WO2023070867A1 - Vermiculite nanosheet and preparation method therefor - Google Patents

Abstract

The present invention provides a vermiculite nanosheet and a preparation method therefor. The preparation method comprises: adding vermiculite into an alkali metal salt solution modifier for intercalation treatment, stripping to obtain a vermiculite nanosheet; every milligram of vermiculite is added to the alkali metal salt modifier at a concentration of 0.1-10 moles per liter. The vermiculite nanosheet provided by the present invention can be used as a nano-reinforcement material in industries such as papermaking, coatings, paints and plastics, rubber, etc., and can also be used as an oxygen self-supply platform for generating oxygen and a variety of active oxygen. Moreover, said nanosheet can be effectively used to prepare biomedical photodynamic therapy drugs, overcome tumor hypoxia, and enhance the efficacy of photodynamic therapy. In addition, the preparation method for a vermiculite nanosheet provided by the present invention is simple in process, is green and environmentally friendly, and is convenient for industrial application.

Description

A kind of vermiculite nano sheet and preparation method thereof technical field

The invention belongs to the technical field of nanomaterials, and in particular relates to a vermiculite nanosheet and a preparation method thereof.

Background technique

Two-dimensional nanomaterials and vermiculite have attracted extensive attention due to their physicochemical properties. Vermiculite is a sheet-like naturally layered clay consisting of octahedral layers of magnesium oxide and iron oxide sandwiched between two identical tetrahedral layers of aluminum oxide and silicon dioxide. Vermiculite has the advantages of good crystallization, stable properties, easy sorting, and abundant resources. In addition, it also has excellent properties such as heat preservation, light weight, antifreeze, and antibacterial. At the same time, vermiculite also has the following functions: Fe ³⁺ catalyzes the tumor microenvironment (that is, consumes glutathione to generate oxygen), and Fe ²⁺ generates hydrogen peroxide ions through phenolphthalein reaction. Therefore, the research and development of two-dimensional nano-vermiculite materials will improve the effectiveness of tumor treatment and have broader application prospects.

At present, methods for preparing vermiculite nanosheets include physical methods and chemical methods, among which the physical method is to mix expanded vermiculite with high expansion rate and hydrogen peroxide solution to obtain expanded vermiculite suspension and suspension. The expanded vermiculite suspension is nano-exfoliated and dispersed to obtain a crude vermiculite nanosheet dispersion, and finally it is subjected to precipitation and separation to obtain a refined vermiculite nanosheet dispersion and bottom sediment, which are subjected to solid-liquid separation and dried to obtain For vermiculite nanosheets, filtrate and waste liquid are produced in this link, and the production process is highly polluted. Vermiculite sheets cannot be peeled off more completely, and the thickness is thick.

At present, the vermiculite stripping technology is mainly through chemical modification and mechanical stripping of vermiculite raw ore. In the preparation process, either organic additives are used, or the equipment and process are complicated, or the yield is low, and most of them are in the laboratory stage, and the waste liquid generated is difficult to handle and causes great environmental pollution. At the same time, the obtained vermiculite flakes or composite products are only suitable for specific fields, which is not conducive to popularization and use, and limits the application range of vermiculite mineral resources. Unmodified or single vermiculite nanosheet independent products have not been prepared, and there are no technical solutions and methods related to the preparation of the vermiculite nanosheet.

technical problem

In order to overcome the defects of the above-mentioned prior art, the present invention proposes a vermiculite nanosheet and a preparation method thereof. The vermiculite nanosheet can not only be used as a nano-reinforcing material in industries such as papermaking, coatings, paints, plastics, and rubber, but also It can be used as an oxygen self-sufficient platform to generate oxygen and a variety of active oxygen, which can be effectively used to prepare biomedical photodynamic therapy drugs, overcome tumor hypoxia, and enhance the efficacy of photodynamic therapy. In addition, the preparation method of the vermiculite nanosheets provided by the invention is simple in process, environmentally friendly and convenient for industrial application.

technical solution

A method for preparing vermiculite nanosheets, comprising adding vermiculite to an alkali metal salt solution modifier for intercalation treatment, exfoliating to obtain vermiculite nanosheets, wherein, adding 0.1-10 moles per liter of vermiculite Alkali metal salt modifier. In every milligram of vermiculite, if the concentration of the added alkali metal salt modifier is lower than 0.1 mole per liter, the thickness of the prepared vermiculite sheet will be thickened; if the concentration of the alkali metal modifier is higher than 10 moles per liter, longer wash times are required to remove the alkali metal modifier.

