CN104489922B - A kind of preparation and application of graphene oxide bonded silica gel composite - Google Patents

Abstract

The invention provides a method for preparing a graphene oxide-bonded silica gel composite material, which comprises the following steps: 1) adding sodium nitrate and concentrated sulfuric acid to graphite powder for pre-oxidation treatment, adding potassium permanganate and stirring, adding water to dilute Continue to stir, then add warm water and hydrogen peroxide to stir evenly, centrifuge, filter, and finally wash and dry to obtain graphene oxide powder; 2) Add graphene oxide powder to N,N-dimethylformamide for ultrasonic dispersion , and then add amino silica gel and dicyclohexylcarbodiimide to heat and reflux, centrifuge, filter, wash and then dry to obtain a graphene oxide bonded silica gel composite material. The present invention further provides a cigarette filter rod added with graphene oxide bonded silica gel composite material. The graphene oxide bonded silica gel composite material provided by the invention can effectively reduce the content of TSNAs in mainstream smoke of cigarettes, and has a very good effect.

Description

Preparation and application of a graphene oxide bonded silica gel composite material

technical field

The invention belongs to the technical field of cigarette materials, and relates to the preparation and application of functional materials in the field of cigarettes, in particular to the preparation of a graphene oxide bonded silica gel composite material and its addition to cigarette filter rods to reduce cigarette mainstream smoke Application of nitrosamines.

Background technique

During the burning process of cigarettes, cancer-promoting and carcinogenic substances will be produced, such as fused-ring aromatic hydrocarbons, phenols, tobacco-specific nitrosamines (TSNAs) and free radicals. Among them, tobacco-specific nitrosamines (TSNAs) have been reported, and 8 species have been identified so far. However, there are four main types in cigarettes: N-nitrosonornicotine (NNN), 4-(methylnitrosamine)-1-(3-pyridyl)-1-butanone (NNK), N - Nitrosoanatabine (NAT), N-nitrosoanabatin (NAB). Among them, NNN and NNK have been proved to be carcinogenic in animals, and induced lung cancer in mice, rats and Syrian golden voles. In metabolic activities, NNN and NNK can methylate the DNA in animal living and isolated human tissues. This result can be obtained from 07-methylguanine and 06-methylguanine isolated from human tissues prove.

At present, there are many ways to reduce harmful substances in cigarettes, including punching filter rods, adding expanded shredded tobacco, expanded shredded stems, and blending tobacco flakes in the formula. But most of these methods have a great impact on the fragrance and mouthfeel of cigarettes while reducing harmful substances such as tar release amount or nicotine content.

In recent years, nanomaterials have been considered as additives for cigarette filter rods due to their adsorption properties brought about by their unique structures. Among them, graphene is a two-dimensional nanomaterial with a thickness of only one carbon atom. It is composed of carbon atoms with sp2 hybrid orbitals to form a honeycomb regular hexagonal lattice configuration. Electron mobility, unique π bond conjugated adsorption. Graphene oxide (GO) is the precursor of graphene prepared by chemical method. Its surface is rich in hydroxyl, carboxyl and epoxy functional groups, easy to form chemical bonds with other polar groups, and has good hydrophilicity. Therefore, it is very necessary to conduct in-depth discussion and research on the application of graphene materials in cigarette harm reduction and tar reduction.

Contents of the invention

In view of the shortcomings of the prior art described above, the object of the present invention is to provide a preparation and application of a graphene oxide bonded silica gel composite material, by loading graphene oxide (GO) on a silica gel carrier to prepare graphene oxide Bonded silica gel (GO/silica gel) composite material, added to cigarette filter rods, can effectively reduce the content of TSNAs in cigarette mainstream smoke.

In order to achieve the above object and other related objects, the invention provides a method for preparing a graphene oxide bonded silica gel composite material, comprising the following steps:

1) Add sodium nitrate and concentrated sulfuric acid to the graphite powder for pre-oxidation treatment, then add potassium permanganate and stir, add water to dilute and continue stirring, then add warm water and hydrogen peroxide, stir evenly, centrifuge, filter, and finally wash and dry. To obtain graphene oxide (GO) powder;

Preferably, the weight ratio of graphite powder to sodium nitrate is 2:0.9-1.1.

Preferably, the weight ratio of graphite powder to sodium nitrate is 2:1.

Preferably, the solid-to-liquid ratio of the added weight of the graphite powder to the added volume of the concentrated sulfuric acid is: 1:21-25 (g/ml).

