Silica-modified metal-organic framework composites, methods of making and using the same

Abstract

The application relates to the technical field of gas recovery, and discloses a silica gel modified metal organic framework composite material and a preparation method and application thereof. The composite material comprises a coordination metal and a silica gel modified organic ligand; in the silica gel modified organic ligand, silica gel and the organic ligand are covalently connected through esterification. The composite material has a large specific surface area and a suitable pore size, has a high adsorption capacity and a good vacuum desorption effect when used for gas (such as volatile organic gas, benzene series) adsorption, and can ensure that the gas emission concentration of a device meets standard requirements.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of gas recovery, in particular to a silica gel modified metal organic framework composite material and a preparation method and application thereof. BACKGROUND

[0002] BTEX is an important chemical raw material, such as benzene, toluene is an important organic solvent and basic chemical raw material, ethylbenzene is a raw material for producing styrene, polystyrene, ABS resin, and p-xylene is an important raw material for producing polyester fiber. However, BTEX is also a common industrial pollutant, which has great toxicity to the human body, especially benzene gas which is easy to induce leukemia, and is difficult to biodegrade due to its stable molecular structure. Therefore, controlling the emission and recycling of BTEX gas is of great significance to environmental protection, personnel health and economic benefits. In recent years, the "absorption-adsorption" process is a common way to treat BTEX, and the development of high-performance adsorbents is the key to recycling BTEX.

[0003] CN104888694A discloses an adsorbent material for efficiently adsorbing indoor formaldehyde and toluene gas, which mainly uses high specific surface ZSM-5 molecular sieve, silica gel or X molecular sieve as a carrier skeleton material, and loads active component materials such as copper, zinc and nickel thereon, and is prepared by dipping and calcining processes, so as to realize effective adsorption of formaldehyde, toluene and other substances.

[0004] CN101693206A discloses a catalyst for removing low-concentration BTEX from gas at room temperature, which is characterized in that Ag and Cu or one of them are used as the main active components of the catalyst, and are loaded on a ZSM-5 type molecular sieve carrier, and the weight percentage of Ag or Cu is 0-10%.

[0005] The above adsorbent material uses molecular sieve or silica gel material only as a carrier when adsorbing BTEX, and has a small specific surface area and poor adsorption performance, and is not suitable for adsorption and desorption recovery of BTEX gas, so it is necessary to seek an adsorbent material with good adsorption and desorption performance for volatile organic gas (such as BTEX). SUMMARY

[0006] The present application aims to overcome the above technical problems in the prior art, and provides a silica gel modified metal organic framework composite material and a preparation method and application thereof.

[0007] Therefore, in order to achieve the above purpose, the present application provides a silica gel modified metal organic framework composite material, which comprises a coordination metal and a silica gel modified organic ligand; in the silica gel modified organic ligand, silica gel and organic ligand are covalently connected through an ester group.

[0008] The second aspect of the present application provides a method for preparing a composite material, comprising the following steps:

[0009] (1) modifying an organic ligand with silica gel to obtain a silica gel modified organic ligand;

[0010] (2) performing a coordination reaction between the silica gel modified organic ligand and a metal source to be coordinated to obtain the composite material.

[0011] The third aspect of the present application provides a composite material prepared by the method of the second aspect.

[0012] The fourth aspect of the present application provides an application of the composite material of the first aspect or the third aspect or the method of the second aspect in gas adsorption, in particular in benzene series absorption.

[0013] Compared with the prior art, the present application provides a silica gel modified metal organic framework composite material, which is prepared by performing a coordination reaction between a silica gel modified organic ligand and a coordination metal, has a large specific surface area and a suitable pore size, has a high adsorption capacity and a good vacuum desorption effect when used for gas (such as volatile organic gas, benzene series) adsorption, and can ensure that the gas emission concentration of the device meets the standard requirements. Meanwhile, the present application also provides a method for preparing the composite material, which has the advantage of simple process. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 is an infrared spectrum of silica gel;

[0015] Figure 2 is an infrared spectrum of the silica gel modified organic ligand prepared in Example 1;

[0016] Figure 3 is a pore size distribution diagram of silica gel and the silica gel modified metal organic framework composite material (composite material) obtained in Example 1 of the present application. DETAILED DESCRIPTION

[0017] The endpoints of the ranges and any values disclosed herein are not limited to the precise values stated. The endpoints of the ranges and any values should be interpreted as approximately between the stated values and include the values between the endpoints. For values having an increment, the endpoints between any lower limit and any upper limit, and any lower limit, any upper limit, and single value, can be combined to create a new range or a new value. The new range or the new value is to be construed as disclosable herein.