Further, it specifically includes the following steps:

S1: adding vermiculite to the alkali metal salt solution modifier to expand the vermiculite;

S2: separate after expansion, and collect the upper layer of colloidal slurry;

S3: Ultrasonic treatment is performed on the colloidal slurry in the upper layer, and the vermiculite nanosheets are obtained by peeling off.

Preferably, the alkali metal salt solution modifier is one or more of lithium salt solution, potassium salt solution or sodium salt solution.

More preferably, the alkali metal salt solution modifier is one or more of lithium chloride solution, lithium ethylenediaminetetraacetate solution or lithium citrate solution. The chemically expanded vermiculite treated with the lithium salt modifier, compared with the thermally expanded or hydrogen peroxide-expanded physically expanded vermiculite, the vermiculite flakes can be exfoliated more completely and thinner. Lithium ethylenediamine tetraacetate and lithium citrate modifiers have the best expansion effect on vermiculite, which can reduce the order degree of vermiculite-phlogopite mixed layer minerals and phlogopite crystals in vermiculite, and vermiculite can be stripped more completely.

Further, the condition of step S1 is heating under reflux at a temperature of 80-90° C. for 24-36 hours.

Further, in step S2, the separation adopts centrifugation, the centrifugation speed is 2500-3500rpm, and the centrifugation time is 20-30min.

Preferably, in step S3, the duration of the ultrasonic treatment is 0.3-0.6h.

The present invention also provides vermiculite nanosheets prepared according to the above preparation method, the average thickness of the vermiculite nanosheets is 1.0-1.2nm; the average width of the vermiculite nanosheets is 300-330nm; the vermiculite nanosheets The average length of the flakes is 300-330 nm.

Beneficial effect

1. The method yield of preparing vermiculite nanosheet provided by the invention is high;

2. The thickness of the prepared vermiculite nanosheets is thin, the equipment selection and control are universal, the production process is green and environmentally friendly, and the chemical additives are non-polluting, which is convenient for industrial production;

3. The application field of the prepared vermiculite nanosheets is not limited to a specific traditional field, and has a wide range of applications in biomedical and other industries. For example, vermiculite nanosheets are not only used in papermaking, coatings, paints, plastics, rubber and other industries It can be used as a nano-enhanced material or as an oxygen self-sufficient platform to generate oxygen and a variety of active oxygen. It can be effectively used in biomedical photodynamic therapy to overcome tumor hypoxia and enhance the efficacy of photodynamic therapy.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings that need to be used in the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application. For those skilled in the art, other drawings can also be obtained based on these drawings without creative effort.

Fig. 1 is block vermiculite appearance figure;

Fig. 2 is the scanning electron micrograph of massive vermiculite;

Fig. 3 is the solution of the vermiculite nanoplate of embodiment;

Fig. 4 is the transmission electron micrograph of the vermiculite nanosheet of embodiment;

Fig. 5 is the atomic force microscope figure of the vermiculite nanoplate of embodiment;

Fig. 6 is the schematic diagram of the preparation process of the vermiculite nanosheet of embodiment;

Fig. 7 is the size measurement result of the vermiculite nanoplate of embodiment;

Fig. 8 is the scanning electron microscope energy spectrum analysis result of the vermiculite nanosheet of the embodiment.

Embodiments of the present invention

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

The invention provides a preparation method of vermiculite nanosheets, comprising adding vermiculite to an alkali metal salt solution modifier for intercalation treatment, and exfoliating to obtain vermiculite nanosheets, wherein the addition of vermiculite per milligram is 0.1 - 10 moles per liter of alkali metal salt modifier. In every milligram of vermiculite, if the concentration of the added alkali metal salt modifier is lower than 0.1 mole per liter, the thickness of the prepared vermiculite sheet will be thickened; if the concentration of the alkali metal modifier is higher than 10 moles per liter, longer wash times are required to remove the alkali metal modifier.