Preferably, the solid-to-liquid ratio of the added weight of the graphite powder to the added volume of the concentrated sulfuric acid is: 1:23 (g/ml).

Preferably, the pre-oxidation treatment conditions are: reaction temperature: 0-5°C; reaction time: 20-40 minutes; stirring times: 150-250 times/min.

Preferably, the pre-oxidation treatment conditions are: reaction temperature: 0° C.; reaction time: 30 minutes; stirring times: 200 times/min.

Preferably, the weight ratio of graphite powder to potassium permanganate is 1:2.8-3.2.

Preferably, the weight ratio of graphite powder to potassium permanganate is 1:3.

Preferably, the stirring conditions of the potassium permanganate are: stirring temperature: room temperature; stirring time: 110-130 minutes; stirring frequency: 100-150 times/min.

Preferably, the stirring conditions of the potassium permanganate are: stirring temperature: 20-25° C.; stirring time: 120 minutes; stirring frequency: 120 times/min.

After the potassium permanganate is added and stirred, the mixture will turn into a brown slurry. The principle of producing the brown slurry is that the graphite powder is oxidized, and functional groups such as hydroxyl, carboxyl, and epoxy groups are formed on the surface, the large conjugated π bond system is broken, and the spectral absorption changes, so the color changes from black to brown.

Preferably, the solid-to-liquid ratio of the added weight of the graphite powder to the added volume of water is: 1:48-52 (g/ml). The dilution with water is beneficial to release heat and facilitate oxidation.

Preferably, the solid-to-liquid ratio of the added weight of the graphite powder to the added volume of water is: 1:50 (g/ml).

Preferably, the stirring conditions for adding water are: stirring time: 110-130 minutes; stirring frequency: 150-250 times/minute.

Preferably, the stirring conditions for adding water are: the stirring time is 120 minutes; the stirring frequency is 200 times/min.

Preferably, the warm water is deionized water with a water temperature of 30-50°C. The addition of the warm water is beneficial to prevent the re-generation of precipitation in the reaction and increase the dissolution effect.

Preferably, the solid-to-liquid ratio of the added weight of the graphite powder to the added volume of warm water is: 1:95-105 (g/ml).

Preferably, the solid-to-liquid ratio of the added weight of the graphite powder to the added volume of warm water is: 1:100 (g/ml).

Preferably, the hydrogen peroxide is 30% hydrogen peroxide (v/v).

Preferably, the solid-to-liquid ratio of the added weight of the graphite powder to the added volume of hydrogen peroxide is: 1:9.5-10.5 (g/ml).

Preferably, the solid-to-liquid ratio of the added weight of the graphite powder to the added volume of hydrogen peroxide is: 1:10 (g/ml).

Preferably, the stirring conditions of warm water and hydrogen peroxide are: stirring time is 15-25 minutes; stirring frequency: 150-250 times/min.

Preferably, the stirring conditions of warm water and hydrogen peroxide are: stirring time is 20 minutes; stirring frequency: 200 times/min.

Preferably, the centrifugation and filtration refer to centrifuging the reactants to separate layers, then filtering off the solvent, and retaining the solid powder.

Preferably, the centrifugation conditions are: centrifugation time: 9.5-10.5 min; rotation speed: 4800-5200 rpm/min.

More preferably, the centrifugation conditions are: centrifugation time: 10 min; rotation speed: 5000 rpm/min.

Preferably, the cleaning is to centrifuge and separate the reactants added with the cleaning agent, and then filter the cleaning agent to keep the solid powder.

Preferably, the cleaning agent is dilute hydrochloric acid or water.

Preferably, the cleaning method is: firstly wash twice with dilute hydrochloric acid, and then wash twice with water. The dilute hydrochloric acid cleaning is beneficial to remove metal oxides on the surface of the material.

More preferably, the dilute hydrochloric acid is 5% dilute hydrochloric acid (v/v).

More preferably, the ratio of the volume of dilute hydrochloric acid used for each cleaning to the added weight of graphite powder is 95-105:1 (ml/g).

Optimally, the ratio of the volumetric dosage of the dilute hydrochloric acid to the added weight of the graphite powder is 100:1 (ml/g).

More preferably, the ratio of the volume of water used for each cleaning to the added weight of graphite powder is 95-105:1 (ml/g).

Optimally, the ratio of the volume of water used for each cleaning to the added weight of graphite powder is 100:1 (ml/g).

