A heterogeneous iron-based catalyst, its preparation method and application

Abstract

The present invention relates to a heterogeneous iron-based catalyst FeOOH@WS2, a preparation method thereof, and a method for degrading antibiotics. The heterogeneous iron-based catalyst FeOOH@WS2 is a composite material prepared by a chemical precipitation method using NH4Fe(SO4)2 and WS2 as raw materials, and is used for activating persulfate (PS) to degrade sulfachloropyridazine (SCP) in water. It exhibits excellent catalytic performance without the need for external energy, has a high SCP removal rate, and also has the advantages of good stability, simple process, and recyclability.

Description

Technical Field

[0001] The present invention belongs to the technical field of water pollution treatment, and more specifically, relates to a new heterogeneous iron-based catalyst, a preparation method thereof, and a method for degrading antibiotics. Background Art

[0002] Antibiotics are regarded as emerging environmental pollutants in aquatic ecosystems due to their abuse in human health and animal husbandry and their long-term environmental persistence. In addition, the abuse and misuse of antibiotics have led to the rapid emergence of antibiotic-resistant bacteria (ARBs). ARBs are considered to spread between humans and animals through the food chain or direct or indirect environmental transfer. As a widely used drug, sulfachloropyridazine (SCP) has been identified as a concerning pollutant in surface water and groundwater. However, due to the non-degradable characteristics and polymer structure of antibiotics, traditional biological processes cannot completely remove them. Therefore, it is imperative to explore new control measures to address the challenges of organic pollutants.

[0003] Advanced Oxidation Processes (AOPs) are considered a promising drinking water technology for treating organic pollutants. Advanced oxidation methods based on persulfate (PS) activation can remove various organic pollutants. Heat, ultraviolet light, ultraviolet radiation, microwave radiation, transition metals, electrochemical reactions, and heterogeneous catalysts are commonly used as activators for activating persulfate (PS) and peroxymonosulfate (PMS), which can generate a large amount of SO4 ·- radicals.

[0004] Iron is a widely used metal activator due to its advantages such as high corrosion resistance, low cost, and ease of use. However, in a homogeneous Fe 2+ system, Fe 2+ is easily oxidized to Fe ·- by SO4 3+ , resulting in low PS activation efficiency and the formation of sludge (iron precipitates). The durability and stability of Fe 2+ are very important factors in the catalytic system. Due to the slow conversion rate of Fe 3+ / Fe 2+ , Fe 2+ is difficult to regenerate, leading to the rapid consumption of Fe 2+ and the accumulation of Fe 3+ . How to accelerate the cycle of Fe 3+ / Fe 2+ and improve the activation efficiency of PS has become the core of research in recent years.

[0005] Chinese patent document CN113499789A discloses a tungsten disulfide / nabokovite heterogeneous Fenton-like catalyst for degrading antibiotics in water. However, its scope of application is narrow, and the removal rate of levofloxacin antibiotics is only 60% under near-neutral room temperature conditions. The preparation method is complex, including steps such as the preparation of tungsten disulfide nanosheets, the preparation of nabokovite, and the preparation of tungsten disulfide / nabokovite heterogeneous Fenton catalyst by the blending method. It takes a long time and special equipment such as a high-pressure reactor with a polytetrafluoroethylene lining is also required.

[0006] Therefore, in the field of antibiotic sewage treatment, in-depth research on advanced oxidation technology still needs to be carried out. Summary of the Invention

[0007] To solve the problems in the prior art, the object of the present invention is to provide a heterogeneous iron-based catalyst FeOOH@WS2 with low cost, high catalytic efficiency and simple preparation process, and a method for activating persulfate (PS) to degrade sulfachloropyridazine (SCP) in water using the same.

[0008] One of the technical solutions of the present invention is to provide a preparation method of a heterogeneous iron-based catalyst FeOOH@WS2, which is characterized by including the following steps:

[0009] Step 1. Uniformly disperse tungsten disulfide WS2 into an ethanol aqueous solution to obtain a suspension;

[0010] Step 2. Under stirring, dropwise add an NH4Fe(SO4)2 solution into the suspension obtained in Step 1, and stir and react at 50-90 °C for 2-10 hours, wherein the molar ratio of NH4Fe(SO4)2 to WS2 is (1-4):1;

[0011] Step 3. Filter, wash and dry the product obtained in Step 2 to obtain the heterogeneous iron-based catalyst FeOOH@WS2.