Further, it specifically includes the following steps:

S1: adding vermiculite to the alkali metal salt solution modifier to expand the vermiculite;

S2: separate after expansion, and collect the upper layer of colloidal slurry;

S3: Ultrasonic treatment is performed on the colloidal slurry in the upper layer, and the vermiculite nanosheets are obtained by peeling off.

Preferably, the alkali metal salt solution modifier is one or more of lithium salt solution, potassium salt solution or sodium salt solution.

More preferably, the alkali metal salt solution modifier is one or more of lithium chloride solution, lithium ethylenediaminetetraacetate solution or lithium citrate solution. The chemically expanded vermiculite treated with the lithium salt modifier, compared with the thermally expanded or hydrogen peroxide-expanded physically expanded vermiculite, the vermiculite flakes can be exfoliated more completely and thinner. Lithium ethylenediamine tetraacetate and lithium citrate modifiers have the best expansion effect on vermiculite, which can reduce the order degree of vermiculite-phlogopite mixed layer minerals and phlogopite crystals in vermiculite, and vermiculite can be stripped more completely.

Further, the condition of step S1 is heating under reflux at a temperature of 80-90° C. for 24-36 hours.

Further, in step S2, the separation adopts centrifugation, the centrifugation speed is 2500-3500rpm, and the centrifugation time is 20-30min.

Preferably, in step S3, the duration of the ultrasonic treatment is 0.3-0.6h.

The present invention also provides vermiculite nanosheets prepared according to the above preparation method, the average thickness of the vermiculite nanosheets is 1.0-1.2nm; the average width of the vermiculite nanosheets is 300-330nm; the vermiculite nanosheets The average length of the flakes is 300-330 nm.

Example 1

A preparation method of vermiculite nanosheets, comprising the following steps:

S1: Add 50 mg of commercial vermiculite powder to 5 moles per liter of lithium chloride solution, heat at 80°C for 24 hours under reflux, and intercalate the vermiculite powder to make it expand;

S2: After the expansion is completed, centrifuge at a speed of 3000rpm for 20 minutes to collect the upper colloidal slurry;

S3: Ultrasonic treatment is performed on the upper colloidal slurry for 0.5 hours several times, and the vermiculite nanosheets are obtained by exfoliation.

The thickness of the vermiculite nanosheets prepared by the above method is 1.1 nm, the width of the vermiculite nanosheets is 320 nm, and the length is 320 nm.

What Fig. 1 shows is the external form of massive vermiculite, and Fig. 2 is the scanning electron microscope picture that massive vermiculite is carried out, and Fig. 3 is the solution of the vermiculite nanosheet that this embodiment provides, and Fig. 4 is that this embodiment provides Transmission electron microscopy images of vermiculite nanosheets.

The vermiculite nanosheet of the present invention is prepared by lithium ion intercalation method, the modifier is added to the vermiculite, and the lithium ions in the modifier are inserted between the two-dimensional layers of vermiculite through proton exchange, resulting in A large amount of expansion between the two-dimensional layers, followed by centrifugation and other operations, can easily peel off the two-dimensional layers of vermiculite, thereby obtaining the vermiculite nanosheets of the present invention. Figure 5 is a schematic diagram of the preparation process.

Fig. 6 is the atomic force microscope figure of the vermiculite nano-sheet of the present embodiment, measures the thickness of the vermiculite nano-sheet along No. nm.

FIG. 8 is the scanning electron microscope energy spectrum analysis result of the vermiculite nanosheets of this embodiment. It can be seen from the figure that the vermiculite nanosheets contain elements such as iron, oxygen, aluminum, magnesium, and silicon.

Example 2

A preparation method of vermiculite nanosheets, comprising the following steps:

S1: Add 50 mg of commercial vermiculite powder into 100 moles per liter of lithium ethylenediamine tetraacetate solution, heat at reflux at 90°C for 30 h, and intercalate the vermiculite powder to make it expand;

S2: After the expansion is completed, centrifuge at a speed of 2500rpm for 25 minutes to collect the upper colloidal slurry;

S3: The upper colloidal slurry was subjected to multiple ultrasonic treatments for 0.3 hours, and the vermiculite nanosheets were peeled off.

