Silica gel modified adsorbent as well as preparation method and application thereof

Abstract

The invention discloses a silica gel modified adsorbent as well as a preparation method and application thereof, and the method comprises the following steps: (1) activating a silica gel adsorbent to obtain an activated silica gel adsorbent; (2) mixing the activated silica gel adsorbent, 3-ureido propyl trimethoxy silane and methylbenzene, heating and stirring under the protection of nitrogen, and then filtering, washing and drying to obtain an intermediate product; and (3) mixing the intermediate product, ethylenediamine tetraacetic acid dianhydride and N-methyl-2-pyrrolidone, heating and stirring under the protection of nitrogen, and then filtering, washing and drying to obtain the modified silica gel adsorbent. Therefore, the method is easy to operate, low in cost and low in energy consumption, and the prepared modified silica gel adsorbent has large adsorption capacity.

Description

Technical Field

[0001] The invention relates to the field of adsorption technology, and in particular to a silica gel modified adsorbent and a preparation method and application thereof. Background Art

[0002] Ultra-clean high-purity methanol, an ultra-clean high-purity reagent commonly used in cleaning agents in the electronics industry, is mainly used as a substrate cleaning agent in the electronics industry and as a solvent for etching agents in wet etching processes. In my country, the market for ultra-clean high-purity reagents for the electronics industry, including high-purity methanol, presents a situation of "high-end dependence on imports and fierce competition in low-end products". Domestic high-purity methanol generally has a low purity level and general quality; while more than 90% of the high-end products of ultra-clean high-purity methanol used in China come from imported products. Ultra-clean high-purity methanol is a refined product obtained by further purification of industrial methanol. For the domestic industrial methanol industry with overcapacity, developing high-end ultra-clean high-purity methanol production technology is undoubtedly a good way to extend the industrial chain, enhance product value, increase competitive advantages, and expand the market. The process of preparing ultra-clean high-purity methanol by purifying industrial methanol is mainly divided into two parts: one is to remove organic impurities by distillation, and the other is to remove metal ion impurities by adsorption or membrane separation. Among them, compared with membrane separation and other methods, the separation of metal ions by adsorption has the advantages of low cost, low energy consumption, easy operation, and good removal performance. Therefore, the process of removing metal ions from methanol by adsorption has good prospects.

[0003] Chinese patent CN115106067A discloses the preparation and application of a functional organic silica gel material, wherein a siloxane monomer and an organic monomer containing a functional group are subjected to a free radical polymerization reaction in the presence of a free radical initiator and a solvent to obtain a copolymer containing siloxane and a functional group, and then the copolymer is subjected to a hydrolysis and polycondensation reaction in the presence of water and a catalyst to obtain a functional organic silica gel material, which can be used for the adsorption of metal ions. Chinese patent CN113426417A discloses the application of a silica gel adsorbent modified with an aminocarboxyl ligand, which can also be used for the adsorption of metal ions.

[0004] Silica gel has good stability, is easy to modify and analyze, and has a low production cost. As an excellent adsorption material, it has received widespread attention. The application of modified silica gel in existing patents is mostly focused on the adsorption of metal ions in wastewater, and there has been no report on its use in removing metal ions from methanol. This is a technical disadvantage. Summary of the invention

[0005] The present invention aims to make up for the above technical shortcomings. To this end, according to the characteristics of adsorption separation in methanol medium, a modified silica gel adsorbent and its preparation method and application are proposed. The method is easy to operate, low in cost and energy consumption, and the prepared modified silica gel adsorbent has a large adsorption capacity.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0007] In the first aspect of the present invention, the present invention provides a method for preparing a modified silica gel adsorbent. According to an embodiment of the invention, the method comprises:

[0008] (1) activating a silica gel adsorbent to obtain an activated silica gel adsorbent;

[0009] (2) mixing the activated silica gel adsorbent, 3-ureidopropyltrimethoxysilane and toluene, heating and stirring under nitrogen protection, and then filtering, washing and drying to obtain an intermediate product;

[0010] (3) The intermediate product, ethylenediaminetetraacetic acid dianhydride and N-methyl-2-pyrrolidone are mixed, heated and stirred under nitrogen protection, and then filtered, washed and dried to obtain a modified silica gel adsorbent.

