A magnetic nano-adsorption material, its preparation method and application

Abstract

This invention discloses a magnetic nano-adsorbent material, which is a magnetic composite nanosphere modified with silane on its surface. The magnetic nano-adsorbent material has a core-shell structure, and the silane modification includes hydrophilic and lipophilic groups. The hydrophilic and lipophilic groups modified with silane exhibit excellent synergistic effects in improving the adsorption rate of drugs, especially tetrahydrocannabinol (THC-COOH), NKET, and 6-AM, demonstrating a significant improvement in adsorption efficiency. This allows for efficient and selective enrichment and purification of multiple illicit drugs in water. Furthermore, the magnetic nano-adsorbent material of this invention possesses strong magnetism, allowing for rapid separation of the adsorbent material using a magnet, achieving rapid solid-liquid separation, and enabling material recycling and regeneration. This invention employs a sol-gel method to prepare the magnetic nano-adsorbent material, which has simple synthesis conditions, a short one-pot synthesis time, and results in magnetic nano-adsorbent materials with good monodispersity and uniform particle size.

Description

Technical Field

[0001] This invention belongs to the field of environmental protection materials, specifically relating to a magnetic nano-adsorption material, its preparation method, and its application. Background Technology

[0002] Wastewater drug monitoring technology analyzes the concentration of drugs or metabolites in municipal wastewater to estimate drug consumption and other data. It can be used to monitor drug abuse and its patterns in specific areas, providing objective data for drug control efforts. In recent years, it has been widely used worldwide. Because the concentration of target drugs in wastewater is low and the matrix is ​​complex, wastewater samples must be enriched and purified before analysis. Currently, solid phase extraction (SPE) has become the most commonly used pretreatment technique for wastewater drug analysis. Commonly used SPE columns for pretreatment of abused drugs in wastewater include MCX, HLB, and MAX columns. The pretreatment process involves multiple steps such as activation, sample loading, rinsing, elution, and nitrogen blowing reconstitution, which has disadvantages such as long processing time (1-2 hours), high cost, cumbersome operation, and high specialization. Furthermore, due to the lipophilic nature of cannabis metabolite THC-COOH, it is easily adsorbed onto the container walls during wastewater sample collection, transportation, and storage, making THC-COOH difficult to detect. However, cannabis is the most widely used drug in the world. Traditional wastewater drug collection and detection methods are prone to causing loss of THC-COOH content. In addition, they are costly, complicated to operate, and highly specialized, making it difficult to meet the needs of on-site wastewater drug detection.

[0003] Magnetic solid-phase extraction (MSPE) technology has been widely used for the extraction of organic pollutants, pesticides, and heavy metal ions from wastewater due to its advantages such as simple operation, speed, material recyclability, low cost, and environmental friendliness. This technology mainly utilizes the magnetic properties and adsorption specificity of magnetic nanoparticles (MNPs) to selectively adsorb target analytes in solution, and finally achieves rapid separation of MNPs and target analytes using a magnet. In addition to its high efficiency and convenience, MNPs with different specific effects can be designed and prepared according to the physicochemical properties of the target analytes, enabling the simultaneous specific adsorption of multiple targets.

[0004] The prior art CN114832793A discloses a magnetic nanomaterial for detecting tetrahydrocannabinol and synthetic cannabinoid drugs, its preparation method, and its application. Fe3O4 nanoparticles are ultrasonically dispersed in Tris buffer solution, dopamine hydrochloride is added, and the mixture is mechanically stirred for 10-24 hours. Fe3O4@PDA nanoparticles are then separated using a magnet. After washing and vacuum drying, Fe3O4@PDA is ultrasonically dispersed in acetonitrile. Following stirring, MAA methacrylate, EGDMA ethylene glycol dimethacrylate, and AIBN are added sequentially. The reaction is carried out at a constant temperature of 85-95℃ until the solution turns light gray. The reaction is then stopped, and the resulting composite material is separated using a magnet. After repeated washing in acetonitrile and water, and vacuum drying, Fe3O4@PDA@poly(MAA-co-EGDMA) magnetic nanomaterials are obtained. This method requires first grafting Fe3O4 nanoparticles, then reacting the grafted Fe3O4@PDA nanoparticles with MAA methacrylate, EGDMA, and AIBN to obtain Fe3O4@PDA@poly(MAA-co-EGDMA) magnetic nanomaterials. This process involves numerous steps, a lengthy grafting process, and low efficiency. Furthermore, the preparation method for this magnetic nanomaterial is complex and costly, and its adsorption effect on THC-COOH is only moderate, with a maximum recovery rate of only 69.3±2.25%. Moreover, it can only enrich tetrahydrocannabinol and synthetic cannabinoids. Therefore, this method still falls short of meeting the needs of on-site drug detection in wastewater.

