Application of molybdenum disulfide / polyaniline composite synergized with copper ion activated persulfate in degradation of antibiotics in water

Abstract

The application belongs to the field of water treatment, and particularly relates to application of a molybdenum disulfide / polyaniline composite MoS2@PANI in cooperation with copper ion activated persulfate in degradation of antibiotics in water. The MoS2@PANI is synthesized by modification of MoS2 with PANI. The degradation method is to add MoS2@PANI, Cu(II) and persulfate into water containing antibiotics to be treated to form a degradation reaction system, and then to degrade and remove the antibiotics. The application is green and efficient, and can effectively improve the removal rate of Cu(II) / persulfate in degradation of antibiotics in water by adding MoS2@PANI as a catalyst, thereby reducing the addition amount of Cu(II) and persulfate, further expanding the applicable pH environment, and having a broad industrial application prospect.

Description

Technical Field

[0001] This invention belongs to the field of water pollution treatment technology, specifically relating to a molybdenum disulfide / polyaniline composite material and its preparation method, as well as the application of this composite material as a catalyst to synergistically activate copper ions to degrade antibiotics in water using persulfate. Background Technology

[0002] Antibiotics, as a class of persistent organic pollutants in the aquatic environment, are widely used in daily life. Due to their potential harm to human health and the aquatic ecosystem, they have received increasing attention in recent years. Sulfathiazole (ST), a commonly used sulfonamide anti-inflammatory drug, is widely used in veterinary medicine and is composed of sulfonamides, aromatic aldehydes, and ketones. Due to its large usage and wide application, it has been frequently reported to be detected in water bodies, soil, and crops. In my country, ST is frequently detected in surface water, urban sewage, and pig farm wastewater at levels of ng / L or even μg / L, posing a potential threat to public health.

[0003] Advanced persulfate (PMS) oxidation technology has attracted widespread attention due to its high efficiency in degrading antibiotics. Persulfate can generate highly oxidizing sulfate radicals after being activated by light, heat, ultrasound, and transition metals. Among the many ways to activate PMS, transition metal ions have attracted widespread attention due to their low cost and simple operation. Homogeneous copper ions (Cu(II)) have been widely used in persulfate activation systems and have a good effect on removing recalcitrant organic matter in water. However, the Cu(II) / PMS system has obvious limitations: (1) High concentrations of metal ions are required to completely remove pollutants. The large dosage of Cu(II) leads to high cost. Cu(II) is easy to precipitate, and the large amount of metal ions remaining in the effluent is harmful to the ecological environment; (2) Excessive concentration of metal ions can easily lead to free radical scavenging effect, thereby weakening the treatment effect; (3) Cu(II) / Cu(I) is difficult to cycle and transform; (4) The pH conditions of the solution have a large impact on the catalytic effect.

[0004] Therefore, there is a need in this field to seek suitable materials to promote Cu(II) / Cu(I) cyclic conversion, achieve continuous activation of PMS, and achieve better activation effect. Summary of the Invention

[0005] The purpose of this invention is to overcome the limitations of the current copper ion persulfate activation system (Cu(II) / PMS), and to provide a novel catalyst and its preparation method, as well as the application of this catalyst in synergistically activating copper ions to degrade antibiotics in water using a green and efficient method.

[0006] In this invention, the terms "Cu(II)" or "copper ion" both refer to divalent copper ions.

[0007] Molybdenum disulfide (MoS2), a typical two-dimensional layered transition metal sulfide, has a structure similar to graphene. It is a sandwich structure composed of S-Mo-S atoms, with a Mo atom layer in the middle and S atom layers on either side. The layers are bonded by strong covalent bonds within the layers and by van der Waals forces between them. Due to its unique layered structure and properties, MoS2 is widely used in electronic devices, catalysts, and biomedicine. In water pollution treatment, MoS2 has proven to be a good catalyst for Cu(II) / PMS, promoting the Cu(II) / Cu(I) conversion cycle. However, MoS2 readily aggregates in water, leading to a decrease in active sites and suboptimal catalytic performance, thus requiring further modification.

[0008] Polyaniline (PANI), as a typical conductive polymer, has good reversible electrochemical redox properties, reversible doping / dedoping properties, high conductivity at room temperature, low price, low density and abundant active sites. It has been used in batteries, energy storage and catalysis.

[0009] To improve catalyst performance, this invention modifies MoS2 with PANI, and synthesizes a novel molybdenum disulfide / polyaniline composite material based on PANI and combined with MoS2, named MoS2@PANI.

[0010] This invention also provides a method for preparing the molybdenum disulfide / polyaniline composite material MoS2@PANI, comprising the following steps:

[0011] Step (1): Ammonium molybdate is dispersed in nitric acid aqueous solution to form a dispersion. The dispersion is then placed in an autoclave and hydrothermally reacted at 180-210°C for 20-24 hours. After cooling, the precipitate is collected, washed, and dried to obtain molybdenum trioxide.

