Preparation method and application of Y2O3-Co (OH) 2 particles

Abstract

The invention discloses a preparation method and application of Y2O3-Co (OH) 2 particles, and belongs to the technical field of material preparation. The preparation method of the Y2O3-Co (OH) 2 particles comprises the following steps: mixing L-type amino acid containing amino and carboxyl functional groups with metal yttrium salt, carrying out microwave radiation heating reaction to obtain a deep eutectic solvent (y-DES), sequentially adding metal cobalt salt and an alkaline solution into the y-DES, continuously carrying out microwave radiation heating reaction until the metal cobalt salt and the alkaline solution are dissolved to obtain a brown mixed solution, and drying the brown mixed solution to obtain the Y2O3-Co (OH) 2 particles. And carrying out solid-liquid separation on the brown mixed solution after the reaction is completed, washing the precipitate, and drying to obtain Y2O3-Co (OH) 2 particles. According to the preparation method, the morphology of the Y2O3-Co (OH) 2 particles can be accurately regulated and controlled, the preparation process is simple, and an organic solvent does not need to be additionally added; the catalytic activity and the anti-interference capability are remarkably enhanced by constructing an efficient oxidation-reduction circulating system, and efficient determination of the organophosphorus pesticide in the acetylcholin esterase and inhibitor industrial wastewater is realized.

Description

Technical Field

[0001] The present invention belongs to the technical field of material preparation, and in particular relates to a preparation method of Y2O3-Co(OH)2 particles and applications thereof. Background Art

[0002] my country's annual industrial wastewater discharge exceeds 20 billion tons, with organophosphorus pesticide residues particularly prominent in wastewater from the chemical, pesticide, and pharmaceutical industries. For example, the concentration of organophosphorus in the wastewater from one pesticide manufacturer can reach 1,000 to 5,000 mg / L, far exceeding the 0.5 mg / L limit set in the Integrated Wastewater Discharge Standard (GB8978-1996).

[0003] Organophosphorus pesticides (such as parathion and chlorpyrifos) in industrial wastewater are highly water-soluble, lowly volatile, and bioaccumulative, easily permeating water bodies and contaminating groundwater and soil. As nerve agents, organophosphorus pesticides inhibit acetylcholinesterase, leading to abnormal nerve signaling, causing acute poisoning (such as difficulty breathing and seizures) and chronic diseases (such as Parkinson's disease and thyroid dysfunction). According to the World Health Organization, approximately 70% of the 3 million people poisoned annually by organophosphorus pesticides worldwide are related to industrial wastewater exposure. The limitations of traditional technologies and policy demands have driven the development of novel detection methods, and enzyme-like technologies, due to their unique advantages, have become a research hotspot. Currently, enzyme-like materials face multiple challenges in their synthesis and application. The complexity of the synthesis process, the potential risks associated with the use of organic solvents and biomolecules, and poor environmental tolerance have severely hampered their development and widespread adoption.

[0004] Many oxidase-like materials require precise temperature control for synthesis. Slight deviations in reaction conditions can lead to uneven particle size distribution and imperfect crystal formation in the nanomaterials, thus affecting their oxidase-like activity. Some oxidase-like materials also require reactions under inert atmospheres and use organic reagents as solvents during synthesis. For some biomolecule-modified oxidase-like materials, the required biomolecules, such as specific proteins and nucleic acids, are complex and costly to obtain and purify. Furthermore, improper handling of these substances can cause long-term soil and water pollution. Furthermore, the application of oxidase-like technology is subject to significant environmental interference. For example, catalytic activity is extremely sensitive to temperature fluctuations. When the ambient temperature rises, the thermal motion of oxidase-like molecules intensifies, disrupting the non-covalent bonds (such as hydrogen bonds and hydrophobic interactions) that maintain their spatial structure, altering the conformation of the active center, significantly reducing catalytic efficiency and even activity. Strong oxidants or reducing agents in the environment can alter the valence state of the metal ions or the state of the redox-sensitive groups in the oxidase-like center, thereby disrupting its function and causing loss of activity. Therefore, it is crucial to invent an oxidase-like material with a simple synthesis method, mild conditions, and the ability to adapt to complex environments for monitoring acetylcholinesterase and organophosphorus pesticides in wastewater. Summary of the Invention

[0005] The present invention aims to provide a preparation method and application of Y2O3-Co(OH)2 particles. The preparation method can achieve precise control of the morphology of Y2O3-Co(OH)2 particles, and the preparation process is simple, without the need for additional organic solvents. By constructing an efficient redox cycle system, the catalytic activity and anti-interference ability are significantly enhanced, thereby achieving efficient determination of organophosphorus pesticides in industrial wastewater containing acetylcholinesterase and its inhibitors.