[0018] The first aspect of the present application provides a silica gel modified metal organic framework composite material, which comprises a coordination metal and a silica gel modified organic ligand; in the silica gel modified organic ligand, silica gel and an organic ligand are covalently connected through an ester group.

[0019] According to some embodiments of the present application, the particle size of the composite material is in the range of 1-8mm, preferably 1-5mm; the specific surface area is in the range of 250-800m 2 / g, preferably 350-600m 2 / g, further preferably 350-500m 2 / g; the pore volume is in the range of 0.5-2cm 3 / g, preferably 0.7-1.2cm 3 / g; the average pore size is in the range of 5-20nm, preferably 8-15nm.

[0020] According to some embodiments of the present application, the saturated adsorption capacity of the composite material for benzene vapor is in the range of 3-40wt%, preferably 5-30wt%.

[0021] In order to obtain better adsorption effect, the structure parameters of the silica gel are limited, the silica gel is spherical silica gel and / or amorphous silica gel, the particle size of the silica gel is in the range of 1-5mm, preferably 2-4mm; the specific surface area is in the range of 200-700m 2 / g (200m 2 / g, 250m 2 / g, 300m 2 / g, 350m 2 / g, 400m 2 / g, 425m 2 / g, 450m 2 / g, 500m 2 / g, 550m 2 / g, 600m 2 / g, 700m 2 / g or any value between the above values), preferably 300-500m 2 / g; the average pore size is in the range of 2-20nm (2nm, 5nm, 7nm, 8nm, 10nm, 11nm, 12nm, 13nm, 15nm, 17nm, 19nm, 20nm or any value between the above values), preferably 4-10nm; the pore volume is in the range of 0.5-2cm 3 / g (0.5cm 3 / g, 0.6cm 3 / g, 0.7cm 3 / g, 0.8cm 3 / g, 0.9cm 3 / g, 1.0cm 3 / g, 1.1cm 3 / g, 1.2cm 3 / g, 1.3cm 3 / g, 1.4cm3 / g, 1.6 cm 3 / g, 1.8 cm 3 / g, 2.0 cm 3 / g or any value between the above values), preferably 0.8-1.5 cm 3 / g.

[0022] According to some embodiments of the present application, the organic ligand is a polybasic organic acid, which can be at least one selected from polybasic carboxylic acids containing aromatic rings, polybasic acids containing aliphatic functional groups, and polybasic acids containing heteroatoms (such as nitrogen atoms, sulfur atoms, etc.), preferably polybasic carboxylic acids containing aromatic rings.

[0023] Preferably, the polybasic carboxylic acid containing aromatic rings is at least one selected from trimesic acid, terephthalic acid, naphthalene-2,6-dicarboxylic acid, maleic acid, adipic acid, 5-nitro-1,2,3-benzene tricarboxylic acid, and 5-bromo-isophthalic acid, more preferably trimesic acid and / or terephthalic acid.

[0024] According to some embodiments of the present application, the coordinated metal can be at least one selected from Zn, Ni, Cu, Al, Fe, and Cr; preferably at least one selected from Cu, Fe, and Al.

[0025] According to some embodiments of the present application, the molar ratio of the coordinated metal to the silica gel-modified organic ligand in the modified metal framework material can be (0.3-5):1, preferably (1-3):1.

[0026] According to some embodiments of the present application, the silica gel-modified organic ligand is obtained by esterification of the hydroxyl groups on the surface of the silica gel with the carboxyl groups on the organic ligand (such as polybasic organic acid).