[0012] Step (2): Disperse the molybdenum trioxide obtained in step (1) into water at a dosage of 7-9 g / L, and then mix it with hydrochloric acid solution of aniline. The aniline content in the mixture is 8-10 g / L and the HCl content is 20-25 g / L. Then, under the condition of maintaining 0-5℃, add an aqueous solution of persulfate dropwise to the mixture. After the addition is completed, the persulfate content reaches 2-8 g / L. Then, polymerize at room temperature for 4-7 hours. After collecting the precipitate, washing with water and drying, molybdenum trioxide / polyaniline composite is obtained.

[0013] Step (3): Disperse the molybdenum trioxide / polyaniline composite obtained in step (2) into a thiourea aqueous solution to form a dispersion. Then place the dispersion in an autoclave and hydrothermally react at 180-210°C for 18-24 hours. After cooling, collect the precipitate and wash with water to obtain the molybdenum disulfide / polyaniline composite material MoS2@PANI.

[0014] In the above preparation method, the term "water" refers to deionized water, "room temperature" refers to 20-30℃, and dispersion can be achieved by means of oscillation, ultrasonic treatment, etc.

[0015] Furthermore, in step (1), ammonium molybdate (AHM) is a commercially available reagent with the molecular formula (NH4)6Mo7O. 24 ·4H2O; the nitric acid concentration in the aqueous nitric acid solution is 5-15 v / v, and the ammonium molybdate content in the dispersion is 15-50 g / L.

[0016] Furthermore, in step (1), the equipment used for the hydrothermal reaction is an autoclave, preferably a stainless steel autoclave with a Teflon lining. Different specifications can be selected as needed, for example, with a capacity of 25-2000 mL, including but not limited to the following specifications: 25 mL, 50 mL, 75 mL, 100 mL, 150 mL, 200 mL, 250 mL, 300 mL, 400 mL, 500 mL, 1000 mL, and 2000 mL. The maximum operating temperature is 230℃, and the maximum operating pressure is 3 MPa.

[0017] Further, in step (1), after the hydrothermal reaction is completed, the mixture is cooled to room temperature, the precipitate is collected (collection is carried out using conventional methods in the art, such as filtration and centrifugation), the precipitate is then rinsed, and the rinsing solvent is selected from water, ethanol or an aqueous ethanol solution. Finally, the mixture is dried (drying is carried out using conventional methods in the art, such as drying in a drying oven), the drying temperature is 50 to 70°C, and the drying time is 8 to 12 hours.

[0018] Further, in step (2), the persulfate is selected from at least one of sodium persulfate, potassium persulfate, or ammonium persulfate.

[0019] Further, step (2) is carried out under stirring. The mixing requires continuous stirring for 0.5 to 1 hour.

[0020] Furthermore, in step (2), the drying temperature is 50-70°C and the drying time is 20-30 hours;

[0021] Furthermore, in step (3), the concentration of the thiourea aqueous solution is 5-20 g / L, and the content of the molybdenum trioxide / polyaniline composite in the dispersion is 1.5-4 g / L.

[0022] Furthermore, in step (3), the prepared molybdenum disulfide / polyaniline composite material MoS2@PANI is stored in water for later use.

[0023] The molybdenum disulfide / polyaniline composite material MoS2@PANI of the present invention, as measured by scanning electron microscopy (SEM), has a morphology in which molybdenum disulfide nanosheets are vertically and uniformly coated on the surface of polyaniline nanotubes in a flower-like manner.

[0024] This invention successfully prepared a novel MoS2@PANI composite material through hydrothermal reaction and in-situ polymerization. The composite material expands the lattice spacing of molybdenum disulfide through PANI, increasing the active sites of molybdenum disulfide, and can better synergistically activate persulfate (PMS) with trace amounts of Cu(II).

[0025] Therefore, this invention also provides the application of molybdenum disulfide / polyaniline MoS2@PANI composite material in the synergistic degradation of antibiotics in water by Cu(II)-activated bisulfate. Further, the degradation method includes: adding MoS2@PANI, Cu(II), and bisulfate to the water containing antibiotics to form a degradation reaction system, thereby degrading and removing the antibiotics. Preferably, the antibiotic is a sulfonamide antibiotic; more preferably, the sulfonamide antibiotic is sulfathiazole (ST).

[0026] The concentration of sulfathiazole in the water to be treated is generally no more than 20 mg / L, preferably no more than 5 mg / L.

[0027] The source of Cu(II) is a divalent copper compound soluble in water, including but not limited to copper sulfate, copper nitrate, copper halides, copper oxides, and copper hydroxides. Preferably, the source of Cu(II) is selected from at least one of copper sulfate, copper nitrate, or copper chloride. Preferably, the source of Cu(II) is fed in the form of an aqueous solution.

[0028] The peroxymonosulfate is selected from at least one of potassium peroxymonosulfate, sodium peroxymonosulfate, potassium peroxymonosulfate complex salt, or sodium peroxymonosulfate complex salt. Potassium peroxymonosulfate complex salt is preferred, with the molecular formula 2KHSO5. . KHSO4 . K2SO4, for example, trade names Oxone(TM) and Degussa. Preferably, the persulfate is added in the form of an aqueous solution.