[0005] Given the various problems existing in current technologies, there is an urgent need to develop a simple, efficient, highly selective, and high-adsorption-rate pretreatment technology suitable for the enrichment and purification of multi-target illegal drugs in wastewater. Summary of the Invention

[0006] To overcome the problems existing in the prior art, one objective of this invention is to provide a magnetic nano-adsorbent material. A second objective is to provide a method for preparing the magnetic nano-adsorbent material. A third objective is to provide the application of this magnetic nano-adsorbent material in the pretreatment of trace amounts of illicit drugs in wastewater. A fourth objective is to provide a method for detecting trace amounts of illicit drugs in wastewater.

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

[0008] The first aspect of the present invention provides a magnetic nano-adsorbent material, wherein the magnetic nano-adsorbent material is a magnetic composite nanosphere modified with surface silane, the magnetic composite nanosphere comprising magnetic nanoparticles located in the core and SiO2 located in the outer layer, and the surface silane modification includes hydrophilic group modification and esterophilic group modification.

[0009] Optionally, the particle diameter of the magnetic nano-adsorption material is 100–700 nm; preferably, the diameter range is 200–700 nm; and more preferably, the diameter range is 200–400 nm.

[0010] Optionally, the diameter of the core magnetic nanoparticles is 50–650 nm; preferably, the diameter range is 100–600 nm; and more preferably, the diameter range is 100–300 nm.

[0011] Optionally, the magnetic nanoparticles include Fe3O4 nanoparticles. The magnetic nano-adsorbent material is a Fe3O4@SiO2 magnetic composite nanosphere modified with silane on its surface. The Fe3O4@SiO2 magnetic composite nanosphere has a core-shell structure, comprising Fe3O4 in the core and SiO2 in the outer layer. The surface silane modification includes hydrophilic group modification and esterophilic group modification.

[0012] The second aspect of the present invention provides a method for preparing the magnetic nano-adsorbent material described in the first aspect, comprising the following steps: mixing magnetic nanoparticles and a silane reagent, and performing a sol-gel reaction to obtain the magnetic nano-adsorbent material; wherein the silane reagent includes a silane coupling agent, a hydrophilic silane, and an ester-silane; wherein the silane coupling agent includes a tetraethoxysilane, the hydrophilic silane includes at least one of ureosilane and aminosilane, and the ester-silane includes a phenylsilane.

[0013] Optionally, the magnetic nanoparticles include Fe3O4 nanoparticles.

[0014] Optionally, the diameter of the magnetic nanoparticles is 50–650 nm; preferably, the diameter range is 100–600 nm; and more preferably, the diameter range is 100–300 nm.

[0015] Optionally, the hydrophilic silane is selected from at least one of ureapropyltriethoxysilane, ureapropyltrimethoxysilane, or N-[3-(trimethoxysilyl)propyl]ethylenediamine.

[0016] Optionally, the phenylsilane is selected from at least one of monophenylsilane or diphenylsilane. More preferably, the phenylsilane is selected from at least one of diphenyldimethoxysilane, trimethyloxyphenylsilane, diphenyldiethoxysilane, diphenyldipropoxysilane, or diphenyl-ethoxymethoxysilane.

[0017] Optionally, the solid-liquid ratio of the magnetic nanoparticles to the silane reagent is 1 g: (1-8) mL; more preferably, the solid-liquid ratio of the magnetic nanoparticles to the silane reagent is 1 g: (1.5-6) ​​mL.

[0018] Optionally, the volume ratio of the silane coupling agent, hydrophilic silane, and esterophilic silane is 1:(0.1-0.5):(0.5-1); more preferably, the volume ratio of the silane coupling agent, hydrophilic silane, and esterophilic silane is 1:(0.1-0.3):(0.7-1).

[0019] Optionally, the solvent for the sol-gel reaction is an alcohol solution; more preferably, the solvent for the sol-gel reaction is an aqueous ethanol solution.

[0020] Optionally, the volume concentration of the alcohol solution is 70% to 80%.

[0021] Optionally, the volume ratio of the solvent to the silane reagent is (1-50):1.

[0022] Optionally, the conditions for the sol-gel reaction are selected from one or more of the following:

[0023] A) Reaction temperature 40–80℃;

[0024] B) Reaction time: 7–10 hours;

[0025] C) The solution pH is 10–12.

[0026] Alternatively, the reaction temperature is 50–70°C.

[0027] Alternatively, the reaction time is 7–9 hours.

[0028] Alternatively, the pH of the solution is 10.5 to 11.5.

[0029] The third aspect of this invention provides the application of the magnetic nano-adsorption material described in the first aspect in the pretreatment of trace amounts of illicit drugs in wastewater.