Preferably, the drying method is to dry the sample in a vacuum oven at room temperature.

Preferably, the drying conditions are: reaction temperature: room temperature; reaction container: vacuum oven; container power: 1.8-2.0kW; drying time: 23.5-24.5 hours.

More preferably, the drying conditions are as follows: reaction temperature: 20-25° C.; reaction container: vacuum oven; container power: 1.9 kW; drying time: 24 hours.

2) Add graphene oxide powder into N,N-dimethylformamide for ultrasonic dispersion, then add amino silica gel and dicyclohexylcarbodiimide for heating and reflux, centrifuge, filter, wash and dry, that is Graphene oxide bonded silica gel composites were obtained.

Preferably, the solid-to-liquid ratio of the added weight of the graphene oxide powder to the added volume of N,N-dimethylformamide is: 2:4.8-5.2 (g/ml).

Preferably, the solid-to-liquid ratio of the added weight of the graphene oxide powder to the added volume of N,N-dimethylformamide is: 2:5 (g/ml).

Preferably, the ultrasonic conditions are: ultrasonic time: 20-40 minutes; ultrasonic power: 480-520W; ultrasonic temperature: room temperature.

Preferably, the ultrasonic conditions are: ultrasonic time: 30 minutes; ultrasonic power: 500W; ultrasonic temperature: 20-25°C.

Preferably, the graphene oxide powder, amino silica gel, and dicyclohexylcarbodiimide are added in a weight ratio of 1:23-27:0.9-1.1.

Preferably, the graphene oxide powder, amino silica gel, and dicyclohexylcarbodiimide are added in a weight ratio of 1:25:1.

Preferably, the heating and reflux conditions: heating temperature: 50±0.5° C.; reflux time: 30±0.1 hours.

Preferably, the heating and reflux conditions: heating temperature: 50° C.; reflux time: 30 hours.

Preferably, the centrifugation and filtration refer to centrifuging the reactants to separate layers, then filtering off the solvent, and retaining the solid powder.

Preferably, the centrifugation conditions are: centrifugation time: 9.5-10.5 min; rotation speed: 4800-5200 rpm/min.

More preferably, the centrifugation conditions are: centrifugation time: 10 min; rotation speed: 5000 rpm/min.

Preferably, the cleaning is to centrifuge and separate the reactants added with the cleaning agent, and then filter the cleaning agent to keep the solid powder.

Preferably, the cleaning agent is methanol or water.

Preferably, the cleaning method is: first perform centrifugal cleaning twice with water, and then perform centrifugal cleaning twice with methanol.

More preferably, the ratio of the volume of water used for each cleaning to the added weight of graphite powder is: 2300-2700: 1 (ml/g).

Optimally, the ratio of the volume of water used for each cleaning to the added weight of graphite powder is: 2500:1 (ml/g).

More preferably, the ratio of the volume of methanol used for each cleaning to the added weight of graphite powder is 2300-2700: 1 (ml/g).

Optimally, the ratio of the volume of methanol used for each cleaning to the added weight of graphite powder is 2500:1 (ml/g).

More preferably, the methanol is anhydrous methanol.

Preferably, the drying method is to dry the sample in a vacuum oven at room temperature.

Preferably, the drying conditions are: reaction temperature: room temperature; reaction container: vacuum oven; container power: 1.8-2.0 kW; drying time: 29.5-30.5 hours.

More preferably, the drying conditions are as follows: reaction temperature: 20-25°C; reaction container: vacuum oven; container power: 1.9kW; drying time: 30 hours.

Preferably, the water used in the present invention is all deionized water.

The invention also discloses a graphene oxide bonded silica gel composite material obtained by the above method.

Preferably, the specific surface area of the graphene oxide material is 280-295m ² /g.

Preferably, the specific surface area of the graphene oxide material is 287m ² /g.

Preferably, the specific surface area of the graphene oxide-bonded silica gel composite material is 330-340 m ² /g.

Preferably, the specific surface area of the graphene oxide-bonded silica gel composite material is 336m ² /g.

The present invention further discloses a cigarette filter rod added with the above-mentioned graphene oxide bonded silica gel composite material.

Preferably, the cigarette filter rod contains 3-8 mg/piece of graphene oxide bonded silica gel composite material. Preferably, the cigarette filter rod contains 5 mg/piece of graphene oxide bonded silica gel composite material.