[0029] In the degradation reaction system, the initial content of MoS2@PANI is 10-100 mg / L, preferably 10-50 mg / L; the initial concentration of Cu(II) is 40-320 μmol / L, preferably 40-160 μmol / L; and the initial concentration of persulfate is 0.25-4.0 mmol / L, preferably 0.5-2.0 mmol / L.

[0030] The preferred order of feeding to form the degradation reaction system is as follows: first add MoS2@PANI and Cu(II) and mix well, then add hydrogen persulfate.

[0031] Preferably, the initial pH value of the degradation reaction system is 3-10, more preferably 3-9. The pH value can be adjusted using an inorganic base (such as NaOH) or an inorganic acid (such as HCl).

[0032] Preferably, the degradation is carried out under stirring. The stirring speed is, for example, 500-800 rpm.

[0033] Preferably, the degradation time is 30 to 120 minutes, more preferably 40 to 60 minutes.

[0034] Preferably, the degradation temperature is 5–45°C, more preferably 15–25°C.

[0035] Preferably, to reduce wastewater treatment costs, after the degradation reaction, the MoS2@PANI in the water is separated, recovered, washed, dried, and reused. Specific procedures for each step can be found in the MoS2@PANI preparation method. Furthermore, the reuse process can be repeated multiple times.

[0036] The technical principle of this invention is as follows:

[0037] Currently, the copper divalent ion-activated persulfate system suffers from problems such as the large amount of Cu(II) required for precipitation, difficulty in recycling Cu(II) / Cu(I) and its inability to be recovered and reused, and the need to improve removal efficiency. This invention addresses these issues with the MoS2@PANI composite material, which expands the lattice spacing of molybdenum disulfide through PANI, increasing the number of active sites in molybdenum disulfide. This allows for better synergistic generation of Cu(I) from trace amounts of Cu(II) to activate PMS. More Mo(IV) can also reduce Cu(II) to Cu(I), promoting the Cu(II) / Cu(I) cycle. During the reaction, the increase in Cu(I) enhances electron transfer from Cu(I) to persulfate, exciting the generation of a strong oxidizing agent, HO. · , and 1 O2 further efficiently degrades antibiotics in water, especially sulfonamide antibiotics such as sulfathiazole.

[0038]

[0039] 2Cu(II)+Mo(IV)→2Cu(I)+Mo(VI) (2)

[0040] Cu(I) + HSO5 - →Cu(II)+SO4 ·- +HO - (3)

[0041] SO4 ·- +H2O→HO - +SO4 2- +H + (4)

[0042]

[0043] Cu(I) + O2 → Cu(II) + O2 ·- (6)

[0044] Compared with the shortcomings of existing technologies, the present invention has the following beneficial effects:

[0045] 1. The present invention prepares MoS2@PANI composite material, which not only uses polyaniline to solve the agglomeration problem of molybdenum disulfide, but also optimizes the synthesis route and process conditions to make molybdenum disulfide grow as uniformly as possible on polyaniline nanotubes. Polyaniline can better intercalate molybdenum disulfide, increase more active sites, and ensure the excellent performance of the catalyst and the stable and controllable preparation.

[0046] 2. This invention is the first to use the MoS2@PANI / Cu(II) / PMS system to generate highly active species (HO). · , and 1 O2) degrades antibiotics in water, solving the problems of difficult Cu(II) / Cu(I) recycling and conversion and large Cu(II) dosage causing environmental pollution in the Cu(II) / PMS system. The system requires a small amount of material, has a fast degradation rate and high efficiency, and can completely remove 5 mg / L sulfathiazole from water within 60 minutes.

[0047] 3. The MoS2@PANI / Cu(II) / PMS system of this invention further expands the applicable pH environment. It has a good degradation effect at pH values ​​from 3 to 10, and a very high removal rate at pH values ​​from 3 to 9, which solves the problem of Cu(II) / PMS being difficult to apply in practice due to pH limitations.

[0048] 4. The MoS2@PANI / Cu(II) / PMS system of this invention has certain common anion ( Even in the presence of Cl, sulfathiazole can still be removed, and the removal rate of sulfathiazole is greater than or equal to 92% under different concentrations.

[0049] 5. The MoS2@PANI / Cu(II) / PMS system of this invention has good stability. The catalyst itself is basically unchanged before and after the degradation reaction, and recycling it three times has no effect on the removal effect.

[0050] 6. The application method of this invention is simple, requires no complex equipment, operates under mild conditions, and can rapidly degrade at room temperature. It is highly operable and has broad practical application prospects. In practical applications, MoS2@PANI can also help utilize the trace copper ions inherent in wastewater to activate persulfate degradation of antibiotics, achieving a win-win situation. Attached Figure Description

[0051] Figure 1 This is a scanning electron microscope (SEM) image of MoS2@PANI prepared in Example 1.