[0030] The drugs mentioned include amphetamine (AMP), methamphetamine (METH), 5-methylenedioxyamphetamine (MDA), 3,4-methylenedioxymethamphetamine (MDMA), norketamine (NKET), ketamine (KET), codeine (COD), cocaine (COC), and O. 6 - At least one of monoacetylmorphine (6-AM), tetrahydrocannabinol (THC-COOH), methadone metabolite 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine (EDDP), and methadone (MTD).

[0031] Optionally, the drugs include NKET, 6-AM, and THC-COOH.

[0032] The fourth aspect of this invention provides a method for detecting trace amounts of illicit drugs in wastewater. The method involves pretreating wastewater using the magnetic nano-adsorbent material described in the first aspect of this invention or the magnetic nano-adsorbent material prepared by the method described in the second aspect of this invention, thereby adsorbing the target illicit drug. Then, the wastewater and the magnetic nano-adsorbent material adsorbed with the target illicit drug are separated into solid and liquid components. The adsorbed target illicit drug in the magnetic nano-adsorbent material is eluted and collected, and the content of the target illicit drug in the wastewater is analyzed and calculated.

[0033] Optionally, the wastewater is pretreated with magnetic nano-adsorption materials to adsorb the target illicit drug. After adsorption is complete, the magnetic nano-adsorption materials with the target illicit drug adsorbed are magnetically attracted to the container wall using a magnet, and the excess wastewater is poured out. An elution solvent is added to the container to extract the target illicit drug from the magnetic nano-adsorption materials, and solid-liquid separation is achieved again using a magnet. The extracted elution solvent is collected for instrumental analysis, and the content of the target illicit drug in the wastewater is calculated.

[0034] Optionally, the treatment process is as follows: magnetic nano-adsorbent material is added to wastewater containing drugs, and the magnetic nano-adsorbent material is dispersed in the wastewater using dispersion methods such as vortexing or hand shaking, so that the magnetic nano-adsorbent material adsorbs the target substance. After adsorption is completed, the solid and liquid are separated by magnetic attraction. Then, the target illegal drug is extracted from the magnetic nano-adsorbent material using an eluent, and solid-liquid separation is achieved again using a magnet. Finally, the extracted eluent is collected for instrumental analysis, and the content of the analyte in the wastewater is calculated.

[0035] Optionally, the eluent includes methanol.

[0036] Optionally, 10-50 mg of the above-mentioned magnetic nano-adsorbent material can be added to every 10 mL of wastewater containing trace amounts of drugs at a concentration of 200-1000 ng / L to treat the wastewater containing trace amounts of drugs.

[0037] The beneficial effects of this invention are:

[0038] This invention provides a magnetic nano-adsorbent material, which is a magnetic composite nanosphere modified with silane on its surface. The hydrophilic and lipophilic groups modified with silane on the surface have an excellent synergistic effect in improving the adsorption rate of drugs, especially tetrahydrocannabinol (THC-COOH), which has the best adsorption effect. It can efficiently and selectively enrich and purify illicit drugs with multiple targets in water.

[0039] Specifically, compared with the prior art, the present invention has the following advantages:

[0040] 1) This invention provides a magnetic nano-adsorbent material, which is a magnetic composite nanosphere modified with surface silane. The magnetic composite nanosphere comprises magnetic nanoparticles at the core and SiO2 coated on the outer layer. The surface silane modification includes hydrophilic and lipophilic group modification. The SiO2 on the outer layer and the surface silane modification have an excellent synergistic effect in improving the adsorption rate of drugs, especially tetrahydrocannabinol (THC-COOH), NKET, and 6-AM, which significantly improves the adsorption effect. It can efficiently enrich and purify illicit drugs in water targeting multiple substances. In addition, the magnetic nano-adsorbent material of this invention has strong magnetism, and the adsorbent material can be quickly separated by a magnet, achieving rapid solid-liquid separation, and the material can be recycled and reused.

[0041] 2) This invention uses the sol-gel method to prepare magnetic nano-adsorbent materials. This process is low in cost, the raw materials are cheap and easy to obtain, the synthesis conditions are simple, the "one-pot" synthesis time is short, and the magnetic nano-adsorbent materials obtained have good monodispersity and uniform particle size.

[0042] 3) The magnetic nano-adsorbent material of this invention exhibits strong adsorption performance for drugs and can be applied to the preparation of drug enrichment products and the detection of drugs in wastewater. This magnetic nano-adsorbent material can be used for the on-site enrichment of multi-target illicit drugs, especially improving the enrichment level of tetrahydrocannabinol, and can be used as a pretreatment product in combination with on-site rapid detection instruments or large-scale laboratory analytical instruments. Attached Figure Description

[0043] Figure 1 This is a synthetic route diagram for magnetic nano-adsorption materials;

[0044] Figure 2 This is a scanning electron microscope (SEM) image of the magnetic nano-adsorption material.

