A pesticide residue degradation method based on 3D molybdenum disulfide nanoflower material

Abstract

The application discloses a kind of based on 3D molybdenum disulfide nanoflower material pesticide residue degradation method, belong to pesticide residue degradation field.The application is prepared 3D molybdenum disulfide nanoflower material (MoS2-CF) using hydrothermal reaction, and based on the material is constructed suitable for a variety of neonicotinoid pesticide fruit and vegetable pesticide residue degradation technology, and the degradation mechanism is explained.The results show that MoS2-CF can effectively activate peroxymonosulfate, and its unique flower structure is conducive to the exposure of active site and improves mass transfer efficiency.In 15 minutes, it can realize the degradation rate of residual acetamiprid, imidacloprid and thiamethoxam in tomato 97.1%, 95.3% and 100%.At the same time, the treatment method can effectively remove residual pesticides without damaging the content of aromatic compounds in fresh tomatoes, ensuring the flavor quality of fresh fruits and vegetables, and is an efficient, environmentally friendly fruit and vegetable pesticide residue control method with wide application prospect.

Description

Technical Field

[0001] This invention belongs to the field of pesticide residue degradation, specifically relating to a method for pesticide residue degradation based on 3D molybdenum disulfide nanoflower materials. Background Technology

[0002] The information disclosed in this background section is intended only to enhance understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

[0003] The safety of fruits and vegetables is of paramount importance in my country's food safety system. Pesticide use has become a primary means of ensuring stable and high yields, but improper pesticide use has led to significant problems with excessive pesticide residues. Neonicotinic acid insecticides are frequently detected in fruits and vegetables, seriously impacting human health and import / export trade. Pesticide residues on the surface of fruits and vegetables are a major cause of excessive residues. Due to differences in the physicochemical properties of pesticides, the edible parts of fruits and vegetables, and their surface structure, existing methods are insufficient to meet the needs of pesticide residue removal in various scenarios.

[0004] Tomato (Solanum lycopersicum L.) is a dual-purpose crop (vegetable and fruit) rich in vitamin C, lycopene, carotenoids, and flavonoids, and is widely cultivated and consumed. Because tomatoes are highly susceptible to pests and diseases during growth and storage, pesticides are used extensively. Tomatoes are one of the three vegetables with the highest pesticide detection rates. Tomatoes have a unique aroma and are a ready-to-eat vegetable; approximately one-third of tomatoes are eaten fresh, which significantly increases the potential risk of exposure through dietary intake. Furthermore, pesticide application has been shown to affect the aroma quality of tomato fruit. Therefore, researching efficient, safe, and widely applicable new methods for the degradation of pesticide residues in fruits and vegetables is of great significance for ensuring the safety of fruit and vegetable foods.

[0005] In recent years, methods including washing, peeling, and blanching have been used to remove pesticide residues from fruits and vegetables. Among these, washing is the simplest and most economical method, suitable for both home and industrial-scale food processing. Washing also effectively avoids the waste of nutrients during fruit peel processing. In addition, washing technologies including ozone, ultrasound, water electrolysis, or chemical solutions (such as H2O2 and chlorine compounds) have also been reported as effective methods for removing pesticide residues from food. Catalyst-activated persulfate degradation of pollutants has recently been applied to the removal of pesticides from water. For example, patent CN113716671A discloses a method for treating wastewater based on 1T-phase nano-molybdenum disulfide and a method for preparing this 1T-phase nano-molybdenum disulfide, which utilizes 1T-phase nano-molybdenum disulfide and persulfate to degrade neonicotinoid pesticides under low pH conditions. Because of its demanding degradation conditions, it requires low pH (pH=1-3) to achieve a high degradation effect on neonicotinoid pesticides, and the degradation rate can only reach 70% after 180 minutes. Therefore, it cannot be applied to the degradation of pesticide residues in fruits and vegetables, and the effect of this treatment on the aroma and quality of fruits and vegetables has not yet been studied. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the purpose of this invention is to provide a method for pesticide residue degradation based on 3D molybdenum disulfide nanoflower materials. The 3D molybdenum disulfide nanoflower materials provided by this invention can effectively activate persulfate, rapidly degrade pesticide residues on fruits and vegetables in a short time without damaging the aroma and quality of the fruits and vegetables.

