Graphene oxide-cellulose composite aerogel loaded with hollow carbon microspheres as well as preparation method and application of graphene oxide-cellulose composite aerogel

Abstract

The invention provides graphene oxide-cellulose composite aerogel loaded with hollow carbon microspheres as well as a preparation method and application of the graphene oxide-cellulose composite aerogel. The graphene oxide-cellulose composite aerogel loaded with the hollow carbon microspheres comprises a graphene oxide-cellulose compound and the hollow carbon microspheres loaded on the surface of the graphene oxide-cellulose compound, based on 100% of the mass of the graphene oxide-cellulose composite aerogel loaded with the hollow carbon microspheres, the percentage of the hollow carbon microspheres is 10%-30%, and the percentage of the mass of the graphene oxide-cellulose composite is 70%-90%. The graphene oxide-cellulose composite aerogel loaded with the hollow carbon microspheres has relatively high processability, and has relatively high adsorption effect and clearance rate on various toxins such as IL-6, TNF-alpha, beta2-MG, PTH, creatinine, uric acid and the like; in addition, a lower hemolysis rate is achieved, and the biocompatibility of blood is improved.

Description

Technical Field

[0001] The present invention relates to a graphene oxide - cellulose composite aerogel loaded with hollow carbon microspheres, a preparation method and an application thereof, belonging to the technical field of biomedical materials. Background Art

[0002] Hemoperfusion is an extracorporeal circulation - type life - support technology. Its principle is to draw the patient's blood out of the body, remove toxins in the blood through a purification device, and then transfuse the purified blood back into the patient's body, thereby replacing the patient's detoxification system to achieve the purpose of toxin removal. Therefore, the blood purification therapy based on hemoperfusion has become an effective method for the clinical treatment of uremia.

[0003] The core of hemoperfusion technology is the development of adsorbent materials. These materials need to have the adsorption performance for various toxins, high blood compatibility and good mechanical strength. At the same time, they also need to be combined with efficient material processing and forming processes. Although the development of various new adsorbents in recent years has improved the removal efficiency of hemoperfusion for uremia - related toxins, the adsorbents in the prior art are still difficult to effectively adsorb multiple toxins in the blood of uremic patients simultaneously. In addition, most of the adsorbents in the prior art are processed into microspheres with a size ranging from hundreds of micrometers to millimeters. As a result, in the specific whole - blood adsorption process, due to the complex fluid distribution in the hemoperfusion device, rapid relative movement occurs between the microspheres, causing inevitable friction and collision, thereby triggering the rupture of red blood cells (i.e., hemolytic effect), significantly reducing the blood compatibility of the material.

[0004] Therefore, providing a hemoperfusion adsorbent that can simultaneously achieve selective adsorption of multiple uremia - related toxins and has good processability has become an urgent problem to be solved. Summary of the Invention

[0005] To solve the above - mentioned technical problems, the purpose of the present invention is to provide a graphene oxide - cellulose composite aerogel loaded with hollow carbon microspheres, a preparation method and an application thereof. The graphene oxide - cellulose composite aerogel loaded with hollow carbon microspheres has high processability, has a high adsorption effect and clearance rate for toxins such as IL - 6, TNF - α, β2 - MG, PTH, creatinine, uric acid, etc., and the columnar aerogel has a lower hemolysis rate.

[0006] To achieve the above - mentioned purpose, in the first aspect, the present invention provides a graphene oxide - cellulose composite aerogel loaded with hollow carbon microspheres, wherein the graphene oxide - cellulose composite aerogel loaded with hollow carbon microspheres includes a graphene oxide - cellulose complex and hollow carbon microspheres loaded on the surface of the graphene oxide - cellulose complex;

[0007] Based on the mass of the graphene oxide-cellulose composite aerogel loaded with hollow carbon microspheres being 100%, the proportion of the hollow carbon microspheres is 10% - 30%, and the mass proportion of the graphene oxide-cellulose composite is 70% - 90%.

[0008] According to a specific embodiment of the present invention, preferably, the particle size of the hollow carbon microspheres in the graphene oxide-cellulose composite aerogel loaded with hollow carbon microspheres is 50 - 400 nm, more preferably 200 - 350 nm.

[0009] According to a specific embodiment of the present invention, preferably, the specific surface area of the graphene oxide-cellulose composite aerogel loaded with hollow carbon microspheres is 100 - 2500 m 2 ·g -1 , more preferably 400 - 900 m 2 ·g -1 .

[0010] According to a specific embodiment of the present invention, preferably, the porosity of the graphene oxide-cellulose composite aerogel loaded with hollow carbon microspheres is 10% - 90%, more preferably 60% - 80%.

[0011] In a second aspect, the present invention also provides a method for preparing the graphene oxide-cellulose composite aerogel loaded with hollow carbon microspheres as described above, which includes the following steps:

[0012] Step 1: Disperse the hollow carbon microspheres and graphene oxide in a solvent to form a sol, pre-freeze the sol, and obtain a graphene oxide aerogel loaded with hollow carbon microspheres through freeze-drying treatment;

[0013] Step 2: Immerse the graphene oxide aerogel loaded with hollow carbon microspheres in an aqueous solution of cellulose to obtain a graphene oxide-cellulose composite aerogel loaded with hollow carbon microspheres.

