Composite nano material as well as preparation method and application thereof

Abstract

The invention belongs to the field of nano materials, and provides a composite nano material and a preparation method and application thereof. The composite material has a dendritic cluster structure, the dendritic cluster structure is formed by aggregation of a plurality of primary nanoparticles, and the primary nanoparticles comprise a compound formed by amorphous copper oxide and histidine. The composite nanomaterial provided by the embodiment of the invention has good catalytic activity, and can be used for degrading polysaccharides such as xanthan gum in the absence of electron donors.

Description

Technical Field

[0001] This application relates to the field of nanomaterials technology, and in particular to a composite nanomaterial, its preparation method, and its application. Background Technology

[0002] Xanthan gum, a natural polysaccharide derived from plant seeds, is widely used in various industrial sectors such as food, petroleum, and textiles due to its excellent thickening, stabilizing, and film-forming properties. However, its high molecular weight and high viscosity, while bringing functional advantages, also constitute limitations in its applications. Therefore, the controlled degradation of xanthan gum is of significant necessity.

[0003] Currently, the main methods for degrading xanthan gum fall into two categories: one uses natural enzymes to hydrolyze the glycosidic bonds in xanthan gum to obtain oligosaccharides, thereby breaking down the gum; the other is chemical degradation. Chemical degradation relies on high-intensity reaction conditions such as strong acids and high temperatures, resulting in a violent process that is difficult to precisely control, and placing stringent requirements on equipment and operational safety.

[0004] Bioenzymatic degradation methods offer mild reaction conditions (room temperature and pressure), but are expensive, the proteins themselves are structurally fragile and easily deactivated, and their excellent catalytic performance is only observed within a narrow optimal temperature or pH range. These factors significantly increase process complexity and application costs. Nanozymes represent a new class of artificial enzymes and biocatalysts, blurring the lines between inorganic and organic life. They possess both the physicochemical properties of nanomaterials and unique enzyme-like catalytic activity. Nanozymes exhibit good stability, resistance to high and low temperatures, acid and alkali resistance, tunable activity, and multifunctionality, and have attracted widespread attention, showing great application potential in biomedicine, environmental remediation, green agriculture, and new energy fields. Among them, amino acid-modified Prussian blue-like nanozymes are metal nanozymes capable of polysaccharide degradation. However, these Prussian blue-like nanozyme materials contain cyanide ligands, while CN... - It is toxic, posing significant environmental risks and deficiencies in green production. Furthermore, while this type of Prussian blue nanozyme material can rapidly degrade guar gum, it cannot degrade xanthan gum, limiting its application in the field of polysaccharide degradation. Unlike neutral, flexible guar gum, xanthan gum, due to its unique rigid helical structure and complex negatively charged side chains, presents a challenge. Exploring novel nanozymes capable of degrading such complex polysaccharides will be key to broadening the biomimetic catalytic applications of polysaccharides.

[0005] It should be noted that the above content is not necessarily prior art, nor is it intended to limit the scope of protection of this application. Summary of the Invention

[0006] This application provides a composite nanomaterial, its preparation method, and its application to solve or alleviate one or more of the technical problems mentioned above.

[0007] A first aspect of this application provides a composite nanomaterial having a dendritic cluster structure formed by the aggregation of multiple primary nanoparticles, the primary nanoparticles including a complex formed by amorphous copper oxide and histidine.

[0008] The composite nanomaterials of this application exhibit good catalytic activity and can be used to degrade xanthan gum and other gums in the absence of electron donors. This is because the strong coordination between histidine and copper ions not only effectively inhibits the long-term ordered arrangement of the crystal lattice, leading to the formation of amorphous copper oxide, but also controls the assembly of amorphous copper oxide nanoparticles into dendritic cluster structures, exposing a large number of copper ion active sites. Furthermore, similar to natural polysaccharide degrading enzymes, histidine may participate in electron transfer in the catalytic process, forming a synergistic catalytic interface with copper oxide to catalyze the decomposition of hydrogen peroxide to generate reactive oxygen species that degrade xanthan gum.