[0012] In Step 1 of the above preparation method, the volume ratio of ethanol to water is 1:(5-15); preferably, the volume ratio of ethanol to water is 1:(7-11).

[0013] In Step 1 of the above preparation method, the addition amount of tungsten disulfide is 3-10 g / L.

[0014] In Step 1 of the above preparation method, the dispersion can be carried out by means such as oscillation and ultrasonic treatment.

[0015] In Step 2 of the above preparation method, the solvent of the NH4Fe(SO4)2 solution is selected from water or the same ethanol aqueous solution as in Step 1, the concentration of the NH4Fe(SO4)2 solution is 0.02-0.08 mol / L, the stirring speed is 100-500 revolutions per minute, and the time for dropwise addition is 10-30 minutes.

[0016] In step 3 of the above preparation method, filtration can be carried out by suction filtration, centrifugation, etc., preferably suction filtration with a sintered glass funnel. The solvents for washing are ultrapure water and ethanol, the drying temperature is 50-70 °C, and the drying time is 6-10 hours.

[0017] The second technical solution of the present invention is to provide a heterogeneous iron-based catalyst FeOOH@WS2 prepared by the above preparation method of the present invention. FeOOH@WS2 is a two-dimensional composite material formed by constructing WS2 on the surface of FeOOH, showing a flaky structure, with a particle size distribution range of 1-20 μm, and the particle size is concentrated in the range of 1-10 μm. It is stored for standby in a normal temperature and dry environment and has good stability.

[0018] The third technical solution of the present invention is to provide the application of the heterogeneous iron-based catalyst FeOOH@WS2 prepared by the above preparation method of the present invention in activating persulfate (PS) to degrade sulfachloropyridazine (SCP) in water. WS2 has a high specific surface area, abundant active sites and good electronic conductivity. In the present invention, WS2 is constructed on the surface of FeOOH to form FeOOH@WS2. WS2 can easily reduce Fe 3+ FeOOH back to Fe 2+ FeOOH , and PS is rapidly activated in the FeOOH@WS2 / PS system to generate more reactive species (·OH and SO4 ·- ), which can be applied to the efficient degradation of organic pollutants, especially the antibiotic sulfachloropyridazine.

[0019] The fourth technical solution of the present invention is to provide a method for using the heterogeneous iron-based catalyst FeOOH@WS2 to activate persulfate to degrade sulfachloropyridazine in water. The method is to uniformly disperse the heterogeneous iron-based catalyst FeOOH@WS2 prepared by the preparation method of the present invention into the water containing sulfachloropyridazine, adjust the pH to 3-11, and then add persulfate to degrade sulfachloropyridazine.

[0020] In the method, the content of the heterogeneous iron-based catalyst FeOOH@WS2 is 50-250 mg / L; preferably 100-250 mg / L.

[0021] In the method, the persulfate is selected from sodium persulfate, potassium persulfate or ammonium persulfate; preferably sodium persulfate.

[0022] In the method, the content of the persulfate is 0.25-2.00 mM; preferably 1.00-2.00 mM. In this application, "mM" represents "mmol / L".

[0023] In the method, it is preferred to adjust the pH to 3 - 6; the pH can be adjusted using a 0.1M HCl solution or a 0.1M NaOH solution.

[0024] In the method, the temperature of the degradation reaction is 15 - 25 °C, the time of the degradation reaction is 2 - 60 minutes, and preferably the time of the degradation reaction is 10 - 30 minutes.

[0025] The method can treat water bodies containing sulfachloropyridazine, and the content of sulfachloropyridazine can be 0.5 - 15 mg / L.

[0026] The method can be carried out under stirring, and the stirring speed is 100 - 500 revolutions per minute.

[0027] Furthermore, in order to achieve higher economic benefits, after the degradation reaction is completed, the FeOOH@WS2 in the water body is separated, recovered, washed, and dried to obtain reusable FeOOH@WS2. Washing is generally carried out using ultrapure water and ethanol.