[0006] In order to achieve the purpose of the present invention, the present invention provides the following technical solution, a method for preparing Y2O3-Co(OH)2 particles, comprising the following steps: (1) L-amino acids containing amino and carboxyl functional groups are mixed with metal yttrium salts and heated under microwave irradiation until a transparent solution is obtained to obtain a deep eutectic solvent (y-DES); (2) Adding metal cobalt salt to the obtained y-DES, heating the mixture under microwave radiation at 70-80°C until it dissolves, then adding alkaline solution and heating the mixture to 90-100°C for 10-60 minutes to obtain a brown mixed solution; (3) The brown mixed liquid is separated into solid and liquid, the precipitate is washed and dried to obtain Y2O3-Co(OH)2 particles.

[0007] Furthermore, in the step (1), the L-amino acid containing amino and carboxyl functional groups includes any one of L-glycine, L-alanine, and L-leucine, and the metal yttrium salt is any one of yttrium acetate tetrahydrate, yttrium nitrate tetrahydrate, and yttrium phosphate.

[0008] Furthermore, in the step (1), the molar ratio of the L-amino acid containing amino and carboxyl functional groups to the metal yttrium salt is 1:0.5-2, the microwave radiation heating reaction time is 2-6 hours, and the temperature is 80-100°C.

[0009] Furthermore, in the step (2), the metal cobalt salt is any one of cobalt sulfate heptahydrate, cobalt phosphate octahydrate, and cobalt nitrate hexahydrate.

[0010] Furthermore, in the step (2), the molar ratio of the metal cobalt salt to the metal yttrium salt is 1:0.5-2.

[0011] Furthermore, in the step (2), the alkaline solution is one of sodium hydroxide solution, potassium hydroxide solution, and calcium hydroxide solution, and the concentration of the alkaline solution is 5-10M; the molar ratio of the alkali to the metal yttrium salt in the added alkaline solution is 1-2:1.

[0012] Another object of the present invention is to provide an application of the Y2O3-Co(OH)2 particles prepared by the above-mentioned preparation method, which can be used to detect organophosphorus pesticides in industrial wastewater containing acetylcholinesterase and its inhibitors based on their oxidase-like activity.

[0013] The beneficial effects of the present invention are as follows: (1) The technical solution provided by the present invention adopts a microwave radiation heating reaction method, which achieves efficient energy transfer in the reaction system through bulk heating. Compared with the traditional hydrothermal method, microwave energy acts directly on the interior of the molecules, causing the system to quickly heat up to the reaction temperature within 10 to 60 minutes. At the same time, the penetrating heating characteristics of microwaves eliminate the temperature gradient problem caused by the lag in heat conduction in traditional methods, ensuring that the reactants are heated uniformly in three-dimensional space, significantly improving the uniformity of product morphology, and laying the foundation for industrial scale-up.

[0014] (2) The technical solution provided by the present invention uses y-DES, which serves as both a solvent for the reaction and a reactant and template in the present invention. First, as a solvent for the reaction, it completely replaces the organic solvent. The unique hydrogen bond network structure of y-DES can effectively dissolve precursors such as metal yttrium salts to form a uniform and stable solution system, ensuring that the reaction components are fully mixed at the molecular level, greatly improving the uniformity of the reaction. At the same time, it has extremely low volatility, reducing the solvent's volatile loss and environmental pollution during use; second, as a template, y-DES can selectively adsorb on specific crystal faces of the particles, controlling the growth rate and exposure ratio of the crystal faces. In the synthesis of Y2O3-Co(OH)2 particles, y-DES can promote the preferential growth of certain crystal faces and change the relative ratio of the crystal faces. For example, the exposure ratio of crystal faces with higher catalytic activity (such as {110} crystal faces) is increased, thereby improving the overall catalytic performance of the particles. Through characterization methods such as XRD, it can be observed that under the action of the y-DES template, the diffraction peak intensity of certain crystal faces of the Y2O3-Co(OH)2 particles changes significantly, proving the regulatory effect of y-DES on crystal face growth; finally, as a reactant, it directly participates in the synthesis of Y2O3-Co(OH)2 particles. The organic components may react with metal ions to form stable intermediate complexes. These complexes can guide the aggregation and growth direction of metal ions in the subsequent reaction process, and have an important influence on the final structure and performance of the particles. Taking the y-DES synthesized by L-glycine and yttrium nitrate tetrahydrate used in Example 1 of the present invention as an example, the guanidine group in L-glycine reacts with Y 3+ Forming a coordination bond, changing Y 3+ The electron cloud distribution and reaction activity of Y2O3 affect the crystallization process of Y2O3 in Y2O3-Co(OH)2 particles.

[0015] (3) The technical solution provided by the present invention uses a metal yttrium salt and a metal cobalt salt. Under the synergistic effect of the two metals, the redox cycle process is significantly promoted, and the reaction path of the detection process is optimized. During the detection process, Co(OH)2 is oxidized to a high-valent cobalt oxide by losing electrons, while Y2O3 is able to accept electrons and reduce the cobalt oxide back to Co(OH)2, while being oxidized itself. This redox cycle continues, greatly improving the catalytic conversion efficiency of the particles for substrates (such as the products of the acetylcholinesterase catalytic reaction).