[0014] In the present invention, the hollow carbon microspheres and graphene oxide are uniformly dispersed in water under ultrasonic conditions to form a sol with a certain viscosity. During the pre-freezing process of the sol, ice crystals grow inside it. After freeze-drying to remove the ice crystals, a porous structure templated by the ice crystals is formed. The graphene oxide aerogel loaded with hollow carbon microspheres is fully infiltrated in an aqueous solution of cellulose and then transferred to distilled water, and cellulose will precipitate on the surface of the aerogel, thereby improving its mechanical strength.

[0015] In the above preparation method, preferably, in step one, based on the mass fraction of the graphene oxide aerogel loaded with hollow carbon microspheres being 100%, the mass fraction of the hollow carbon microspheres is below 70%, and the mass fraction of the graphene oxide is 30% - 80%; more preferably, based on the mass fraction of the graphene oxide aerogel loaded with hollow carbon microspheres being 100%, the mass fraction of the hollow carbon microspheres is 25% - 45%, and the mass fraction of the graphene oxide is 55% - 80%; further preferably, the mass fraction of the hollow carbon microspheres is 30% - 40%, and the mass fraction of the graphene oxide is 60% - 70%. If there are too many hollow carbon microspheres, the coating will be incomplete and prone to peeling, thus causing blood compatibility problems; if there are too few hollow carbon microspheres, the adsorption effect will be poor; if there is too much graphene oxide, the coating will be too dense, resulting in a poor adsorption effect and high cost; if there is too little graphene oxide, the mechanical strength of the aerogel will deteriorate and it will be prone to peeling.

[0016] In the above preparation method, preferably, in step one, the temperature of the freeze-drying treatment is -90 °C to -20 °C, more preferably -90 °C to -50 °C.

[0017] In the above preparation method, preferably, in step one, the time of the freeze-drying treatment is 6 - 72 h, more preferably 36 - 60 h, and further preferably 40 - 55 h.

[0018] In the above preparation method, preferably, in step one, the hollow carbon microspheres and the graphene oxide are formed into a sol in water by ultrasonic dispersion.

[0019] In the above preparation method, preferably, in step one, the sol is dropped into liquid nitrogen or placed in a metal mold under liquid nitrogen cryogenic treatment to achieve pre-freezing of the sol.

[0020] In the above preparation method, preferably, during the pre-freezing process of the sol, the dropping speed of the liquid nitrogen is 1 - 5 drops per second.

[0021] In the above preparation method, preferably, during the pre-freezing process of the sol, the metal mold has the following structure:

[0022] The metal mold is disc-shaped, the diameter of the disc is 2 - 10 cm, and the depth is 1 - 20 cm;

[0023] The disc-shaped interior is provided with 10 - 50 cylinders, the diameter of each cylinder is 0.25 - 2 mm, and the height is 1 - 20 cm; the distance between adjacent cylinders is 0.5 - 5 mm. More preferably, the diameters and heights of each cylinder are the same, and the adjacent cylinders are evenly distributed;

[0024] The material of the metal mold is one of brass, stainless steel and pure copper. If the depth of the metal mold is too low, the prepared sample does not meet the actual perfusion requirements, which will lead to inapplicability; if the depth of the metal mold is too high, it will cause difficult demolding. If the diameter of the cylinder of the metal mold is too small and the runner size is too small, it will cause difficult demolding, large internal fluid shear stress, and easy blood cell damage; if the diameter of the cylinder of the metal mold is too large and the runner size is too large, the fluid passing speed is too fast, resulting in poor adsorption and clearance efficiency.

[0025] In the preparation process of the graphene oxide aerogel loaded with hollow carbon microspheres of the present invention, the metal mold can provide the design of the runner, so that the sol can coagulate uniformly during the freezing process, promoting the formation of the aerogel structure.

[0026] In the above preparation method, preferably, in step two, the aqueous solution of cellulose further contains N-methyl morpholine-N-oxide; based on the mass of the aqueous solution of cellulose being 100%, the mass fraction of cellulose is 1%-11% (more preferably 5%-11%), and the mass fraction of N-methyl morpholine-N-oxide is 30%-60% (more preferably 40%-50%). N-methyl morpholine-N-oxide can form hydrogen bonds with cellulose molecules, enhance the solubility of cellulose, make cellulose show good uniformity in the aqueous solution, and can fully contact with the graphene oxide aerogel during the soaking process, enhancing the adsorption performance and mechanical properties of the graphene oxide-cellulose composite aerogel loaded with hollow carbon microspheres and improving biocompatibility. If the mass fraction of cellulose is not within the scope of the present invention, cellulose cannot be dissolved and cannot be precipitated subsequently.