Preferably, the cigarette filter rod includes two sections of cellulose acetate at the end of the shredded tobacco and the mouth end, and a section of graphene oxide bonded silica gel composite material located between the two sections of cellulose acetate.

The invention also provides an application of a cigarette filter stick added with graphene oxide bonded silica gel composite material in reducing nitrosamines in cigarette mainstream smoke.

As mentioned above, the preparation and application of a graphene oxide-bonded silica gel composite material for reducing nitrosamines in mainstream cigarette smoke of the present invention is to prepare graphene oxide (GO) by adopting the Hummer method principle, and then according to the GO surface Carboxyl group and amino group bonding route on the surface of silica gel, graphene oxide (GO) was loaded onto silica gel carrier, and graphene oxide bonded silica gel (GO/silica gel) composite material was prepared, which was added to cigarette filter rods, and its reduction The filtering effect of TSNAs in mainstream cigarette smoke provides an effective reference for the in-depth application of the latest nanotechnology in cigarette harm reduction and tar reduction.

The GO/silica gel composite material obtained by the preparation method of the present invention has a large specific surface area, is easy to fully contact with TSNAs in flue gas, and has strong adsorption capacity. At the same time, GO/silica gel composites also have carboxyl functional groups. The nitrogen atoms in TSNAs molecules can attack the carbon atoms in carboxyl groups through nucleophilic substitution reactions, and finally form amide bonds, which are effectively adsorbed on the surface of GO/silica gel composites. It will not enter the smoker's body through the cigarette filter rod. The GO/silica gel composite material prepared by the present invention can effectively reduce NAB, NAT, NNK, and NNN in mainstream smoke to 18.95%, 16.33%, 26.55%, and 6.43%, respectively, and has a very good effect.

Description of drawings

Fig. 1 is shown as the X-ray diffraction figure of a kind of GO/silica gel composite material of the present invention

Fig. 2 is shown as the Raman spectrogram of a kind of GO/silica gel composite material of the present invention

Fig. 3 is shown as the nitrogen adsorption isotherm curve figure of a kind of GO/silica gel composite material of the present invention

Fig. 4 is shown as the transmission electron micrograph of a kind of GO/silica gel composite material of the present invention

detailed description

The present invention will be further described below in conjunction with specific examples. It should be understood that these examples are only used to illustrate the present invention and are not intended to limit the protection scope of the present invention.

Embodiments of the present invention are described below through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific implementation modes, and various modifications or changes can be made to the details in this specification based on different viewpoints and applications without departing from the spirit of the present invention.

The following reagents and equipment used in the following examples

1. Reagents

Graphite powder (commercially available); concentrated sulfuric acid, sodium nitrate, potassium permanganate, hydrogen peroxide, methanol, hydrochloric acid, ammonium acetate (analytical grade, Sinopharm); N,N-dimethylformamide, amino silica gel, dicyclohexyl Carbodiimide (analytical grade, Agilent); deionized water (made by pure water machine)

2. Equipment

D8 type X-ray diffractometer (X-ray is Cu target, Bruker, Germany); RM2000 spectrometer (Renishw, UK); JEM 2010 high-resolution transmission electron microscope (JEOL, Japan); ASAP 2010 nitrogen adsorption specific surface tester (Mike); SM450 linear smoking machine (Cerulean, UK) company); VD-115 vacuum oven (BINDER company); KH5200DE ultrasonic cleaner (Kunshan Hechuang company); 2487 high performance liquid chromatography mass spectrometer (Water company)

Example 1

1. Preparation of GO

Add 10 g of graphite powder, 5 g of NaNO ₃ and 230 ml of concentrated sulfuric acid into a large beaker with a volume of 2 L, and stir at 0 °C for 30 min for pre-oxidation treatment. After the pre _- oxidation treatment, 30 g of KMnO4 was added slowly, and then the mixture was stirred at room temperature until it turned into a brown slurry. After stirring for 120 minutes, 500ml of deionized water was slowly added to the brown slurry, and the reaction temperature rose sharply at this time, and stirring was continued for 120 minutes. Then add 1 L of warm water and 100 ml of 30% H ₂ O ₂ , stir evenly, centrifuge and filter. The sample obtained after filtration was washed twice with dilute hydrochloric acid, then twice with deionized water, and dried in a vacuum oven at room temperature to finally obtain GO powder.

