Composite aerogel and preparation method and application thereof
By preparing a composite aerogel of sodium carboxymethyl cellulose and gold nanoclusters, the problem of limited functionality in the detection and removal of oxytetracycline was solved, achieving rapid and sensitive detection and efficient removal, while reducing operational complexity and cost.
Patent Information
- Application Number
- CN202610513947.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-04-17
- Publication Date
- 2026-06-12
AI Technical Summary
Existing materials cannot simultaneously achieve sensitive detection and efficient removal of oxytetracycline, and existing technologies suffer from problems such as expensive equipment, complex operation, and limited functionality.
A composite aerogel was prepared by gelation reaction using sodium carboxymethyl cellulose, hydroquinone, and gold nanoclusters to form a three-dimensional porous network structure. The gold nanoclusters served as a fluorescence sensing unit and a visible light responsive photosensitizer, integrating fluorescence detection and photocatalytic degradation functions.
Rapid and sensitive detection and efficient removal of oxytetracycline were achieved, with a detection limit of 0.44 μg/L and a total removal rate of up to 96.7%. The material is easy to recycle and is stable for repeated use, reducing preparation costs and energy consumption.
Smart Images
Figure CN122183489A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of new materials technology, specifically to a composite aerogel, its preparation method, and its applications. Background Technology
[0002] Oxytetracycline (OTC), a broad-spectrum tetracycline antibiotic, is widely used in livestock and aquaculture. Due to its difficulty in being completely metabolized by organisms, approximately 30%–90% of the active ingredient enters the aquatic environment through excrement. Residual oxytetracycline not only causes toxic effects on aquatic ecosystems but also induces the emergence and spread of drug-resistant strains, posing a serious threat to public health. Therefore, developing functional materials capable of simultaneously and sensitively detecting and efficiently removing oxytetracycline from water bodies has significant academic value and engineering application implications.
[0003] Currently, the detection of oxytetracycline mainly relies on instrumental methods such as high-performance liquid chromatography (HPLC) and liquid chromatography-mass spectrometry (LC-MS). Although these methods are sensitive and accurate, they have limitations such as expensive equipment, complex operation, and difficulty in rapid on-site detection. Fluorescence sensing methods have attracted attention due to their high sensitivity, rapid response, and ease of operation. However, most fluorescent probes are in solution, making them difficult to recover, and they do not have the function of removing contaminants.
[0004] In existing technologies, single adsorption methods only achieve phase transfer of pollutants, and the adsorbent after adsorption saturation needs to be regenerated or disposed of as hazardous waste, which is costly. Single photocatalysis methods have weak enrichment capacity for low concentrations of antibiotics, and the low probability of collision between photogenerated free radicals and target molecules leads to slow reaction kinetics and incomplete mineralization. In recent years, although there have been reports of adsorption-photocatalysis synergistic materials, these materials generally lack pollutant detection capabilities and cannot rapidly assess the degree of pollution before degradation.
[0005] Therefore, developing a multifunctional material that integrates fluorescence detection, efficient adsorption, and visible light photocatalytic degradation is a technical problem that urgently needs to be solved in this field. Summary of the Invention
[0006] The technical problem to be solved by the present invention is to provide a composite aerogel that can solve the technical problem that existing materials have single function and are difficult to achieve sensitive detection and efficient removal of OTC at the same time.
[0007] The first aspect of this invention is to provide a composite aerogel, the technical solution of which is:
[0008] A composite aerogel is prepared by gelation reaction of sodium carboxymethyl cellulose, hydroquinone, and gold nanoclusters under hydrogen peroxide oxidation-induced reaction.
[0009] The composite aerogel has a three-dimensional porous network structure, wherein sodium carboxymethyl cellulose serves as the gel skeleton, the polymer formed by cross-linking and polymerization of hydroquinone serves as the adsorption site, and gold nanoclusters serve as the fluorescence sensing unit and visible light responsive photosensitizer, which are uniformly dispersed in the sodium carboxymethyl cellulose gel skeleton.
[0010] Furthermore, based on the total volume of the reaction mixture, the final concentration of each component is:
[0011] The mass-volume concentration of sodium carboxymethyl cellulose is 1.0%~3.0%;
[0012] The concentration of hydroquinone is 0.05~0.2 M;
[0013] The concentration of gold nanoclusters was 0.1–0.5 mM (based on Au atoms).
