnO-MoO3 material loaded with oxygen vacancies comprises the following steps:

[0039] 1) Weigh ZnO and MoO3 in a mass ratio of 30:1 and initially mix them using an oscillator;

[0040] 2) The initial mixture of ZnO and MoO3 is placed in a ball mill, and then placed in a ball mill for ball milling to achieve deep mixing. The ball milling speed is 600 r / min and the ball milling is carried out for 2 hours. The purpose is to fully mix ZnO and MoO3 and reduce the particle size of the mixture. The ball-milled mixed powder is then placed in a tube furnace and calcined under nitrogen at a temperature of 600°C for 6 hours. The calcined sample is collected and cooled to room temperature to obtain the oxygen vacancy-loaded ZnO-MoO3 material, which is labeled as the 1:30 calcined ZnO-MoO3 material. Its specific surface area is 195.37 m 2 / g, microscopic morphology Figure 1b .

[0041] The preparation method of calcined ZnO is based on the preparation method of ZnO@MoO3 material loaded with oxygen vacancies. The only difference is that the amount of MoO3 added is changed to 0, and other conditions remain unchanged. The microstructure of calcined ZnO is shown in Figure 1a.contrast Figure 1a -b characterization results, Figure 1b The white spots attached to the ZnO surface are MoO3, which shows that MoO3 is successfully loaded on the ZnO surface.

[0042] In addition, the oxygen vacancy-loaded ZnO-MoO3 material was prepared according to the above steps. When the mass ratio of ZnO and MoO3 was changed to 10:1 and 60:1 respectively, the other conditions remained unchanged. The finally prepared oxygen vacancy-loaded ZnO@MoO3 material can be labeled as 1:10 calcined ZnO-MoO3 material and 1:60 calcined ZnO-MoO3 material, respectively.

[0043] The preparation steps of the 1:30 calcined ZnO-MoO3 material were repeated, except that the mixed powder after ball milling was no longer calcined at high temperature under nitrogen, and was marked as the uncalcined ZnO-MoO3 material with a mass ratio of 1:30.

[0044] Example 1:

[0045] This example is to explore the activation effect of calcined ZnO-MoO3 material (Figures 1 to 4 show the characteristics of the material) on ferrate (Fe(VI)), and the following steps are performed:

[0046] First, 100 mL of boric acid buffer solution containing TMP (0.2 mol / L boric acid solution mixed with 0.05 mol / L sodium tetraborate solution in a specific ratio) was prepared to simulate a water sample with a pH of 7-7.5. The initial concentration of the contaminant TMP was 5 mg / L. An appropriate amount of calcined ZnO-MoO3 material (1:30) was then added to the water sample. A magnetic stirrer was used at 60 rpm to uniformly disperse the material in the water. Subsequently, an appropriate amount of Fe(VI) was added to ensure a molar ratio of Fe(VI) to the contaminant TMP of 5:1 and a mass ratio of 1:30 calcined ZnO-MoO3 to Fe(VI) of 1:1. TMP degradation was evaluated at specific reaction time points.

[0047] The experimental results are as follows: the TMP removal rate reaches more than 99% in 60 minutes. The specific TMP removal rate and inorganic mineralization removal rate results are shown in Figure 3 (a) and Figure 3 (b) The curve results corresponding to “1:30 calcined ZnO-MoO3”.

[0048] The XRD results of the calcined ZnO-MoO3 material with a mass ratio of 1:30 and the uncalcined ZnO-MoO3 material with a mass ratio of 1:30 are shown in Figure 2. Figure 2(a) "Calcinated MoO3-ZnO" and "Uncalcined MoO3-ZnO". 1:30 Calcinated ZnO-MoO3, the TPD-O2 graph results before the material reaction, the uncalcined material and after the reaction for 60 minutes are shown in Figure 2 (b) shows that the calcined ZnO-MoO3 material carries oxygen vacancies (in the box in the figure); in addition, the oxygen vacancy peak of the material disappears after the reaction, indicating that the oxygen vacancies in the above material participate in the activation reaction of Fe(VI).