[0027] According to some embodiments of the present application, the silica gel is used in an amount such that the molar ratio of the hydroxyl groups on the surface of the silica gel to the organic ligand is (1-5):1, further preferably (2-3):1.

[0028] The second aspect of the present application provides a method for preparing a composite material, characterized in that the method comprises the following steps:

[0029] (1) modifying an organic ligand with silica gel to obtain a silica gel-modified organic ligand;

[0030] (2) coordinating the silica gel-modified organic ligand with a source of a metal to be coordinated to obtain the composite material.

[0031] In the present application, before modifying the ligand with silica gel, the following pretreatment step of silica gel is further included: drying the silica gel at 120-180°C for 1-5h.

[0032] According to some embodiments of the present invention, in step (1), the modification is performed by contacting the silica gel with the organic ligand in the presence of a catalyst and a first solvent.

[0033] According to some embodiments of the present invention, the contact conditions may include: a temperature of 70-250°C (70°C, 80°C, 90°C, 100°C, 110°C, 120°C, 130°C, 140°C, 145°C, 150°C, 155°C, 160°C, 170°C, 180°C, 190°C, 200°C, 250°C or any value between the above), preferably 80-160°C; and a time of 1-10 hours, preferably 2-6 hours.

[0034] According to some embodiments of the present invention, the amount of the silica gel and the organic ligand is such that the molar ratio of the hydroxyl groups on the surface of the silica gel to the organic ligand is (1-5):1, more preferably (2-3):1.

[0035] The organic ligands and silica gel described in the second aspect of this invention have the same definitions as those in the first aspect, and will not be repeated here.

[0036] According to some embodiments of the present invention, the catalyst is an organic acid or organic base, which may be selected from formic acid, acetic acid, diethylamine, triethylamine and pyridine, preferably formic acid or triethylamine.

[0037] According to some embodiments of the present invention, the weight ratio of the silica gel to the catalyst is (3-25):1, preferably (5-20):1.

[0038] According to some embodiments of the present invention, the first solvent may be selected from at least one of N,N-dimethylformamide, butyl acetate, acetonitrile, ethanol, isopropanol and toluene, preferably from N,N-dimethylformamide and / or acetonitrile.

[0039] According to some embodiments of the present invention, the amount of the first solvent used is 0.2-5 mL, preferably 0.5-2 mL, relative to 1 g of silica gel.

[0040] In this invention, the modified system of step (1) can be used directly in the next reaction without purification.

[0041] According to some embodiments of the present application, the conditions of the coordination reaction can include: temperature of 70-250℃ (70℃, 80℃, 90℃, 100℃, 110℃, 120℃, 130℃, 140℃, 145℃, 150℃, 155℃, 160℃, 170℃, 180℃, 190℃, 200℃, 250℃ or any value between the above-mentioned values), preferably 80-160℃; time of 15-30h, preferably 20-24h.

[0042] Preferably, the molar ratio of the metal source to be coordinated to the silica gel modified organic ligand is 1:(0.3-5), preferably 1:(1-3).

[0043] According to some embodiments of the present application, the metal source to be coordinated is provided by a salt and / or a base of the coordination metal.

[0044] According to some embodiments of the present application, the metal source to be coordinated can be selected from at least one of (Zn(NO3)2, NiCl2, Cu(OH)2, Cu(NO3)2, Al(NO3)3, FeCl3, CrCl3 and their hydrates), preferably at least one of Cu(OH)2, Cu(NO3)2 and their hydrates.

[0045] According to some embodiments of the present application, the coordination reaction is carried out in the presence of a second solvent, wherein the second solvent is selected from at least one of N,N-dimethylformamide, butyl acetate, acetonitrile, ethanol, isopropanol and toluene, preferably N,N-dimethylformamide and / or acetonitrile.

[0046] The present application does not have a particular limitation on the amount of the second solvent as long as the requirement of the present application can be met, for example, the amount of the second solvent is 0.5-5mL relative to 1g of silica gel.

[0047] In the present application, the first solvent and the second solvent can be the same or different.