[0007] To achieve the above objectives, the technical solution of the present invention is as follows:

[0008] In a first aspect, the present invention provides a method for preparing 3D molybdenum disulfide nanoflower materials, comprising the following steps:

[0009] (1) The molybdenum source and the sulfur source are mixed and dissolved in water to obtain a mixed solution;

[0010] (2) The mixed solution was subjected to a hydrothermal reaction. After the hydrothermal reaction was completed, the product was collected, washed and dried to obtain 3D molybdenum disulfide nanoflower material.

[0011] In some embodiments of the present invention, the molybdenum source is a molybdate, including but not limited to sodium molybdate and ammonium molybdate.

[0012] In some embodiments of the present invention, the sulfur source is a sulfur-containing compound, including thiourea and thioacetamide.

[0013] In some embodiments of the present invention, the molybdenum source is ammonium heptamolybdate tetrahydrate, and the sulfur source is thiourea; the mass ratio of ammonium heptamolybdate tetrahydrate to thiourea is 1-1.5:2-2.5, g:g.

[0014] Preferably, the mass ratio of ammonium heptamolybdate tetrahydrate to thiourea is 1.24:2.28 (g:g).

[0015] In some embodiments of the present invention, a molybdenum source and a sulfur source are mixed and dissolved in water, and the mixture is stirred to obtain a mixed solution. The mixed solution is then transferred to a hydrothermal reactor for a hydrothermal reaction. To avoid damage to the hydrothermal reactor from high temperatures, a hydrothermal reactor with a polyphenol liner can be used.

[0016] In some embodiments of the present invention, the hydrothermal reaction is carried out at 190–210°C for 10–14 h.

[0017] In some embodiments of the present invention, after the hydrothermal reaction is completed, the product can be collected by centrifugation. The collected product can be washed several times with deionized water and ethanol, and then dried.

[0018] This invention does not limit the drying method of the target product, as long as thorough drying is achieved. For example, vacuum drying can be used, drying overnight at 60°C.

[0019] In a second aspect, the present invention provides a 3D molybdenum disulfide nanoflower material, which is prepared by the above-described preparation method;

[0020] The 3D molybdenum disulfide nanoflower material contains a 2H phase and a 1T phase.

[0021] The 3D molybdenum disulfide nanoflower material provided by this invention possesses a unique flower-like structure, exhibiting a distinctive cornflower-like morphology. This unique flower-like structure facilitates the exposure of active sites and improves mass transfer efficiency. Furthermore, the 3D molybdenum disulfide nanoflower material provided by this invention undergoes a transformation from the 2H phase to the 1T phase.

[0022] A third aspect of the present invention provides an application of the above-mentioned 3D molybdenum disulfide nanoflower material in conjunction with persulfate in the degradation of pesticide residues.

[0023] In some embodiments of the present invention, the application is to degrade pesticide residues on fruits and vegetables.

[0024] Preferably, the fruits and vegetables include, but are not limited to, tomatoes.

[0025] In some embodiments of the present invention, the application involves adding the above-mentioned 3D molybdenum disulfide nanoflower material and persulfate to water containing fruits and vegetables.

[0026] In some embodiments of the present invention, the pesticide residue is a neonicotinoid pesticide, including but not limited to acetamiprid, imidacloprid and thiamethoxam.

[0027] A fourth aspect of the present invention provides a method for pesticide residue degradation based on 3D molybdenum disulfide nanoflower materials, comprising the following steps:

[0028] The above-mentioned 3D molybdenum disulfide nanoflower material was mixed with persulfate and added to water containing fruits and vegetables.

[0029] The pesticide residue degradation method provided by this invention is simple and convenient to operate, and the degradation effect is excellent. Specifically, the method of this invention can achieve rapid degradation of pesticide residues using a small amount of 3D molybdenum disulfide nanoflower material and persulfate. Within 15 minutes, the degradation rates of acetamiprid, imidacloprid, and thiamethoxam can reach 97.1%, 95.3%, and 100%, respectively.