[0009] A second aspect of this application provides a method for preparing a composite nanomaterial, comprising the following steps: mixing a solution containing copper ions with histidine to obtain a coordination intermediate solution; alkalizing the coordination intermediate solution to form a colloidal precursor; and subjecting the colloidal precursor to a hydrothermal reaction to obtain the composite nanomaterial, wherein the alkalization treatment transforms the structure of the coordination intermediate formed by the copper ions and histidine to form the colloidal precursor, the coordination intermediate solution being blue, and the colloidal precursor being dark blue.

[0010] In the method of this application embodiment, the amino, imidazole nitrogen, and carboxyl groups in histidine undergo a coordination reaction with Cu ions to form a copper-histidine coordination intermediate. The large blue color of this coordination intermediate represents hydrated copper ions ([Cu(H2O)6)). 2+ The characteristic color of the coordination intermediate structure indicates that the copper ion is in an isolated, highly hydrated octahedral coordination environment. This step ensures that copper and histidine are uniformly mixed at the molecular scale, laying the foundation for subsequent uniform nucleation. The carboxyl and amino groups of histidine are deprotonated under alkaline conditions, and the coordination ability of imidazole nitrogen is also changed, causing the structure of the coordination intermediate to recombine and form a more complex polynuclear copper-histidine-hydroxyl / oxygen-bridged colloidal precursor. The colloidal precursor changes from bright blue to dark blue, indicating that the coordination environment of copper has changed drastically, which is the basis for the formation of amorphous copper oxide precursor. The colloidal precursor undergoes a hydrothermal reaction, which causes the histidine ligands to rearrange and amorphous copper oxide to be further formed, ultimately resulting in a composite nanomaterial with a dendritic cluster structure.

[0011] A third aspect of this application provides the application of the composite nanomaterial described in the first aspect or the composite nanomaterial prepared by the method described in the second aspect in the degradation of polysaccharide colloids. Histidine participates in the electron transfer of the catalytic process, forming a synergistic catalytic interface with copper oxide, catalyzing the decomposition of hydrogen peroxide to generate reactive oxygen species that degrade the polysaccharide colloids. Attached Figure Description

[0012] In the accompanying drawings, unless otherwise specified, the same reference numerals throughout the various drawings denote the same or similar parts or elements. These drawings are not necessarily drawn to scale. It should be understood that these drawings depict only some embodiments disclosed in this application and should not be construed as limiting the scope of this application.

[0013] Figure 1 This is a TEM image of the composite nanomaterial from Example 1; Figure 2 The image shows a comparison of the infrared spectra of the composite nanomaterial and histidine in Example 1. Figure 3 This is a TEM image of copper oxide from Comparative Example 1; Figure 4 These are the XRD patterns of the composite nanomaterial of Example 1 and the copper oxide of Comparative Example 1; Figure 5 This is a comparison chart showing the degradation effects of the composite nanomaterial of Example 1, copper oxide, HisCuCoPBA, hydrogen peroxide and Control on xanthan gum in Comparative Example 1. Figure 6 This is a comparison chart showing the degradation effects of the composite nanomaterial of Example 1, copper oxide of Comparative Example 1, and Control on guar gum. Detailed Implementation

[0014] The embodiments of this application are described in detail below. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other.

[0015] In this application, when numerical intervals (i.e., numerical ranges) are involved, unless otherwise specified, the distribution of selectable numerical values ​​within the numerical interval is considered continuous, and includes the two endpoints of the numerical interval (i.e., the minimum and maximum values), as well as every numerical value between these two endpoints. Unless otherwise specified, when a numerical interval refers only to integers within that numerical interval, it includes the two endpoint integers of the numerical range, as well as every integer between the two endpoints, which is equivalent to directly listing every integer. When multiple numerical ranges are provided to describe features or characteristics, these numerical ranges can be merged. In other words, unless otherwise specified, the numerical ranges disclosed in this application should be understood to include any and all subranges included therein. The "numerical value" in the numerical interval can be any quantitative value, such as a number, percentage, ratio, etc. The term "numerical interval" can be broadly included to include percentage intervals, ratio intervals, proportion intervals, etc.

[0016] Accordingly, a first aspect of this application provides a composite nanomaterial. The composite material has a dendritic cluster structure, which is formed by the aggregation of multiple primary nanoparticles, the primary nanoparticles including a complex formed from amorphous copper oxide and histidine.

