Graphene oxide-cellulose composite aerogel loaded with hollow carbon microspheres and its preparation method and application

Abstract

The present invention provides a graphene oxide-cellulose composite aerogel loaded with hollow carbon microspheres, and its preparation method and application. 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; based on the mass of the graphene oxide-cellulose composite aerogel loaded with hollow carbon microspheres as 100%, the proportion of the hollow carbon microspheres is 10%-30%, and the mass proportion of the graphene oxide-cellulose complex is 70%-90%. The graphene oxide-cellulose composite aerogel loaded with hollow carbon microspheres of the present invention has high processability, high adsorption and clearance of various toxins such as IL-6, TNF-α, β2-MG, PTH, creatinine, uric acid, etc.; in addition, it also has a lower hemolysis rate, thereby improving the biocompatibility of blood.

Description

Technical Field

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

[0002] Hemoperfusion is an extracorporeal life support technology that draws blood from the patient's body, removes toxins through a purification device, and then returns the purified blood to the patient, replacing the patient's detoxification system and achieving the goal of toxin removal. Therefore, hemoperfusion-based blood purification therapy has become an effective clinical treatment for uremia.

[0003] The core of hemoperfusion technology lies in the development of adsorption materials. These materials need to possess the ability to adsorb multiple toxins, possess high blood compatibility, and possess good mechanical strength. They also need to be compatible with efficient material processing and molding techniques. Although the development of a variety of new adsorbents in recent years has improved the efficiency of hemoperfusion in removing uremia-related toxins, adsorbents in existing technologies still struggle to effectively adsorb multiple toxins from the blood of uremic patients simultaneously. Furthermore, adsorbents in existing technologies are often processed into microspheres ranging from hundreds of micrometers to millimeters. This results in rapid relative motion between microspheres during specific whole blood adsorption processes due to the complex fluid distribution within the perfusion device, causing unavoidable friction and collisions, which in turn trigger the rupture of red blood cells (i.e., hemolysis), significantly reducing the material's blood compatibility.

[0004] Therefore, providing a blood perfusion 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] In order to solve the above technical problems, the purpose of the present invention is to provide a graphene oxide-cellulose composite aerogel loaded with hollow carbon microspheres and its preparation method and application. The graphene oxide-cellulose composite aerogel loaded with hollow carbon microspheres has high processability, 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 objectives, in a 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 comprises a graphene oxide-cellulose composite and hollow carbon microspheres loaded on the surface of the graphene oxide-cellulose composite;

[0007] Taking the mass of the graphene oxide-cellulose composite aerogel loaded with hollow carbon microspheres as 100%, the mass of the hollow carbon microspheres accounts for 10%-30%, and the mass of the graphene oxide-cellulose composite accounts for 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 further provides a method for preparing the above-mentioned graphene oxide-cellulose composite aerogel loaded with hollow carbon microspheres, which comprises the following steps:

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

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

[0014] The method evenly disperses hollow carbon microspheres and graphene oxide in water under ultrasonic conditions to form a sol with a certain viscosity. During the pre-freezing process, ice crystals grow within the sol. After freeze-drying and removal of the ice crystals, a porous structure using the ice crystals as a template is formed. The graphene oxide aerogel loaded with hollow carbon microspheres is fully immersed in a cellulose aqueous solution and then transferred to distilled water. The cellulose precipitates on the aerogel surface, thereby improving its mechanical strength.

[0015] In the above preparation method, preferably, in step 1, based on the mass fraction of the graphene oxide aerogel loaded with hollow carbon microspheres as 100%, the mass fraction of the hollow carbon microspheres is 70% or less, 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 as 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 is incomplete and easily peels off, thereby causing blood compatibility problems; if there are too few hollow carbon microspheres, the adsorption effect is poor; if there is too much graphene oxide, the coating is too dense, resulting in poor adsorption effect and high cost; if there is too little graphene oxide, the mechanical strength of the aerogel deteriorates and it is easy to peel off.

[0016] In the above preparation method, preferably, in step 1, 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 1, the freeze-drying treatment time is 6-72 h, more preferably 36-60 h, and further preferably 40-55 h.