[0027] In the above preparation method, preferably, in step two, the cellulose is selected from carboxymethyl cellulose and / or carboxyethyl cellulose.

[0028] In the above preparation method, preferably, the hollow carbon microspheres are prepared by the following steps:

[0029] The hollow carbon microsphere precursor is subjected to high-temperature carbonization in an inert gas and then etched with an alkaline solution to obtain hollow carbon microspheres;

[0030] Among them, the temperature of the high-temperature carbonization is 500-1500 °C, and the time of the high-temperature carbonization is 0.5-10 h;

[0031] The temperature of the etching is 60-95 °C, and the time of the etching is 0.5-4 h.

[0032] In the above preparation method, preferably, the temperature of the high-temperature carbonization is 700 - 1000 °C. If the temperature of the high-temperature carbonization is too high, the pore structure of the carbon material may be damaged, which will reduce its adsorption capacity; if the temperature is too low, the precursor cannot be completely converted into carbon, affecting the purity and performance of the product.

[0033] In the above preparation method, preferably, the time of the high-temperature carbonization is 1 - 6 h.

[0034] In the above preparation method, preferably, the time of the etching is 2 - 4 h.

[0035] In the above preparation method, preferably, the alkaline substance in the alkaline solution is selected from sodium hydroxide and / or potassium hydroxide, and more preferably sodium hydroxide.

[0036] In the above preparation method, preferably, the concentration of the alkaline solution is 0.1 - 10 mol·L -1 , and more preferably 0.5 - 5 mol·L -1 .

[0037] In the above preparation method, preferably, the inert atmosphere is argon or nitrogen.

[0038] In the above preparation method, preferably, the hollow carbon microsphere precursor is prepared by the following steps:

[0039] Mix formaldehyde and resorcinol in a solvent, add tetraethoxysilane, and adjust the pH of the solution to 8 - 13 with ammonia water, and stir to synthesize the hollow carbon microsphere precursor;

[0040] Among them, the molar ratio of formaldehyde, resorcinol, and tetraethoxysilane is (1 - 1.5):(0.4 - 0.8):(1 - 5).

[0041] In the above preparation method, preferably, the solvent for mixing formaldehyde and resorcinol is water, and more preferably distilled water or deionized water.

[0042] In the above preparation method, preferably, after adjusting the pH of the solution with ammonia water, stir for 1 - 48 h, and more preferably 20 - 30 h.

[0043] In the third aspect, the present invention also provides an adsorbent, which is prepared from the above graphene oxide-cellulose composite aerogel loaded with hollow carbon microspheres. The adsorbent has a through-flow channel, and the diameter size of the through-flow channel is 100 - 800 μm.

[0044] The adsorbent provided by the present invention is a shaped adsorbent material formed based on the mold used in the composite aerogel, and can be in the shape of a cylinder, a cuboid, or a cube, with a vertically penetrating flow channel in the middle.

[0045] The graphene oxide-cellulose composite aerogel loaded with hollow carbon microspheres of the present invention can be used as an adsorbent, which has vertically penetrating flow channels formed with a metal mold as a template and allows fluids to pass through. The columnar adsorbent with through-flow channels has a lower hemolysis rate. Based on the vertically penetrating flow channels formed by the mold of the present invention, it is beneficial to accelerate the diffusion and mass transfer processes during the perfusion adsorption process and improve the clearance efficiency; it also helps to reduce the collision between blood cells and the adsorbent, lower the hemolysis rate, and thus improve blood compatibility.

[0046] Fourthly, the present invention also provides a blood purification method, which separates and removes IL-6, TNF-α, β2-MG, PTH, creatinine, and uric acid in the blood through the above-mentioned adsorbent.

[0047] Compared with the prior art, the present invention has the following beneficial effects:

[0048] The present invention makes a sol of hollow carbon microspheres and graphene oxide. During the pre-freezing process, ice crystals grow inside the sol, and after freeze-drying to remove the ice crystals, a porous structure templated by the ice crystals can be formed, that is, graphene oxide aerogel loaded with hollow carbon microspheres. Then it is immersed in an aqueous solution of N-methylmorpholine-N-oxide and cellulose, and cellulose will precipitate on the surface of the aerogel, thereby improving its mechanical strength.