[0030] In some embodiments of the present invention, the concentration of 3D molybdenum disulfide nanoflower material in the water containing fruits and vegetables is 0.02-0.04 g / L, and the concentration of persulfate is 0.7-0.9 mM.

[0031] In some embodiments of the present invention, the pesticide residue is a neonicotinoid pesticide, including acetamiprid, imidacloprid, and thiamethoxam.

[0032] The beneficial effects of this invention are as follows:

[0033] This invention prepares 3D molybdenum disulfide nanoflower materials with a unique flower-like structure through a simple hydrothermal reaction, and the preparation method is simple and efficient. To address the shortcomings of existing technologies, this invention constructs a pesticide residue degradation technology for fruits and vegetables based on the prepared 3D molybdenum disulfide nanoflower material (MoS2-CF), applicable to various neonicotinoid pesticides, and elucidates the degradation mechanism. Results show that MoS2-CF can effectively activate permonosulfate (PMS), and its unique flower-like structure facilitates the exposure of active sites and improves mass transfer efficiency. Within 15 minutes, the degradation rates of acetamiprid, imidacloprid, and thiamethoxam residues in fruits and vegetables can reach 97.1%, 95.3%, and 100%, respectively. Simultaneously, this treatment method effectively removes pesticide residues without damaging the aromatic compound content of fresh fruits and vegetables, ensuring their flavor and quality. It is a highly efficient and environmentally friendly new method for controlling pesticide residues in fruits and vegetables, with broad application prospects. Attached Figure Description

[0034] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0035] Figure 1 The images shown are morphological images of the materials prepared in Example 1 of the present invention, wherein a is a TEM image of bulk-MoS2, b is a TEM image of MoS2-NS, c is an HRTEM image of MoS2-NS, d and e are TEM images of MoS2-CF, and f is an HRTEM image of MoS2-CF.

[0036] Figure 2 Images of MoS2-NS and MoS2-CF prepared in Example 1 of this invention are shown, where a is an XRD spectrum, b is an XPS spectrum, c is a high-resolution XPS spectrum of Mo 3d, and d is a high-resolution XPS spectrum of S2p.

[0037] Figure 3 The data graph shows the degradation of pesticide residues by MoS2-CF prepared in Example 1 of this invention, where a is the removal rate of three NEOs in tomatoes and b is the concentration of residual NEOs in the corresponding treated water.

[0038] Figure 4 The effects of different consumables on the efficiency of degradation of (a) acetamiprid, (b) imidacloprid and (c) thiamethoxam in the MoS2-CF / PMS system, and the corresponding reaction rate values ​​(d); (e) 1 O2 and (f)·OH / SO4 ·- The EPR spectrum. Detailed Implementation

[0039] To enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below with reference to specific embodiments.

[0040] Example 1

[0041] 1. Experimental Section

[0042] 1.1 Preparation of MoS2 series materials

[0043] Accurately weigh 1.24g of (NH4)6Mo7O 24 • 4H₂O and 2.28 g of thiourea were dispersed in 70 mL of deionized water and stirred at room temperature for 30 minutes. The solution was then transferred to a 100 mL hydrothermal reactor lined with polyphenol and reacted at 200 °C for 12 hours. After the reaction, the product was collected by centrifugation, washed several times with deionized water and ethanol, and dried overnight at 60 °C in a vacuum drying oven. The obtained material was labeled as MoS₂-CF.

[0044] In addition, a liquid-phase exfoliation method was used to exfoliate commercially available bulk MoS2 to obtain two-dimensional molybdenum disulfide nanosheets, which were labeled as MoS2-NS.

[0045] 1.2 Degradation Experiment

[0046] The research subjects were neonicotinoid pesticides (NEOs) acetamiprid (ACE), imidacloprid (IMI), and thiamethoxam (THI). First, 100 mL of a 1000 mg / L solution was prepared using acetonitrile. -1Three neonicotinic pesticide standard solutions were prepared. The standard solutions were then applied to tomato fruits and air-dried at room temperature (addition level: 0.5 mg / L). -1 Tomato samples were randomly collected after contamination, and the initial NEO residue was tested. Subsequently, the same number of tomatoes were placed in a 5-liter stainless steel food container containing 2 liters of water, with 0.03 g of NEO added. -1 MoS2-CF, 0.8 mM PMS (these two concentrations are in aqueous solution), or a combination of both. The treatment time was set to 15 min. A control experiment was conducted in purified water. Each process was repeated three times.