[0018] In the above preparation method, preferably, in step 1, the hollow carbon microspheres and graphene oxide are dispersed ultrasonically in water to form a sol.

[0019] In the above preparation method, preferably, in step 1, the sol is dropped into liquid nitrogen or placed in a metal mold treated with liquid nitrogen at low temperature to achieve pre-freezing of the sol.

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

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

[0022] The metal mold is in the shape of a disk with a diameter of 2-10 cm and a depth of 1-20 cm;

[0023] The disc is provided with 10-50 cylinders, each with a diameter of 0.25-2 mm and a height of 1-20 cm; the spacing between adjacent cylinders is 0.5-5 mm, more preferably, the diameter and height of each cylinder are the same, and adjacent cylinders are distributed at equal intervals;

[0024] The metal mold is made of brass, stainless steel, or pure copper. If the mold depth is too low, the prepared sample will not meet actual perfusion requirements and will be unusable. If the mold depth is too high, demolding will be difficult. If the mold's cylindrical diameter is too small, the flow channel size is too small, making demolding difficult and increasing internal fluid shear stress, which can easily damage blood cells. If the mold's cylindrical diameter is too large, the flow channel size is too large, causing the fluid to pass through too quickly, resulting in poor adsorption and removal 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 a flow channel design, so that the sol can be uniformly condensed during the freezing process, thereby promoting the formation of the aerogel structure.

[0026] In the above preparation method, preferably, in step 2, the cellulose aqueous solution also contains N-methylmorpholine-N-oxide; based on the mass of the cellulose aqueous solution as 100%, the mass fraction of cellulose is 1%-11% (more preferably 5%-11%), and the mass fraction of N-methylmorpholine-N-oxide is 30%-60% (more preferably 40%-50%). N-methylmorpholine-N-oxide can form hydrogen bonds with cellulose molecules, enhancing cellulose solubility and making the cellulose uniform in the aqueous solution. During the immersion process, it can fully contact with the graphene oxide aerogel, enhancing the adsorption and mechanical properties of the hollow carbon microsphere-loaded graphene oxide-cellulose composite aerogel and improving biocompatibility. If the mass fraction of cellulose is outside the range of the present invention, the cellulose will not dissolve and subsequent precipitation will be impossible.

[0027] In the above preparation method, preferably, in step 2, 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 carbonized at high temperature in an inert gas, and then etched with an alkaline solution to obtain the hollow carbon microsphere;

[0030] Wherein, 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 etching temperature is 60-95° C., and the etching time is 0.5-4 h.

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

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

[0034] In the above preparation method, preferably, the etching time 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, more preferably sodium hydroxide.

[0036] In the above preparation method, preferably, the concentration of the alkaline solution is 0.1-10 mol·L -1 , 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] Formaldehyde and resorcinol are mixed in a solvent, tetraethoxysilane is added, the pH of the solution is adjusted to 8-13 with ammonia water, and the mixture is stirred to synthesize a hollow carbon microsphere precursor;

[0040] Wherein, 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 the mixture of formaldehyde and resorcinol is water, more preferably distilled water or deionized water.

[0042] In the above preparation method, preferably, after adjusting the pH of the solution with aqueous ammonia, stirring is performed for 1-48 h, more preferably 20-30 h.

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

[0044] The adsorbent provided by the present invention is an adsorbent material with a certain shape formed based on the mold used in the composite aerogel, which can be in the shape of a cylinder, a cuboid, or a cube, and has a vertical through-flow channel in the middle.

[0045] The present invention utilizes a graphene oxide-cellulose composite aerogel loaded with hollow carbon microspheres, which can be used as an adsorbent. It features vertical through-flow channels formed using a metal mold as a template, allowing fluid to pass through. This columnar adsorbent with these through-flow channels exhibits a lower hemolysis rate. The mold-based vertical through-flow channels accelerate diffusion and mass transfer during the perfusion adsorption process, improving removal efficiency. They also help reduce collisions between blood cells and the adsorbent, lowering the hemolysis rate and ultimately improving blood compatibility.