[0049] The graphene oxide-cellulose composite aerogel loaded with hollow carbon microspheres of the present invention has high processability and can be processed into spherical or columnar aerogels by dropping liquid nitrogen or assisted by a metal mold. As an adsorbent, this aerogel has a high adsorption effect and clearance rate on various toxins such as IL-6, TNF-α, β2-MG, PTH, creatinine, and uric acid; in addition, the columnar aerogel has a lower hemolysis rate, improves the biocompatibility of blood, and hardly causes hemolytic reactions. Description of the Drawings

[0050] Figure 1 is a schematic diagram of the metal mold structure provided in Example 1 of the present invention;

[0051] Figure 2 is a transmission electron microscope (TEM) image of the graphene oxide-cellulose composite aerogel loaded with hollow carbon microspheres in Example 1 of the present invention;

[0052] Figure 3It is the scanning electron microscope (SEM) image of the graphene oxide-cellulose composite aerogel loaded with hollow carbon microspheres in Example 1 of the present invention;

[0053] Figure 4 It is the high-magnification scanning electron microscope (SEM) image of the graphene oxide-cellulose composite aerogel loaded with hollow carbon microspheres in Example 1 of the present invention;

[0054] Figure 5 It is the scanning electron microscope (SEM) image of the graphene oxide-cellulose composite aerogel loaded with hollow carbon microspheres in Example 2 of the present invention;

[0055] Figure 6 It is the high-magnification scanning electron microscope (SEM) image of the graphene oxide-cellulose composite aerogel loaded with hollow carbon microspheres in Example 2 of the present invention;

[0056] Figure 7 It is the bar chart of the clearance rates of IL-6, TNF-α, β2-MG, and PTH by the graphene oxide-cellulose composite aerogel loaded with hollow carbon microspheres in Examples 1-2 of the present invention;

[0057] Figure 8 It is the bar chart of the clearance rates of creatinine and uric acid by the graphene oxide-cellulose composite aerogel loaded with hollow carbon microspheres in Examples 1-2 of the present invention;

[0058] Figure 9 It is the bar chart of the hemolysis rate of the graphene oxide-cellulose composite aerogel loaded with hollow carbon microspheres in Examples 1-2 of the present invention. Detailed implementation manners

[0059] For a clearer understanding of the technical features, objectives, and beneficial effects of the present invention, the technical solutions of the present invention are described in detail below, but it should not be construed as a limitation on the scope of implementation of the present invention.

[0060] Example 1

[0061] This example provides a preparation method for a graphene oxide-cellulose composite columnar aerogel loaded with hollow carbon microspheres, and the specific steps are as follows:

[0062] (1) Preparation of hollow carbon microspheres: 1.7 mL of a 35% formaldehyde solution and 1.2 g of resorcinol were mixed uniformly in 200 mL of distilled water, then 10 mL of tetraethoxysilane was added, and the pH of the solution was adjusted to 9 with ammonia water, and the mixture was stirred evenly for 24 h to synthesize the precursor of hollow carbon microspheres; after centrifugal separation, it was carbonized in an argon atmosphere at a temperature of 700 °C for 2 h. After the reaction ended, at 85 °C, 300 mL of a 1 mol·L -1The hollow carbon microspheres were prepared by etching with sodium hydroxide solution for 2 h;

[0063] (2) Preparation of graphene oxide aerogel loaded with hollow carbon microspheres: 300 mg of the hollow carbon microspheres (particle size 200 - 300 nm) prepared in step (1) and 500 mg of graphene oxide were ultrasonically dispersed in 10 mL of water to obtain a hollow carbon microsphere - graphene oxide sol. The above sol was added to the metal mold shown in Figure 1 for pre - freezing of the sol. After freeze - drying at - 90 °C for 48 h, the graphene oxide aerogel loaded with hollow carbon microspheres was obtained;

[0064] The above - mentioned metal mold is as shown in Figure 1 and has the following structure:

[0065] The metal mold is disc - shaped, with a diameter of 2 cm and a depth of 2 cm;

[0066] There are 49 cylinders inside the disc - shaped mold, each cylinder having a diameter of 0.5 mm and a height of 2 cm;

[0067] The spacing between adjacent cylinders is 1 mm;

[0068] The material of the metal mold is brass;

[0069] (3) Preparation of graphene oxide - cellulose composite aerogel loaded with hollow carbon microspheres: Approximately 800 mg of the graphene oxide aerogel loaded with hollow carbon microspheres prepared in step (2) was immersed in 20 mL of an aqueous solution of N - methylmorpholine - N - oxide and cellulose, where the mass fraction of cellulose in the aqueous solution of N - methylmorpholine - N - oxide and cellulose is 10% and the mass fraction of N - methylmorpholine - N - oxide is 50%. After sufficient infiltration, it was transferred to distilled water to precipitate cellulose, and the graphene oxide - cellulose composite aerogel loaded with hollow carbon microspheres was obtained, where the cellulose is carboxymethyl cellulose.