[0014] The concentration of hydrogen peroxide is 0.1~0.5 M.
[0015] Furthermore, the gold nanoclusters are synthesized using chloroauric acid and BSA as raw materials.
[0016] The second aspect of this invention is to provide a method for preparing composite aerogels, the technical solution of which is:
[0017] A method for preparing a composite aerogel includes the following steps:
[0018] Step S1, synthesis of gold nanoclusters;
[0019] Step S2: Dissolve sodium carboxymethyl cellulose in deionized water to prepare a solution with a mass-volume concentration of 1.5% to 3.0%.
[0020] Step S3: Add hydroquinone and the gold nanoclusters from step S1, and stir until homogeneous. The final concentration of hydroquinone is 0.05~0.2 M, and the final concentration of gold nanoclusters is 0.1~0.5 mM (based on Au atoms).
[0021] In step S4, hydrogen peroxide is slowly added dropwise under continuous stirring until its final concentration is 0.1~0.5 M, and the liquid gradually solidifies to form a hydrogel.
[0022] Step S5: After standing and maturing, wash and freeze-dry to obtain the composite aerogel.
[0023] Further, in step S1, the synthesis of the gold nanoclusters includes:
[0024] Chloroauric acid and BSA were mixed in a molar ratio of 1:1.2 to 1:2, and the pH was adjusted to 6.5 to 7.5. The mixture was stirred in a water bath at 30 to 40°C for 18 to 30 hours to obtain a gold nanocluster solution.
[0025] Furthermore, in step S4, the hydrogen peroxide is added at a rate of 0.3~1.0 mL / min.
[0026] A third aspect of the present invention is to provide an application of a composite aerogel in the detection of oxytetracycline.
[0027] A fourth aspect of the present invention is to provide the application of a composite aerogel in the adsorption and / or photocatalytic degradation of oxytetracycline.
[0028] Compared with existing technologies, the composite aerogel, its preparation method, and its applications provided by this invention have the following advantages:
[0029] I. The composite aerogel provided by this invention integrates the fluorescence detection function and adsorption-photocatalytic degradation function of oxytetracycline into the same material system. AuNCs simultaneously serve as a fluorescent probe and photosensitizer, achieving the integration of "detection" and "removal" and avoiding the cumbersome operation of multiple materials and multiple steps.
[0030] II. The composite aerogel provided by the present invention achieves both the polymerization of hydroquinone and the formation of a three-dimensional network at room temperature through one-step oxidation-induced gelation with hydrogen peroxide, without the need for high temperature, high pressure or organic crosslinking agents, which significantly reduces the preparation cost and energy consumption.
[0031] III. The composite aerogel provided by this invention, based on the fluorescence quenching mechanism of AuNCs, has a detection range of 0-500 μg / L for oxytetracycline, a limit of detection (LOD) of 0.44 μg / L, and a short detection time with good selectivity, enabling rapid on-site screening of oxytetracycline in samples. Hydroquinone, in the presence of hydrogen peroxide, rapidly reacts and cross-links with functional groups such as hydroxyl, carboxyl, and amino groups under the catalysis of BSA-AuNCs, and can also oxidize itself to form polymers, providing abundant π-π stacking sites, enriching oxytetracycline molecules around AuNCs, and increasing the collision probability between photogenerated free radicals and target pollutants. Experiments show that the total removal rate (adsorption + photocatalysis) of the composite aerogel of this invention is as high as 96.7%.
[0032] IV. The composite aerogel provided by this invention has a macroscopic block morphology, which facilitates recovery after reaction; after being recycled 5 times, the total removal rate still remains above 90%, showing good prospects for engineering applications. Attached Figure Description
[0033] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0034] Figure 1 This is a schematic diagram illustrating the synthesis principle of the composite aerogel of the present invention.
[0035] Figure 2 A photograph of the composite aerogel prepared in Example 1 of this invention;
[0036] Figure 3 This is a scanning electron microscope (SEM) image of the composite aerogel prepared in Example 1 of the present invention;
[0037] Figure 4 The fluorescence emission spectrum of the composite aerogel prepared in Example 1 of this invention;
[0038] Figure 5 The fluorescence images of the composite aerogel in this invention for different concentrations of oxytetracycline are shown.