[0052] Figure 2 The image shows the X-ray diffraction (XRD) pattern of MoS2@PANI prepared in Example 1; the horizontal axis is 2θ (°) and the vertical axis is intensity (au); the XRD patterns from top to bottom represent MoS2@PANI before degradation and MoS2@PANI after degradation, respectively.

[0053] Figure 3 This is a graph showing the degradation efficiency of sulfathiazole under different catalytic activation systems in Example 3; the horizontal axis represents time (minutes), and the vertical axis represents C. t (mg / L).

[0054] Figure 4 This is a graph showing the degradation efficiency of sulfathiazole using the MoS2@PANI / Cu(II) / PMS system under different PMS dosages in Example 4; the horizontal axis represents time (minutes), and the vertical axis represents C. t (mg / L).

[0055] Figure 5 This is a graph illustrating the degradation efficiency of sulfathiazole using the MoS2@PANI / Cu(II) / PMS system under different Cu(II) dosages in Example 5; the horizontal axis represents time (minutes), and the vertical axis represents C. t (mg / L).

[0056] Figure 6 This is a graph illustrating the degradation efficiency of sulfathiazole using the MoS2@PANI / Cu(II) / PMS system under different MoS2@PANI dosages in Example 6; the horizontal axis represents time (minutes), and the vertical axis represents C. t (mg / L).

[0057] Figure 7 This is a graph showing the degradation efficiency of sulfathiazole using the MoS2@PANI / Cu(II) / PMS system at different initial pH values ​​in Example 7; the horizontal axis represents time (minutes), and the vertical axis represents C. t (mg / L).

[0058] Figure 8Example 8 applies the MoS2@PANI / Cu(II) / PMS system with different concentrations of HCO3-. - 3. Degradation efficiency graph of sulfathiazole; the horizontal axis is time (minutes), and the vertical axis is C. t (mg / L).

[0059] Figure 9 Example 9 applies the MoS2@PANI / Cu(II) / PMS system with different concentrations of Cl - Degradation efficiency graph of sulfathiazole; x-axis is time (minutes), y-axis is C t (mg / L). Detailed Implementation

[0060] The present invention will be further described in detail below through specific embodiments and in conjunction with the accompanying drawings, but the scope of protection of the present invention is not limited to these embodiments.

[0061] Unless otherwise specified, all experiments were conducted at room temperature.

[0062] Example 1: Preparation of MoS2@PANI

[0063] Step (1) Mix 40 mL of deionized water and 20 mL of 30 wt% nitric acid to prepare a nitric acid aqueous solution; add 2.0 g of ammonium molybdate [(NH4)6Mo7O 24 The molybdenum trioxide (MoO3) was ultrasonically dispersed in the above nitric acid aqueous solution. The resulting dispersion was then transferred to a stainless steel autoclave (100 mL) lined with Teflon and hydrothermally synthesized at 180 °C for 24 hours. After cooling to room temperature, the precipitate was collected by filtration, washed three times with deionized water and ethanol, and dried in a drying oven at 60 °C for 10 hours to obtain molybdenum trioxide (MoO3).

[0064] Step (2) Dissolve 0.3 mL of aniline in 10 mL of 7% hydrochloric acid solution to prepare an aniline hydrochloric acid solution; weigh 0.2 g of MoO3 obtained in step (1) and ultrasonically disperse it in 25 mL of deionized water, then mix it with the above aniline hydrochloric acid solution and stir continuously for 0.5 h to obtain a mixture; add sodium persulfate aqueous solution (0.18 g of sodium persulfate dissolved in 15 mL of deionized water) dropwise to the above mixture under the condition of maintaining 0-5℃, and then polymerize at room temperature for 5 hours; after the polymerization reaction is completed, filter and collect the precipitate, wash it with water 3 times, and dry it in a drying oven at 60℃ for 24 h to obtain 0.24 g of molybdenum trioxide / polyaniline composite MoO3@PANI.

[0065] In step (3), 0.685 g of thiourea was dissolved in 70 mL of deionized water to prepare an aqueous solution of thiourea; 0.11 g of MoO3@PANI obtained in step (2) was dispersed in the above aqueous solution of thiourea to form a dispersion; then the dispersion was transferred to a stainless steel autoclave (100 mL) lined with Teflon and hydrothermally reacted at 200 °C for 20 hours; after cooling to room temperature, the precipitate was collected by centrifugation and washed with water 3 times to obtain the molybdenum disulfide / polyaniline composite material (stored in water).

[0066] The MoS2@PANI prepared in Example 1 was observed by scanning electron microscopy (SEM) using a Hitachi S4800 scanning electron microscope with an operating voltage of 5.0 kV. The results are as follows. Figure 1 As shown in the image, the SEM image on the left shows that the morphology of the molybdenum disulfide / polyaniline composite material MoS2@PANI is a flower-like structure in which molybdenum disulfide nanosheets are vertically and uniformly coated on the surface of polyaniline nanotubes. The particle distribution is narrow, which allows polyaniline to better intercalate molybdenum disulfide, increasing the number of active sites and ensuring excellent catalyst performance. It also demonstrates that the preparation method is stable and reliable. The image on the right is a magnified view of the details of molybdenum disulfide.