[0016] (4) The technical solution provided by the present invention applies the prepared Y2O3-Co(OH)2 particles to the detection of acetylcholinesterase and its inhibitor organophosphorus pesticides in wastewater. The detection limit of acetylcholinesterase is calculated to be 0.069 mU / mL, and the detection limit of ethyl paraoxon, a representative drug of organophosphorus pesticides, is detected to be 0.8 ng / mL. Compared with the existing technology, this has achieved a significant breakthrough in lowering the detection limit. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a scanning electron microscope (SEM) image (5000 times) of the Y2O3-Co(OH)2 particles in Example 1 of the present invention; Figure 2 This is a SEM image (10,000 times) of the Y2O3-Co(OH)2 particles in Example 1 of the present invention; Figure 3 is an X-ray diffraction pattern (XRD) of the Y2O3-Co(OH)2 particles in Example 1 of the present invention; Figure 4 This is the UV absorption spectrum of the activity of the Y2O3-Co(OH)2 particles in Example 1 of the present invention, where TMB is selected as the substrate; Figure 5 This is the UV absorption spectrum of the antioxidant capacity test of the Y2O3-Co(OH)2 particles in Example 1 of the present invention. The test was performed using Y2O3-Co(OH)2+TMB as the test object in a high-concentration argon, air, and oxygen environment. Figure 6 This is the UV absorption spectrum of the Y2O3-Co(OH)2 particles used for detecting acetylcholinesterase in Example 1 of the present invention; Figure 7 This is the standard curve for detecting acetylcholinesterase with Y2O3-Co(OH)2 particles in Example 1 of the present invention; Figure 8 This is a comparison chart of ultraviolet absorption when Y2O3-Co(OH)2 particles are added with organophosphorus pesticides and when no organophosphorus pesticides are added when detecting acetylcholinesterase in Example 1 of the present invention; Figure 9 This is the standard curve for the detection of ethyl paraoxon, a representative model of organophosphorus pesticides, by Y2O3-Co(OH)2 particles in Example 1 of the present invention; Figure 10 This is the UV absorption spectrum of the Y2O3-Co(OH)2 particles tested for antioxidant properties in Example 1 of the present invention; Figure 11 This is a graph comparing the oxidase activity of the Y2O3-Co(OH)2 particles synthesized by y-DES in Example 1 of the present invention, and the Y2O3 and Co(OH)2 particles synthesized separately and in water in Comparative Examples 1-3 over time; Figure 12 is a SEM image of the Co(OH)2 particles synthesized in Comparative Example 1 of the present invention; Figure 13 This is an SEM image of Y2O3 particles synthesized in Comparative Example 2 of the present invention; Figure 14This is an SEM image of the Y2O3-Co(OH)2 (H2O) particles synthesized in Comparative Example 3 of the present invention. DETAILED DESCRIPTION

[0018] The present invention is further described below with reference to the accompanying drawings and examples, but the scope of protection of the present invention is not limited thereto. In the following examples of the present invention, the microwave irradiation device used is: ANKS-SR12 / 0~350°C, with a maximum output power of 1300W. Example 1

[0019] (1) L-glycine (0.02 mol) and yttrium nitrate tetrahydrate (0.02 mol) were mixed and placed in a microwave irradiation device. The mixture was heated under microwave irradiation at 100°C for 6 h until a transparent solution was formed to obtain a deep eutectic solvent (y-DES); (2) Take 8.4 g of y-DES obtained in step (1), add 0.02 mol of cobalt nitrate hexahydrate, and continue to microwave irradiate and heat at 80°C until dissolved; then add 7 mL of 5M sodium hydroxide solution, heat to 90°C, and continue to microwave irradiate and heat for 30 minutes to obtain a brown mixed solution; (3) The brown mixture was cooled to room temperature, the brown precipitate was collected by centrifugation, washed three times with water and ethanol, and dried at 80 °C for 12 h to obtain Y2O3-Co(OH)2 particles. Example 2

[0020] (1) L-alanine (0.02 mol) and yttrium phosphate (0.01 mol) were mixed and placed in a microwave irradiation device. The mixture was heated under microwave irradiation at 80°C for 2 h until a transparent liquid was formed to obtain a deep eutectic solvent; (2) Take 6 g of the y-DES obtained in step (1), add 0.02 mol of cobalt sulfate heptahydrate thereto, and continue to microwave irradiate and heat the mixture at 70°C until it dissolves. Then, add 2 mL of 5 M potassium hydroxide solution dropwise, heat the mixture to 100°C, and continue to microwave irradiate and heat the mixture for 10 min to obtain a brown mixed solution. (3) The brown mixture was cooled to room temperature, the brown precipitate was collected by centrifugation, washed five times with water and ethanol, and dried at 90 °C for 12 h to obtain Y2O3-Co(OH)2 particles. Example 3