[0049] Example 2:

[0050] To illustrate that ZnO-MoO3 materials can be used to enhance the degradation of pollutants by ferrate, this example is carried out in the following steps:

[0051] Two ferrate-resistant pollutants, carbamazepine (CBZ) and trimethoprim (TMP), were selected. A 200 mL borate buffer solution (0.2 mol / L boric acid solution mixed with 0.05 mol / L sodium tetraborate solution in a specific ratio) containing these pollutants was prepared to simulate a water sample with a pH of 7-7.5. Both CBZ and TMP concentrations were 5 mg / L. An appropriate amount of a 1:30 calcined ZnO-MoO3 material was weighed and added to the water sample under test, stirring with a magnetic stirrer. After the material was evenly dispersed in the water sample, a fixed amount of ferrate (at a molar ratio of 5:1 to pollutant) was weighed and added to the water sample under test, achieving a 1:1 mass ratio of 1:30 calcined ZnO-MoO3 material to ferrate. Samples were taken at specific times and quenched with excess sodium thiosulfate. The pH of the reaction solution was monitored regularly.

[0052] The experimental results are as follows: the TMP removal rate can reach 87% and the CBZ removal rate can reach 82% in 60 minutes. Figure 5 .

[0053] Example 3:

[0054] This example further illustrates the feasibility of using ZnO-MoO3 materials to enhance the degradation of pollutants by ferrate in actual water treatment. The reaction solution in Example 2 was changed from boric acid buffer solution to simulated surface water. As is known in the art, the components of simulated surface water are dissolved oxygen (5-6 mg / L), COD cr (15-20 mg / L), BOD5 (3-4 mg / L), ammonia nitrogen (0.5-1.0 mg / L), total phosphorus (P: 0.1-0.2 mg / L), fecal coliform group (2000-10000 / L). Other experimental procedures are the same as those in Example 2.

[0055] The purpose is to demonstrate the buffering effect of calcined ZnO-MoO3 material on pH and to illustrate that this method has an activation effect on Fe(VI) pollutant removal in actual water bodies.

[0056] The experimental results are as follows: the TMP removal rate can reach 69% and the CBZ removal rate can reach 67% in 60 minutes. Figure 5 .

[0057] Comparative Example 1:

[0058] This comparative example illustrates the effect of adding ZnO-MoO3 on the ferrate oxidation degradation of pollutants. Unlike Example 1, no calcined ZnO-MoO3 was added during the experimental procedure. Other steps and parameters were the same as those in Example 1.

[0059] The experimental results are as follows: the TMP removal rate in 60 minutes is 17%. The specific TMP removal rate and inorganic mineralization removal rate results are shown in Figure 3 (a) and Figure 3 (b) The curve results corresponding to “Fe(VI)”.

[0060] Comparative Example 2:

[0061] This comparative example illustrates the difference in ferrate activation effects between calcined and uncalcined ZnO-MoO3 materials. This example differs from Example 1 in that the same mass of uncalcined ZnO-MoO3 was added at a ratio of 1:30. Other steps and parameters were the same as those in Example 1.

[0062] The experimental results are as follows: the TMP removal rate reaches 46% in 60 minutes. The specific TMP removal rate and inorganic mineralization removal rate results are shown in Figure 3 (a) and Figure 3 The results corresponding to “1:30 uncalcined ZnO-MoO3” in (b).

[0063] Comparative Example 3:

[0064] This comparative example was designed to investigate the activation effect of ZnO undoped with MoO3 on ferrate during calcination. The difference from Example 1 was that the same mass of undoped MoO3 and calcined ZnO was added during the experimental steps. Other steps and parameters were the same as those in Example 1.