[0067] The MoS2@PANI prepared in Example 1 was subjected to X-ray diffraction (XRD) pattern analysis on Ultima IV at a scan rate of 10° / min within an angle range of 5 to 90°. The results are as follows: Figure 2 As shown in the figure, comparing the XRD patterns before and after the degradation reaction reveals that the patterns, peak positions, and peak heights are similar, indicating that MoS2@PANI did not undergo significant structural changes after the reaction and possesses structural stability.

[0068] Example 2: Preparation of MoS2@PANI

[0069] Step (1) Mix 50 mL of deionized water and 10 mL of 30% nitric acid to prepare a nitric acid aqueous solution; add 3.0 g of ammonium molybdate [(NH4)6Mo7O 24 The molybdenum trioxide (MoO3) was ultrasonically dispersed in the above nitric acid aqueous solution. The resulting dispersion was then transferred to a stainless steel autoclave (100 mL) lined with Teflon and hydrothermally synthesized at 200 °C for 20 hours. After cooling to room temperature, the precipitate was collected by filtration, washed three times with deionized water and ethanol, and dried in a drying oven at 70 °C for 8 hours to obtain molybdenum trioxide (MoO3).

[0070] Step (2) Dissolve 0.35 mL of aniline in 12 mL of 7% hydrochloric acid solution to prepare aniline hydrochloric acid solution; weigh 0.2 g of MoO3 obtained in step (1) and ultrasonically disperse it in 25 mL of deionized water, then mix it with the above aniline hydrochloric acid solution and stir continuously for 0.5 h to obtain a mixture; add potassium persulfate aqueous solution (0.3 g potassium persulfate dissolved in 15 mL of deionized water) dropwise to the above mixture under the condition of maintaining 0-5℃, and then polymerize at room temperature for 6 hours; after the polymerization reaction is completed, filter and collect the precipitate, wash it with water 3 times, and dry it in a drying oven at 70℃ for 20 hours to obtain molybdenum trioxide / polyaniline composite MoO3@PANI.

[0071] In step (3), 1.2 g of thiourea was dissolved in 70 mL of deionized water to prepare an aqueous solution of thiourea; 0.25 g of MoO3@PANI obtained in step (2) was dispersed in the above aqueous solution of thiourea to form a dispersion; then the dispersion was transferred to a stainless steel autoclave (100 mL) with a Teflon lining and hydrothermally reacted at 200 °C for 24 hours; after cooling to room temperature, the precipitate was collected by centrifugation and washed with water 3 times to obtain the molybdenum disulfide / polyaniline composite material MoS2@PANI (stored in water).

[0072] The MoS2@PANI prepared in Example 2 was subjected to SEM and XRD tests, and the results were consistent with those in Example 1, which will not be described in detail here.

[0073] Example 3: Application of MoS2@PANI

[0074] The removal efficiency of sulfathiazole under different catalytic activation conditions.

[0075] Nine groups of sulfathiazole aqueous solutions with an initial concentration of 5 mg / L (initial pH of sulfathiazole aqueous solution = 6) were taken to simulate antibiotic wastewater systems. Different catalytic activating agents were added to each group, and then the mixture was stirred at room temperature for 60 min to carry out the degradation reaction. The different catalytic activating agents are as follows (1) to (9):

[0076] (1) Potassium persulfate compound salt 0.5 mmol / L.

[0077] (2) MoS2@PANI 50mg / L, potassium persulfate compound salt 0.5mmol / L.

[0078] (3) MoS2@PANI 50mg / L.

[0079] (4) MoS2@PANI 50mg / L, copper sulfate 80μmol / L, potassium persulfate complex salt 0.5mmol / L.

[0080] (5) MoS 250mg / L, copper sulfate 80μmol / L, potassium persulfate complex salt 0.5mmol / L.

[0081] (6) MoS 250mg / L, potassium persulfate compound salt 0.5mmol / L.

[0082] (7) MoS 250mg / L.

[0083] (8) Copper sulfate 80 μmol / L, potassium persulfate complex salt 0.5 mmol / L.

[0084] (9) Copper sulfate 80 μmol / L.

[0085] Sampling during the degradation reaction: 0.8 mL of solution was taken at 0 min, 2 min, 4 min, 6 min, 8 min, 10 min, 15 min, 20 min, 30 min, 45 min and 60 min respectively and added to a centrifuge tube containing 0.2 mL of 16 mM sodium thiosulfate. The degradation reaction was terminated by shaking. The solution was filtered through a 0.22 μm filter membrane and stored in a 2 mL liquid chromatography vial for the determination of sulfathiazole concentration.

[0086] Removal rate determination: The HPLC vial containing the sulfathiazole sample was placed in a high-performance liquid chromatograph (HPLC) for detection. The sample was analyzed at an absorption wavelength of 285 nm using a symmetrical C18 column (HPLC, SHIMADZULC-2030, Japan). The mobile phase consisted of acetonitrile and 0.1% formic acid in a 30 / 70 ratio (flow rate 1.0 mL / min, temperature 40 °C). Each sample was analyzed for 7 minutes. The removal rate of sulfathiazole was calculated as follows: Removal rate = (C0 - C...) t ) / C0×100%, where C t C0 and C0 represent the time point t of degradation and the concentration of sulfathiazole in water under the initial conditions, respectively.