[0017] The composite nanomaterials of this application exhibit good catalytic activity and can be used to degrade xanthan gum and other gums in the absence of electron donors. This is because the strong coordination between histidine and copper ions not only effectively inhibits the long-term ordered arrangement of the crystal lattice, leading to the formation of amorphous copper oxide, but also controls the assembly of amorphous copper oxide nanoparticles into dendritic cluster structures, exposing a large number of copper ion active sites. Furthermore, similar to natural polysaccharide degrading enzymes, histidine may participate in electron transfer in the catalytic process, forming a synergistic catalytic interface with copper oxide to catalyze the decomposition of hydrogen peroxide to generate reactive oxygen species that degrade xanthan gum.

[0018] It is understandable that the reducing properties of histidine in composite nanomaterials lead to the presence of monovalent copper ion species, ensuring that highly active monovalent copper ion sites are maintained in the product.

[0019] In some embodiments, histidine is an amino acid with zwitterionic properties, whose molecular structure includes an imidazole ring, an amino group, and a carboxyl group. These functional groups can coordinate with amorphous copper oxide precursors (such as copper ions), influencing the nucleation and growth kinetics of nanoparticles. This interaction can guide primary nanoparticles to aggregate in a non-close-packed manner, promoting the formation of dendritic cluster structures. The amino, imidazole nitrogen, and carboxyl oxygen groups of histidine are all good coordinating atoms, capable of forming stable coordination complexes with copper ions. Optionally, based on the total mass of the composite nanomaterial, the mass percentage of histidine is 30%-40%, for example, 30%, 32%, 35%, 38%, 40%, etc.

[0020] In some embodiments, the primary nanoparticles have a particle size of 10nm-20nm, such as 10nm, 13nm, 17nm, 19nm, 20nm, etc. The primary nanoparticles have an extremely high specific surface area, meaning that a large number of copper and histidine complex active sites are exposed on the surface, allowing direct contact with xanthan gum and thus enhancing the degradation effect.

[0021] In some embodiments, the particle size of the composite nanomaterial is 50 nm-300 nm.

[0022] A second aspect of this application provides a method for preparing composite nanomaterials. The method includes the following steps: S100: A solution containing copper ions is mixed with histidine to obtain a coordination intermediate solution; S200: The coordination intermediate solution is alkalized to form a colloidal precursor; S300: The colloidal precursor is subjected to a hydrothermal reaction to obtain composite nanomaterials. The alkalization treatment transforms the structure of the coordination intermediate formed by the copper ions and histidine, forming the colloidal precursor. The coordination intermediate solution is blue, and the colloidal precursor is dark blue.

[0023] In the method of this application embodiment, the amino, imidazole nitrogen, and carboxyl groups in histidine undergo a coordination reaction with Cu ions to form a copper-histidine coordination intermediate. The large blue color of this coordination intermediate represents hydrated copper ions ([Cu(H2O)6)). 2+ The characteristic color of the coordination intermediate structure indicates that the copper ion is in an isolated, highly hydrated octahedral coordination environment. This step ensures that copper and histidine are uniformly mixed at the molecular scale, laying the foundation for subsequent uniform nucleation. The carboxyl and amino groups of histidine are deprotonated under alkaline conditions, and the coordination ability of imidazole nitrogen is also changed, causing the structure of the coordination intermediate to recombine and form a more complex polynuclear copper-histidine-hydroxyl / oxygen-bridged colloidal precursor. The colloidal precursor changes from bright blue to dark blue, indicating that the coordination environment of copper has changed drastically, which is the basis for the formation of amorphous copper oxide precursor. The colloidal precursor undergoes a hydrothermal reaction, which causes the histidine ligands to rearrange and amorphous copper oxide to be further formed, ultimately resulting in a composite nanomaterial with a dendritic cluster structure.

[0024] According to the embodiments of the application itself, S100: A solution containing copper ions is mixed with histidine to obtain a coordination intermediate solution.

[0025] This step is fundamental to the formation of the copper-histidine coordination intermediate.