[0039] Figure 6 This is the standard working curve of oxytetracycline concentration versus G / R ratio in this invention;
[0040] Figure 7 This is the experimental result of the selectivity of the composite aerogel for the detection of oxytetracycline in this invention;
[0041] Figure 8 The adsorption kinetics curves of the composite aerogel in this invention for oxytetracycline solutions of different concentrations are shown.
[0042] Figure 9 This invention relates to the effect of composite aerogel on the photocatalytic degradation of OTC by H2O2. Detailed Implementation
[0043] To enable those skilled in the art to better understand the technical solutions in the embodiments of the present invention, and to make the above-mentioned objectives, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be further described below.
[0044] The endpoints and any values of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, the endpoint values of the various ranges, the endpoint values of the various ranges and individual point values, and individual point values can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.
[0045] Example 1
[0046] Please see Figure 1 A method for preparing a composite aerogel includes the following steps:
[0047] Step S1, Synthesis of gold nanoclusters (AuNCs)
[0048] 0.1 mmol of chloroauric acid (HAuCl4·3H2O) was dissolved in 20 mL of deionized water, and 0.15 mmol of bovine serum albumin (BSA) was added. The mixture was magnetically stirred for 10 minutes. The pH was adjusted to 7.0–7.5 with 1 M NaOH solution. The mixture was then transferred to a 40°C water bath and stirred in the dark for 24 hours to obtain an orange-yellow transparent solution, which was the AuNCs solution (Au concentration approximately 5 mM). Fluorescence spectroscopy showed a maximum excitation wavelength of 510 nm and a maximum emission wavelength of 649 nm. Transmission electron microscopy revealed that the AuNCs particle size was 1.8–2.5 nm, with an average particle size of 2.1 nm.
[0049] Step S2: Weigh 2 g of sodium carboxymethyl cellulose (viscosity 500 mPa·s) and dissolve it in 100 mL of deionized water. Stir until completely dissolved to obtain a 2% (w / v) CMC-Na solution.
[0050] Step S3: Take 50 mL of CMC-Na solution, add hydroquinone to a final concentration of 0.1 M (i.e., add 0.55 g), add the AuNCs solution obtained in step 1 to a final Au concentration of 0.3 mM (i.e., add 3 mL of 5 mM mother liquor), and stir for 30 minutes;
[0051] In step S4, while stirring at room temperature, slowly add 30% hydrogen peroxide at a rate of 0.5 mL / min until the final concentration is 0.3 M (about 1.7 mL). The liquid will slowly solidify and gradually form a hydrogel.
[0052] Step S5: Allow to stand for 12 hours to mature, wash three times with deionized water, and freeze-dry for 48 hours to obtain a black composite aerogel. The composite aerogel prepared in Example 1 is designated as HQ / CMC / AuNCs aerogel.
[0053] Example 2 Characterization of composite aerogel
[0054] Macroscopic morphology and microstructure: The composite aerogel prepared in Example 1 is porous and blocky (e.g. Figure 2 As shown), it is lightweight and possesses a certain degree of mechanical strength. Scanning electron microscopy (SEM) observations show (e.g.) Figure 3 As shown in the figure, the aerogel has an interconnected three-dimensional porous structure with pore sizes ranging from 50 to 200 μm and pore wall thicknesses of about 1 to 5 μm. The pore walls are covered with nanoscale wrinkles.
[0055] Fluorescence properties: The composite aerogel exhibits a red fluorescence when excited at 370 nm (e.g., the fluorescence is red). Figure 4(As shown). After adding OTC, the fluorescence gradually turns green as the concentration increases. The reason for this greening is that the OTC molecule inserts into the BSA protein molecule structure, forming a BSA-OTC complex structure, which emits green fluorescence.