[0046] In a fourth aspect, the present invention further provides a blood purification method, which separates and removes IL-6, TNF-α, β2-MG, PTH, creatinine, and uric acid in the blood by using the above-mentioned adsorbent.

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

[0048] The present invention prepares a sol by preparing hollow carbon microspheres and graphene oxide. During the pre-freezing process, ice crystals grow inside the sol. After freeze-drying and removing the ice crystals, a porous structure with the ice crystals as a template can be formed, i.e., graphene oxide aerogel loaded with hollow carbon microspheres. The aerogel is then immersed in an aqueous solution of N-methylmorpholine-N-oxide and cellulose. The cellulose precipitates on the surface of the aerogel, thereby improving its mechanical strength.

[0049] The present invention's hollow carbon microsphere-loaded graphene oxide-cellulose composite aerogel has high processability and can be formed into spherical or cylindrical aerogels by dripping liquid nitrogen or using metal molds to assist in molding. As an adsorbent, this aerogel exhibits high adsorption and clearance rates for a variety of toxins, including IL-6, TNF-α, β2-MG, PTH, creatinine, and uric acid. Furthermore, the cylindrical aerogel has a lower hemolysis rate, improving blood biocompatibility and causing virtually no hemolytic reactions. BRIEF 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 according to Example 1 of the present invention;

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

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

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

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

[0056] Figure 7 This is a bar graph showing the clearance rates of IL-6, TNF-α, β2-MG, and PTH by the hollow carbon microsphere-loaded graphene oxide-cellulose composite aerogel of Example 1-2 of the present invention;

[0057] Figure 8 4 is a bar graph showing the clearance rates of creatinine and uric acid by the hollow carbon microsphere-loaded graphene oxide-cellulose composite aerogel of Examples 1-2 of the present invention;

[0058] Figure 9 It is a bar graph of the hemolysis rate of the graphene oxide-cellulose composite aerogel loaded with hollow carbon microspheres according to Examples 1-2 of the present invention. DETAILED DESCRIPTION

[0059] In order to have a clearer understanding of the technical features, objectives and beneficial effects of the present invention, the technical solution of the present invention is now described in detail below, but it should not be understood as limiting the scope of implementation of the present invention.

[0060] Example 1

[0061] This embodiment provides a method for preparing 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 35% formaldehyde solution and 1.2 g of resorcinol as a prepolymer were mixed evenly in 200 mL of distilled water, and then 10 mL of tetraethoxysilane was added. The pH of the solution was adjusted to 9 with ammonia water. The mixture was stirred evenly for 24 h to synthesize the hollow carbon microsphere precursor. After centrifugation, the mixture was carbonized in an argon atmosphere at 700 °C for 2 h. After the reaction was completed, 300 mL of 1 mol·L -1Hollow 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 of 200-300 nm) prepared in step (1) and 500 mg of graphene oxide were ultrasonically dispersed in 10 mL of water to prepare hollow carbon microsphere-graphene oxide sol. The sol was added to a liquid nitrogen low-temperature treated aerogel as shown in FIG. Figure 1 In the metal mold shown, the sol was pre-frozen and freeze-dried at -90 °C for 48 h to obtain graphene oxide aerogel loaded with hollow carbon microspheres;

[0064] The above metal mold is as follows Figure 1 As shown, it has the following structure:

[0065] The metal mold is in the shape of a disk with a diameter of 2 cm and a depth of 2 cm;

[0066] The disc has 49 cylinders inside, each with a diameter of 0.5 mm and a height of 2 cm;

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

[0068] The metal mold is made of brass;

[0069] (3) Preparation of graphene oxide-cellulose composite aerogel loaded with hollow carbon microspheres: about 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, wherein the mass fraction of cellulose in the aqueous solution of N-methylmorpholine-N-oxide and cellulose was 10% and the mass fraction of N-methylmorpholine-N-oxide was 50%. After being fully soaked, the aerogel was transferred to distilled water to precipitate the cellulose, thereby obtaining a graphene oxide-cellulose composite aerogel loaded with hollow carbon microspheres, wherein the cellulose was carboxymethyl cellulose.