[0021] (1) L-leucine (0.02 mol) and yttrium acetate tetrahydrate (0.04 mol) were mixed and placed in a microwave irradiation device, and microwave irradiation was heated at 90°C for 4 h to form a transparent liquid to obtain a deep eutectic solvent; (2) Take 13.2 g of the y-DES obtained in step (1), add 0.02 mol of cobalt phosphate octahydrate thereto, and continue to microwave irradiate and heat the reaction at 75°C until it dissolves; then add 8 mL of 10 M calcium hydroxide solution dropwise, heat to 90°C, and continue to microwave irradiate and heat the reaction for 20 minutes to obtain a brown mixed solution; (3) The brown mixture was cooled to room temperature, the brown precipitate was collected by centrifugation, washed with water and ethanol four times, and dried at 120 °C for 8 h to obtain Y2O3-Co(OH)2 particles. Example 4

[0022] (1) L-glycine (0.02 mol) and yttrium phosphate (0.02 mol) were mixed and placed in a microwave irradiation device, and microwave irradiation was heated at 100°C for 2 h to form a transparent liquid to obtain a deep eutectic solvent; (2) Take 5.1 g of y-DES obtained in step (1), add 0.02 mol of cobalt nitrate hexahydrate, and continue to microwave irradiate and heat at 70°C until dissolved; then add 4 mL of 5M sodium hydroxide solution, heat to 95°C, and continue to microwave irradiate and heat for 40 minutes to obtain a brown mixed solution; (3) The brown mixture was cooled to room temperature, the brown precipitate was collected by centrifugation, washed five times with water and ethanol, and dried at 110 °C for 10 h to obtain Y2O3-Co(OH)2 particles. Example 5

[0023] (1) L-alanine (0.02 mol) and yttrium nitrate tetrahydrate (0.02 mol) were mixed and placed in a microwave irradiation device, and microwave irradiation was heated at 90°C for 3 h to form a transparent liquid to obtain a deep eutectic solvent; (2) Take 11.2 g of the y-DES obtained in step (1), add 0.02 mol of cobalt sulfate heptahydrate thereto, and continue to microwave irradiate and heat the mixture at 80°C until it dissolves; then add 4 mL of 5 M sodium hydroxide solution dropwise, heat the mixture to 90°C, and continue to microwave irradiate and heat the mixture for 50 min to obtain a brown mixed solution; (3) The brown mixture was cooled to room temperature, the brown precipitate was collected by centrifugation, washed four times with water and ethanol, and dried at 90 °C for 10 h to obtain Y2O3-Co(OH)2 particles. Example 6

[0024] (1) L-glycine (0.02 mol) and yttrium nitrate tetrahydrate (0.02 mol) were mixed and placed in a microwave irradiation device, and microwave irradiation was heated at 100°C for 2 h to form a transparent liquid to obtain a deep eutectic solvent; (2) Take 8.4 g of y-DES obtained in step (1), add 0.02 mol of cobalt nitrate hexahydrate thereto, and continue to microwave irradiate and heat the mixture at 75°C until it dissolves; then add 7 mL of 5 M potassium hydroxide solution dropwise, heat the mixture to 100°C, and continue to microwave irradiate and heat the mixture for 60 min to obtain a brown mixed solution; (3) The brown mixture was cooled to room temperature, the brown precipitate was collected by centrifugation, washed three times with water and ethanol, and dried at 100 °C for 10 h to obtain Y2O3-Co(OH)2 particles. Comparative Example 1

[0025] (1) Add 0.02 mol of cobalt nitrate hexahydrate to 8.4 g of water and continue to microwave irradiate and heat the reaction until it dissolves. The reaction time is 6 hours at a temperature of 100°C. Then, add 7 mL of 5 M sodium hydroxide solution dropwise and continue to microwave irradiate and heat the reaction for 30 minutes at a temperature of 90°C to obtain a light blue mixed solution. (2) The light cyan mixture was cooled to room temperature, the brown precipitate was collected by centrifugation, washed with water and ethanol three times, and dried at 80 °C for 12 h to obtain Co(OH)2 particles. Comparative Example 2

[0026] (1) Add 0.02 mol of yttrium nitrate tetrahydrate to 8.4 g of water, place in a microwave irradiation device, and continue to microwave irradiate and heat for 6 hours until dissolved; then add 7 mL of 5M sodium hydroxide solution, adjust the temperature to 90 ° C, and continue to microwave irradiate and heat for 30 minutes to obtain an off-white mixed solution; (2) The off-white mixture was cooled to room temperature, the brown precipitate was collected by centrifugation, washed with water and ethanol three times, and dried at 80 °C for 12 h to obtain Y2O3 particles. Comparative Example 3

[0027] (1) L-glycine (0.02 mol) and yttrium nitrate tetrahydrate (0.02 mol) were added to 8.4 g of water, placed in a microwave irradiation device, and microwave-heated for 6 h at 100 °C; (2) Then, 0.02 mol of cobalt nitrate hexahydrate was added and the mixture was heated under microwave irradiation at 80°C until dissolved. Then, 7 mL of 5 M sodium hydroxide solution was added dropwise and the temperature was raised to 90°C and the mixture was heated under microwave irradiation for 30 min to obtain a brown mixed solution. (3) The brown mixture was cooled to room temperature, the brown precipitate was collected by centrifugation, washed three times with water and ethanol, and dried at 80 °C for 12 h to obtain Y2O3-Co(OH)2 (H2O) particles. Comparative Example 4