[0056] Example 3: Fluorescence detection of oxytetracycline by composite aerogel
[0057] 1. Determination of standard curve
[0058] (1) Weigh 10 mg of the composite aerogel prepared in Example 1 and add it to a series of 10 mL oxytetracycline (OTC) standard solutions (concentration range: 0 ug / L, 40 ug / L, 80 ug / L, 100 ug / L, 300 ug / L, 500 ug / L, 800 ug / L, 1 mg / L, 5 mg / L, 10 mg / L, 20 mg / L, pH=7.0);
[0059] (2) Shake the reaction for 10 minutes under dark conditions;
[0060] (3) The fluorescence intensity of each system was measured using 370 nm as the excitation wavelength;
[0061] (4) Plot the G / R (fluorescence ratio) against the OTC concentration to establish a standard working curve.
[0062] Experimental results are as follows Figure 5 and Figure 6 As shown.
[0063] Depend on Figure 6 It can be seen that within the concentration range of 0-500 ug / L, G / R shows a good linear relationship with OTC concentration, and the linear regression equation is: G / R = 0.0016C. OTC The correlation coefficient R² = 0.9929 is +0.0042. The limit of detection (LOD) is 0.44 ug / L.
[0064] 2. Selective Experiments
[0065] Under the same experimental conditions, the following interfering substances (all at a concentration of 20 mg / L) were added: oxytetracycline (OTC), propyl gallate (PG), 4-amino-xylene musk (AMX), acetazolamide (AZM), adenosine monophosphate (AMP), erythrosine B (ERY), potassium metabisulfite (PMB), caprolactam (CPL), antioxidant GM, primidone (PRM), and chlorpromazine (CPZ). The G / R values of each system were then determined. The experimental results are as follows: Figure 7 As shown. By Figure 7It is evident that the composite aerogel of the present invention exhibits a significant fluorescence response intensity to oxytetracycline, while showing no obvious fluorescence change to other common antibiotics. This indicates that the composite aerogel of the present invention can be used for the selective detection of oxytetracycline.
[0066] 3. Spike Recovery Experiment of Experimental Samples
[0067] Water samples from tap water, river water, and aquaculture wastewater were collected, filtered through a 0.45 μm filter membrane, and then OTC standard solutions of different concentrations (5, 10, and 20 μM) were added. After adding the composite aerogel from Example 1, the samples were tested according to the above method, and the recovery rate was calculated.
[0068] The experimental results are shown in Table 1.
[0069] Table 1: Results of Spike Recovery Experiments on Actual Water Samples
[0070]
[0071] As shown in Table 1, the recovery rate of the composite aerogel of the present invention in actual water samples was 93.0%~98.0%, and the relative standard deviation (RSD) was less than 4.5%, indicating that the material has good practical application potential and can be used for rapid detection of oxytetracycline in water samples with different matrices.
[0072] Example 4: Synergistic adsorption-photocatalytic degradation of oxytetracycline by composite aerogel
[0073] 1. Adsorption experiment
[0074] The composite aerogels of Example 1 were immersed in OTC solutions of 10-1000 mg / L, pH=7.0, respectively; under light-protected conditions and at 25°C, they were magnetically stirred, and their adsorption capacity was measured at regular intervals.
[0075] Measurement results as follows Figure 8 As shown. By Figure 8 It can be seen that after the initial rapid adsorption phase, the adsorption rate of OTC gradually slows down after 80 min, reaching equilibrium within 120 min. The amount of OTC absorbed is directly related to the initial concentration of OTC in the solution; higher OTC concentrations lead to greater absorption. For an OTC solution of 1000 mg / L, the maximum adsorption capacity is 368.60 mg / g. Several factors contribute to this high adsorption capacity: firstly, the aerogel has a three-dimensional porous structure; secondly, hydroquinone forms numerous adsorption sites during polymerization as a cross-linking agent; and thirdly, BSA itself exhibits a strong binding effect with OTC.
[0076] 2. Photocatalytic degradation experiment
[0077] After adsorption equilibrium was reached (120 min of adsorption in a dark field), different concentrations of H2O2 (0.5 wt%, 1.0 wt%, and 5.0 wt%) were added to the reaction system, followed by illumination. The illumination conditions were: a 500W halogen lamp at a distance of 20 cm. Measurements were taken at regular intervals after the illumination began.