The thickness of the vermiculite nanosheets prepared by the above method is 1.0 nm, the width of the vermiculite nanosheets is 300 nm, and the length is 310 nm.

Example 3

A preparation method of vermiculite nanosheets, comprising the following steps:

S1: Add 50 mg of commercial vermiculite powder to 250 moles per liter of lithium citrate solution, heat at 85°C for 30 h under reflux, and intercalate the vermiculite powder to make it expand;

S2: After the expansion is completed, centrifuge at a speed of 3500rpm for 30 minutes to collect the upper colloidal slurry;

S3: The upper colloidal slurry is ultrasonically treated for 0.6 hours for several times, and the vermiculite nanosheets are obtained by exfoliation.

The thickness of the vermiculite nanosheets prepared by the above method is 1.2nm, the width of the vermiculite nanosheets is 310nm, and the length is 330nm.

Example 4

A preparation method of vermiculite nanosheets, comprising the following steps:

S1: Add 50 mg of commercial vermiculite powder into 500 moles per liter of sodium carbonate salt solution, heat under reflux at 85°C for 30 h, and intercalate the vermiculite powder to make it expand;

S2: After the expansion is completed, centrifuge at a speed of 3000rpm for 25 minutes to collect the upper colloidal slurry;

S3: Ultrasonic treatment is performed on the upper colloidal slurry for 0.4 hours for several times, and the vermiculite nanosheets are peeled off.

The thickness of the vermiculite nanosheets prepared by the above method is 1.2nm, the width of the vermiculite nanosheets is 310nm, and the length is 300nm.

In summary, the method for preparing vermiculite nanosheets provided by the present invention has a high yield, and the thickness of the prepared vermiculite nanosheets is thin, and the equipment selection and control are universally applicable, and the production process is green and environmentally friendly. No pollution, easy for industrial production; the application field of the prepared vermiculite nanosheets is not limited to a specific traditional field, and has a wide range of applications in biomedical and other industries. For example, vermiculite nanosheets are not only used in papermaking, coatings, paints and plastics , Rubber and other industries can be used as nano-reinforced materials, and can also be used as an oxygen self-sufficient platform to generate oxygen and a variety of active oxygen, which can be effectively used in biomedical photodynamic therapy to overcome tumor hypoxia and enhance the efficacy of photodynamic therapy.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection of the present invention. within range.

Claims (10)

A preparation method of vermiculite nanosheets, characterized in that, comprising adding vermiculite to an alkali metal salt solution modifier for intercalation treatment, peeling off to obtain vermiculite nanosheets, wherein, adding 0.1- 10 moles per liter of alkali metal salt modifier. The preparation method of vermiculite nanosheet according to claim 1, is characterized in that, specifically comprises the following steps: S1: adding vermiculite to the alkali metal salt solution modifier to expand the vermiculite; S2: separate after expansion, and collect the upper layer of colloidal slurry; S3: Ultrasonic treatment is performed on the colloidal slurry in the upper layer, and the vermiculite nanosheets are obtained by peeling off. The preparation method of vermiculite nanosheets according to claim 1, wherein the alkali metal salt solution modifier is one or more of lithium salt solution, potassium salt solution or sodium salt solution. The preparation method of vermiculite nanoplate according to claim 3, is characterized in that, described alkali metal salt solution modifying agent is a kind of in lithium chloride solution, lithium edetate solution or lithium citrate solution or more. The method for preparing vermiculite nanosheets according to claim 2, characterized in that, the condition of step S1 is heating under reflux at a temperature of 80-90°C for 24-36h. The preparation method of vermiculite nanosheets according to claim 5, characterized in that, in step S2, the separation adopts a centrifugation method, the centrifugation speed is 2500-3500rpm, and the centrifugation time is 20-30min. The method for preparing vermiculite nanosheets according to claim 5, characterized in that, in step S3, the duration of ultrasonic treatment is 0.3-0.6h. A vermiculite nanosheet prepared according to any one of the preparation methods of claims 1-7, characterized in that the average thickness of the vermiculite nanosheet is 1.0-1.2nm. The vermiculite nanosheet according to claim 1, characterized in that the average width of the vermiculite nanosheet is 300-330nm. The vermiculite nanosheet according to claim 1, characterized in that the average length of the vermiculite nanosheet is 300-330nm.