[0070] Based on the mass of the graphene oxide aerogel loaded with hollow carbon microspheres being 100%, the proportion of hollow carbon microspheres is approximately 37.5% and the proportion of graphene oxide is approximately 67.5%;

[0071] In the graphene oxide - cellulose composite aerogel loaded with hollow carbon microspheres, the proportion of hollow carbon microspheres is 25% and the mass proportion of the graphene oxide - cellulose composite is 75%;

[0072] The specific surface area of the graphene oxide - cellulose composite aerogel loaded with hollow carbon microspheres is 842.3 m 2 ·g -1 , and the porosity is 73.8%;

[0073] The SEM and high-magnification SEM images of the graphene oxide-cellulose composite columnar aerogel microspheres loaded with hollow carbon microspheres prepared in this example are as Figure 2 , Figure 3 , Figure 4 shown. It can be seen from Figures 2 - 4 that the obtained composite columnar aerogel has vertical flow channels formed with a metal mold as a template, which can allow fluids to pass through. Cellulose and graphene oxide form a composite as the supporting part of the aerogel, and there is an obvious structure of hollow carbon microspheres loaded on the graphene oxide-cellulose thin layer. The vertical flow channels formed based on the mold are beneficial to accelerating the diffusion and mass transfer processes during the perfusion adsorption process, improving the clearance efficiency; it also helps to reduce the collision between blood cells and the adsorbent, lower the hemolysis rate, and improve blood compatibility.

[0074] Example 2

[0075] This example provides a preparation method of a graphene oxide-cellulose composite spherical aerogel loaded with hollow carbon microspheres. The specific steps are as follows:

[0076] (1) Preparation of hollow carbon microspheres: Mix 1.7 mL of formaldehyde solution with a concentration of 35% and 1.2 g of resorcinol as prepolymers evenly in 200 mL of distilled water, add 10 mL of tetraethoxysilane, and adjust the pH of the solution to 9 with ammonia water. Stir the reaction evenly for 24 h to synthesize the precursor of hollow carbon microspheres; after centrifugal separation, carbonize in an argon atmosphere at a temperature of 700 °C for 2 h. After the reaction is completed, at 85 °C, etch with 300 mL of sodium hydroxide solution with a concentration of 1 mol·L -1 for 2 h to obtain hollow carbon microspheres;

[0077] (2) Preparation of graphene oxide aerogel loaded with hollow carbon microspheres: Ultrasonically disperse 300 mg of the hollow carbon microspheres (particle size 200 - 300 nm) prepared in step (1) and 500 mg of graphene oxide in 10 mL of water to obtain a hollow carbon microsphere-graphene oxide sol. Drop the above sol directly into liquid nitrogen for pre-freezing at a rate of 1 drop per second, and freeze-dry at -90 °C for 48 h to obtain a graphene oxide aerogel loaded with hollow carbon microspheres.

[0078] (3) Preparation of graphene oxide-cellulose composite aerogel loaded with hollow carbon microspheres: Immerse 800 mg of the graphene oxide aerogel loaded with hollow carbon microspheres prepared in step (2) into 20 mL of an aqueous solution of N-methyl morpholine-N-oxide and cellulose, wherein the mass fraction of cellulose in the aqueous solution of N-methyl morpholine-N-oxide and cellulose is 10%, and the mass fraction of N-methyl morpholine-N-oxide is 50%. After sufficient infiltration, transfer it to distilled water to precipitate cellulose, and obtain the graphene oxide-cellulose composite aerogel loaded with hollow carbon microspheres, wherein the cellulose is carboxymethyl cellulose.

[0079] Based on the mass of the graphene oxide aerogel loaded with hollow carbon microspheres being 100%, the proportion of the hollow carbon microspheres is about 37.5%, and the proportion of graphene oxide is about 67.5%;

[0080] In the graphene oxide-cellulose composite aerogel loaded with hollow carbon microspheres, the proportion of the hollow carbon microspheres is 23%, and the mass proportion of the graphene oxide-cellulose composite is 77%;

[0081] The specific surface area of the graphene oxide-cellulose composite aerogel loaded with hollow carbon microspheres is 863.6 m 2 ·g -1 , the porosity is 77.2%; the particle size is about 1 mm.

[0082] The TEM, SEM and high-magnification SEM photos of the spherical graphene oxide-cellulose composite aerogel loaded with hollow carbon microspheres prepared in this example are as shown in Figure 5 、 Figure 6 . It can be seen from Figures 5 - 6 that the obtained composite spherical aerogel has good sphericity; there is also an obvious structure on its surface where hollow carbon microspheres are loaded on the graphene oxide-cellulose thin layer. The coating thin layer can prevent the hollow carbon microspheres from falling off during the adsorption process and has little influence on the adsorption efficiency.

[0083] Example 3

[0084] This example provides a preparation method of a graphene oxide-cellulose composite columnar aerogel loaded with hollow carbon microspheres. The difference from Example 1 is only that:

[0085] During the process of preparing hollow carbon microspheres in step (1), the carbonization conditions are: carbonize for 6 h in an argon atmosphere at a temperature of 1000 °C.

[0086] In the graphene oxide-cellulose composite aerogel loaded with hollow carbon microspheres, the proportion of the hollow carbon microspheres is 25%, and the mass proportion of the graphene oxide-cellulose composite is 75%;

[0087] The specific surface area of the graphene oxide-cellulose composite aerogel loaded with hollow carbon microspheres is 483.4 m 2 ·g -1 , and the porosity is 79.4%.