[0045] Figure 3 The Fourier transform infrared (FT-IR) spectrum of the magnetic nano-adsorption material is shown.

[0046] Figure 4 A schematic diagram illustrating the detection and analysis applications of magnetic nano-adsorption materials;

[0047] Figure 5 The figures show the adsorption results of tetrahydrocannabinol (THC-COOH) by the magnetic nano-adsorption materials of Examples 1-7 and Comparative Examples 1-2.

[0048] Figure 6 The figures show the adsorption results of various illicit drugs and their metabolites by the magnetic nano-adsorption materials of Examples 1-7 and Comparative Examples 1-2. Detailed Implementation

[0049] The present invention will be further described in detail below through specific embodiments.

[0050] The Fe3O4 nanomaterials and silane reagents used in the following examples were commercially available from Aladdin. The Fe3O4 nanomaterials had a particle size of 100–600 nm; the silane reagents had a purity greater than 90%.

[0051] Example 1: Preparation of Magnetic Nanoparticle Adsorption Materials

[0052] In this embodiment, the ureosilane and phenylsilane are ureopropyltriethoxysilane and diphenyldimethoxysilane, respectively. The synthesis route of the magnetic nano-adsorbent material is shown in the figure below. Figure 1 As shown, the specific preparation process is as follows:

[0053] 0.50 g of Fe3O4 nanospheres with a particle size of 100 nm were added to a three-necked flask and ultrasonically mixed with 10 mL of ultrapure water and 40 mL of anhydrous ethanol. The mixed flask was preheated in a 60°C constant temperature water bath. After the solution temperature reached 60°C, 1.00 mL of tetraethoxysilane, 0.15 mL of ureapropyltriethoxysilane, and 0.85 mL of diphenyldimethoxysilane (volume ratio 1:0.15:0.85) were added under mechanical stirring at 300 rpm and mixed. The pH was adjusted to 10 with ammonia water. Finally, the sol-gel reaction was carried out under mechanical stirring at 300 rpm for 8 h at 60°C. After the reaction, 50 mL of 50% methanol aqueous solution was added and ultrasonically washed three times. After washing, a small amount of water was added to dissolve the residue, and then the mixture was freeze-dried to obtain the magnetic nano-adsorbent material.

[0054] Example 2: Preparation of Magnetic Nanoparticle Adsorption Materials

[0055] In this embodiment, the ureosilane and phenylsilane are ureopropyltriethoxysilane and diphenyldimethoxysilane, respectively, and the specific preparation process is as follows:

[0056] 0.10 g of Fe3O4 nanospheres with a particle size of 100 nm were added to a three-necked flask and ultrasonically mixed with 4 mL of ultrapure water and 16 mL of anhydrous ethanol. The mixed flask was preheated in a constant temperature water bath at 40 °C. After the solution temperature reached 40 °C, 0.20 mL of tetraethoxysilane, 0.03 mL of ureapropyltriethoxysilane, and 0.17 mL of diphenyldimethoxysilane (volume ratio 1:0.15:0.85) were mixed under mechanical stirring, and the pH was adjusted to 11 with ammonia. Finally, the mixture was mechanically stirred at 300 rpm for 8 h in a 40 °C water bath to carry out the sol-gel reaction. After the reaction, 50 mL of 60% methanol aqueous solution was added and ultrasonically washed three times. After washing, a small amount of water was added to dissolve the mixture, and then it was freeze-dried to obtain the magnetic nano-adsorbent material.

[0057] Example 3: Preparation of Magnetic Nanoparticle Adsorption Materials

[0058] In this embodiment, the ureosilane and phenylsilane are ureopropyltriethoxysilane and diphenyldimethoxysilane, respectively, and the specific preparation process is as follows:

[0059] 1.50 g of Fe3O4 nanospheres with a particle size of 100 nm were added to a three-necked flask and ultrasonically mixed with 30.0 mL of ultrapure water and 120.0 mL of anhydrous ethanol. The mixed flask was preheated in an 80°C water bath. After the solution temperature reached 80°C, 3 mL of tetraethoxysilane, 0.45 mL of ureapropyltriethoxysilane, and 2.55 mL of diphenyldimethoxysilane (volume ratio 1:0.15:0.85) were mixed under mechanical stirring, and the pH was adjusted to 12 with ammonia. Finally, the sol-gel reaction was carried out by mechanical stirring at 300 rpm for 8 h in an 80°C water bath. After synthesis, 50 mL of 40% methanol aqueous solution was added and ultrasonically washed three times. After washing, a small amount of water was added to dissolve the mixture, and then it was freeze-dried to obtain the magnetic nano-adsorbent material.