[0026] In some embodiments, the solution containing copper ions is a solution containing divalent copper ions. Optionally, the solution containing copper ions includes a copper sulfate solution. The significance of choosing copper sulfate lies in the weak coordination characteristics of the sulfate ion, which allows it to act only as a charge-balancing anion and not compete for the binding site of histidine, thus ensuring the formation of a coordination intermediate including histidine and copper ions.

[0027] Furthermore, in the coordination intermediate solution, the concentration of the copper sulfate solution is 30mM-33mM, for example, 30mM, 31mM, 32mM, 33mM, etc.

[0028] Furthermore, in the coordination intermediate solution, the concentration of histidine is 30mM-33mM, for example 30mM, 31mM, 32mM, 33mM, etc.

[0029] In some embodiments, the molar ratio of copper ions to histidine is 1:(1-2), such as 1:1, 1:2, etc. This results in the formation of a highly saturated, sterically hindered coordination intermediate between copper ions and histidine.

[0030] In some embodiments, the mixing is carried out under stirring conditions, wherein the stirring speed is 500 r / min-1000 r / min and the time is 30 min-90 min. Mixing under the aforementioned conditions can further promote the formation of highly saturated coordination intermediates with large steric hindrance.

[0031] According to an embodiment of this application, S200: The coordination intermediate solution is alkalized to form a colloidal precursor. The carboxyl and amino groups of histidine are deprotonated under alkaline conditions, and the coordination ability of the imidazole nitrogen also changes, causing the structure of the coordination intermediate to recombine, forming a more complex polynuclear copper-histidine-hydroxyl / oxygen-bridged colloidal precursor. This colloidal precursor changes from bright blue to dark blue, indicating a drastic change in the coordination environment of copper, which is the basis for the formation of the amorphous copper oxide precursor.

[0032] In some embodiments, the alkalization treatment includes adding an alkali solution dropwise to the coordination intermediate solution and stirring at 10°C-35°C for 1-3 hours. Temperatures above 35°C accelerate the reaction, resulting in a blue solution instead of a gel-like precursor. Temperatures below 10°C lead to incomplete reactions, resulting in a larger product radius and decreased degradation efficiency. A time exceeding 3 hours causes the stable gel-like precursor to transform into a dark blue solution, reducing the overall performance of the product. A time less than 1 hour results in incomplete reactions and low yield.

[0033] Furthermore, the alkali solution is added slowly, which helps to reduce the formation of local over-alkali and makes the microstructure of the product more uniform. Optionally, the dripping rate is 1 ml every 5 min to 10 min.

[0034] In some embodiments, the alkaline solution is a sodium hydroxide solution with a concentration of 0.5-2M; the molar ratio of sodium hydroxide to copper ions is 1:(0.4-0.6). This results in the formation of a highly saturated, sterically hindered coordination intermediate between copper ions and histidine.

[0035] According to an embodiment of this application, S300: The colloidal precursor is subjected to a hydrothermal reaction to obtain a composite nanomaterial. The colloidal precursor undergoes a hydrothermal reaction, causing histidine ligands to rearrange and amorphous copper oxide to further form, ultimately resulting in a composite nanomaterial with a dendritic cluster structure.

[0036] In some embodiments, the hydrothermal reaction temperature is 120°C-130°C, such as 120°C, 123°C, 126°C, 130°C, etc. High temperature promotes the coordination bond exchange rate, causing histidine molecules on the surface of the colloidal precursor to redistribute to lower-energy, more stable coordination configurations, exposing more copper active sites, while retaining the synergistic catalytic function of histidine.

[0037] In some embodiments, the hydrothermal reaction time is 2-4 hours, such as 2 hours, 2.5 hours, 3 hours, 3.5 hours, 4 hours, etc. This yields composite nanomaterials with controllable structure and excellent performance, and these composite nanomaterials are catalysts without electron donors.

[0038] In some embodiments, after the hydrothermal reaction and before obtaining the composite nanomaterial, the process further includes drying the hydrothermal reaction product under vacuum conditions for 12-18 hours at a temperature of 45°C-55°C.

[0039] A third aspect of this application provides the application of the composite nanomaterial described in the first aspect or the composite nanomaterial prepared by the method described in the second aspect in the degradation of polysaccharide colloids. Histidine participates in the electron transfer of the catalytic process, forming a synergistic catalytic interface with copper oxide, catalyzing the decomposition of hydrogen peroxide to generate reactive oxygen species that degrade the polysaccharide colloids.