[0048] In the present application, the post-treatment of the coordination reaction in step (2) is not particularly limited as long as the requirement of the present application can be met, for example, the post-treatment step can include: filtering the crude product obtained from the coordination reaction with a sieve mesh (not greater than 1mm, preferably 0.75mm-1mm), and washing the sieved solid with a washing solvent, and then vacuum drying at 100-150℃ for 2-10h to obtain the silica gel modified metal organic framework composite material of the present application. The washing solvent can be selected from at least one of N,N-dimethylformamide, ethanol and toluene. The amount of the washing solvent is not particularly limited as long as the unreacted raw material on the above-mentioned solid can be removed.

[0049] The third aspect of the present application provides a silica gel modified metal organic framework composite material prepared by the method of the second aspect.

[0050] The fourth aspect of the present application provides an application of the silica gel modified metal organic framework composite material of the first aspect or the third aspect or the method of the second aspect in gas adsorption, in particular, in benzene series absorption.

[0051] In the present application, the benzene series is at least one selected from benzene, toluene, ethylbenzene and xylene.

[0052] The present application will be described in detail below through examples.

[0053] In the following examples, the raw materials used are commercially available without special instructions.

[0054] Example 1

[0055] The silica gel used in this example is spherical: the particle size range is 2-4mm, the specific surface area is 305.38m 2 / g, the pore volume is 1.02cm 3 / g, the average pore size is 13.3nm, and the infrared spectrum of the silica gel is shown in Figure 1 ;

[0056] (1) 200g (0.4mol of hydroxyl groups) of silica gel was dried in an oven at 150°C for 2h, then placed in a three-necked flask, 300mL of N,N-dimethylformamide (DMF) was added and stirred uniformly, then 20mL of formic acid was added as a catalyst, 100mL of a DMF solution containing 32g (0.15mol) of trimesic acid was added under stirring, and the condensation reflux reaction was carried out at 160°C for 4h to obtain a material containing silica gel modified organic ligand;

[0057] (2) 10g of Cu(OH)2 (the molar ratio of the coordination metal source to the organic ligand polybasic organic acid is 1:1.5) was dissolved in 100mL of DMF to obtain a mixed solution of 1.03mol / L, and the mixed solution was slowly added to the material containing silica gel modified organic ligand obtained in step (1) for 15min, after the dropwise addition was completed, the condensation reflux was carried out at 160°C and a rotation speed of 200rpm for 24h to carry out the coordination reaction, and a crude product was obtained; the obtained crude product was cooled to room temperature and filtered on a sieve with a size of 1mm, the sieved solid sample was washed with a solvent (DMF, 100mL) for 3-5 times under stirring to remove the unreacted raw material (Cu(OH)2), and then dried in a vacuum oven at 120°C for 4h to obtain the composite material.

[0058] The silicone-modified organic ligands obtained in step (1) were subjected to infrared spectroscopy (using an IS10 FT-IR spectrometer (Thermoelectric-Nicolay Instruments, Inc., USA)) and the pore size distribution of the composite material obtained in step (2) was tested (using an ASAP 2020M+C physical adsorption analyzer (McTech Instruments, Inc., USA). The infrared spectra are as follows: Figure 2 Aperture distribution as follows Figure 3 .

[0059] Figure 2 In the study, the silica-modified organic ligand sample was tested at a wavenumber of 3000 cm⁻¹. -1 -3100cm -1 A stretching vibration peak of the hydrogen atom in the benzene ring appears at 1450 cm⁻¹; -1 -1630cm -1 Skeletal vibration peaks appear at these two locations, which are characteristic peaks of the benzene functional group.

[0060] from Figure 3 As can be seen, the silica gel exhibits a uniform macropore size distribution; the silica gel-modified metal-organic framework composite material prepared in this embodiment shows both macropores and pore sizes close to micropores (bimodal structure), indicating that the silica gel and organic ligands are successfully connected, forming a modified metal-organic framework composite material including coordination metal and silica gel-modified organic ligands.

[0061] Example 2

[0062] The procedure was carried out in accordance with Example 1, except that 18.8g of Cu(NO3)2 was used instead of 10g of Cu(OH)2.

[0063] Example 3

[0064] The procedure was carried out in accordance with Example 1, except that 4.9g of Cu(OH)2 was used instead of 10g of Cu(OH)2.