[0028] (1) L-proline (0.02 mol) and yttrium nitrate tetrahydrate (0.02 mol) were mixed and placed in a microwave irradiation device, and microwave irradiation was heated at 100°C for 6 h to form a transparent liquid to obtain a deep eutectic solvent; (2) Take 9.2 g of the y-DES obtained in step (1), add 7 mL of 5 mol / L sodium hydroxide solution, and heat under microwave radiation at 90°C for 30 min to obtain a brown mixed solution; (3) The brown mixture was cooled to room temperature, the brown precipitate was collected by centrifugation, washed with water and ethanol several times, and dried for 12 hours to obtain the precipitate. Comparative Example 5

[0029] (1) L-glycine (0.02 mol) and cerium nitrate hexahydrate (0.02 mol) were mixed and placed in a microwave irradiation heating reaction until a transparent liquid was formed. The reaction time was 6 h and the temperature was 100 ° C. Thus, a deep eutectic solvent was obtained; (2) Take 10 g of the y-DES obtained in step (1), add 7 mL of 5 mol / L sodium hydroxide solution, and heat under microwave irradiation for 30 min at 90 °C to obtain a brown mixed solution; (3) The brown mixture was cooled to room temperature, the brown precipitate was collected by centrifugation, washed with water and ethanol three times, and dried at 80°C for 12 h to obtain the precipitate.

[0030] The Y2O3-Co(OH)2 particles obtained in Example 1 were used to conduct oxidase activity detection experiments, acetylcholinesterase detection, organophosphorus pesticide detection in wastewater, mechanism exploration, and antioxidant capacity exploration.

[0031] Oxidase activity detection experiment For the oxidase activity test, 800 μL HAc-NaAc buffer (100 mM, pH = 4.4) and 100 μL Y2O 3- Co(OH)2 particles (1.0 mg / mL) were added to 1.5 mL centrifuge tubes in sequence, and then 100 μL of TMB (10 mM) was added thereto. The mixture was incubated at room temperature for 15 min, and the absorbance at 652 nm was measured.

[0032] Comparison of oxidase-like activity in different reaction systems of Y2O3-Co(OH)2 particles: 800μL HAc-NaAc buffer (100mM, pH=4.4) was added to a 1.5mL centrifuge tube, followed by 100μL Y2O3, Co(OH)2, Y2O3-Co(OH)2 (H2O), and Y2O3-Co(OH)2 (y-DES) at a concentration of 1.0mg / mL, and finally 100μL TMB (10mM). After mixing, the mixture was reacted in the same environment for the same time, and the absorbance of the solution at 652nm was measured to compare the strength of the oxidase-like activity.

[0033] Acetylcholinesterase test To detect acetylcholinesterase activity, thiocholine, the product of acetylcholine hydrolysis by acetylcholinesterase, can reduce TMB oxidation. First, 100 μL of 20 mU / mL acetylcholinesterase was added to 10 μL of phosphate buffer (100 mM, pH = 8.0) containing 10 mM acetylcholine. After mixing, the mixture was incubated at 37°C for 30 minutes. Subsequently, 690 μL of HAc-NaAc buffer, 100 μL of 1.0 mg / mL Y2O3-Co(OH)2 particles, and 100 μL of 10 mM TMB were added in sequence. After mixing, the mixture was incubated at room temperature for various times. The absorbance of the solution was measured at 652 nm.

[0034] The experiment optimized the hydrolysis of acetylcholine by acetylcholinesterase, and experimental verification showed that the optimal hydrolysis time was 30 minutes. The absorbance at 652 nm decreased with increasing acetylcholinesterase activity, and the decrease in absorbance at 652 nm showed a good linear relationship with the acetylcholinesterase concentration within the range of 0.2-22 mU / mL. The calculated limit of detection for acetylcholinesterase was 0.069 mU / mL, demonstrating the method's good sensitivity, comparable to or superior to results reported in the literature.

[0035] Detection of organophosphorus pesticides in wastewater The effect of reaction time between organophosphorus pesticides and acetylcholinesterase on organophosphorus pesticide detection was investigated by mixing two aliquots of 100µL of 180mU / mL acetylcholinesterase with 10µL of each organophosphorus pesticide at different concentrations (0.001 and 5µg / mL). The mixture was incubated at 37°C for different time periods. Then, 10µL of 10mM acetylcholine was added to each aliquot. After mixing thoroughly, the mixture was reacted at 37°C for 30 minutes. Next, 680µL of acetate buffer, 100µL of 1mg / mL L₂O₃-Co(OH)₂ particles, and 100µL of 10mM TMB solution were added to the aliquots. The mixture was incubated at 25°C for 15 minutes. Finally, the absorbance at 652nm was recorded.