[0087] The results of Example 3 are as follows Figure 3 As shown. Figure 3The results showed that, at an initial concentration of 5.0 mg / L and a pH of 6, the degradation effects of Cu(II), MoS2@PANI, and MoS2 alone on sulfathiazole within 60 min were not significant, with removal rates of only 2%, 7%, and 3%, respectively. The removal rate of PMS alone within 60 min was only 30%. Adding a small amount of copper ions increased the degradation rate of Cu(II) / PMS from 30% to 50%; however, in the MoS2 / Cu(II) / PMS system, there was no significant difference in removal rate within 60 min compared to the Cu(II) / PMS system. Furthermore, the removal rate of MoS2@PANI / PMS within 60 min was 76%, indicating that MoS2@PANI of this invention can promote the activation of PMS; and the removal rate of MoS2@PANI / Cu(II) / PMS was significantly improved after adding a trace amount of Cu(II), achieving complete removal within 60 minutes. In summary, Cu(II) can activate PMS and improve pollutant degradation rate, while the addition of MoS2@PANI can accelerate the Cu(II) / Cu(I) cycle. Continuous activation of PMS by Cu(II) can significantly promote pollutant removal. Therefore, the combination of trace amounts of copper with MoS2@PANI can achieve the ideal effect of PMS activation. Furthermore, compared to MoS2 / Cu(II) / PMS, the introduction of PANI can also significantly improve the co-catalyst performance of MoS2.

[0088] Example 4: Application of MoS2@PANI

[0089] Effect of different dosages of persulfate on the degradation efficiency of sulfathiazole by MoS2@PANI / Cu(II) / PMS.

[0090] Five groups of sulfathiazole aqueous solutions with an initial concentration of 5 mg / L (initial pH = 6) were prepared to simulate antibiotic wastewater systems. Each group was treated with 50 mg / L MoS2@PANI and 80 μmol / L copper sulfate, followed by the addition of 0.25, 0.5, 1.0, 2.0, and 4.0 mmol / L potassium persulfate complex salts, respectively. The mixtures were then stirred at room temperature for 60 min to allow for degradation. Samples were taken during the degradation reaction, and the removal rate was measured. The procedure was the same as in Example 3. The results are as follows: Figure 4 As shown.

[0091] Figure 4The results showed that, with an initial sulfathiazole concentration of 5.0 mg / L and a pH of 6, the removal rates of sulfathiazole at 60 min were 74%, 98%, 80%, 84%, and 100% for MoS2@PANI / Cu(II) / PMS dosages of 0.25, 0.5, 1.0, 2.0, and 4.0 mmol / L, respectively. Since PMS is the main source of active species in the catalytic system, it is a key factor in the catalytic degradation of sulfathiazole. When the PMS concentration increased from 0.25 mmol / L to 0.5 mmol / L, the removal rate increased from 74% to 98%, which is because higher PMS concentrations generate more active species. When the PMS concentration was increased to 1.0 mmol / L and 2.0 mmol / L, the sulfathiazole removal rates were 80% and 84%, respectively, showing no significant increase, likely due to the self-quenching effect of PMS. However, when the PMS concentration was 4.0 mmol / L, the removal rate increased to 100%, possibly because the sufficiently high PMS concentration could offset the degradation. and HO · Therefore, the consumption of PMS does not inhibit the degradation of sulfathiazole but rather promotes it. In practical applications, considering the cost of industrial water treatment, a concentration of 0.5–2.0 mmol / L is preferred.

[0092] Example 5: Application of MoS2@PANI

[0093] Effect of different Cu(II) dosages on the degradation efficiency of sulfathiazole by MoS2@PANI / Cu(II) / PMS.

[0094] Four groups of sulfathiazole aqueous solutions with an initial concentration of 5 mg / L (initial pH of sulfathiazole aqueous solution = 6) were prepared to simulate antibiotic wastewater systems. Each group was treated with 50 mg / L MoS2@PANI, followed by the addition of 40, 80, 160, and 320 μmol / L copper nitrate, respectively. Then, each group was treated with 0.5 mmol / L potassium persulfate compound salt. The mixture was stirred at room temperature for 60 min to allow for degradation. Samples were taken during the degradation reaction, and the removal rate was measured. The procedure was the same as in Example 3. The results are as follows: Figure 5 As shown.

[0095] Figure 5The results showed that, with an initial concentration of sulfathiazole of 5.0 mg / L and a pH of 6, the removal rates of sulfathiazole at 60 min were 59%, 98%, 100%, and 74% for Cu(II) dosages of 40, 80, 160, and 320 μmol / L in MoS2@PANI / Cu(II) / PMS, respectively. Higher degradation efficiency was observed at low Cu(II) dosages (40–160 μmol / L), and the removal rate increased with increasing Cu(II) dosage. This phenomenon can be attributed to the increased number of catalytic sites resulting from the increased Cu(II) dosage, which activates more PMS to generate active species. When the Cu(II) dosage was increased to 320 μmol / L, the removal rate at 60 min was 74%, which may be because excessively high Cu(II) dosage quenches free radicals, thus inhibiting degradation.