[0028] The technical principle of the present invention is as follows:

[0029] Constructing WS2 on the surface of FeOOH, i.e., FeOOH@WS2, to activate PS for the degradation of the organic pollutant SCP. Due to the synergistic effect between PS and the FeOOH@WS2 catalyst, FeOOH@WS2 can effectively activate PS to generate more reactive species and oxidize SCP. From another perspective, since WS2 can easily reduce Fe 3+ FeOOH back to Fe 2+ FeOOH and enhance the electron transfer rate, PS can be rapidly activated in the FeOOH@WS2 / PS system. Therefore, there is a co-catalytic reaction mechanism for the activation of PS by FeOOH and WS2 in this system. The mechanisms of WS2 and FeOOH in FeOOH@WS2 / PS may be involved in the following reactions.

[0030] Fe 2+ FeOOH + S2O8 2- → Fe 3+ FeOOH + SO4 ·- + SO4 2- (1)

[0031] Fe 2+ FeOOH + SO4 ·- → SO4 2- + Fe 3+ FeOOH (2)

[0032] 2Fe3+ FeOOH +W 4+ →2Fe 2+ FeOOH +W 6+ (3)

[0033] Compared with fresh FeOOH@WS2, the relative content of W in FeOOH@WS2 after reacting with PS increases by 40%. However, the activation of PS by alone WS2 has a low removal efficiency for SCP. Therefore, the significant increase of W 6+ / W 4+ is not due to the reaction between W and PS, but the redox reaction between Fe 6+ and WS2. In addition, W 6+ can provide electrons to promote the generation of W 3+ FeOOH . To maintain the electron balance on the catalyst surface, W 4+ can accept electrons and then be converted to W 6+ , showing a redox cycle of W 6+ -W 4+ -W 4+ -W 6+ -W 4 during the PS activation process. In this way, a redox cycle of Fe 2+ FeOOH / Fe 3+ FeOOH is also realized, so no external energy is required during the reaction process.

[0034] Compared with the prior art, the present invention has the following advantages and effects:

[0035] 1. FeOOH@WS2 has good stability. Comparing the XRD patterns of FeOOH@WS2 before and after the degradation reaction, the powders are highly similar, indicating that there is no obvious structural change in FeOOH@WS2 after the reaction; comparing the XPS spectra of FeOOH@WS2 before and after the degradation reaction, the peaks of each element do not shift significantly, proving that FeOOH@WS2 is relatively stable during the reaction process.

[0036] 2. FeOOH@WS2 has excellent catalytic efficiency for activating PS to degrade SCP, with a fast speed and a high removal rate. Within 20 minutes, the removal rate of SCP by the FeOOH@WS2 / PS system can reach over 96.0%, and no external energy is required during the reaction process, and the operation is simple.

[0037] 3. The applicable pH range is relatively wide. FeOOH@WS2 can degrade SCP at pH values in the range of 3 - 11, and the removal rate of SCP under acidic conditions is significantly better than that under alkaline conditions.

[0038] 4. The catalyst has good recyclability and stability. The removal rate after the second use decreased from 96.8% in the first use to 87.2%, and the third and fourth uses also reached 78.9% and 70.2% respectively.

[0039] 5. After ICP-OES testing, there is almost no homogeneous iron ions in the degradation solution, with a low risk of metal leakage and no secondary pollution generated.

[0040] 6. The preparation method of FeOOH@WS2 is simple and low-cost. Description of the Drawings

[0041] Figure 1 XRD characterization was performed on the FeOOH@WS2 prepared in Example 1; the abscissa is 2θ (°), and the ordinate is intensity (a.u.); the XRD patterns from bottom to top represent FeOOH, WS2, FeOOH@WS2 before the degradation reaction, and FeOOH@WS2 after the degradation reaction respectively.

[0042] Figure 2 XPS characterization was performed on the FeOOH@WS2 prepared in Example 1; the abscissa is binding energy (eV), and the ordinate is intensity (a.u.); the XPS patterns from bottom to top represent FeOOH@WS2 before the degradation reaction and FeOOH@WS2 after the degradation reaction respectively.

[0043] Figure 3 SEM detection was performed on the FeOOH@WS2 prepared in Example 1, where (a) is separate FeOOH, (b) is separate WS2, (c) is FeOOH@WS2 before the reaction, and (d) is FeOOH@WS2 after the reaction.