[0088] Example 4

[0089] This example provides a preparation method of a graphene oxide-cellulose composite columnar aerogel loaded with hollow carbon microspheres. The difference from Example 1 is only that:

[0090] In the process of preparing the graphene oxide aerogel loaded with hollow carbon microspheres in step (2), the dosage of hollow carbon microspheres (with a particle size of 200-300 nm) is 200 mg, and the dosage of graphene oxide is 600 mg.

[0091] In the graphene oxide-cellulose composite aerogel loaded with hollow carbon microspheres, the proportion of hollow carbon microspheres is 25%, and the mass proportion of the graphene oxide-cellulose composite is 75%;

[0092] The specific surface area of the graphene oxide-cellulose composite aerogel loaded with hollow carbon microspheres is 668.3 m 2 ·g -1 , and the porosity is 75.4%.

[0093] Example 5

[0094] This example provides a preparation method of a graphene oxide-cellulose composite columnar aerogel loaded with hollow carbon microspheres. The difference from Example 1 is only that:

[0095] In the process of preparing the graphene oxide-cellulose composite aerogel loaded with hollow carbon microspheres in step (3), the mass fraction of cellulose in the aqueous solution of N-methyl morpholine-N-oxide and cellulose is 6%.

[0096] In the graphene oxide-cellulose composite aerogel loaded with hollow carbon microspheres, the proportion of hollow carbon microspheres is 26%, and the mass proportion of the graphene oxide-cellulose composite is 74%;

[0097] The specific surface area of the graphene oxide-cellulose composite aerogel loaded with hollow carbon microspheres is 783.2 m 2 ·g -1 , and the porosity is 64.6%.

[0098] Comparative Example 1

[0099] This comparative example provides a preparation method of a graphene oxide-cellulose composite columnar aerogel loaded with hollow carbon microspheres. The difference from Example 1 is only that:

[0100] In step (3) during the preparation of the graphene oxide-cellulose composite aerogel loaded with hollow carbon microspheres, a cellulose aqueous dispersion with a mass fraction of 10% is used to replace the aqueous solution of N-methyl morpholine-N-oxide and cellulose with a concentration of 10% in Example 1.

[0101] In the graphene oxide-cellulose composite aerogel loaded with hollow carbon microspheres, the proportion of hollow carbon microspheres is 32%, and the mass proportion of the graphene oxide-cellulose composite is 68%;

[0102] The specific surface area of the graphene oxide-cellulose composite aerogel loaded with hollow carbon microspheres is 667.4 m 2 ·g -1 , and the porosity is 75.3%.

[0103] In this comparative example, a cellulose dispersion is used in step (3) without adding a cosolvent. It is difficult to achieve the composite of cellulose, which will lead to poor overall mechanical strength of the aerogel material.

[0104] Comparative Example 2

[0105] This comparative example provides a method for preparing a graphene oxide-cellulose composite columnar aerogel loaded with a hollow carbon microsphere precursor. The difference from Example 1 is only that:

[0106] In step (1), the hollow carbon microsphere precursor is not subjected to high-temperature carbonization but is directly used in step (2).

[0107] In the graphene oxide-cellulose composite aerogel loaded with the hollow carbon microsphere precursor, the proportion of the hollow carbon microsphere precursor is 30%, and the mass proportion of the graphene oxide-cellulose composite is 70%;

[0108] The specific surface area of the graphene oxide-cellulose composite aerogel loaded with hollow carbon microspheres is 223.4 m 2 ·g -1 , and the porosity is 62.2%.

[0109] In this comparative example, in step (1), the hollow carbon microsphere precursor is not subjected to high-temperature carbonization but is directly used in step (2). The hollow carbon microspheres that play a major role in adsorption and scavenging are still in the precursor state (phenolic resin-coated silica core), with no pore structure and adsorption capacity, resulting in poor adsorption and scavenging effects.

[0110] Comparative Example 3

[0111] This comparative example provides a method for preparing a graphene oxide-cellulose composite columnar aerogel loaded with hollow carbon microspheres. The difference from Example 1 is only that:

[0112] In step (1) during the preparation of hollow carbon microspheres, the carbonization conditions were: carbonization in an argon atmosphere at a temperature of 300 °C.

[0113] In the graphene oxide-cellulose composite aerogel loaded with hollow carbon microspheres, the proportion of hollow carbon microspheres was 28%, and the mass proportion of the graphene oxide-cellulose composite was 72%;

[0114] The specific surface area of the graphene oxide-cellulose composite aerogel loaded with hollow carbon microspheres was 495.3 m 2 ·g -1 , and the porosity was 74.2%.

[0115] In this comparative example, the temperature for high-temperature carbonization of the hollow carbon microsphere precursor in step (1) was relatively low, resulting in low carbonization degree and underdeveloped pore structure of the hollow carbon microspheres, and thus poor adsorption and removal effects.

[0116] Comparative Example 4

[0117] This comparative example provides a method for preparing a graphene oxide-cellulose composite columnar aerogel loaded with hollow carbon microspheres, which is only different from Example 1 in that:

[0118] In step (2) during the preparation of the graphene oxide aerogel loaded with hollow carbon microspheres, the freeze-drying temperature was -10 °C.