[0047] 1.3 Analytical Methods

[0048] A modified QuEChERS method was used to quantify pesticide residues. 10.0 g of homogenized tomato fruit sample was weighed into a 50 mL centrifuge tube. 10 mL of acetonitrile was added, and the sample was vortexed for 2 min. Then, 3 g of NaCl was added, and the sample was vortexed for another 2 min. After centrifugation at 3800 rpm for 5 min, 6 mL of the supernatant was transferred to a commercially available dispersion solid-phase extraction nanotube (trade number 5982-5256, Agilent Technologies), vortexed for 2 min, and then centrifuged at 10000 rpm for 2 min. 1 mL of the supernatant was filtered through a 0.22 μm nylon filter and transferred to a vial for further analysis.

[0049] The concentration of the target pesticide was analyzed using ultra-high performance liquid chromatography (UPLC, Waters) and orbital trap mass spectrometry (MS, SCIEX). Gradient elution was performed using an ACQUITY UPLC BEH C18 column (1.7 μm, 2.1 mm × 100 mm, Waters). The mobile phase was acetonitrile (A) and 0.1 vol% formic acid (B), and the flow rate was 0.35 mL / min. -1 The gradient elution procedure was as follows: 0 min 10% A; 1 min 10% A; 4.5 min 90% A; 5.5 min 90% A; 5.6 min 10% A; 6.5 min 10% A, with an injection volume of 2 μL. Detection was performed in MRM(+) mode. The mass spectrometry ratios of the three neonicotinoid pesticides are shown in Table 1.

[0050] Table 1. Molecular structures and mass spectrometry information of three neonicotinoid pesticides

[0051]

[0052] Qualitative ion pairs

[0053] 2 Results

[0054] 2.1 Characterization of Nanomaterials

[0055] The microstructure of the obtained MoS2 series materials was characterized using scanning tunneling electron microscopy (TEM). For example... Figure 1 As shown, the commercially available bulk-MoS2 material is a tightly packed lamellar structure. After liquid-phase exfoliation, the number of layers in the resulting MoS2-NS material is significantly reduced, with a large number of exposed edges. High-resolution transmission electron microscopy (HRTEM) characterization confirmed the presence of the (100) crystal plane in MoS2-NS. The MoS2-CF material exhibits a unique cornflower-like morphology, and HRTEM further confirmed that the MoS2-CF material is a 3D structure with a significantly increased interlayer spacing.

[0056] Figure 2 The XRD patterns shown in Figure a indicate a significant difference in the crystal phases of MoS2-NS and MoS2-CF. The typical peak of the (002) plane is located at 14.2°, indicating that the structure of MoS2-NS is mainly composed of the 2H phase. However, this diffraction peak shifts to 9.0° and weakens in MoS2-NS, indicating that the structure of MoS2-CF transforms from the 2H phase to the 1T phase, and the interplanar spacing increases. Based on the Bragg equation, the interplanar spacing of MoS2-CF is calculated to be 0.982 nm, consistent with the HRTEM measurement. Figure 1 f).

[0057] The chemical composition and surface morphology of the prepared MoS2 samples were investigated using XPS. Figure 2 As shown in b, the element types of MoS2-CF are the same as those of MoS2-NS. Furthermore, the main Mo 3d peaks of MoS2-NS include Mo 3d... 5 / 2 (229.70 eV) and Mo3d 3 / 2 (232.86 eV), corresponding to the 2H phase ( Figure 2 c). In contrast, MoS2-CF also contains 1T phase MoS2 with Mo 3d. 5 / 2 and Mo 3d 3 / 2 The peaks have binding energies of 228.93 eV and 232.12 eV, respectively. From the S2p spectrum, it can be seen that the two characteristic peaks of MoS2-NS at 162.53 and 163.69 eV can be attributed to the S2p region of 2H-MoS2. 3 / 2 and 2p 1 / 2 Furthermore, the standard peaks in MoS2-CF with binding energies of 161.71 and 163.06 eV should be attributed to 1T-MoS2, further confirming that the MoS2-CF material has undergone a transformation from the 2H phase to the 1T phase.