[0044] Figure 4 Graph showing the effect of activating PS with different contents of FeOOH@WS2 on the degradation efficiency of SCP in Example 2; the abscissa is time (minutes), and the ordinate is C t / C0.

[0045] Figure 5 Graph showing the effect of different contents of sodium persulfate in the activation of FeOOH@WS2 on the degradation efficiency of SCP in Example 3; the abscissa is time (minutes), and the ordinate is C t / C0.

[0046] Figure 6 Graph showing the effect of activating PS with FeOOH@WS2 under different pH conditions on the degradation efficiency of SCP in Example 4; the abscissa is time (minutes), and the ordinate is C t / C0.

[0047] Figure 7Influence diagram of the degradation efficiency of SCP by FeOOH@WS2 reused multiple times in Example 5; the abscissa is time (minutes), and the ordinate is C t / C0.

[0048] Figure 8 Influence diagram of the degradation efficiency of SCP by different catalytic systems in Comparative Example 1; the abscissa is time (minutes), and the ordinate is C t / C0. Detailed implementation manners

[0049] The present invention will be further specifically described below through specific embodiments in conjunction with the accompanying drawings, but the protection scope of the present invention is not limited to these embodiments.

[0050] Example 1

[0051] (I) Preparation of the heterogeneous iron-based catalyst FeOOH@WS2, including the following steps:

[0052] Step 1. Ultrasonically treat 0.496 g (2 mmol) of tungsten disulfide WS2 and uniformly disperse it in 100 ml of an ethanol aqueous solution to obtain a uniformly mixed suspension, where the volume ratio of ethanol to water is 1:9;

[0053] Step 2. Under magnetic stirring at 200 revolutions per minute, gradually add 80 mL of 0.05 M NH4Fe(SO4)2 aqueous solution (4 mmol) dropwise to the WS2 suspension in Step 1 within 20 minutes, and raise the temperature to 70 °C and stir for reaction for 4 hours;

[0054] Step 3. Filter the product obtained in Step 2 with a sintered glass funnel, wash the solid with ultrapure water and ethanol, and dry it at 60 °C for 8 hours to obtain the heterogeneous iron-based catalyst FeOOH@WS2.

[0055] The obtained FeOOH@WS2 is stored for standby in a normal temperature and dry environment.

[0056] (II) Use the FeOOH@WS2 prepared in (I) to activate PS to degrade SCP, including the following steps: Under magnetic stirring, uniformly disperse the prepared FeOOH@WS2 into 200 mL of sulfachloropyridazine (SCP) aqueous solution, adjust the pH to 6, and then add sodium persulfate to degrade SCP. The degradation reaction temperature is 20 °C, and the degradation reaction time is 30 minutes, where the content of FeOOH@WS2 is 100 mg / L, the content of SCP is 5 mg / L, and the content of sodium persulfate is 1 mM.

[0057] During the degradation reaction process, at selected time points (2 minutes, 4 minutes, 6 minutes, 8 minutes, 10 minutes, 15 minutes, 20 minutes, and 30 minutes), 0.8 mL of the reaction solution was pipetted using a 1000 μL pipette into a 2 mL centrifuge tube containing 0.2 mL of methanol. After shaking evenly, it was aspirated with a syringe, filtered through a 0.22 μm needle filter, and injected into a liquid phase vial to obtain a water sample after SCP degradation.

[0058] HPLC determination of the SCP concentration in the water sample: It was detected by high performance liquid chromatography (HPLC, SHIMADZU LC - 2030) using a symmetric C18 chromatographic column. A mixture of methanol and 0.1% formic acid with a volume ratio of 3:2 was used as the mobile phase. It was carried out at a column temperature of 40 °C and a flow rate of 1.0 mL / min, and the detection wavelength was set at 270 nm. The injection volume for each sample was 10 μL, and it was analyzed for 5.5 minutes.

[0059] The removal rate of SCP = (C0 - C t ) / C0 × 100%, where C t and C0 (mg / L) are the concentrations of SCP at their respective time points and initial state. The removal rate of SCP in Example 1 was 95.8% within 15 min.

[0060] After the degradation reaction ended, the FeOOH@WS2 in the water was separated and recovered by suction filtration, washed with ultrapure water and ethanol, and dried to obtain reusable FeOOH@WS2.