[0070] Taking the mass of the graphene oxide aerogel loaded with hollow carbon microspheres as 100%, the proportion of hollow carbon microspheres is about 37.5%, and the proportion of graphene oxide is about 67.5%;

[0071] In the graphene oxide-cellulose composite aerogel loaded with hollow carbon microspheres, the mass proportion of hollow carbon microspheres is 25%, and the mass proportion of 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 , 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 embodiment are shown in FIG. Figure 2 、 Figure 3 、 Figure 4 As shown by Figure 2-Figure 4 The resulting composite columnar aerogel features vertical fluid-passing channels formed using a metal mold as a template. Cellulose and graphene oxide form a composite supporting the aerogel, with a distinct structure of hollow carbon microspheres supported on a graphene oxide-cellulose layer. The mold-based vertical channels accelerate diffusion and mass transfer during perfusion adsorption, improving removal efficiency. They also help minimize collisions between blood cells and the adsorbent, reducing hemolysis and improving blood compatibility.

[0074] Example 2

[0075] This embodiment provides a method for preparing graphene oxide-cellulose composite spherical aerogel loaded with hollow carbon microspheres, and the specific steps are as follows:

[0076] (1) Preparation of hollow carbon microspheres: 1.7 mL of 35% formaldehyde solution and 1.2 g of resorcinol as prepolymer were mixed evenly in 200 mL of distilled water, 10 mL of tetraethoxysilane was added, and the pH of the solution was adjusted to 9 with ammonia water. The mixture was stirred evenly for 24 h to synthesize the hollow carbon microsphere precursor; after centrifugation, the mixture was carbonized under an argon atmosphere at a temperature of 700 °C for 2 h. After the reaction was completed, 300 mL of 1 mol·L -1 Hollow carbon microspheres were prepared by etching with sodium hydroxide solution for 2 h.

[0077] (2) Preparation of graphene oxide aerogel loaded with hollow carbon microspheres: 300 mg of the hollow carbon microspheres (particle size of 200-300 nm) prepared in step (1) and 500 mg of graphene oxide were ultrasonically dispersed in 10 mL of water to prepare hollow carbon microsphere-graphene oxide sol. The above sol was directly dropped into liquid nitrogen for pre-freezing at a rate of 1 drop / second. The sol was freeze-dried at -90 °C for 48 h to prepare graphene oxide aerogel loaded with hollow carbon microspheres.

[0078] (3) Preparation of graphene oxide-cellulose composite aerogel loaded with hollow carbon microspheres: 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, wherein the mass fraction of cellulose in the aqueous solution of N-methylmorpholine-N-oxide and cellulose was 10% and the mass fraction of N-methylmorpholine-N-oxide was 50%. After being fully soaked, the aerogel was transferred to distilled water to precipitate the cellulose, thereby obtaining a graphene oxide-cellulose composite aerogel loaded with hollow carbon microspheres, wherein the cellulose was carboxymethyl cellulose.

[0079] Taking the mass of the graphene oxide aerogel loaded with hollow carbon microspheres as 100%, the proportion of 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 mass proportion of hollow carbon microspheres is 23%, and the mass proportion of 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% and the particle size is about 1 mm.

[0082] The TEM, SEM and high-magnification SEM images of the graphene oxide-cellulose composite spherical aerogel loaded with hollow carbon microspheres prepared in this embodiment are shown in FIG. Figure 5 、 Figure 6 As shown. Figure 5-Figure 6 It can be seen that the obtained composite spherical aerogel has good sphericity; its surface also has an obvious structure of hollow carbon microspheres loaded on a graphene oxide-cellulose thin layer. The coating thin layer can prevent the hollow carbon microspheres from falling off during the adsorption process, and at the same time has little effect on the adsorption efficiency.