[0058] 2.2 Pesticide residue degradation efficiency

[0059] Tomato fruit samples contaminated with pesticides were immersed in tap water or water containing MoS2-CF / PMS. Each experiment was repeated three times. Before sample analysis, all tomatoes were rinsed under tap water for 10 seconds to simulate the actual home tomato consumption process. Figure 3 As shown in Figure a, in the control experiment, the removal rates of the three NEOs were only 7.8%-9.2%, indicating that only a very small amount of NEOs could be removed in a short washing time. The removal rates of ACE, IMI, and THI by tap water soaking were 44.1%, 49.8%, and 46.9%, respectively. However, with the participation of MoS2-CF / PMS, the removal rates of ACE, IMI, and THI in tomatoes increased to 97.1%, 95.3%, and 100%, respectively. Figure 3 As shown in Figure b, the concentrations of all three NEOs in the water were relatively high, indicating that some residual NEOs were transferred from the tomatoes to the treated water during the soaking process. In contrast, treating tomatoes with MoS2-CF / PMS can completely degrade residual NEOs, thereby reducing the possibility of secondary pollution.

[0060] 2.3 Evaluation of Tomato Flavor Quality

[0061] After MoS2-CF / PMS treatment, the aroma components of tomatoes remained unchanged in both quality and quantity (Table 2). Furthermore, the top 10 aroma components with the highest odor activity (OAV) values ​​were identical to those in the untreated samples, and no new volatile off-odors were detected in the treated samples, indicating that MoS2-CF / PMS treatment effectively removed pesticide residues without negatively impacting the aroma characteristics of tomatoes. Quantitative data on odorants showed that only 5 of the 24 aroma components exhibited significant changes in OAV. The contribution of 1-hexanol decreased by 85.28%, while the aroma potency of phenylacetaldehyde, 2-phenylethanol, β-citral, and (E,E)-2,4-decaenoal increased by 50.87%, 44.94%, 34.68%, and 19.51%, respectively. However, quantitative descriptive analysis of aroma extracts showed that the decrease in 1-hexanol OAV did not cause a significant change in the intensity of the tomato "fresh aroma," which may be because (Z)-3-hexenal, hexanal, and 1-penten-3-1 primarily contribute to the tomato's fresh aroma. Similarly, the increases in phenylacetaldehyde, 2-phenylethanol, β-citral, and (E,E)-2,4-dodecenal OAV did not significantly alter the sweetness and floral aroma intensity of the MoS2-CF / PMS-treated samples. These results also demonstrate that there were no significant sensory differences between untreated and MoS2-CF / PMS-treated tomato fruit samples.

[0062] Table 2. Identification of aroma activation in tomato fruit homogenate based on DSE-SAFE-GC-O / AEDA and OAV.

[0063]

[0064]

[0065] a Identification of the compounds was performed by comparingtheirmass spectra(MS-EI),retention indices(RI)on capillaries DB5 andDB-WAX,aswell as the odor quality during sniffing with data ofreference compounds.

[0066] b Odor-quality perceived at the sniffing-port.

[0067] c Retention index.

[0068] d Flavor dilution factor.

[0069] e Odor threshold in water(mg / kg)

[0070] f Concentration was calculated as the mean value of twodifferentworkups,and expressed in ug / g tomato puree.RSD of all duplicateswereall<15%.

[0071] g Odor activity value

[0072] * Odorants were only perceived during sniffing but has no MS signal

[0073] #Odorants showed significant difference in untreated and MoS2-CF / PMStreated tomato samples.