[0061] The prepared FeOOH@WS2 was characterized by XRD. Using an X - ray diffractometer (XRD, Ultima IV), it was scanned at a rate of 10 °min in the angular range of 10 - 80°, as -1 shown. Figure 1 shown. Figure 1The bottom-up XRD patterns correspond to FeOOH, WS2, FeOOH@WS2 before the degradation reaction, and FeOOH@WS2 after the degradation reaction, respectively. For FeOOH, the peaks in the XRD pattern at 14.2°, 43.4°, 50.0° and 60.0° correspond to the (020), (131), (061) and (200) planes of the FeOOH standard card 70–0713. For WS2, the XRD pattern has strong diffraction peaks at (14.4°, 14.4°), (29.0°, 28.9°), (32.8°, 32.8°), (33.6°, 33.6°), (40.0°, 39.6°), (44.1°, 44.0°), (50.0°, 49.7°), (58.5°, 58.4°), (60.1°, 60.0°) and (76.1°, 76.0°), corresponding to the (002), (004), (100), (101), (103), (006), (105), (110), (112) and (116) planes of the WS2 standard card 84–1398, respectively. Comparing the FeOOH@WS2 patterns before and after the degradation reaction shows that the powders are highly similar, indicating that there is no obvious structural change in FeOOH@WS2 after the reaction, and it has structural stability.

[0062] The prepared FeOOH@WS2 was characterized by XPS. The X-ray photoelectron spectroscopy (XPS) spectrum was recorded using a Kratos AXIS Supra photoelectron spectrometer, and the spectrum was observed with Al Kα (hv = 1486.6 eV) radiation on a Thermo Fisher Scientific K-Alpha device, as Figure 2 shown. The characterizations of tungsten (W4f), sulfur (S2p), carbon (C1s), oxygen (O1s) and iron (Fe2p) were carried out, and the binding energy peaks at 712 eV, 531.3 eV, 284.8 eV, 163.2 eV and 34.7 eV correspond to Fe 2p, O1s, C 1s, S 2p and W 4f, respectively. Figure 2 The bottom-up XPS patterns correspond to FeOOH@WS2 before the degradation reaction and FeOOH@WS2 after the degradation reaction, respectively. By comparing the two patterns, it shows that there is no obvious shift in the peaks of each element after the reaction, indicating that the prepared FeOOH@WS2 is relatively stable during the reaction and has structural stability.

[0063] The morphology of the prepared FeOOH@WS2 was observed using a Hitachi S4800 scanning electron microscope (SEM) with a working voltage of 5.0 kV, as Figure 3 shown, presenting a flaky structure. Through Figure 3Image comparison shows that FeOOH@WS2 did not change significantly after the reaction, indicating that the prepared FeOOH@WS2 was relatively stable during the reaction.

[0064] The particle size distribution of the prepared FeOOH@WS2 was tested using a laser particle size analyzer Zetasizer Nano-S90 (Malvern Instruments, UK). The results showed that the particle size distribution range was 1 - 20 μm, and the particle size was concentrated in the range of 1 - 10 μm.

[0065] The leaching rate of metal elements was measured by inductively coupled plasma (ICP-OES, Varian 725-ES ICP). It was found that there was almost no homogeneous iron ions in the solution of the degradation reaction of the present invention, indicating that the activation of PS by FeOOH@WS2 mainly occurred on the material surface, with a low risk of metal leakage and no secondary pollution generated.

[0066] Example 2

[0067] This Example 2 is basically the same as Example 1, except that in step (ii) of this Example 2, the contents of FeOOH@WS2 were 50 mg / L, 150 mg / L, 200 mg / L, and 250 mg / L respectively.

[0068] The effect of activating PS with different contents of FeOOH@WS2 (Example 2 and Example 1) on the degradation efficiency of SCP was studied, and the results are as Figure 4 shown.