[0036] Mechanism exploration Experiments investigating the mechanism of oxidase activity in Y2O3-Co(OH)2 particles revealed that, after optimizing experimental conditions, the optimal concentration of Y2O3-Co(OH)2 particles was 1 mg / mL, the TMB concentration was 10 mM, the reaction temperature was room temperature, the pH of the reaction buffer was 4.4, and the reaction time was 10 min. 800 μL of HAc-NaAc buffer (100 mM, pH 4.4) and 100 μL of Y2O3-Co(OH)2 (1.0 mg / mL) were added sequentially to a 1.5 mL centrifuge tube. The tube was then placed in an ice bath maintained at 0-4°C. High-purity oxygen, argon, and air were introduced for 20 min, respectively, with continuous shaking. Then, 100 μL of TMB (10 mM) was added. After incubation at room temperature for 15 min, the absorbance at 652 nm was measured.

[0037] Study on antioxidant capacity 900µL of DPPH (100µM) and 100µL of Y2O3-Co(OH)2 particles of different concentrations were incubated at room temperature in the dark for 30min and then the absorbance was measured.

[0038] The above detection experiments and research results are described below with reference to the accompanying drawings.

[0039] Figure 1 、 2 This is the SEM image of the synthesized Y2O3-Co(OH)2 particles. From the test results, it can be seen that they are relatively regular triangular pyramids, and the surface of the particles can be observed to be relatively smooth ( Figure 1 ), but some subtle textures or step structures may be visible at high resolutions ( Figure 2 ), the diameter of the conical structure gradually decreases from the base to the tip, forming a natural concentration gradient-driven channel, which can accelerate the mass transfer rate of target molecules (such as acetylcholine and organic pollutants) to the active site (2-5 times higher than that of the planar structure).

[0040] Figure 3This is the XRD characterization diagram of Y2O3-Co(OH)2 particles, which describes the unique diffraction peaks contained in Y2O3-Co(OH)2 particles. The experimental data graph is at ~20.8°, ~24.7°, ~37.56°, ~50.94°, and ~59.65°, which belong to the (110) crystal plane, (210) crystal plane, and (211) crystal plane of Co(OH)2; at the same time, ~19.41°, ~29.25°, ~43.65°, and ~47.94° correspond to the (211) crystal plane, (222) crystal plane, (411) crystal plane, and (440) crystal plane of Y2O3, respectively; the 2θ angle of the diffraction peak in the experimental spectrum is highly consistent with the peak position of the target material, and the deviation is within the allowable error range of the instrument, which strongly proves that the synthesized material has the same crystal structure as the target material and verifies the successful synthesis of Y2O3-Co(OH)2 particles.

[0041] Figure 4 The UV absorption spectrum of the Y2O3-Co(OH)2 particles in Example 1 of the present invention is shown. TMB was selected as the chromogenic substrate for the oxidase activity investigation. Figure 4 As shown, Y2O3-Co(OH)2 particles can catalyze the oxidation of colorless TMB to blue ox-TMB with a maximum absorbance at 652 nm.

[0042] Figure 5 This is the UV absorption spectrum of the antioxidant capacity of the Y2O3-Co(OH)2 particles in Example 1 of the present invention. The antioxidant capacity of the Y2O3-Co(OH)2 particles in Example 1 of the present invention is necessary for detecting organophosphorus compounds in wastewater. The Y2O3-Co(OH)2 particles prepared by y-DES have oxidase-like activity. The antioxidant capacity of oxidase-like enzymes can resist the interference of other oxidizing or reducing substances in the wastewater. For example, there may be some oxidizing heavy metal ions (such as Fe 3+ 、Cu 2+ ) or other strong oxidants, which will attack the active center of the oxidase-like enzyme, causing the enzyme to be inactivated. Similarly, when organophosphorus compounds are in the environment or during the detection process, they may trigger the generation of free radicals. These free radicals will react with other substances in the detection system and interfere with the detection signal. The antioxidant property of the oxidase-like enzyme can promptly remove these free radicals and prevent the free radicals from damaging the substrate, indicator and other substances in the detection system. In order to explore the effect of the gas environment on the activity of the oxidase-like enzyme, we conducted a control experiment to verify whether the oxidase-like activity of Y2O3-Co(OH)2 particles depends on oxygen. In the saturated atmosphere of oxygen, air and argon, there was no significant difference in the absorbance at 652nm, indicating that the gas environment has little effect on the oxidase-like activity of Y2O3-Co(OH)2 particles. The oxidase-like activity can still be maintained well in non-pure oxygen and inert gases, which is beneficial for subsequent applications.

[0043] Figure 6 This is the ultraviolet absorption spectrum of the Y2O3-Co(OH)2 particles used to detect acetylcholinesterase in Example 1 of the present invention. Thiocholine, the product of acetylcholine hydrolysis by acetylcholinesterase, can reduce the oxidation of TMB. As shown in the figure, when acetylcholinesterase and acetylcholine coexist, the absorbance of the system at 652nm decreases significantly, indicating that the system can be used for the detection of acetylcholinesterase.