[0083] Example 3

[0084] This embodiment provides a method for preparing graphene oxide-cellulose composite columnar aerogel loaded with hollow carbon microspheres, which differs from Example 1 only in that:

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

[0086] In the graphene oxide-cellulose composite aerogel loaded with hollow carbon microspheres, the mass proportion of hollow carbon microspheres is 25%, and the mass proportion of 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 , the porosity is 79.4%.

[0088] Example 4

[0089] This embodiment provides a method for preparing graphene oxide-cellulose composite columnar aerogel loaded with hollow carbon microspheres, which differs from Example 1 only in that:

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

[0091] In the graphene oxide-cellulose composite aerogel loaded with hollow carbon microspheres, the mass proportion of hollow carbon microspheres is 25%, and the mass proportion of 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 , the porosity is 75.4%.

[0093] Example 5

[0094] This embodiment provides a method for preparing graphene oxide-cellulose composite columnar aerogel loaded with hollow carbon microspheres, which differs from Example 1 only in 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-methylmorpholine-N-oxide and cellulose is 6%.

[0096] In the graphene oxide-cellulose composite aerogel loaded with hollow carbon microspheres, the mass proportion of hollow carbon microspheres is 26%, and the mass proportion of 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 , the porosity is 64.6%.

[0098] Comparative Example 1

[0099] This comparative example provides a method for preparing a graphene oxide-cellulose composite columnar aerogel loaded with hollow carbon microspheres, which differs from Example 1 only in that:

[0100] In the process of preparing the graphene oxide-cellulose composite aerogel loaded with hollow carbon microspheres in step (3), the 10% aqueous solution of N-methylmorpholine-N-oxide and cellulose in Example 1 is replaced by a 10% by mass cellulose aqueous dispersion.

[0101] In the graphene oxide-cellulose composite aerogel loaded with hollow carbon microspheres, the mass proportion of hollow carbon microspheres is 32%, and the mass proportion of 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 , the porosity is 75.3%.

[0103] In this comparative example, a cellulose dispersion is used in step (3) without adding a cosolvent, which makes it difficult to achieve cellulose composite, resulting in 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, which differs from Example 1 only in 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 hollow carbon microsphere precursor, the mass 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 , the porosity is 62.2%.

[0109] In this comparative example, the hollow carbon microsphere precursor was not subjected to high-temperature carbonization in step (1), but was directly used as step (2). The hollow carbon microspheres that played the main adsorption and removal role were still in the precursor state (phenolic resin coated silica core), without a porous structure and adsorption capacity, resulting in poor adsorption and removal effect.

[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, which differs from Example 1 only in that:

[0112] In the process of preparing hollow carbon microspheres in step (1), the carbonization conditions are: 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 mass proportion of hollow carbon microspheres is 28%, and the mass proportion of graphene oxide-cellulose composite is 72%;

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

[0115] In this comparative example, the temperature at which the hollow carbon microsphere precursor is subjected to high-temperature carbonization in step (1) is relatively low, which results in a low degree of carbonization and an underdeveloped pore structure of the hollow carbon microspheres, thereby leading to a poor adsorption and removal effect.

[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 differs from Example 1 only in that:

[0118] In the process of preparing the graphene oxide aerogel loaded with hollow carbon microspheres in step (2), the freeze-drying temperature is -10 °C.

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

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

[0121] In the process of preparing the graphene oxide aerogel loaded with hollow carbon microspheres in step (2) of this comparative example, the freeze-drying temperature is high, and the ice crystal removal is poor. The ice crystals that are not removed by freeze-drying dissolve at room temperature and pressure, which will cause the aerogel pore structure to collapse and the porosity to decrease, thereby causing the adsorption and removal effect to deteriorate.

[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 differs from Example 1 only in that:

[0124] 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-methylmorpholine-N-oxide and cellulose is 20%.

[0125] In the graphene oxide-cellulose composite aerogel loaded with hollow carbon microspheres, the mass proportion of hollow carbon microspheres is 21%, and the mass proportion of 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 , porosity 71.5%.