[0011] In the second aspect of the present invention, the present invention provides a modified silica gel adsorbent. According to the embodiment of the present invention, the modified silica gel adsorbent is prepared by the method described in the first aspect of the present invention.

[0012] In the third aspect of the present invention, the present invention provides a method for removing metal ions from methanol by adsorption. According to the embodiment of the invention, the adsorption comprises: loading the modified silica gel adsorbent described in the second aspect of the present invention into an adsorption column, allowing the methanol solution containing metal ions to flow through the adsorption column and fully contact with the modified silica gel adsorbent.

[0013] The technical solution of the present invention has the following advantages compared with the prior art:

[0014] (1) The present invention adopts a heterogeneous method to prepare a modified silica gel adsorbent, which is simple to operate, low in cost, and mild in reaction conditions. The pore size of the adsorbent can be controlled by controlling the amount of 3-ureidopropyltrimethoxysilane and ethylenediaminetetraacetic acid dianhydride added, thereby realizing mass production;

[0015] (2) The modified silica gel adsorbent prepared by the method of the present invention has a high adsorption capacity, and the functional groups are tightly combined with the matrix material through covalent bonds. Through the synergistic effect of physical and chemical adsorption, efficient adsorption and separation of metal ions in methanol is achieved;

[0016] (3) The modified silica gel adsorbent adsorption and removal of metal ions in methanol adopts dynamic adsorption, which is convenient for large-scale application in industrial production. The method has a short process flow, simple operation, is green and environmentally friendly, and has a significant adsorption effect.

[0017] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. DETAILED DESCRIPTION

[0018] The embodiments of the present invention are described in detail below, which are intended to be used to explain the present invention, but cannot be understood as limiting the present invention. The embodiments described below are exemplary, which are intended to be used to explain the present invention, but cannot be understood as limiting the present invention.

[0019] In the first aspect of the present invention, the present invention provides a method for preparing a modified silica gel adsorbent. According to an embodiment of the invention, the method comprises:

[0020] S100: activating the silica gel adsorbent to obtain an activated silica gel adsorbent.

[0021] In some embodiments, the activation treatment comprises: mixing the silica gel adsorbent and acid solution, heating and refluxing at 115-125° C. for 2-5 hours, then washing the reaction solution to neutrality, and finally drying to obtain the activated silica gel adsorbent.

[0022] In some embodiments, the mixing ratio of the silica gel adsorbent and the acid solution is 1 g: (3-5) mL.

[0023] In some embodiments, the acid solution is a 65-68 wt % nitric acid solution.

[0024] In some embodiments, the diameter of the silica gel adsorbent is 0.18-0.85 mm.

[0025] In some embodiments, the drying comprises: first placing in an electric hot air drying oven for drying at 120-200° C. for 5-10 hours, and then placing in a vacuum drying oven for drying at 100-120° C. for 12-24 hours.

[0026] S200: The activated silica gel adsorbent, 3-ureidopropyltrimethoxysilane and toluene are mixed, heated and stirred under nitrogen protection, and then filtered, washed and dried to obtain an intermediate product.

[0027] In this step, the specific reaction process is as follows:

[0028]

[0029] In some embodiments, the mixing ratio of the activated silica gel adsorbent, 3-ureidopropyltrimethoxysilane and toluene is 1 g: (0.3-0.5) mL: (10-20) mL.

[0030] In some embodiments, the drying temperature is 60-70° C. and the drying time is 24-48 hours;

[0031] In some embodiments, the heating temperature is 75-85° C. and the heating time is 24-48 hours.

[0032] S300: The intermediate product, ethylenediaminetetraacetic acid dianhydride and N-methyl-2-pyrrolidone are mixed, heated and stirred under nitrogen protection, and then filtered, washed and dried to obtain a modified silica gel adsorbent.

[0033] In this step, the specific reaction process is as follows:

[0034]

[0035] In some embodiments, the drying temperature is 60-70° C. and the drying time is 24-48 hours;

[0036] In some embodiments, the heating temperature is 75-85° C. and the heating time is 24-48 hours.