[0069] Figure 4 The results showed that: with the increase of the dosage of FeOOH@WS2, the degradation efficiency of SCP increased. When the content of FeOOH@WS2 increased from 50 mg / L to 250 mg / L, the removal rate of SCP within 15 min increased from 54.3% to 98.4%. This was because the amount of reactive species (i.e., ·OH and SO4 ·- ) increased with the increase of the catalyst dosage. When the content of FeOOH@WS2 increased from 50 mg / L to 100 mg / L, the removal rate increased from 54.3% to 95.8%. However, when the content of FeOOH@WS2 increased from 100 mg / L to 250 mg / L, the increase in the removal rate was only from 95.8% to 98.4%, which meant that 100 mg / L of FeOOH@WS2 could fully activate 1 mM of PS. From an economic perspective, 100 mg / L of FeOOH@WS2 could be selected as the optimal dosage for activating PS. When the content of FeOOH@WS2 was 50 mg / L, the removal rate of SCP could increase to 78.0% within 30 min.

[0070] Example 3

[0071] Example 3 is basically the same as Example 1, except that: in step (ii) of this Example 3, the contents of sodium persulfate are 0.25 mM, 0.5 mM, 1.5 mM, and 2 mM respectively.

[0072] The effects of activating PS with different contents of sodium persulfate (Example 3 and Example 1) by FeOOH@WS2 on the degradation efficiency of SCP were studied, and the results are as Figure 5 shown.

[0073] Figure 5 The results show that: as the content of sodium persulfate slightly increases from 0.25 mM to 1 mM, the removal rate of SCP within 15 min increases from 56.0% to 96.0%. A higher concentration of sodium persulfate leads to faster degradation of SCP because more sodium persulfate provides more free radicals to degrade SCP. When the content of sodium persulfate further increases from 1 mM to 1.5 mM and 2 mM, the removal rates of SCP within 15 min still remain high (96.0%, 97.0%). When the contents of sodium persulfate are 0.25 mM and 0.5 mM, the degradation time is extended to 30 minutes, and the SCP removal rates can reach 73.0% and 91.0%. The increase in the SCP removal rate between 0.25 - 0.5 mM of sodium persulfate content is greater than that between 1 - 2 mM, because the generated SO4 ·- may be consumed by the excess sodium persulfate or through its self - combination reaction (the formula is as follows), which limits the further increase in the SCP degradation efficiency.

[0074] SO4 ·– +S2O8 2- →SO4 2- +S2O8 ·– (4)

[0075] SO4 ·– +SO4 ·– →S2O8 2- (5)

[0076] Example 4

[0077] Example 4 is basically the same as Example 1, except that: in step (ii) of this Example 4, the pH values are adjusted to 3, 5, 7, 9, and 11 respectively.

[0078] The effects of activating PS by FeOOH@WS2 under different pH conditions (Example 4 and Example 1) on the degradation efficiency of SCP were studied, and the results are as Figure 6 shown.

[0079] Figure 6The results show that the degradation effect of SCP under acidic conditions is better than that under alkaline conditions. Specifically, at initial pH values of 3, 5, and 6, the removal rates of SCP within 15 minutes are 98.0%, 88.0%, and 90.8% respectively. This phenomenon may be because the FeOOH layer on the surface of WS2 dissolves in a strongly acidic environment. Obviously, when the initial pH value increases from 5 to 7, the SCP removal rate decreases from 88.0% to 47.6% within 15 minutes. When operating under alkaline conditions, the SCP removal rates reach 13.1% and 6.6% respectively. At pH 7, the SCP removal rate can still reach 77.7% when the degradation time is extended to 60 minutes. These results fully demonstrate that the FeOOH@WS2 / PS system can effectively remove the pollutant SCP within a wide pH range.

[0080] Example 5

[0081] This Example 5 is basically the same as Example 1, and the difference lies in that: in this Example 5, the FeOOH@WS2 is recycled for the second, third, and fourth times. Each recycling is to recycle, wash, and dry the used FeOOH@WS2 according to the method of Example 1, and then reuse it according to step (2) of Example 1 to activate PS for the degradation of SCP.

[0082] The effects of recycling FeOOH@WS2 to activate PS for the degradation efficiency of SCP in Example 5 and Example 1 were studied, and the results are as Figure 7 shown.

[0083] Figure 7 The results show that: after the second use of FeOOH@WS2, the catalytic activity decreases from 96.8% of the SCP removal rate in the first time to 87.2%, proving that the catalyst has good stability and reusability. The SCP removal rates can also reach 78.9% and 70.2% during the third and fourth recycling of FeOOH@WS2. The potential reason may be that the residual SCP and its degradation intermediates are adsorbed on the surface of FeOOH@WS2 and occupy the active sites, and the adsorbed intermediates cannot be removed by ordinary water washing, which limits the interaction between FeOOH@WS2 and PS.