[0040] In some embodiments, the degradation process includes the following steps: providing a degradation solution comprising composite nanomaterials and hydrogen peroxide; and using the degradation solution to degrade the polysaccharide colloid, wherein the polysaccharide colloid comprises at least one of xanthan gum and guar gum. This degradation process requires only a mixture of hydrogen peroxide and composite nanomaterials to degrade the polysaccharide colloid, is simple, and does not introduce toxic or harmful substances.

[0041] Furthermore, the degradation temperature is 10℃-50℃; during the degradation process, the pH of the mixture formed by the degradation solution and the polysaccharide colloid is 5-9.

[0042] Furthermore, for every 1g of adhesive degraded, the amount of the composite nanomaterial used is 0.005g-0.02g, and the amount of hydrogen peroxide used is 0.01g-0.3g.

[0043] In other embodiments, the degradation solution includes ascorbic acid, and for every 1g of adhesive degraded, the amount of the composite nanomaterial is 0.0002g-0.001g, the amount of hydrogen peroxide is 0.03g-0.1g, and the amount of ascorbic acid is 0.003g-0.05g.

[0044] Exemplary embodiments according to this application will now be described in more detail with reference to the accompanying drawings. It should be understood that these exemplary embodiments may be implemented in many different forms and should not be construed as being limited to the embodiments set forth herein.

[0045] Example 1 1 mmol of CuSO4·5H2O solid was dissolved in 30 mL of ultrapure water. 1 mmol of histidine was added to a copper sulfate solution at 25 °C and a magnetic stirring speed of 600 rpm. The solution was premixed and stirred for 90 min at 600 rpm to form a blue coordination intermediate. 2.5 mL of freshly prepared 1 M sodium hydroxide solution was slowly added dropwise to the histidine-copper sulfate mixture, and the reaction was continued with stirring for 2 h to obtain a dark blue gelatinous precursor. The product obtained in the previous step was placed in a reactor for hydrothermal reaction for 2 h to obtain the hydrothermal reaction product. The hydrothermal reaction product was washed alternately by centrifugation with water and ethanol, dried under vacuum at 45 °C, and then ground into powder for later use.

[0046] Figure 1 This is a TEM image of the composite nanomaterial from Example 1, which illustrates that the composite nanomaterial has a dendritic cluster structure.

[0047] Figure 2 The image shows a comparison of the infrared spectra of the composite nanomaterial (CuO@L-His) and histidine (L-His) in Example 1. This image illustrates that the composite material is composed of histidine and copper oxide.

[0048] Example 2 1 mmol of CuSO4·5H2O solid was dissolved in 30 mL of ultrapure water. 1 mmol of histidine solid was added to a copper sulfate solution at 25 °C and a magnetic stirring speed of 600 r / min. The solution was premixed and stirred for 60 min at 1000 r / min. 2.5 mL of freshly prepared 1 M sodium hydroxide solution was slowly added dropwise to the histidine-copper sulfate mixed precursor solution, and the reaction was continued for 2 h to obtain a dark blue gelatinous precursor. The product obtained in the previous step was placed in a reactor for hydrothermal reaction for 2 h. The product obtained in the previous step was washed alternately by centrifugation with water and ethanol, dried under vacuum at 45 °C, and then ground into powder for later use.

[0049] Example 3 2 mmol of CuSO4·5H2O solid was dissolved in 55 mL of ultrapure water. 2.2 mmol of histidine solid was added to a copper sulfate solution at 20 °C and a magnetic stirring speed of 600 r / min. The solution was premixed and stirred for 60 min at 1000 r / min. 5.4 mL of 1 M sodium hydroxide solution was slowly added dropwise to the histidine-copper sulfate mixed precursor solution, and the reaction was continued with stirring for 2 h. The product obtained in the previous step was placed in a reaction vessel for hydrothermal reaction for 2 h. The product obtained in the previous step was washed alternately by centrifugation with water and ethanol, dried under vacuum at 60 °C, and then ground into powder for later use.