[0037] In some embodiments, the intermediate product, ethylenediaminetetraacetic acid dianhydride (hereinafter referred to as "EDTA dianhydride") and N-methyl-2-pyrrolidone are mixed in a ratio of 1 g: (0.1-0.6) g: (8-20) mL.

[0038] In the second aspect of the present invention, the present invention provides a modified silica gel adsorbent. According to the embodiment of the present invention, the modified silica gel adsorbent is prepared by the method described in the first aspect of the present invention.

[0039] In some embodiments, the structure of the modified silica gel adsorbent is:

[0040] Among them, SG is silica gel particles.

[0041] In some embodiments, the pore volume of the modified silica gel adsorbent is 0.80 to 0.95 cm 3 / g.

[0042] In some embodiments, the specific surface area of ​​the modified silica gel adsorbent is 210 to 350 m 2 / g.

[0043] In some embodiments, the nitrogen content of the modified silica gel adsorbent is 5.5-6.5 wt %.

[0044] In some embodiments, the carbon content of the modified silica gel adsorbent is 20.7-24.4 wt %.

[0045] It should be noted that the features and advantages described above for the method for preparing the modified silica gel adsorbent are also applicable to the modified silica gel adsorbent and will not be described in detail here.

[0046] In the third aspect of the present invention, the present invention provides a method for removing metal ions from methanol by adsorption. According to the embodiment of the invention, the adsorption comprises: loading the modified silica gel adsorbent described in the second aspect of the present invention into an adsorption column, allowing the methanol solution containing metal ions to flow through the adsorption column and fully contact with the modified silica gel adsorbent.

[0047] In some embodiments, the metal ions include at least one of copper ions, iron ions, and nickel ions.

[0048] In some embodiments, the concentration of the metal ions is 0.1-5 mmol / L.

[0049] In some embodiments, the liquid space velocity of the methanol solution is 1 to 50 h -1 .

[0050] In some embodiments, the adsorption temperature is 20-40°C.

[0051] In some embodiments, the adsorption pressure of the adsorption is 0.5 to 1.5 bar.

[0052] It should be noted that the characteristics and advantages described above for the modified silica gel adsorbent and its preparation method are also applicable to the method for removing metal ions from methanol by adsorption, and will not be described in detail here.

[0053] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0054] Unless otherwise specified, the preparation processes in the following examples and comparative examples are all conventional means in the prior art, and the raw materials or instruments used without indicating the manufacturer are all conventional products that can be purchased commercially. Therefore, no further description is given.

[0055] Example 1

[0056] (1) 5.00 g of silica gel with a particle diameter of 0.250 to 0.425 mm was placed in a round-bottom flask, 20 mL of 65 wt% nitric acid was added, and the mixture was stirred and refluxed at 120° C. for 3 h. The mixture was filtered, washed with deionized water until neutral, and dried in an electric hot air drying oven at 200° C. for 10 h, and then dried in a vacuum drying oven at 120° C. for 24 h.

[0057] (2) 0.650 mL of 3-ureidopropyltrimethoxysilane was mixed with 25 mL of toluene solvent, and 2.00 g of activated silica gel was added. The mixture was heated and stirred at 80° C. for 24 h under N2 protection to obtain a mixture containing an intermediate product. The intermediate product mixture was filtered to obtain a solid. The solid was washed with toluene, ethanol, and water respectively until the filtrate was colorless and clear. Finally, the washed solid was dried in a vacuum drying oven at 60° C. for 24 h to obtain a dry intermediate product.

[0058] (3) 0.20 g of EDTA dianhydride was mixed with 25 mL of N-methyl-2-pyrrolidone, and 2.6 g of the intermediate product was added. The mixture was heated and stirred at 80° C. for 24 h under N2 protection to obtain a mixture containing a modified silica gel adsorbent. The mixture containing the modified silica gel adsorbent was filtered to obtain a solid. The solid was washed with N-methyl-2-pyrrolidone, ethanol, and water respectively until the filtrate was colorless and clear. Finally, the washed solid was dried in a vacuum drying oven at 60° C. for 24 h to obtain a modified silica gel adsorbent.

[0059] Example 2

[0060] The amount of EDTA dianhydride added was 0.25 g, and the rest was the same as in Example 1. The prepared modified silica gel adsorbent had a nitrogen content of 6.01 wt%, a carbon content of 21.16 wt%, and a specific surface area of ​​328.73 m 2 ·g -1 , pore volume is 0.84cm 3 ·g -1 .