[0044] Figure 7 This is the standard curve for detecting acetylcholinesterase in Example 1 of the present invention. Experiments show that the Y2O3-Co(OH)2 particles of the present invention can show a linear relationship in the detection of acetylcholinesterase in the range of 0.2-22 mU / mL, with a wider linear range, and accurate determination can be achieved in a wider concentration range. The detection limit can reach 0.069 mU / mL, indicating that the method has good sensitivity, which is comparable to or better than the results reported in the literature.

[0045] Figure 8 This is a comparison chart of ultraviolet absorption when Y2O3-Co(OH)2 particles are added with organophosphorus pesticides and when no organophosphorus pesticides are added when detecting acetylcholinesterase in Example 1 of the present invention. Organophosphorus pesticides are irreversible inhibitors of acetylcholinesterase. They can form covalent bonds with the active site of acetylcholinesterase, inhibiting the activity of acetylcholinesterase, resulting in a decrease in the formation of thiocholine, and more TMB is catalytically oxidized by Y2O3-Co(OH)2 particles. In order to explore the feasibility of the Y2O3-Co(OH)2 particle / TMB system for detecting organophosphorus pesticides, ethyl paraoxon was selected as a model of organophosphorus pesticides. Figure 8 As shown, when organophosphorus pesticides are present, the absorbance of the system at 652 nm is restored, and organophosphorus pesticides have no effect on the Y2O3-Co(OH)2 particle / TMB detection system.

[0046] Figure 9 This is the standard curve of ethyl paraoxon, a representative model of organophosphorus pesticides, detected by Y2O3-Co(OH)2 particles in Example 1 of the present invention. Experiments have shown that the detection limit of ethyl paraoxon can reach 0.8 ng / mL.

[0047] Figure 10This is a UV absorption spectrum of the Y2O3-Co(OH)2 particles from Example 1 of the present invention. The five colored curves represent the absorbance curves of 100µL of each Y2O3-Co(OH)2 particle solution at five different concentrations incubated with 900µL of 100µM DPPH at room temperature for 30 minutes in the dark. The blue curve represents a concentration of 1.0 mg / mL, the orange curve represents a concentration of 0.8 mg / mL, the red curve represents a concentration of 0.6 mg / mL, the purple curve represents a concentration of 0.4 mg / mL, and the green curve represents a concentration of 0.2 mg / mL. This test verifies the antioxidant capacity of the material. 1,1-Diphenyl-2-picrylhydrazyl (DPPH) is most commonly used to evaluate the free radical scavenging ability of antioxidants. When Y2O3-Co(OH)2 particles act as antioxidants, the hydrogen atoms they donate can combine with DPPH radicals, causing the DPPH solution to lighten in color and enhance UV absorption. As can be seen from the figure, as the concentration of Y2O3-Co(OH)2 particles increases, its antioxidant activity gradually increases, but even at the lowest concentration of 0.2 mg / mL, the antioxidant activity is very excellent.

[0048] Figure 11 This is a comparison chart of the oxidase-like activity over time of the Y2O3-Co(OH)2 particles synthesized by y-DES in Example 1 of the present invention, and the Y2O3 and Co(OH)2 synthesized separately in Comparative Examples 1-3, and the Y2O3-Co(OH)2 particles synthesized in water. It can be seen from the figure that the oxidase-like activity of all materials prepared increases with increasing reaction time, but the growth of Y2O3-Co(OH)2 particles is the most obvious. Thanks to the special reaction conditions created by y-DES and the synergistic effect between Y2O3 and Co(OH)2, the prepared bimetallic particle material exhibits more excellent performance in the oxidase-like activity test.

[0049] Figure 12 This is an SEM image of the Co(OH)2 particles synthesized in Comparative Example 1 of the present invention. It can be seen from the figure that the Co(OH)2 particles synthesized alone have disordered morphology, showing microstructural characteristics of irregular orientation and uneven morphological distribution. It is impossible to synthesize a uniformly dispersed conical morphology and increase the mass transfer rate.

[0050] Figure 13 This is the SEM image of the Y2O3 particles synthesized in Comparative Example 2 of the present invention. It is also found that the individual Y2O3 particles cannot form a conical morphology, but a careful observation reveals that some cubic particles are distributed therein, which is the characteristic morphology of Y2O3 particles.

[0051] Figure 14This is an SEM image of the Y2O3-Co(OH)2 (H2O) particles synthesized in Comparative Example 3 of the present invention. Y2O3-Co(OH)2 (H2O) synthesized alone in water cannot form a specific conical morphology, proving that y-DES acts as a template and selectively adsorbs on specific crystal faces of the particles, affecting the growth rate and morphology of the material.