[0119] In the graphene oxide-cellulose composite aerogel loaded with hollow carbon microspheres, the proportion of hollow carbon microspheres was 28%, and the mass proportion of the graphene oxide-cellulose composite was 72%;

[0120] The specific surface area of the graphene oxide-cellulose composite aerogel loaded with hollow carbon microspheres was 340.4 m 2 ·g -1 , and the porosity was 57.3%.

[0121] In this comparative example, in step (2) during the preparation of the graphene oxide aerogel loaded with hollow carbon microspheres, the freeze-drying temperature was relatively high, resulting in poor ice crystal removal. The ice crystals not removed by freeze-drying dissolved under normal temperature and pressure, leading to the collapse of the pore structure of the aerogel and a decrease in porosity, and thus a deterioration of the adsorption and removal effects.

[0122] Comparative Example 5

[0123] This comparative example provides a method for preparing a graphene oxide-cellulose composite columnar aerogel loaded with hollow carbon microspheres, which is only different from Example 1 in that:

[0124] In step (3) during the preparation of the graphene oxide-cellulose composite aerogel loaded with hollow carbon microspheres, the mass fraction of cellulose in the aqueous solution of N-methylmorpholine-N-oxide and cellulose was 20%.

[0125] In the graphene oxide-cellulose composite aerogel loaded with hollow carbon microspheres, the proportion of hollow carbon microspheres is 21%, and the mass proportion of the graphene oxide-cellulose composite is 79%;

[0126] The specific surface area of the graphene oxide-cellulose composite aerogel loaded with hollow carbon microspheres is 704.3 m 2 ·g -1 , and the porosity is 71.5%.

[0127] In this comparative example, the mass fraction of cellulose in the aqueous solution of N-methyl morpholine-N-oxide and cellulose used in step (3) is relatively high, and the excessive cellulose coating reduces the overall adsorption and scavenging ability of the aerogel.

[0128] Experimental example

[0129] Test example 1

[0130] Take 100 mg each of the graphene oxide-cellulose composite aerogels loaded with hollow carbon microspheres prepared in Example 1 and Example 2, and mix them with 50 mL of plasma taken from real uremic patients respectively. Incubate them in a constant temperature water bath shaker at 37 °C at a rotation speed of 120 rpm for 2 h. Separate the graphene oxide-cellulose composite aerogels loaded with hollow carbon microspheres in Example 1 and Example 2 from the plasma of uremic patients, and measure the concentrations of IL-6, TNF-α, β2-MG, PTH, creatinine, and uric acid in the plasma before and after adsorption respectively, and calculate the clearance rate based on this;

[0131] Clearance rate = (concentration before adsorption - concentration after adsorption) / concentration before adsorption × 100%;

[0132] Among them, the concentration values of IL-6, TNF-α, β2-MG, PTH, creatinine, and uric acid in the plasma before and after adsorption and the clearance rate are shown in Table 1, Figure 7 , Figure 8 as follows:

[0133] Table 1

[0134]

[0135] From Table 1 and Figure 7 , Figure 8It can be seen that the clearance rates of the composite columnar aerogel prepared in Example 1 for IL-6, TNF-α, β2-MG, and PTH are 85.4%, 69.2%, 96.5%, and 97.2%, respectively; the clearance rates for creatinine and uric acid are 93.2% and 94.2%, respectively; the clearance rates of the composite spherical aerogel prepared in Example 2 for IL-6, TNF-α, β2-MG, and PTH are 85.8%, 68.9%, 96.3%, and 98.3%, respectively; the clearance rates for creatinine and uric acid are 90.5% and 89.4%, respectively. This shows that the graphene oxide-cellulose composite aerogel loaded with hollow carbon microspheres of the present invention has a high adsorption effect and clearance rate for several representative toxins in plasma, among which the composite columnar aerogel of Example 1 has a higher clearance rate for TNF-α, β2-MG, creatinine, and uric acid.

[0136] Test Example 2

[0137] 100 mg of each of the graphene oxide-cellulose composite aerogel loaded with hollow carbon microspheres prepared in Example 1 and Example 2 were taken and fully mixed with 50 mL of red blood cell suspension, respectively, and incubated at 120 rpm in a constant temperature water bath shaker at 37 °C for 2 h. The graphene oxide-cellulose composite aerogel loaded with hollow carbon microspheres in Example 1 and Example 2 was separated from the red blood cell suspension, and the absorbance of the red blood cell suspension at 545 nm was measured using an ELISA instrument to calculate the hemolysis rate; the hemolysis rate results are shown in FIG. Figure 9 shown.

[0138] Depend on Figure 9 It can be seen that the hemolysis rate of the composite columnar aerogel prepared in Example 1 is 2.2%, which is lower than the hemolysis rate of the composite spherical aerogel prepared in Example 2 of 4.6%; it can be seen that compared with the spherical aerogel particles, the columnar aerogel with vertical channels has a lower hemolysis rate, which is due to the high processability of the aerogel provided in the present invention and the high flexibility of the preparation method.