[0084] Example 6

[0085] (1) Preparation of the heterogeneous iron-based catalyst FeOOH@WS2, including the following steps:

[0086] Step 1. Ultrasonically disperse 0.496 g of tungsten disulfide WS2 into 80 ml of an ethanol aqueous solution to obtain a uniformly mixed suspension, where the volume ratio of ethanol to water is 1:7;

[0087] Step 2. Under magnetic stirring at 300 rpm, 150 mL of 0.04 M aqueous solution of NH4Fe(SO4)2 was added dropwise to the WS2 suspension in Step 1 within 30 minutes, and the temperature was raised to 60 °C and stirred for reaction for 6 hours;

[0088] Step 3. The product obtained in Step 2 was filtered by a sintered funnel, and the solid was washed with ultrapure water and ethanol and dried at 50 °C for 10 hours to obtain the heterogeneous iron-based catalyst FeOOH@WS2.

[0089] The obtained FeOOH@WS2 was stored for standby in a normal temperature and dry environment.

[0090] (2) Using the FeOOH@WS2 prepared in (1) to activate PS for degrading SCP, including the following steps: Under magnetic stirring, the prepared FeOOH@WS2 was uniformly dispersed into 200 mL of aqueous solution of sulfachloropyridazine (SCP), the pH was adjusted to 4, and then sodium persulfate was added to degrade SCP. The degradation reaction temperature was 25 °C, and the degradation reaction time was 60 minutes. The content of FeOOH@WS2 was 150 mg / L, the content of SCP was 10 mg / L, and the content of sodium persulfate was 1.5 mM.

[0091] XRD, XPS, SEM, particle size distribution, and ICP-OES tests were carried out on the prepared FeOOH@WS2. The test results were very similar to those in Example 1 and will not be elaborated here; the SCP removal rate was 93.0%.

[0092] Example 7

[0093] (1) Preparation of the heterogeneous iron-based catalyst FeOOH@WS2, including the following steps:

[0094] Step 1. 0.496 g of tungsten disulfide WS2 was ultrasonically treated and uniformly dispersed into 120 ml of ethanol aqueous solution to obtain a uniformly mixed suspension, where the volume ratio of ethanol to water was 1:11;

[0095] Step 2. Under magnetic stirring at 300 rpm, 50 mL of 0.08 M NH4Fe(SO4)2 solution (the solvent was ethanol aqueous solution, and the volume ratio of ethanol to water was 1:11) was added dropwise to the WS2 suspension in Step 1 within 10 minutes, and the temperature was raised to 80 °C and stirred for reaction for 3 hours;

[0096] Step 3. The product obtained in Step 2 was filtered by a sintered funnel, and the solid was washed with ultrapure water and ethanol and dried at 70 °C for 6 hours to obtain the heterogeneous iron-based catalyst FeOOH@WS2.

[0097] The obtained FeOOH@WS2 was stored for standby in a normal temperature and dry environment.

[0098] (2) Using the prepared FeOOH@WS2 to activate PS for the degradation of SCP, which includes the following steps: Under magnetic stirring, the prepared FeOOH@WS2 was evenly dispersed into 200 mL of sulfachloropyridazine (SCP) aqueous solution, the pH was adjusted to 5, and then potassium persulfate was added to degrade SCP. The degradation reaction temperature was 22 °C, and the degradation reaction time was 40 minutes. The concentration of FeOOH@WS2 was 70 mg / L, the content of SCP was 3 mg / L, and the content of sodium persulfate was 0.8 mM.

[0099] The prepared FeOOH@WS2 was tested by XRD, XPS, SEM, particle size distribution, and ICP-OES. The test results were very similar to those of Example 1 and will not be elaborated here; the SCP removal rate was 98.0%.

[0100] Comparative Example 1

[0101] In Comparative Example 1, different catalytic systems were used to degrade SCP, and the different catalytic systems were as follows:

[0102] Using PS to degrade the same SCP water body as in Example 1;

[0103] Using FeOOH / PS to degrade the same SCP water body as in Example 1;

[0104] Using FeOOH@WS2 to degrade the same SCP water body as in Example 1;

[0105] Using WS2 / PS to degrade the same SCP water body as in Example 1.