[0050] Example 4 1 mmol of CuSO4·5H2O solid was dissolved in 25 mL of ultrapure water. At 25 °C and a magnetic stirring speed of 1000 r / min, 1 mmol of histidine was added to 5 mL of ultrapure water, ultrasonically dispersed, and then added dropwise to a copper sulfate solution. The solution was premixed and stirred for 60 min at 1000 r / min. 2.3 mL of 1 M sodium hydroxide solution was slowly added dropwise to the histidine-copper sulfate mixed precursor solution, and the reaction was continued with stirring for 90 min. The product obtained in the previous step was placed in a reaction vessel for hydrothermal reaction for 4 h. The product obtained in the previous step was washed alternately by centrifugation with water and ethanol, dried under vacuum at 40 °C, and then ground into powder for later use.

[0051] Comparative Example 1 1 mmol of CuSO4·5H2O solid was dissolved in 30 mL of ultrapure water. 2.5 mL of freshly prepared 1 M sodium hydroxide solution was slowly added dropwise to the copper sulfate solution, and the reaction was stirred continuously for 2 hours. The product obtained in the previous step was then subjected to a hydrothermal reaction in a reactor for 2 hours. The product was washed alternately by centrifugation with water and ethanol, dried under vacuum at 45 °C, and ground into powder for later use, yielding copper oxide.

[0052] Figure 3 This is a TEM image of copper oxide in Comparative Example 1. The image shows that under the synthesis conditions, a sheet-like structure with a length of 100 nm-300 nm was generated in the absence of histidine.

[0053] Figure 4 It is the composite nanomaterial (Cu) of Example 1 x XRD patterns of O@L-His and copper oxide (CuO) of Comparative Example 1 are shown. The figures illustrate that the composite nanomaterial is amorphous, and the characteristic diffraction peaks in the figures indicate crystalline copper oxide.

[0054] Test Case A Utilizing degradable materials: The composite nanomaterial (Cu) of Example 1 x Xanthan gum was degraded using O@L-His, copper oxide (CuO) of Comparative Example 1, HisCuCoPBA (a histidine-modified copper cobalt Prussian blue analog obtained from Experimental Sample 1 of Application No.: 202310432686.0 uniformly dispersed in ultrapure water), hydrogen peroxide, and ultrapure water (Control), respectively. The specific degradation process was as follows: At room temperature, 9.8 mL of ultrapure water was added to a 20 mL glass bottle, and 25 mg of xanthan gum powder was added while stirring. The mixture was stirred for 240 min to allow it to swell fully. The pH of the solution was adjusted to 7.0. Then, 200 μL of degradation material with a concentration of 10 mg / mL and 100 μL of hydrogen peroxide with a concentration of 3 M were added to the xanthan gum solution to form a mixture. After stirring evenly, the mixture was poured into an Ubbelohde viscometer. The time required for the liquid to flow through the capillary of the Ubbelohde viscometer was measured with a stopwatch. The change in xanthan gum viscosity over time was obtained as a kinetic graph.

[0055] like Figure 5 As shown, the composite nanomaterials of this application have a much higher degradation efficiency for xanthan gum than single copper oxide nanomaterials and CuCoPBA materials, indicating that the prepared copper oxide-based composite nanomaterials have a significant advantage in catalyzing the degradation of xanthan gum.

[0056] Test Case B Utilizing degradable materials: The composite nanomaterial (Cu) of Example 1 x Guar gum was degraded using O@L-His, copper oxide (CuO) from Comparative Example 1, and ultrapure water (Control), respectively. The specific degradation process was as follows: At room temperature, 9.8 mL of ultrapure water was added to a 20 mL glass bottle, and 30 mg of guar gum powder was added while stirring. The mixture was stirred for 240 min to allow it to swell fully. The pH of the solution was adjusted to 7.0. Then, 100 μL of degradation material with a concentration of 10 mg / mL and 100 μL of hydrogen peroxide with a concentration of 3M were added to the guar gum solution to form a mixture. After stirring evenly, the mixture was poured into an Ubbelohde viscometer. The time required for the liquid to flow through the capillary tube of the Ubbelohde viscometer was measured with a stopwatch. The change in guar gum viscosity over time was obtained as a kinetic graph.