[0060] Example 4: Preparation of Magnetic Nanoparticle Adsorption Materials

[0061] In this embodiment, the ureosilane and phenylsilane are ureopropyltriethoxysilane and trimethyloxyphenylsilane, respectively, and the specific preparation process is as follows:

[0062] 1.65 g of Fe3O4 nanospheres with a particle size of 300 nm were added to a three-necked flask and ultrasonically mixed with 10 mL of ultrapure water and 40 mL of anhydrous ethanol. The mixed flask was preheated in a 60°C constant temperature water bath. After the solution temperature reached 60°C, 1.00 mL of tetraethoxysilane, 0.50 mL of ureapropyltriethoxysilane, and 0.50 mL of trimethyloxyphenylsilane (volume ratio 1:0.5:0.5) were added under mechanical stirring at 300 rpm and mixed. The pH was adjusted to 10 with ammonia water. Finally, the sol-gel reaction was carried out under mechanical stirring at 300 rpm for 8 h at 60°C. After the reaction, 50 mL of 50% methanol aqueous solution was added and ultrasonically washed three times. After washing, a small amount of water was added to dissolve the residue, and then the mixture was freeze-dried to obtain the magnetic nano-adsorbent material.

[0063] Example 5: Preparation of Magnetic Nanoparticle Adsorption Materials

[0064] In this embodiment, the aminosilane and phenylsilane are N-[3-(trimethoxysilyl)propyl]ethylenediamine and diphenyldimethoxysilane, respectively, and the specific preparation process is as follows:

[0065] 0.80 g of Fe3O4 nanospheres with a particle size of 600 nm were accurately weighed and added to a three-necked flask, where they were ultrasonically mixed with 30.0 mL of ultrapure water and 120.0 mL of anhydrous ethanol. The mixed flask was preheated in an 80°C constant temperature water bath. After the solution temperature reached 80°C, 1.8 mL of tetraethoxysilane, 0.55 mL of N-[3-(trimethoxysilyl)propyl]ethylenediamine, and 1.75 mL of diphenyldimethoxysilane (volume ratio 1:0.3:1) were mixed under mechanical stirring, and the pH was adjusted to 12 with ammonia. Finally, the mixture was mechanically stirred at 300 rpm for 8 h in an 80°C water bath to carry out the sol-gel reaction. After the reaction, 50 mL of 40% methanol aqueous solution was added and ultrasonically washed three times. After washing, a small amount of water was added to dissolve the mixture, and then it was freeze-dried to obtain the magnetic nano-adsorbent material.

[0066] Example 6: Preparation of Magnetic Nanoparticle Adsorption Materials

[0067] In this embodiment, the ureosilane and phenylsilane are ureopropyltriethoxysilane and diphenyldimethoxysilane, respectively, and the specific preparation process is as follows:

[0068] 1 g of Fe3O4 nanospheres with a particle size of 100 nm were added to a three-necked flask and ultrasonically mixed with 10 mL of ultrapure water and 40 mL of anhydrous ethanol. The mixed flask was preheated in a 60°C constant temperature water bath. After the solution temperature reached 60°C, 0.5 mL of tetraethoxysilane, 0.15 mL of ureapropyltriethoxysilane, and 0.35 mL of diphenyldimethoxysilane (volume ratio 1:0.3:0.7) were added under mechanical stirring at 300 rpm and mixed. The pH was adjusted to 10 with ammonia water. Finally, the sol-gel reaction was carried out under mechanical stirring at 300 rpm for 8 h at 60°C. After the reaction, 50 mL of 50% methanol aqueous solution was added and ultrasonically washed three times. After washing, a small amount of water was added to dissolve the residue, and then the mixture was freeze-dried to obtain the magnetic nano-adsorbent material.

[0069] Example 7: Preparation of Magnetic Nanoparticle Adsorption Materials

[0070] In this embodiment, the ureosilane and phenylsilane are ureopropyltriethoxysilane and diphenyldimethoxysilane, respectively, and the specific preparation process is as follows:

[0071] 0.75 g of Fe3O4 nanospheres with a particle size of 100 nm were added to a three-necked flask and ultrasonically mixed with 4 mL of ultrapure water and 16 mL of anhydrous ethanol. The mixed flask was preheated in a constant temperature water bath at 40 °C. After the solution temperature reached 40 °C, 3 mL of tetraethoxysilane, 0.45 mL of ureapropyltriethoxysilane, and 2.55 mL of diphenyldimethoxysilane (volume ratio 1:0.15:0.85) were mixed under mechanical stirring, and the pH was adjusted to 11 with ammonia. Finally, the mixture was mechanically stirred at 300 rpm for 8 h in a 40 °C water bath to carry out the sol-gel reaction. After the reaction, 50 mL of 60% methanol aqueous solution was added and ultrasonically washed three times. After washing, a small amount of water was added to dissolve the mixture, and then it was freeze-dried to obtain the magnetic nano-adsorbent material.