[0065] Example 4

[0066] The procedure was carried out in accordance with Example 1, except that 29.4g of Cu(OH)2 was used instead of 10g of Cu(OH)2.

[0067] Example 5

[0068] The procedure was carried out in accordance with Example 1, except that terephthalic acid was used instead of trimesic acid in equal molar amounts.

[0069] Example 6

[0070] The procedure was carried out in accordance with Example 1, except that the silica gel used had a particle size range of 2-4 mm and a specific surface area of ​​418.3 m². 2 / g, pore volume 0.68 cm 3 / g, average pore diameter 6.5 nm.

[0071] Example 7

[0072] The silica gel used in this example was spherical in shape: particle size range 2-4 mm, specific surface area 305.38 m 2 / g, pore volume 1.02 cm 3 / g, average pore diameter 13.3 nm.

[0073] (1) 200 g (0.4 mol of hydroxyl groups) of silica gel was dried in an oven at 150 °C for 2 h, placed in a three-necked flask, 300 mL of N,N-dimethylformamide (DMF) was added and stirred until uniform, then 20 mL of formic acid was added as a catalyst, 100 mL of a DMF solution containing 17.4 g (0.15 mol) of maleic acid was added dropwise under stirring, and the reaction was carried out under reflux condensation at 140 °C for 4 h to obtain a material containing silica gel-modified organic ligand;

[0074] (2) 10 g of Cu(OH)2(the molar ratio of the metal source to be coordinated to the organic ligand polybasic organic acid was 1:1.5) was dissolved in 100 mL of DMF to obtain a mixture solution of 1.03 mol / L, and the mixture solution was slowly added to the material containing silica gel-modified organic ligand obtained in step (1) for 15 min, after the dropwise addition was completed, the coordination reaction was carried out under reflux condensation at 160 °C and a rotation speed of 200 rpm for 24 h to obtain a crude product; the crude product was cooled to room temperature and filtered on a sieve with a size of 1 mm, and the sieved solid sample was washed with a solvent (DMF, 100 mL) for 3-5 times under stirring to remove unreacted raw material (Cu(OH)2), and then dried in a vacuum oven at 120 °C for 4 h to obtain a composite material.

[0075] Example 8

[0076] The silica gel used in this example was spherical in shape: particle size range 2-4 mm, specific surface area 305.38 m 2 / g, pore volume 1.02 cm 3 / g, average pore diameter 13.3 nm.

[0077] (1) 200 g (0.4 mol of hydroxyl groups) of silica gel was dried in an oven at 150 °C for 2 h, placed in a three-necked flask, 300 mL of N,N-dimethylformamide (DMF) was added and stirred until uniform, then 20 mL of formic acid was added as a catalyst, 100 mL of a DMF solution containing 17.4 g (0.15 mol) of maleic acid was added dropwise under stirring, and the reaction was carried out under reflux condensation at 140 °C for 4 h to obtain a material containing silica gel-modified organic ligand;

[0078] (2) 10 g of Cu(OH)2(the molar ratio of the metal source to be coordinated to the organic ligand polybasic organic acid is 1:1.5) was dissolved in 100 mL of DMF to obtain a mixture of 1.03 mol / L, and the mixture was slowly added to the silica gel modified organic ligand material obtained in step (1) for 15 min. After the dropwise addition was completed, condensation reflux was carried out at 160°C and a rotation speed of 200 rpm for 24 h to obtain a crude product. The obtained crude product was cooled to room temperature and filtered on a sieve with a size of 1 mm. The sieved solid sample was washed with a solvent (DMF, 100 mL) for 3-5 times under stirring to remove unreacted raw material Cu(OH)2. Then, the product was dried in a vacuum oven at 120°C for 4 h to obtain a composite material.

[0079] Comparative Example 1

[0080] The silica gel used has a particle size range of 2-4 mm, a specific surface area of 418.3 m 2 / g, a pore volume of 0.68 cm 2 / g, and an average pore size of 6.5 nm. The silica gel was heated to 750°C at a rate of 15°C / min and maintained at this temperature for 4 h. After cooling to room temperature, the product was removed as the final product.