[0057] like Figure 6 As shown, the composite nanomaterials of this application have a much higher degradation efficiency for guar gum than single-component copper oxide, and a significantly improved degradation efficiency compared to xanthan gum. This is also due to the structural differences between flexible guar gum and rigid xanthan gum.

[0058] The materials obtained in Examples 1-4 and Comparative Example 1 were tested as follows, and the results are shown in Table 1.

[0059] Viscosity reduction rate: Using the degradation method of test example A, xanthan gum was degraded using materials obtained from different examples and comparative examples. The viscosity reduction rate was obtained according to Y=(Y1-Y2) / Y2, where Y1 represents the viscosity of the mixture before degradation and Y2 represents the viscosity of the mixture after 120 min of degradation.

[0060] Table 1

[0061] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0062] It should also be noted that the above are merely preferred embodiments of this application and do not limit the scope of protection of this application. Any equivalent structural or procedural transformations made based on the content of this application’s specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the scope of protection of this application.

Claims

1. A composite nanomaterial, characterized in that, The composite material has a dendritic cluster structure formed by aggregation of a plurality of primary nanoparticles, the primary nanoparticles comprising a complex of amorphous copper oxide and histidine.

2. The composite nanomaterial of claim 1, wherein, The mass percentage of histidine in the total mass of the composite nanomaterial is 30%-40%; And / or, the particle size of the primary nanoparticles is 10-20 nm; The particle size of the composite nanomaterial is 50-300 nm.

3. A method for preparing a composite nanomaterial, characterized in that, The method comprises the following steps: A solution containing copper ions and histidine are mixed to obtain a coordination intermediate solution; The coordination intermediate solution is subjected to alkalization treatment to form a colloidal precursor; The colloidal precursor is subjected to hydrothermal reaction to obtain a composite nanomaterial, The alkalization treatment is a transformation of the coordination intermediate structure formed by the copper ions and histidine to form the colloidal precursor, the coordination intermediate solution is blue, and the colloidal precursor is dark blue.

4. The production method according to claim 3, characterized by, The solution containing copper ions comprises a copper sulfate solution, and the concentration of the copper sulfate solution in the coordination intermediate solution is 30-33 mM; And / or, the concentration of histidine in the coordination intermediate solution is 30-33 mM; And / or, the molar ratio of copper ions to histidine is 1:(1-2); And / or, the mixing conditions include that the stirring speed is 500-1000 r / min and the stirring time is 30-90 min.

5. The preparation method according to claim 3, characterized in that, The alkalization treatment is performed by adding an alkali solution dropwise to the coordination intermediate solution and stirring at 10-35 °C for 1-3 h; And / or, the alkali solution is a sodium hydroxide solution, and the concentration of the sodium hydroxide solution is 0.5-2 M; And / or, the molar ratio of sodium hydroxide to copper ions is 1:(0.4-0.6).

6. The preparation method according to claim 3, characterized in that, The hydrothermal reaction satisfies at least one of the following conditions: Temperature: 120-130 °C; Time: 2-4 h.

7. The production method according to claim 6, wherein After the hydrothermal reaction, before obtaining the composite nanomaterial again, the following step is further included: The product obtained by the hydrothermal reaction is dried under vacuum conditions, the drying time is 12-18 h, and the temperature is 45-55 °C.

8. Use of the composite nanomaterial of claim 1 or 2 or the composite nanomaterial prepared by the method of any one of claims 3-7 in degrading a polysaccharide colloid.

9. Use according to claim 8, characterized in that, The degradation process comprises the following steps: A degradation solution is provided, the degradation solution comprising a composite nanomaterial and hydrogen peroxide; The polysaccharide colloid is degraded by using the degradation solution, the polysaccharide colloid comprising at least one of xanthan gum and guar gum.

10. Use according to claim 9, characterized in that, The degradation temperature is 10-50 °C; During the degradation process, the pH of the mixed solution formed by the degradation solution and the polysaccharide colloid is 5-9; For every 1 g of colloid degraded, the amount of the composite nanomaterial is 0.005-0.02 g, and the amount of hydrogen peroxide is 0.01-0.3 g; The amount of the composite nanomaterial is 0.0002g-0.001g, the amount of hydrogen peroxide is 0.03g-0.1g, and the amount of ascorbic acid is 0.003g-0.05g per 1g of the glue degraded.

Images