[0072] Comparative Example 1: Preparation of Magnetic Nanoparticle Adsorption Materials

[0073] This embodiment does not use hydrophilic silanes, but only phenylsilanes. The specific preparation process is as follows:

[0074] 0.50 g of Fe3O4 nanospheres with a particle size of 100 nm were added to a three-necked flask and ultrasonically mixed with 10.00 mL of ultrapure water and 40.00 mL of anhydrous ethanol. The mixed flask was preheated in a 60°C constant temperature water bath. After the solution temperature reached 60°C, 1.00 mL of tetraethoxysilane and 0.85 mL of diphenyldimethoxysilane were added under mechanical stirring and mixed. The pH was adjusted to 10.5 with ammonia water. Finally, the sol-gel reaction was carried out by mechanical stirring at 300 rpm for 8 hours in a 60°C water bath. After the reaction, 60% acetonitrile aqueous solution was added and ultrasonically washed three times. After washing, a small amount of water was added to dissolve the nanoparticles, and then the mixture was freeze-dried to obtain the magnetic nano-adsorbent material.

[0075] Comparative Example 2: Preparation of Magnetic Nanoparticle Adsorption Materials

[0076] This embodiment does not use phenylsilane, but only hydrophilic silane. The specific preparation process is as follows:

[0077] 1.50 g of Fe3O4 nanospheres with a particle size of 100 nm were added to a three-necked flask and ultrasonically mixed with 10.00 mL of ultrapure water and 40.00 mL of anhydrous ethanol. The mixed flask was preheated in a 60°C water bath. After the solution temperature reached 60°C, 1.00 mL of tetraethoxysilane and 0.5 mL of ureapropyltriethoxysilane were added under mechanical stirring and mixed. The pH was adjusted to 11.5 with ammonia. Finally, the mixture was mechanically stirred at 300 rpm for 8 hours in a 60°C water bath. After synthesis, the mixture was ultrasonically washed three times with a 60% acetonitrile aqueous solution. After washing, a small amount of water was added to dissolve the mixture, and then it was freeze-dried to obtain the magnetic nano-adsorbent material.

[0078] Microstructure analysis and characterization of samples from Experimental Example 1 and Example 1

[0079] Figure 2 The image shown is a scanning electron microscope (SEM) image of the magnetic nano-adsorbent material prepared in Example 1, obtained using a TESCANMIRA LMS scanning electron microscope from the Czech Republic. It can be seen that the magnetic nano-adsorbent material prepared in this invention has a uniform particle size, a slightly rough surface, and good monodispersity, with a particle size of approximately 200 nm. This demonstrates that 100 nm commercially available Fe3O4 nanospheres have been coated with a silanizing agent, forming a core-shell structure of Fe3O4@SiO2 magnetic composite nanospheres. The remaining examples, after verification, also show core-shell structured Fe3O4@SiO2 magnetic composite nanospheres. The particle size of the Fe3O4@SiO2 magnetic composite nanospheres is 50–100 nm larger than that of the Fe3O4 nanospheres, meaning the coating thickness of the silanizing agent around the core-shell structure is 25 nm–50 nm.

[0080] Figure 3 The Fourier transform infrared spectrum of the magnetic nano-adsorption material prepared in Example 1 was obtained using a Nicolet 6700 intelligent Fourier transform infrared spectrometer. The value at 587.21 cm⁻¹ is shown. -1 Characteristic Fe-O-Fe absorption is observed at 1116.48 cm⁻¹. -1 The characteristic absorption of Si-O-Si is observed at 1428.97 cm⁻¹. -1 and 1550.73cm -1 The characteristic absorption of the benzene ring C=C is located at 3200-3700 cm⁻¹. -1 The broad peaks are characteristic absorption peaks of -OH, at 3071.00 and 3328.56 cm⁻¹. -1 The peaks are for NH primary amines, at 3474.95 cm⁻¹. -1 It is a moderate intensity singlet of secondary ammonia; at 1590.12 cm⁻¹. -1 The peak at 1659.12 is a characteristic absorption peak of primary amines, and 1659.12 is a strong characteristic absorption peak of carbonyl C=O. It can be seen that the surface of the Fe3O4@SiO2 magnetic composite nanospheres is modified with hydrophilic and esterophilic groups. The Fe3O4@SiO2 magnetic composite nanospheres in the other embodiments were also verified to have surface modifications with hydrophilic and esterophilic groups.

[0081] Application Example 1

[0082] 1. Adsorption experiments of tetrahydrocannabinic acid (THC-COOH) on magnetic nano-adsorbent materials of Examples 1-7 and Comparative Examples 1-2.