[0096] Example 6: Application of MoS2@PANI

[0097] Effect of different dosages of MoS2@PANI on the degradation efficiency of sulfathiazole by MoS2@PANI / Cu(II) / PMS.

[0098] Five groups of sulfathiazole aqueous solutions with an initial concentration of 5 mg / L (initial pH of sulfathiazole aqueous solution = 6) were prepared to simulate antibiotic wastewater systems. MoS2@PANI concentrations of 10, 20, 30, 40, and 50 mg / L were added to each group, followed by the addition of 80 μmol / L copper sulfate and 0.5 mmol / L sodium persulfate complex salt. The mixtures were then stirred at room temperature for 60 min to allow for degradation. Samples were taken during the degradation reaction, and the removal rate was measured. The procedure was the same as in Example 3. The results are as follows: Figure 6 As shown.

[0099] Figure 6 The results showed that, with an initial concentration of sulfathiazole of 5.0 mg / L and a pH of 6, the removal efficiencies of sulfathiazole over 60 min were 51%, 62%, 73%, 87%, and 98% for MoS2@PANI / Cu(II) / PMS at dosages of 10, 20, 30, 40, and 50 mg / L, respectively. The removal rate increased with increasing MoS2@PANI dosage because appropriately increasing the MoS2@PANI dosage introduces more Mo(IV) into the system, thereby accelerating the Cu(II) / Cu(I) cycle and generating more active free radicals. Considering degradation efficiency and economic benefits, the optimal dosage of MoS2@PANI is 30–50 mg / L.

[0100] Example 7: Application of MoS2@PANI

[0101] Effect of different initial pH values ​​on the degradation efficiency of sulfathiazole by MoS2@PANI / Cu(II) / PMS.

[0102] Five groups of sulfathiazole aqueous solutions with an initial concentration of 5 mg / L (initial pH of sulfathiazole aqueous solution = 6) were prepared to simulate antibiotic wastewater systems. The pH values ​​of each group were adjusted to 3, 5, 6, 9, and 10, respectively. Then, 50 mg / L MoS2@PANI, 80 μmol / L copper sulfate, and 0.5 mmol / L potassium persulfate complex salt were added to each group. The mixture was then stirred at room temperature for 60 min to allow for degradation. Samples were taken during the degradation reaction, and the removal rate was measured. The procedure was the same as in Example 3. The results are as follows: Figure 7 As shown.

[0103] Figure 7 The results showed that, with an initial concentration of sulfathiazole of 5.0 mg / L, the removal rates of sulfathiazole at 60 min using the MoS2@PANI / Cu(II) / PMS system at initial pH values ​​of 3, 5, 6, 9, and 10 were 97%, 90%, 98%, 94%, and 85%, respectively. When the initial pH decreased from 6 to 3, the removal rate first decreased from 98% to 90% and then increased to 97%. This decrease in removal rate may be related to the amount of active material in the system; as the pH decreased, the edge S of MoS2 could capture more H+. + This exposes more Mo(Ⅳ) to promote the Cu(II) / PMS reaction. When the initial pH increases from 6 to 10, the removal rate decreases from 98% to 85%, because PMS can self-decompose under strongly alkaline conditions and has a stronger oxidizing capacity. With OH - The reaction produces HO, which has weak oxidizing power. · In general, the degradation of sulfathiazole by the MoS2@PANI / Cu(II) / PMS system is not significantly affected by pH, especially when the pH range is 3–9, the removal rate is very high.

[0104] Example 8: Application of MoS2@PANI

[0105] different Effect of concentration on the degradation efficiency of sulfathiazole by MoS2@PANI / Cu(II) / PMS.

[0106] Four groups of sulfathiazole aqueous solutions with an initial concentration of 5 mg / L (initial pH of sulfathiazole aqueous solution = 6) were taken to simulate antibiotic wastewater systems. Each group was treated with 50 mg / L MoS2@PANI and 80 μmol / L copper sulfate, followed by the addition of 0 mM, 2 mM, 8 mM, and 16 mM solutions of [unspecified substance]. Then, 0.5 mmol / L of sodium persulfate complex salt was added, and the mixture was stirred at room temperature for 60 min to carry out the degradation reaction. Samples were taken during the degradation reaction to determine the removal rate, following the same procedure as in Example 3. The results are as follows: Figure 8 As shown.

[0107] Figure 8 The results showed that, under the conditions of an initial sulfathiazole concentration of 5.0 mg / L and a pH of 6, the application of the MoS2@PANI / Cu(II) / PMS system resulted in the following effect: At concentrations of 2 mM, 8 mM, and 16 mM, the removal rates of ST were 90%, 94%, and 93%, respectively. The effect on ST was minimal at a concentration of 8 mM. Overall, the degradation of sulfathiazole by the MoS2@PANI / Cu(II) / PMS system was influenced by... The impact is minimal; the removal rates are all very high.