[0065] The experimental results are as follows: the TMP removal rate reaches 35% in 60 minutes. The specific TMP removal rate and inorganic mineralization removal rate results are shown in Figure 3 (a) and Figure 3 (b) The results corresponding to “calcined ZnO without MoO3”.

[0066] Comparative Example 4:

[0067] This comparative example is to optimize the mass ratio of ZnO and MoO3 during the calcination process. The difference from Example 1 is that the materials added in the experimental steps are calcined ZnO-MoO3 materials with the same mass ratio of 1:10. The other steps and parameters are the same as those in Example 1. The experimental results are as follows: The TMP removal rate reaches 88% in 60 minutes. The specific removal effect is shown in Figure 4 .

[0068] Comparative Example 5:

[0069] This comparative example is to optimize the mass ratio of ZnO and MoO3 during the calcination process. The difference from Example 1 is that the materials added in the experimental steps are calcined ZnO-MoO3 materials with the same mass ratio of 1:60. The other steps and parameters are the same as those in Example 1. The experimental results are as follows: the TMP removal rate reaches 62% in 60 minutes. The specific removal effect is shown in Figure 4 .

[0070] The contents described in this specification are merely an enumeration of implementation forms of the inventive concept, and the protection scope of the present invention should not be considered as being limited to the specific forms described in the embodiments.

Claims

1. A method for preparing a ZnO-MoO3 material loaded with oxygen vacancies, characterized in that The following steps are involved: 1) Weigh ZnO and MoO3 in a mass ratio of 10:1 to 80:1 and initially mix using an oscillator; 2) The primary mixture of ZnO and MoO3 is placed in a ball mill jar, and then placed in a ball mill for ball milling to achieve deep mixing. The mixed powder is then placed in a tube furnace and calcined under an inert atmosphere at a calcination temperature of 300-900°C for 2-10 hours. The calcined sample is collected and cooled to room temperature to obtain the oxygen vacancy-loaded ZnO-MoO3 material.

2. The method for preparing a ZnO-MoO3 material loaded with oxygen vacancies according to claim 1, wherein The mass ratio of ZnO to MoO3 in step 1) is 25~35:

1.

3. The method for preparing a ZnO-MoO3 material loaded with oxygen vacancies according to claim 1, wherein In step 2), the inert atmosphere is nitrogen, the calcination temperature is 580-620° C., and the calcination time is 4-7 hours.

4. The method for preparing a ZnO-MoO3 material loaded with oxygen vacancies according to claim 1, wherein In step 2), the ball milling speed is 500-700 r / min and the ball milling is performed for 1-4 hours. The purpose is to fully mix ZnO and MoO3 and reduce the particle size of the mixture.

5. A ZnO-MoO3 material loaded with oxygen vacancies prepared by the method according to any one of claims 1 to 4.

6. Use of the oxygen vacancy-loaded ZnO-MoO3 material as claimed in claim 5 in activating ferrate Fe(VI) to degrade water pollutants.

7. The use according to claim 6, characterized in that The pH of the water sample containing organic pollutants to be treated is adjusted to 5-9, and Fe(VI) and the ZnO-MoO3 material loaded with oxygen vacancies are simultaneously added thereto and stirred. The ZnO-MoO3 material loaded with oxygen vacancies activates Fe(VI), thereby improving the oxidative degradation performance of Fe(VI) and achieving efficient degradation and removal of organic pollutants in the water.

8. The use according to claim 7, characterized in that The molar ratio of Fe(VI) added to the organic pollutants in the water body is 3:1~20:1, and the mass ratio of the added oxygen vacancy-loaded ZnO-MoO3 activation material to Fe(VI) is controlled in the range of 1:2~2:

1.

9. The use according to claim 8, characterized in that The molar ratio of Fe(VI) added to organic pollutants in water is 5~6:1, and the mass ratio of the added oxygen vacancy-loaded ZnO-MoO3 activation material to Fe(VI) is controlled in the range of 0.8~1.2:1.

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