[0083] Experimental methods: Specific application methods are as follows Figure 4As shown. The nanospheres prepared in Examples 1-7 and Comparative Examples 1 and 2 were used to adsorb and detect THC-COOH. 10 mg of the Fe3O4@SiO2 magnetic composite nanospheres from Examples 1-7 and Comparative Examples 1 and 2 were weighed and added to 10 mL of wastewater containing tetrahydrocannabinol (THC-COOH) at a concentration of 200 ng / L. The adsorption was completed by shaking the centrifuge tube at 2500 rpm for 15 min using a micro vortex mixer. After adsorption, the Fe3O4@SiO2 magnetic composite nanospheres were attached to the centrifuge tube wall using a magnet, and the wastewater was poured out. 4 mL of methanol was added for washing. Using methanol as the eluent, the target illicit drug was extracted from the Fe3O4@SiO2 magnetic composite nanospheres by vortexing at 2000 rpm, followed by solid-liquid separation. The extracted eluent was collected for analysis to calculate the tetrahydrocannabinol content in the wastewater.

[0084] Experimental results: Adsorption detection results are as follows Figure 5 As shown in the test results above, the Fe3O4@SiO2 magnetic composite nanospheres synthesized in Examples 1-7 all exhibit an adsorption rate of over 53% for THC-COOH. Specifically, Examples 1 and 7 show adsorption rates exceeding 70%, with Example 7 reaching 98.7%. The adsorption rate of Comparative Example 1 is 31.8%, and that of Comparative Example 2 is 41.5%. A comparison of Examples 1-7 and Comparative Examples 1-2 clearly demonstrates that hydrophilic silanes (ureidosilanes or aminosilanes) and phenylsilanes have a synergistic effect in improving the adsorption rate of THC-COOH. In particular, the combination of ureapropyltriethoxysilane and diphenyldimethoxysilane exhibits an excellent synergistic effect on improving the adsorption rate, showing a significant adsorption advantage compared to adding hydrophilic silanes or phenylsilanes alone.

[0085] 2. Adsorption experiments of various illicit drugs and their metabolites by magnetic nano-adsorption materials in Examples 1-7 and Comparative Examples 1-2.

[0086] Following the experimental methods described above, the adsorption rates of SiO2@Fe3O4 nanospheres for other illicit drugs and their metabolites in wastewater were measured and calculated. These illicit drugs and their metabolites included: amphetamine (AMP), methamphetamine (METH), 5-methylenedioxyamphetamine (MDA), 3,4-methylenedioxymethamphetamine (MDMA), norketamine (NKET), ketamine (KET), codeine (COD), cocaine (COC), and O. 6 - Monoacetylmorphine (6-AM), tetrahydrocannabinol (THC-COOH), methadone metabolite 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine (EDDP), methadone (MTD). The concentration of each illicit drug and its metabolite was 200 ng / L.

[0087] Figure 6 Adsorption effects of Examples 1-7 (with hydrophilic and esteric silanes added to the synthetic raw materials) and Comparative Examples 1 and 2 (without hydrophilic and esteric silanes added) on mixed solutions of illicit drugs and their metabolites of the same concentration.

[0088] In Example 1, the SiO2@Fe3O4 nanospheres synthesized at the end showed an adsorption rate of over 90% for METH, MDA, MDMA, COC, EDDP, and MTD; and an adsorption rate of over 80% for AMP, NKET, KET, COD, and 6-AM; but a slightly lower adsorption rate of 70.7% for THC-COOH.

[0089] In Example 2, the SiO2@Fe3O4 nanospheres synthesized at the end showed an adsorption rate of over 90% for AMP, METH, MDA, MDMA, COC, EDDP, and MTD; an adsorption rate of over 80% for NKET, KET, COD, and 6-AM; but an adsorption rate of 61.5% for THC-COOH.

[0090] In Example 3, the SiO2@Fe3O4 nanospheres synthesized at the end showed an adsorption rate of over 90% for AMP, METH, MDA, MDMA, KET, COC, EDDP, and MTD; and an adsorption rate of over 80% for NKET and COD; but the adsorption rates for 6-AM and THC-COOH were 72.3% and 53.7%, respectively.

[0091] In Example 4, the synthesized SiO2@Fe3O4 nanospheres showed an adsorption rate of over 80% for KET, COC, EDDP, and MTD; an adsorption rate of over 67% for AMP, MDA, MDMA, COD, and 6-AM; and an adsorption rate of 55%–57% for METH, NKET, and THC-COOH.

[0092] In Example 5, the synthesized SiO2@Fe3O4 nanospheres showed an adsorption rate of over 80% for METH, MDMA, COD, COC, EDDP, and MTD; an adsorption rate of over 67% for NKET, KET, 6-AM, and THC-COOH; and slightly lower adsorption rates for AMP and MDA, at 60.7% and 53.7%, respectively.