[0074] Category:AKET,aliphatic ketones;AALC,aliphatic alcohols;AALD,aliphatic aldehyde;SUL,volatile sulfur compounds;NHCY,

[0075] N-containing heterocyclics; TP, terpene and their derivatives; ARO, aromatics; EST, esters

[0076] 2.4 Degradation Mechanism Research

[0077] The active species (ROS) in the MoS2-CF / PMS system were identified using free radical quenching experiments. Methanol (MeOH) is a ·OH group, and SO42- is another active species. ·- The consumables. Tert-butanol (TBA), p-benzoquinone (p-BQ), and furfuryl alcohol (FFA) were selected as the ·OH and O2, respectively. ·- and 1 Consumables of O2. For example... Figure 4 As shown in Figure ac, each ROS contributes to the degradation of the three NEOs with the same trend. Specifically, the addition of FFA almost completely prevents the degradation of the three NEOs. Within 60 min, the degradation rates of ACE, IMI, and THI were 7.3%, 2.2%, and 1.7%, respectively, indicating that... 1 O2 plays a major role in the MoS2-CF / PMS system. However, O2 ·- The quenching of O2 did not significantly inhibit all three NEOs, indicating that O2... ·- It does not participate in the degradation of NEOs. After adding TBA, the degradation rates of ACE, IMI, and THI decreased by 21.0%, 10.1%, and 13.2% respectively within 60 min. Furthermore, when MeOH was added, the degradation rates of ACE, IMI, and THI decreased by 62.6%, 48.6%, and 58.0% respectively within 60 min. The results confirm that ·OH and SO42- do not participate in the degradation of NEOs. ·- It also participated in the degradation reaction. The order of contribution of the reacting species is as follows: 1 O2>SO4 ·- >·OH>O2 ·- ( Figure 4 d). In short, SO4·- and ·OH-mediated free radical pathways and 1 O2-mediated non-radical pathways all contribute to the degradation of the three NEOs.

[0078] Electron paramagnetic resonance (EPR) spectroscopy analysis confirmed the presence of [a substance] in the MoS2-CF / PMS system. 1 O2 and SO4 ·- / ·OH. TEMP is... 1 A selective probe for O2, DMPO is a selective probe for SO4. ·- A selective probe for OH radicals. Figure 4 In ef, no DMPO-O4 was observed in the absence of MoS2-CF (0 min). ·- DMPO-·OH or TEMP- 1 The O2 signal was observed. However, EPR signals could be detected in both the MoS2-CF / PMS / DMPO and MoS2-CF / PMS / TEMP systems. After adding MoS2-CF, TEMP-... 1 O2 (1:1:1), DMPO-SO4 ·- (6 peaks) and characteristic signals of DMPO-·OH (1:2:2:1). Therefore, MoS2-CF can activate PMS to generate 1 O2, SO4 ·- And ·OH, which is consistent with the aforementioned results of free radical capture.

[0079] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. The application of a 3D molybdenum disulfide nanoflower material in synergistic effect with persulfate in the degradation of pesticide residues; The method for pesticide residue degradation of the 3D molybdenum disulfide nanoflower material includes the following steps: Mix 3D molybdenum disulfide nanoflower material with persulfate and add it to water containing fruits and vegetables; The concentration of the 3D molybdenum disulfide nanoflower material in the water containing fruits and vegetables is 0.02~0.04 g / L, and the concentration of persulfate is 0.7~0.9 mM; the 3D molybdenum disulfide nanoflower material has a unique flower-like structure and exhibits a unique cornflower-like morphology; the 3D molybdenum disulfide nanoflower material contains 2H phase and 1T phase; The fruits and vegetables mentioned include tomatoes; the pesticide residues mentioned are neonicotinoid pesticides, including acetamiprid, imidacloprid, and thiamethoxam. The 3D molybdenum disulfide nanoflower material is prepared through the following steps: (1) The molybdenum source and the sulfur source are mixed and dissolved in water to obtain a mixed solution; (2) The mixed solution was subjected to a hydrothermal reaction. After the hydrothermal reaction was completed, the product was collected, washed and dried to obtain 3D molybdenum disulfide nanoflower material. The hydrothermal reaction is carried out at 190-210 °C for 10-14 h. The degradation rates of acetamiprid, imidacloprid and thiamethoxam residues in fruits and vegetables reached 97.1%, 95.3% and 100% within 15 minutes, respectively.

2. The pesticide residue degradation method as described in claim 1, characterized in that, The molybdenum source is a molybdate, including sodium molybdate and ammonium molybdate; Alternatively, the sulfur source may be a sulfur-containing compound, including thiourea and thioacetamide.

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