Claims

1. A graphene oxide-cellulose composite aerogel loaded with hollow carbon microspheres, characterized in that, The graphene oxide-cellulose composite aerogel loaded with hollow carbon microspheres comprises a graphene oxide-cellulose composite and hollow carbon microspheres loaded on the surface of the graphene oxide-cellulose composite; Based on the mass of the graphene oxide-cellulose composite aerogel loaded with hollow carbon microspheres being 100%, the proportion of the hollow carbon microspheres is 10%-30%, and the mass proportion of the graphene oxide-cellulose composite is 70%-90%.

2. The graphene oxide-cellulose composite aerogel loaded with hollow carbon microspheres according to claim 1, characterized in that, The particle size of the hollow carbon microspheres in the graphene oxide-cellulose composite aerogel loaded with hollow carbon microspheres is 50-400 nm.

3. The graphene oxide-cellulose composite aerogel loaded with hollow carbon microspheres according to claim 1, characterized in that, The specific surface area of the graphene oxide-cellulose composite aerogel loaded with hollow carbon microspheres is 100 - 2500 m 2 ·g -1 .

4. The graphene oxide-cellulose composite aerogel loaded with hollow carbon microspheres according to claim 1, characterized in that, The porosity of the graphene oxide-cellulose composite aerogel loaded with hollow carbon microspheres is 10%-90%.

5. A preparation method of the graphene oxide-cellulose composite aerogel loaded with hollow carbon microspheres according to any one of claims 1-4, characterized in that, It includes the following steps: Step 1: Dispersing hollow carbon microspheres and graphene oxide in a solvent to form a sol, pre-freezing the sol, and performing freeze-drying treatment to obtain a graphene oxide aerogel loaded with hollow carbon microspheres; Step 2: Immersing the graphene oxide aerogel loaded with hollow carbon microspheres in an aqueous solution of cellulose to obtain a graphene oxide-cellulose composite aerogel loaded with hollow carbon microspheres.

6. The preparation method according to claim 5, characterized in that, In Step 1, based on the mass fraction of the graphene oxide aerogel loaded with hollow carbon microspheres being 100%, the mass fraction of the hollow carbon microspheres is below 70%, and the mass fraction of the graphene oxide is 30%-80%.

7. The preparation method according to claim 6, characterized in that, In Step 1, based on the mass fraction of the graphene oxide aerogel loaded with hollow carbon microspheres being 100%, the mass fraction of the hollow carbon microspheres is 25%-45%, and the mass fraction of the graphene oxide is 55%-80%.

8. The preparation method according to claim 5, characterized in that, In Step 1, the temperature of the freeze-drying treatment is -90 °C to -20 °C, and the time of the freeze-drying treatment is 6-72 h.

9. The preparation method according to claim 5, characterized in that, In Step 2, the aqueous solution of cellulose also contains N-methylmorpholine-N-oxide; Based on the mass of the aqueous solution of cellulose being 100%, the mass fraction of the cellulose is 1%-11%, and the mass fraction of the N-methylmorpholine-N-oxide is 30%-60%.

10. The preparation method according to claim 5, characterized in that, In Step 2, the cellulose is selected from carboxymethyl cellulose and / or carboxyethyl cellulose.

11. The preparation method according to claim 5, characterized in that, The hollow carbon microspheres are prepared by the following steps: Performing high-temperature carbonization of the hollow carbon microsphere precursor in an inert gas, and then etching with an alkaline solution to obtain hollow carbon microspheres; Among them, the temperature of the high-temperature carbonization is 500-1500 °C, and the time of the high-temperature carbonization is 0.5-10 h; The temperature of the etching is 60-95 °C, and the time of the etching is 0.5-4 h.

12. The preparation method according to claim 11, characterized in that, The alkaline substance in the alkaline solution is selected from sodium hydroxide and / or potassium hydroxide; and / or, the concentration of the alkaline solution is 0.1 - 10 mol·L -1 .

13. The preparation method according to claim 11, characterized in that, The hollow carbon microsphere precursor is prepared by the following steps: Mixing formaldehyde and resorcinol in a solvent, adding tetraethoxysilane, adjusting the pH of the solution to 8-13 with ammonia water, and stirring to synthesize a hollow carbon microsphere precursor; Among them, the molar ratio of formaldehyde, resorcinol, and tetraethoxysilane is (1-1.5):(0.4-0.8):(1-5).

14. An adsorbent, characterized in that, The adsorbent is prepared from the graphene oxide-cellulose composite aerogel loaded with hollow carbon microspheres as described in any one of claims 1-4. The adsorbent has through-flow channels, and the diameter size of the through-flow channels is 100-800 μm.

15. A blood purification method, characterized in that, This blood purification method separates and removes IL-6, TNF-α, β2-MG, PTH, creatinine, and uric acid in blood through the adsorbent as described in claim 14.

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