[0081] Comparative Example 2

[0082] The commercially available raw material silica gel used has a particle size range of 2-4 mm, a specific surface area of 305.38 m 2 / g, a pore volume of 1.02 cm 3 / g, and an average pore size of 13.3 nm. The physicochemical properties of the product are shown in Table 1.

[0083] Comparative Example 3

[0084] The procedure of Example 1 was followed, except that the silica gel was not modified.

[0085] The structural parameters (specific surface area, pore volume, and pore size) of the products obtained in the above-prepared examples and comparative examples were determined:

[0086] The N2adsorption-desorption isotherms were determined at 77 K using an ASAP2020M+C gas adsorption instrument of Micrometics Corporation of the United States. The above products were first degassed at a temperature of 150°C and a vacuum degree of 100 mmHg for 4 h. The specific surface area of the sample was calculated by the BET method, and the pore volume and pore size distribution of the sample were calculated and analyzed by the BJH method. The results are shown in Table 1.

[0087] Table 1

[0088] Example No. Specific surface area (m 2 / g) Pore volume (cm 3 / g) Average pore size (nm) Example 1 395.44 0.94 9.47 Example 2 425.92 0.97 9.08 Example 3 400.32 0.92 9.12 Example 4 450.33 0.98 8.71 Example 5 386.2 0.95 9.84 Example 6 417.8 0.85 8.12 Example 7 409.45 0.92 8.95 Example 8 359.43 0.78 8.72 Comparative Example 1 350.24 1.01 11.5 Comparative Example 2 305.38 1.02 13.3 Comparative Example 3 1202 0.29 0.95

[0089] Test Example

[0090] Test Examples 1-6 and Comparative Test Examples 1-2

[0091] The benzene liquid in the constant temperature vessel was blown with nitrogen at a rate of 1 L / min to produce benzene vapor, and the inlet concentration of benzene was measured by the PID mode of the volatile gas analyzer, and the inlet flow rate was measured by the mass flow meter. The benzene vapor entered the 500 mL capacity adsorption tank with a height-diameter ratio of 2:1 through the buffer bottle, and was adsorbed by the products (adsorbents) obtained in Examples 1-6 and Comparative Examples 1-2 above (the amount of adsorbent was 180 g, respectively), and the tail gas was discharged from the end of the adsorption tank, and the benzene concentration of the tail gas was measured, and when the concentration reached the required value of 4 mg / m 3 After that, the adsorption was stopped, and desorption was carried out for 15 min by a dry vacuum pump, and at the end of the desorption, the back flushing valve was opened for 5 min for back flushing, and the adsorption and desorption processes were repeated 5 times until the adsorption time was basically unchanged each time, and the adsorption weight gain and desorption weight loss of the adsorbent were weighed, and the adsorption capacity, desorption capacity and desorption efficiency were calculated, and the test results are shown in Table 2. Among them, the adsorption capacity refers to the quotient obtained by dividing the adsorption weight gain by the adsorbent addition amount, the desorption capacity refers to the quotient obtained by dividing the desorption weight loss by the adsorbent addition amount, and the desorption efficiency refers to the percentage obtained by multiplying the quotient obtained by dividing the desorption capacity by the adsorption capacity by 100%.

[0092] Test Example 7

[0093] The test was carried out in the same manner as in Test Examples 1-6, except that the benzene liquid was replaced by cyclohexane liquid to produce cyclohexane gas, and the adsorption was stopped when the outlet concentration reached 25 g / m 3 g / m 3 , and the adsorption capacity was weighed, and then desorption and the next adsorption were carried out. And the product obtained in Example 7 was used as the adsorbent for adsorbing cyclohexane. The test results are shown in Table 2.

[0094] Test Example 8

[0095] The test was carried out in the same manner as in Test Examples 1-6, except that the benzene liquid was replaced by cyclohexane liquid to produce cyclohexane gas, and the adsorption was stopped when the outlet concentration reached 25 g / m 3 g / m 3 , and the adsorption capacity was weighed, and then desorption and the next adsorption were carried out. And the product obtained in Example 8 was used as the adsorbent for adsorbing cyclohexane. The test results are shown in Table 2.