[0108] Example 9: Application of MoS2@PANI (different Cl) - Effect of concentration of MoS2@PANI / Cu(II) / PMS on the degradation efficiency of sulfathiazole.

[0109] Take 100 mL of each of four groups of sulfathiazole aqueous solutions with an initial concentration of 5 mg / L (initial pH of sulfathiazole aqueous solution = 6) to simulate antibiotic wastewater systems. Add 50 mg / L MoS2@PANI and 80 μmol / L copper sulfate to each group, followed by the addition of 0 mM, 2 mM, 8 mM, and 16 mM Cl-, respectively. - Then, 0.5 mmol / L of potassium persulfate complex salt was added, and the mixture was stirred at room temperature for 60 min to carry out the degradation reaction. Samples were taken during the degradation reaction to determine the removal rate, following the same procedure as in Example 3. The results are as follows: Figure 9 Show.

[0110] Figure 9 The results showed that, under the conditions of an initial sulfathiazole concentration of 5.0 mg / L and a pH of 6, the application of the MoS2@PANI / Cu(II) / PMS system resulted in a decrease in Cl... - At concentrations of 2 mM, 8 mM, and 16 mM, the removal rates of ST were 96%, 93%, and 92%, respectively. - The effect on ST was minimal at a concentration of 2 mM. Overall, the degradation of sulfathiazole by the MoS2@PANI / Cu(II) / PMS system was not significantly affected by Cl-, and the removal rates were consistently high.

Claims

1. The application of a molybdenum disulfide / polyaniline composite material MoS2@PANI synergistically with Cu(II) activated bisulfate to degrade antibiotics in water, characterized in that, The degradation method includes: adding MoS2@PANI and Cu(II) to the water containing antibiotics and mixing them, then adding persulfate to form a degradation reaction system. In the degradation reaction system, the initial content of MoS2@PANI is 10~100 mg / L, the initial concentration of Cu(II) is 40~320 μmol / L, the initial concentration of persulfate is 0.25~4.0 mmol / L, and the initial pH value of the degradation reaction system is 3~10. The antibiotics are degraded and removed. The antibiotics are sulfonamide antibiotics. The morphology of the molybdenum disulfide / polyaniline composite material MoS2@PANI is that flower-like molybdenum disulfide nanosheets are vertically and uniformly coated on the surface of polyaniline nanotubes.

2. The application according to claim 1, characterized in that, The preparation method of the molybdenum disulfide / polyaniline composite material MoS2@PANI includes the following steps: Step (1): Ammonium molybdate is dispersed in nitric acid aqueous solution to form a dispersion. The dispersion is then placed in an autoclave and hydrothermally reacted at 180-210℃ for 20-24 hours. After cooling, the precipitate is collected, washed, and dried to obtain molybdenum trioxide. Step (2): Disperse the molybdenum trioxide obtained in step (1) into water at a dosage of 7-9 g / L, and then mix it with the hydrochloric acid solution of aniline. The aniline content in the mixture is 8-10 g / L and the HCl content is 20-25 g / L. Then, under the condition of maintaining 0-5℃, add an aqueous solution of persulfate dropwise to the mixture. After the addition is completed, the persulfate content reaches 2-8 g / L. Then, the polymerization reaction is carried out at room temperature for 4-7 hours. After collecting the precipitate, washing with water and drying, the molybdenum trioxide / polyaniline composite is obtained. Step (3): Disperse the molybdenum trioxide / polyaniline composite obtained in step (2) into a thiourea aqueous solution to form a dispersion. Then place the dispersion in an autoclave and hydrothermally react at 180~210℃ for 18~24 hours. After cooling, collect the precipitate and wash with water to obtain the molybdenum disulfide / polyaniline composite material MoS2@PANI.

3. The application according to claim 2, characterized in that, In step (1), the concentration of nitric acid in the nitric acid aqueous solution is 5~15 v / v%, the content of ammonium molybdate in the dispersion is 15~50 g / L, the rinsing solvent is selected from water, ethanol or ethanol aqueous solution, the drying temperature is 50~70℃, and the drying time is 8~12 hours. In step (2), the persulfate is selected from at least one of sodium persulfate, potassium persulfate or ammonium persulfate, and the drying temperature is 50~70℃ and the drying time is 20~30 hours; In step (3), the concentration of the thiourea aqueous solution is 5~20 g / L, and the content of the molybdenum trioxide / polyaniline composite in the dispersion is 1.5~4 g / L.

4. The application according to claim 1, characterized in that, The source of Cu(II) is selected from at least one of copper sulfate, copper nitrate or copper chloride, and the peroxymonosulfate is selected from at least one of potassium peroxymonosulfate, sodium peroxymonosulfate, potassium peroxymonosulfate complex salt or sodium peroxymonosulfate complex salt.

Images