[0078] Experimental results are as follows Figure 9 As shown. By Figure 9 It can be seen that the degradation rate is highest when the hydrogen peroxide concentration reaches 5.0%, and the degradation rate reaches 96.7% within 180 minutes.
[0079] Example 5: Stability Experiment During Cyclic Use
[0080] After completing one adsorption-photocatalytic degradation experiment (180 minutes of light exposure), the HQ / CMC / AuNCs aerogel of the present invention was taken out, washed three times with a 1:1 mixture of ethanol and water, then washed with deionized water, and freeze-dried. The adsorption-photocatalytic degradation experiment was repeated for a total of 5 cycles.
[0081] The experimental results are shown in Table 2.
[0082] Table 2: Cyclic stability test results of composite aerogels
[0083]
[0084] As shown in Table 2, after five cycles, the total removal rate remained above 90%, indicating that the composite aerogel has good regeneration performance and operational stability.
[0085] The composite aerogel provided by this invention integrates the fluorescence detection function and adsorption-photocatalytic degradation function of oxytetracycline into the same material system. AuNCs simultaneously serve as a fluorescent probe and photosensitizer, achieving the integration of "detection" and "removal" and avoiding the cumbersome operation of multiple materials and multiple steps.
[0086] The embodiments of the present invention have been described in detail above, but the present invention is not limited to the described embodiments. For those skilled in the art, various changes, modifications, substitutions, and variations made to these embodiments without departing from the principles and spirit of the present invention still fall within the protection scope of the present invention.
Claims
1. A composite aerogel, characterized in that, The composite aerogel was prepared by a gelation reaction of sodium carboxymethyl cellulose, hydroquinone, and gold nanoclusters under hydrogen peroxide oxidation-induced reaction. The composite aerogel has a three-dimensional porous network structure, wherein sodium carboxymethyl cellulose serves as the gel skeleton, the polymer formed by cross-linking and polymerization of hydroquinone serves as the adsorption site, and gold nanoclusters serve as the fluorescence sensing unit and visible light responsive photosensitizer, which are uniformly dispersed in the sodium carboxymethyl cellulose gel skeleton.
2. The composite aerogel according to claim 1, characterized in that, Based on the total volume of the reaction mixture, the final concentrations of each component are: The mass-volume concentration of sodium carboxymethyl cellulose is 1.0%~3.0%; The concentration of hydroquinone is 0.05~0.2 M; The concentration of gold nanoclusters was 0.1–0.5 mM (based on Au atoms). The concentration of hydrogen peroxide is 0.1~0.5 M.
3. The composite aerogel according to claim 1, characterized in that, The gold nanoclusters were synthesized using chloroauric acid and BSA as raw materials.
4. A method for preparing a composite aerogel as described in any one of claims 1-3, characterized in that, Includes the following steps: Step S1, synthesis of gold nanoclusters; Step S2: Dissolve sodium carboxymethyl cellulose in deionized water to prepare a solution with a mass-volume concentration of 1.5% to 3.0%. Step S3: Add hydroquinone and the gold nanoclusters from step S1, and stir until homogeneous. The final concentration of hydroquinone is 0.05~0.2 M, and the final concentration of gold nanoclusters is 0.1~0.5 mM (based on Au atoms). In step S4, hydrogen peroxide is slowly added dropwise under continuous stirring until its final concentration is 0.1~0.5 M, and the liquid gradually solidifies to form a hydrogel. Step S5: After standing and maturing, wash and freeze-dry to obtain the composite aerogel.
5. The method for preparing the composite aerogel according to claim 4, characterized in that, In step S1, the synthesis of the gold nanoclusters includes: Chloroauric acid and BSA were mixed in a molar ratio of 1:1.2 to 1:2, and the pH was adjusted to 6.5 to 7.
5. The mixture was stirred in a water bath at 30 to 40°C for 18 to 30 hours to obtain a gold nanocluster solution.
6. The method for preparing the composite aerogel according to claim 4, characterized in that, In step S4, the hydrogen peroxide is added at a rate of 0.3~1.0 mL / min.
7. The application of a composite aerogel as described in any one of claims 1-3 in the detection of oxytetracycline.
8. The application of a composite aerogel as described in any one of claims 1-3 in the adsorption and / or photocatalytic degradation of oxytetracycline.