[0096] Test Example 9

[0097] The test was carried out in the same manner as in Test Examples 1-6, except that the benzene liquid was replaced by cyclohexane liquid to produce cyclohexane gas, and the adsorption was stopped when the outlet concentration reached 25 g / m 3 g / m 3 , and the adsorption capacity was weighed, and then desorption and the next adsorption were carried out. And the product obtained in Example 1 was used as the adsorbent for adsorbing cyclohexane. The test results are shown in Table 2.

[0098] Table 2

[0099]

[0100]

[0101] The preferred embodiments of the present application have been described in detail, but the present application is not limited thereto. Various simple modifications can be made to the technical solutions of the present application within the technical concept of the present application, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be considered as disclosed by the present application and fall within the protection scope of the present application.

Claims

1. A method for preparing composite materials, characterized in that, The method includes the following steps: (1) In the presence of a catalyst and a first solvent, silica gel is brought into contact with an organic ligand, wherein the contact temperature is 80-160°C and the contact time is 1-10h; (2) The silicone-modified organic ligand is subjected to a coordination reaction with the metal source to be coordinated to obtain the composite material, wherein the temperature of the coordination reaction is 80-160℃ and the time is 15-30h; The amount of silica gel and organic ligand used is such that the molar ratio of hydroxyl groups on the surface of silica gel to the molar ratio of organic ligand is (1-5):1; The organic ligand is selected from pyromellitic acid and / or terephthalic acid; The molar ratio of the metal source to be coordinated to the silicone-modified organic ligand is 1:(0.3-5). The metal source to be coordinated is selected from at least one of Cu(OH)2, Cu(NO3)2 and their hydrates; The catalyst is selected from one of formic acid, acetic acid, diethylamine, triethylamine and pyridine; the weight ratio of the silica gel to the catalyst is (3-25):1; the first solvent is selected from at least one of N,N-dimethylformamide, butyl acetate, acetonitrile, ethanol, isopropanol and toluene.

2. The method according to claim 1, wherein, In step (1), the contact time is 2-6 hours.

3. The method according to claim 1, wherein, The silica gel is spherical silica gel and / or amorphous silica gel, with a particle size range of 1-5 mm and a specific surface area of ​​200-700 m². 2 / g; average pore size 2-20nm; pore volume 0.5-2cm³ 3 / g.

4. The method according to claim 1, wherein, The amount of silica gel and organic ligand used is such that the molar ratio of the hydroxyl groups on the surface of the silica gel to the organic ligand is (2-3):1; And / or, the silica gel has a particle size range of 2-4 mm and a specific surface area of ​​300-500 m². 2 / g; average pore size 4-10nm; pore volume 0.8-1.5cm³ 3 / g.

5. The method according to claim 1, wherein, The amount of the first solvent used is 0.2-5 mL relative to 1 g of silica gel.

6. The method according to claim 1 or 5, wherein, The catalyst is formic acid or triethylamine; And / or, the weight ratio of the silica gel to the catalyst is (5-20):1; And / or, the first solvent is selected from N,N-dimethylformamide and / or acetonitrile; And / or, relative to 1g of silica gel, the amount of the first solvent used is 0.5-2mL.

7. The method according to any one of claims 1-5, wherein, The coordination reaction takes 20-24 hours.

8. The method according to any one of claims 1-5, wherein, The molar ratio of the metal source to be coordinated to the silicone-modified organic ligand is 1:(1-3).

9. The method according to claim 8, wherein, The coordination reaction is carried out in the presence of a second solvent, wherein the second solvent is selected from at least one of N,N-dimethylformamide, butyl acetate, acetonitrile, ethanol, isopropanol and toluene.

10. The method according to claim 9, wherein, The second solvent is selected from N,N-dimethylformamide and / or acetonitrile.

11. The composite material obtained by the method according to any one of claims 1-10.

12. The application of the composite material according to claim 11 in gas adsorption.

13. The application according to claim 12, wherein, The application is in the absorption of benzene compounds.

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