2. Preparation of GO/silica gel composites

Take 200mg of GO powder and disperse it into 500ml of N,N dimethylformamide. After ultrasonication for 30 minutes, add 5g of amino silica gel and 200mg of dicyclohexylcarbodiimide, and heat to reflux at 50°C for 30 hours. After the reaction was completed, it was centrifuged and filtered, and the sample obtained after filtration was washed twice with deionized water, then washed twice with methanol, and dried in a vacuum oven at room temperature to finally obtain a GO/silica gel composite material.

3. Preparation of cigarette filter rods

The obtained GO/silica gel composite material was added to cigarette filter sticks at a content of 5 mg/stick, and then prepared into a cigarette sample (added sample) to be tested. The cigarette filter rod comprises two acetate fiber segments located at the shredded tobacco end and the mouth end, and a graphene oxide bonded silica gel composite material segment located between the two acetate fiber segments. At the same time, a cigarette sample (control sample) containing a cigarette filter rod without graphene oxide bonded silica gel composite material was prepared for testing.

Example 2

1. Preparation of GO

Add 10 g of graphite powder, 4.5 g of NaNO ₃ and 210 ml of concentrated sulfuric acid into a large beaker with a volume of 2 L, and stir at 0 °C for 20 min for pre-oxidation treatment. After the pre _- oxidation treatment, 28 g of KMnO4 was slowly added, and then the mixture was stirred at room temperature until it turned into a brown slurry. After stirring for 110 minutes, 480ml of deionized water was slowly added to the brown slurry, and the reaction temperature rose sharply at this time, and the stirring was continued for 110 minutes. Then add 950ml of warm water and 95ml of 30% H ₂ O ₂ , stir evenly, centrifuge and filter. The sample obtained after filtration was washed twice with dilute hydrochloric acid, then twice with deionized water, and dried in a vacuum oven at room temperature to finally obtain GO powder.

2. Preparation of GO/silica gel composites

Disperse 200mg of GO powder into 480ml of N,N dimethylformamide. After ultrasonication for 20 minutes, add 4.6g of amino silica gel and 180mg of dicyclohexylcarbodiimide, and heat to reflux at 49.5°C for 29.9 hours. After the reaction was completed, it was centrifuged and filtered, and the sample obtained after filtration was washed twice with deionized water, then washed twice with methanol, and dried in a vacuum oven at room temperature to finally obtain a GO/silica gel composite material.

3. Preparation of cigarette filter rods

The obtained GO/silica gel composite material was added to cigarette filter sticks at a content of 3 mg/stick, and then prepared into a cigarette sample (added sample) to be tested. The cigarette filter rod comprises two acetate fiber segments located at the shredded tobacco end and the mouth end, and a graphene oxide bonded silica gel composite material segment located between the two acetate fiber segments. At the same time, a cigarette sample (control sample) containing a cigarette filter rod without graphene oxide bonded silica gel composite material was prepared for testing.

Example 3

1. Preparation of GO

Add 10 g of graphite powder, 5.5 g of NaNO ₃ and 250 ml of concentrated sulfuric acid into a large beaker with a volume of 2 L, and stir at 5 °C for 40 min for pre-oxidation treatment. After the pre _- oxidation treatment, 32 g of KMnO4 was added slowly, and then the mixture was stirred at room temperature until it turned into a brown slurry. After stirring for 130 minutes, 520ml of deionized water was slowly added to the brown slurry, and the reaction temperature rose sharply at this time, and stirring was continued for 130 minutes. Then add 1 L of warm water and 105 ml of 30% H ₂ O ₂ , stir evenly, centrifuge and filter. The sample obtained after filtration was washed twice with dilute hydrochloric acid, then twice with deionized water, and dried in a vacuum oven at room temperature to finally obtain GO powder.

2. Preparation of GO/silica gel composites

Take 200mg of GO powder and disperse it into 520ml of N,N dimethylformamide. After ultrasonication for 40 minutes, add 5.4g of amino silica gel and 220mg of dicyclohexylcarbodiimide, and heat to reflux at 50.5°C for 30.1 hours. After the reaction was completed, it was centrifuged and filtered, and the sample obtained after filtration was washed twice with deionized water, then washed twice with methanol, and dried in a vacuum oven at room temperature to finally obtain a GO/silica gel composite material.