[0106] The effects of the above different catalytic systems in Comparative Example 1 and the catalytic system in Example 1 of the present invention on the degradation efficiency of SCP were studied. The results are as Figure 8 shown.

[0107] Figure 8 The results showed that:

[0108] The removal rate of SCP under single PS was only 6.4% within 20 minutes, indicating that the degradation performance of unactivated PS was insufficient.

[0109] The removal rate of SCP in the FeOOH / PS system was 9.4%.

[0110] The adsorption capacity of FeOOH@WS2 for SCP was limited, and the removal rate of SCP was only 4.5%.

[0111] The removal rate of SCP in the WS2 / PS system was 40.6%.

[0112] Under the same conditions, the FeOOH@WS2 / PS catalytic system adopted in the present invention achieves a removal rate of SCP of over 96.0% within 20 minutes. It can be seen that the method for activating PS to degrade SCP using the heterogeneous iron-based catalyst FeOOH@WS2 of the present invention has very remarkable catalytic effects, and this method has a low risk of metal leakage, low cost, simple operation, is safe and reliable, and does not produce secondary pollution.

Claims

1. A preparation method of a heterogeneous iron-based catalyst FeOOH@WS2, characterized in that, It includes the following steps: Step 1. Uniformly disperse tungsten disulfide WS2 into an ethanol aqueous solution with a volume ratio of ethanol to water of 1:(5 - 15), and the addition amount of tungsten disulfide is 3 - 10 g / L to obtain a suspension; Step 2. While stirring, dropwise add the NH4Fe(SO4)2 solution into the suspension obtained in Step 1, and stir and react at 50 - 90 °C for 2 - 10 hours, where the molar ratio of NH4Fe(SO4)2 to WS2 is (1 - 4):

1. The solvent of the NH4Fe(SO4)2 solution is selected from water or the same ethanol aqueous solution as in Step 1. The concentration of the NH4Fe(SO4)2 solution is 0.02 - 0.08 mol / L, the stirring speed is 100 - 500 revolutions per minute, and the time for dropwise addition is 10 - 30 minutes; Step 3. Filter, wash, and dry the product obtained in Step 2 to prepare the heterogeneous iron-based catalyst FeOOH@WS2. FeOOH@WS2 is a two-dimensional composite material formed by constructing WS2 on the surface of FeOOH, showing a flaky structure with a particle size distribution of 1 - 20 μm, and activating persulfate to degrade sulfachloropyridazine in water.

2. The preparation method according to claim 1, wherein In Step 3, filtration is carried out by suction filtration, the washing solvent is ultrapure water and ethanol, the drying temperature is 50 - 70 °C, and the drying time is 6 - 10 hours.

3. The heterogeneous iron-based catalyst FeOOH@WS2 prepared by the preparation method according to Claim 1 or 2, showing a flaky structure, with WS2 constructed on the surface of FeOOH and a particle size distribution of 1 - 20 μm.

4. Application of the heterogeneous iron-based catalyst FeOOH@WS2 prepared by the preparation method according to Claim 1 or 2 in activating persulfate to degrade sulfachloropyridazine in water.

5. Method for activating persulfate by heterogeneous iron-based catalyst FeOOH@WS2 to degrade sulfachloropyridazine in water, characterized in that, Uniformly disperse the heterogeneous iron-based catalyst FeOOH@WS2 prepared by the preparation method according to Claim 1 or 2 into water containing sulfachloropyridazine, adjust the pH to 3 - 11, and then add persulfate to degrade sulfachloropyridazine.

6. The method according to claim 5, wherein The content of the heterogeneous iron-based catalyst FeOOH@WS2 is 50 - 250 mg / L, the content of persulfate is 0.25 - 2.00 mM, and the persulfate is selected from sodium persulfate, potassium persulfate, or ammonium persulfate.

7. The method according to claim 5, wherein Adjust the pH to 3 - 6.

8. The method according to claim 5, characterized in that, The temperature of the degradation reaction is 15 - 25 °C, and the time of the degradation reaction is 2 - 60 minutes.

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