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

[0128] Experimental example

[0129] Test Example 1

[0130] 100 mg of each of the hollow carbon microsphere-loaded graphene oxide-cellulose composite aerogels prepared in Examples 1 and 2 were thoroughly mixed with 50 mL of plasma from a real uremic patient and incubated in a shaker at 120 rpm at 37°C for 2 hours. The hollow carbon microsphere-loaded graphene oxide-cellulose composite aerogels from Examples 1 and 2 were separated from the plasma of the uremic patient, and the concentrations of IL-6, TNF-α, β2-MG, PTH, creatinine, and uric acid in the plasma were measured before and after adsorption, and the clearance rate was calculated based on this.

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

[0132] Among them, the concentrations and clearance rates of IL-6, TNF-α, β2-MG, PTH, creatinine, and uric acid in plasma before and after adsorption are shown in Table 1. Figure 7 、 Figure 8 As shown:

[0133] Table 1

[0134]

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

[0136] Test Example 2

[0137] 100 mg of each of the hollow carbon microsphere-loaded graphene oxide-cellulose composite aerogels prepared in Example 1 and Example 2 were thoroughly mixed with 50 mL of red blood cell suspension and incubated in a constant temperature water bath shaker at 37°C at 120 rpm for 2 h. The hollow carbon microsphere-loaded graphene oxide-cellulose composite aerogels of Example 1 and Example 2 were separated from the red blood cell suspension, and the absorbance of the red blood cell suspension at 545 nm was measured using a microplate reader 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 (4.6%). It can be seen that compared with spherical aerogel particles, the columnar aerogel with vertical flow channels has a lower hemolysis rate, which is due to the high processability of the aerogel provided by 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 as 100%, the mass of the hollow carbon microspheres accounts for 10%-30%, and the mass of the graphene oxide-cellulose composite accounts for 70%-90%; The graphene oxide-cellulose composite aerogel loaded with hollow carbon microspheres is prepared by immersing the graphene oxide aerogel loaded with hollow carbon microspheres in an aqueous solution of N-methylmorpholine-N-oxide and cellulose; Based on the mass of the cellulose aqueous solution being 100%, the mass fraction of the cellulose is 1%-11%, and the mass fraction of the N-methylmorpholine-N-oxide is 30%-60%.

2. The hollow carbon microsphere-loaded graphene oxide-cellulose composite aerogel according to claim 1, wherein: 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 hollow carbon microsphere-loaded graphene oxide-cellulose composite aerogel according to claim 1, wherein: 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 method for preparing the graphene oxide-cellulose composite aerogel loaded with hollow carbon microspheres according to any one of claims 1 to 4, characterized in that: The following steps are involved: Step 1: Dispersing hollow carbon microspheres and graphene oxide in a solvent to form a sol, pre-freezing the sol, and freeze-drying the sol 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 prepare a graphene oxide-cellulose composite aerogel loaded with hollow carbon microspheres.

6. The preparation method according to claim 5, characterized in that In the 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 less than 70%, and the mass fraction of the graphene oxide is 30%-80%.

7. The preparation method according to claim 6, characterized in that In the 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, wherein In the 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 hours.

9. The preparation method according to claim 5, characterized in that In the step 2, the aqueous solution of cellulose further contains N-methylmorpholine-N-oxide; Based on the mass of the cellulose aqueous solution 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 the 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: The hollow carbon microsphere precursor is carbonized at high temperature in an inert gas, and then etched with an alkaline solution to obtain the hollow carbon microsphere; Wherein, 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 etching temperature is 60-95° C., and the etching time 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: Formaldehyde and resorcinol are mixed in a solvent, tetraethoxysilane is added, the pH of the solution is adjusted to 8-13 with ammonia water, and the mixture is stirred to synthesize a hollow carbon microsphere precursor; Wherein, 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 according to any one of claims 1 to 4. The adsorbent has a through flow channel, and the diameter of the through flow channel is 100-800 μm.

15. Use of the adsorbent according to claim 14 in preparing a drug for blood purification, characterized in that: The blood purification refers to the separation and removal of IL-6, TNF-α, β2-MG, PTH, creatinine and uric acid in the blood.

Images