3. Preparation of cigarette filter rods

The obtained GO/silica gel composite material was added to cigarette filter sticks at a content of 8 mg/stick, and then prepared into a cigarette sample (added sample) to be tested. The cigarette filter rod comprises two cellulose acetate segments located at the shredded tobacco end and the mouth end, and a graphene oxide bonded silica gel composite material segment located between the two cellulose acetate segments. At the same time, a cigarette sample (control sample) containing a cigarette filter rod without graphene oxide bonded silica gel composite material was prepared for testing.

Example 4

1. Composition analysis

1.1 Processing of samples to be tested

The additional sample prepared in clause 3 in the above-mentioned embodiment 1 was sucked using SM450 linear smoking machine (suction capacity 35ml/min) according to the standard ISO3308-2000 "Cigarette Smoke Routine Analyzer. Definition and Standard Conditions", and Use a glass fiber filter with a diameter of Φ44mm to capture the total particulate matter in the mainstream smoke of cigarettes. Each filter piece collects the smoke particulate matter of 5 cigarettes, and each sample should be measured twice in parallel.

After smoking the cigarette, put the glass fiber filter in a 50ml Erlenmeyer flask, accurately add 20ml of 100mM (mol/L) ammonium acetate solution, perform ultrasonic extraction at room temperature for 30 minutes, then filter the extract through water Membrane filtration, take 1ml filtrate, to be tested.

1.2 Instrument testing

The filtrate was determined by high-performance liquid chromatography-mass spectrometry (HPLC-MS/MS).

Among them, the analysis conditions of high performance liquid chromatography are: chromatographic column: C18 column (3.2×100mm i.d.1.7μm); flow rate: 0.25ml/min; column temperature: 50°C; injection volume: 10μl; 10mM acetic acid-water solution, phase B is 10mM acetic acid-methanol solution; analysis time: 10min; linear gradient elution.

The gradient elution of Phase A: Phase B satisfies the following conditions:

0-4min Phase A: Phase B volume ratio: 92:8—40:60;

4-5min Phase A: Phase B volume ratio: 40:60—40:60;

5-8min Phase A: Phase B volume ratio: 40:60—5:95;

8-10min Phase A: Phase B volume ratio: 5:95—92:8.

Among them, the mass spectrometry conditions are:

Mass spectrometry ion source parameters: ion source: electrospray ionization source; scan mode: positive ion scan; detection mode: multiple reaction monitoring; electrospray voltage: 5000V; ion source temperature: 600 ℃; auxiliary gas Gas1 pressure: 35psi; auxiliary gas Gas2 Pressure: 35psi.

In addition, the target mass spectrum parameters are shown in Table 1.

Table 1 is the set value of mass spectrometer parameters

2. Results and Discussion

2.1 Detection of GO/Silicone Composite Materials

The GO/silica gel composite material was measured by a D8 X-ray diffractometer, and the X-ray diffraction pattern 1 of the GO/silica gel composite material was obtained. It can be seen from Figure 1 that the diffraction peaks appeared around 10°C, indicating that the original graphite powder was oxidized to generate oxygen-containing functional groups, resulting in the expansion of the interplanar spacing, and GO was successfully synthesized.

The RM2000 spectrometer was used to measure the GO/silica gel composite material, and the Raman spectrum of the GO/silica gel composite material was obtained. It can be seen from Figure 2 that D bands and G etc. appear in the Raman spectrum, further indicating that GO was successfully synthesized.

The GO/silica gel composite was measured by ASAP 2010 nitrogen adsorption specific surface tester, and the nitrogen adsorption isotherm curve of GO/silica gel composite was obtained in Figure 3. It can be seen from Figure 3 that the GO/silica gel composite has a large specific surface area and is theoretically an excellent adsorption material.

The JEM 2010 high-resolution transmission electron microscope was used to measure the GO/silica gel composite material, and the transmission electron microscope figure 4 of the GO/silica gel composite material was obtained. It can be seen from Figure 4 that GO is bonded to the surface of silica gel in the form of a single piece, which maintains a large specific surface area and is suitable for adsorption.

2.2 Detection of TSNAs content

According to the above 1.2, HPLC-MS/MS was used to measure the cigarette sample (added sample) in which the GO/silica gel composite material was added to the filter stick prepared in the above Example 1. Similarly, according to the above 1.2, HPLC-MS/MS was used to measure the cigarette sample (control sample) in which the GO/silica gel composite material was not added to the filter rod prepared in the above Example 1. The specific test results are shown in Table 2.