[0052] At the same time, the performance of the materials of Examples 1-6 and Comparative Examples 1-5 of the present invention are compared and shown in Table 1:

[0053]

[0054]

[0055] In order to test the sensitivity of the obtained materials, the materials prepared in the examples and comparative examples were tested and analyzed. Table 1 is a statistical table of the detection limits of acetylcholinesterase and organophosphorus pesticides in Examples 1-6 and Comparative Examples 1-5. Figure 11 The following is a comparison table of the oxidase-like activity of the materials obtained after the reaction of Example 1 and Comparative Examples 1-3. The experiment found that the detection limit of acetylcholinesterase in Example 1 can reach 0.069mU / mL, and the detection limit of representative drugs of organophosphorus pesticides can reach 0.8ng / mL. The detection sensitivity of the other examples cannot achieve this effect. The separate Y2O3 particles and Co(OH)2 in Comparative Examples 1 and 2 have no detection effect. This is largely attributed to the fact that the penetrating heating characteristics of microwaves in the Y2O3-Co(OH)2 particle synthesis method are conducive to the formation of morphological uniformity. At the same time, the solvent template effect of y-DES forms a conical morphology with uniform particle size, forming an interfacial synergistic effect, increasing the mass transfer rate of acetylcholinesterase or organophosphorus pesticide active sites, and the specific structure optimizes the spatial steric effect, reducing nonspecific detection, resulting in a lower signal-to-noise ratio and higher sensitivity.

[0056] Table 2 compares the methods reported in the literature for detecting acetylcholinesterase. The comparison shows that the detection limits of AuAgNCs and SiO2 materials for detecting acetylcholinesterase are 0.15 mU / mL and 200 mU / mL, respectively. The linear range of the Y2O3-Co(OH)2 particles of the present invention can reach 0.2-22 mU / mL. Within this wide range, the target concentration and the detection signal show good linearity, reducing the error caused by nonlinear fitting. It is particularly suitable for samples with large concentration fluctuations. The detection limit is 0.06 mU / mL, which is much lower than the detection limit reported in the literature. It can identify low-concentration substances that cannot be detected by traditional methods, improving the accuracy and reliability of the analysis.

[0057] Table 3 compares the methods reported in the literature for detecting organophosphorus pesticides. 2、 The detection limits of CeO2NPs materials are 0.97 ng / mL, 1.0 ng / mL, and 18.3 ng / mL, respectively. The linear range of the particles can reach 0.0008-2μg / mL. The wider the linear range, the stronger the applicability of the standard curve, which can cover more concentration ranges of actual samples. The detection limit is 0.8ng / mL, which is much lower than the detection limit reported in the literature. It can identify low-concentration substances that traditional methods cannot detect, thereby improving the sensitivity of detection.

Claims

1. A method for preparing Y2O3-Co(OH)2 particles, characterized in that: The following steps are involved: (1) An L-amino acid containing amino and carboxyl functional groups is mixed with a metal yttrium salt and subjected to microwave irradiation heating reaction until a transparent solution is formed to obtain a deep eutectic solvent; (2) Adding the metal cobalt salt to the low eutectic solvent, continuously heating the solution under microwave radiation at 70-80°C until it dissolves, then adding the alkaline solution and heating the solution to 90-100°C for 10-60 minutes to obtain a brown mixed solution; (3) The brown mixed liquid is separated into solid and liquid, the precipitate is washed and dried to obtain Y2O3-Co(OH)2 particles.

2. The method for preparing Y2O3-Co(OH)2 particles according to claim 1, characterized in that: In the step (1), the L-amino acid containing amino and carboxyl functional groups is any one of L-glycine, L-alanine, and L-leucine; and the metal yttrium salt is any one of yttrium acetate tetrahydrate, yttrium nitrate tetrahydrate, and yttrium phosphate.

3. The method for preparing Y2O3-Co(OH)2 particles according to claim 1, characterized in that: In the step (1), the molar ratio of the L-amino acid containing amino and carboxyl functional groups to the metal yttrium salt is 1:0.5-2, the microwave radiation heating reaction time is 2-6 hours, and the temperature is 80-100°C.

4. The method for preparing Y2O3-Co(OH)2 particles according to claim 1, characterized in that: In the step (2), the metal cobalt salt is any one of cobalt sulfate heptahydrate, cobalt phosphate octahydrate, and cobalt nitrate hexahydrate.

5. The method for preparing Y2O3-Co(OH)2 particles according to claim 1, characterized in that: In the step (2), the molar ratio of the metal cobalt salt to the metal yttrium salt is 1:0.5-2.

6. The method for preparing Y2O3-Co(OH)2 particles according to claim 1, characterized in that: In the step (2), the alkaline solution is one of sodium hydroxide solution, potassium hydroxide solution, and calcium hydroxide solution, the concentration of the alkaline solution is 5-10M, and the molar ratio of the alkali to the metal yttrium salt in the added alkaline solution is 1-2:

1.

7. An application of Y2O3-Co(OH)2 particles prepared by the preparation method according to any one of claims 1 to 6, characterized in that: It was used to detect organophosphorus pesticides in industrial wastewater containing acetylcholinesterase and its inhibitors.

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