[0093] The SiO2@Fe3O4 nanospheres synthesized in Example 6 showed an adsorption rate of over 89% for COC, EDDP, and MTD; an adsorption rate of over 60% for MDMA, COD, and 6-AM; an adsorption rate of less than 37% for AMP and NKET; and an adsorption rate of between 47% and 55% for METH, MDA, KET, and THC-COOH.

[0094] In Example 7, the synthesized SiO2@Fe3O4 nanospheres showed an adsorption rate of over 90% for COC, THC-COOH, EDDP, and MTD; an adsorption rate of over 70% for MDMA, KET, COD, and 6-AM; and an adsorption rate of less than 70% for AMP, METH, MDA, and NKET.

[0095] Comparative Examples 1 and 2 showed adsorption rates of less than 40% for NKET, 6-AM, and THC-COOH.

[0096] The data above shows that adding hydrophilic silanes (ureidosilanes or aminosilanes) as hydrophilic modifying groups significantly improves the adsorption effect on some drugs, such as NKET, KET, COD, 6-AM, and THC-COOH; adding phenylsilanes as lipophilic modifying groups significantly improves the adsorption effect on some drugs, such as AMP, METH, 6-AM, and THC-COOH. This indicates that the proposed scheme using tetraethoxysilane as a crosslinking agent, ureoyl or amino groups as hydrophilic modifying groups, and phenyl groups as lipophilic modifying groups has significant advantages and can effectively achieve the goal of enriching trace amounts of illicit drugs and their metabolites in water.

Claims

1. The application of a magnetic nano-adsorbent material in the pretreatment of trace amounts of illicit drugs in wastewater, characterized in that, The magnetic nano-adsorbent material is a magnetic composite nanosphere modified with silane on its surface. The magnetic composite nanosphere includes magnetic nanoparticles in the core and SiO2 in the outer layer. The surface silane modification includes hydrophilic group modification and lipophilic group modification. The preparation method of the magnetic nano-adsorbent material includes the following steps: mixing magnetic nanoparticles and silane reagents, and performing a sol-gel reaction to obtain the magnetic nano-adsorbent material; the silane reagent includes silane coupling agents, hydrophilic silanes, and esterophilic silanes; the silane coupling agent includes tetraethoxysilane; the hydrophilic silane includes at least one of ureosilane and aminosilane; the esterophilic silane includes phenylsilane; The illegal drugs mentioned include amphetamine, methamphetamine, 5-methylenedioxyamphetamine, 3,4-methylenedioxymethamphetamine, norketamine, ketamine, codeine, cocaine, and O. 6 - At least one of monoacetylmorphine, tetrahydrocannabinol, methadone metabolite 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine, and methadone.

2. The application according to claim 1, characterized in that, The magnetic nano-adsorption material has a particle diameter of 100~700 nm; And / or, the magnetic nanoparticles include Fe3O4 nanoparticles.

3. The application according to claim 1, characterized in that, The phenylsilane is selected from at least one of monophenylsilane or diphenylsilane; And / or, the phenylsilane is selected from at least one of diphenyldimethoxysilane, trimethyloxyphenylsilane, diphenyldiethoxysilane, diphenyldipropoxysilane, or diphenyl-ethoxymethoxysilane.

4. The application according to claim 1, characterized in that, The hydrophilic silane is selected from at least one of ureapropyltriethoxysilane, ureapropyltrimethoxysilane, or N-[3-(trimethoxysilyl)propyl]ethylenediamine.

5. The application according to claim 1, characterized in that, The solid-liquid ratio of the magnetic nanoparticles to the silane reagent is 1 g:(1~8) mL; And / or, the volume ratio of the silane coupling agent, hydrophilic silane, and ester-philic silane is 1:(0.1~0.5):(0.5~1).

6. The application according to claim 1, characterized in that, The solvent for the sol-gel reaction is an alcohol solution; And / or, the volume ratio of the solvent to the silane reagent is (1~50):

1.

7. The application according to claim 1, characterized in that, The conditions for the sol-gel reaction are selected from one or more of the following: A) Reaction temperature 40~80℃; B) Reaction time: 7-10 hours; C) The solution pH is 10-12.

8. A method for detecting trace amounts of illicit drugs in wastewater, characterized in that, The magnetic nano-adsorbent material described in any one of claims 1-7 is used to pretreat wastewater and adsorb the target illegal drug; then, the wastewater and the magnetic nano-adsorbent material adsorbed with the target illegal drug are separated into solid and liquid components. The target illicit drug adsorbed in the magnetic nano-adsorbent material is eluted and collected, and the content of the target illicit drug in the wastewater is analyzed and calculated.

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