Table 2 The results of composite filter sticks reducing 4 kinds of TSNAs in mainstream smoke

As shown in Table 2, the GO/silica gel composite material was added to the cigarette filter stick as an adsorbent to prepare the composite filter stick cigarette, which can significantly reduce the TSNAs in the mainstream smoke of the cigarette. The filter rod can reduce NAB, NAT, NNK and NNN in mainstream cigarette smoke by 18.95%, 16.33%, 26.55% and 6.43%, respectively.

2.3 Sensory evaluation

In addition, the sensory evaluation results of the samples prepared in Example 1 show that the filter stick has no adverse effect on the smoking quality of cigarettes, and the results are shown in Table 3. It can be seen from Table 3 that compared with the cigarette sample without GO/silica gel composite material added to the filter rod (control sample), the cigarette sample with GO/silica gel composite material added to the filter rod (additional sample) has similar smoking evaluation results. It can be seen that the addition of GO /Silicone composite material has basically no influence on the smoking quality of cigarettes and can be applied in practice.

Table 3 Cigarette Sensory Quality Inspection Record Form

The above-mentioned embodiments only illustrate the principles and effects of the present invention, but are not intended to limit the present invention. Anyone skilled in the art can modify or change the above-mentioned embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those skilled in the art without departing from the spirit and technical ideas disclosed in the present invention should still be covered by the claims of the present invention.

Claims (7)

1. a kind of preparation method of graphene oxide bonded silica gel composite, comprises the following steps：

1) sodium nitrate is added in graphite powder and the concentrated sulfuric acid carries out pre-oxidation treatment, adds after potassium permanganate stirring, adds water dilute Continue to stir after releasing, add warm water and hydrogen peroxide stir after centrifugation, filtering, dried after finally cleaning, produce oxidation stone Black alkene powder；

2) graphene oxide powder is added in DMF and carries out ultrasonic disperse, add alkylamino silica gel and two After carbodicyclo hexylimide is heated to reflux, centrifugation, filtering are dried after cleaning, are produced graphene oxide bonded silica gel and are combined Material；

Step 1) in, the pre-oxidation treatment condition is：Reaction temperature：0-5℃；Reaction time：20-40 minutes；Stir number of times： 150-250 beats/min；

Step 1) in, the stirring condition of the potassium permanganate is：Whipping temp：Room temperature；Mixing time：110-130 minutes；Stirring Number of times：100-150 beats/min；The stirring condition that adds water is：Mixing time is 110-130 minutes；Stir number of times：150-250 Beat/min；Warm water and the hydrogen peroxide stirring condition is：Mixing time is 15-25 minutes；Stir number of times：150-250 beats/min；

Step 2) in, the ultrasound condition is：Ultrasonic time：20-40 minutes；Ultrasonic power：480-520W；Ultrasonic temperature：Room Temperature；The heated reflux condition：Heating-up temperature：49.5-50.5℃；Return time：29.9-30.1 hours.

2. a kind of preparation method of graphene oxide bonded silica gel composite according to claim 1, it is characterised in that Step 1) in, the cleaning is will to filter out cleaning agent after the reactant centrifugation layering for adding cleaning agent, retain solid powder；Institute Cleaning agent is stated for watery hydrochloric acid or water；The cleaning way is：First cleaned twice with watery hydrochloric acid, then carry out with water cleaning two It is secondary.

3. a kind of preparation method of graphene oxide bonded silica gel composite according to claim 1, it is characterised in that Step 2) in, the cleaning is will to filter out cleaning agent after the reactant centrifugation layering for adding cleaning agent, retain solid powder；Institute Cleaning agent is stated for methanol or water；The cleaning way is：First eccentric cleaning is carried out with water twice, again with methanol carries out eccentric cleaning Twice.

4. a kind of graphene oxide bonded silica gel composite, any described method is made in claim 1-3.

5. a kind of cigarette filter rod, added with graphene oxide bonded silica gel composite as claimed in claim 4.

6. a kind of cigarette filter rod according to claim 5, it is characterised in that propped up in the cigarette filter rod containing 3-8mg/ Graphene oxide bonded silica gel composite；The cigarette filter rod include positioned at pipe tobacco end and mouth end two sections of acetate fiber sections and Graphene oxide bonded silica gel composite section in the middle of two sections of acetate fiber sections.

7. a kind of cigarette filter rod that with the addition of graphene oxide bonded silica gel composite according to claim 5-6 is in drop Application in low cigarette mainstream flue gas in nitrosamine.