[0061] Example 3

[0062] The addition amount of EDTA dianhydride is 1.20 g, and the rest is the same as in Example 2.

[0063] Example 4

[0064] The amount of 3-ureidopropyltrimethoxysilane added was 0.60 mL, and the rest was the same as in Example 2.

[0065] Example 5

[0066] The amount of 3-ureidopropyltrimethoxysilane added was 1.00 mL, and the rest was the same as in Example 2.

[0067] Example 6

[0068] The diameter of the silica gel particles is 0.425-0.850 mm, and the rest is the same as in Example 2.

[0069] Example 7

[0070] The diameter of the silica gel particles is 0.180-0.250 mm, and the rest is the same as in Example 2.

[0071] Comparative Example 1

[0072] The silica gel particles with a diameter of 0.250 to 0.425 mm are unmodified.

[0073] Application Example 1

[0074] The silica gel adsorbents obtained in each example and comparative example were loaded into an adsorption column (with a diameter of 4 mm) to prepare 3 mmol·L -1 The methanol solution of CuSO4 was heated for 50 h. -1 The liquid space velocity flows through the adsorption column to fully contact with the modified silica gel adsorbent. The temperature in the adsorption column is 30°C and the adsorption pressure is 1 bar.

[0075] Take the methanol sample at the bottom outlet of the adsorption column for testing and obtain the outlet concentration C at time t. t The adsorption amount was calculated according to the following formula (1):

[0076]

[0077] Where: q e is the adsorption amount, unit: mmol·g -1 ;q v is the volume flow rate of methanol solution, unit L·min -1 ; w is the mass of the adsorbent, in g; t is the adsorption time, in min; C0 is the initial concentration of the solution, in mmol·L -1 ; C t is the outlet concentration at time t, in mmol·L -1 The relevant data of the adsorption results are shown in Table 1:

[0078] Table 1

[0079]

[0080] Note: Since the penetration time of Comparative Example 1 was very short (less than 1 min), sufficient outlet samples could not be collected for testing at this time.

[0081] Application Example 2

[0082] The modified silica gel adsorbent prepared in Example 2 and the adsorbent prepared in Comparative Example 1 were loaded into an adsorption column to prepare 0.1 mmol·L-1 The methanol solution of CuSO4 was heated for 50 h. -1 The liquid space velocity flows through the adsorption column to fully contact with the silica gel adsorbent. The temperature in the adsorption column is 30°C and the adsorption pressure is 1 bar.

[0083] Take the methanol sample at the bottom outlet of the adsorption column for testing and obtain the outlet concentration C at time t. t The adsorption amount was calculated according to formula (1), and the relevant data comparison of the results is shown in Table 2:

[0084] Table 2

[0085]

[0086] It can be seen from the comparison results of the embodiments and comparative examples that the technical solution provided by the present invention has well solved the problem of low adsorption of metal ions by ordinary commercial silica gel and achieved good technical effects.

[0087] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0088] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A method for preparing a modified silica gel adsorbent, characterized in that: The method comprises: (1) activating a silica gel adsorbent to obtain an activated silica gel adsorbent; (2) mixing the activated silica gel adsorbent, 3-ureidopropyltrimethoxysilane and toluene, heating and stirring under nitrogen protection, and then filtering, washing and drying to obtain an intermediate product; (3) The intermediate product, ethylenediaminetetraacetic acid dianhydride and N-methyl-2-pyrrolidone are mixed, heated and stirred under nitrogen protection, and then filtered, washed and dried to obtain a modified silica gel adsorbent.

2. The method according to claim 1, characterized in that In step (1), the activation treatment comprises: mixing the silica gel adsorbent and acid solution, heating and refluxing at 115-125° C. for 2-5 hours, then washing the reaction solution to neutrality, and finally drying to obtain the activated silica gel adsorbent; and / or, The mixing ratio of the silica gel adsorbent and the acid solution is 1 g: (3-5) mL; and / or, The acid solution is a 65-68wt% nitric acid solution; and / or, The diameter of the silica gel adsorbent is 0.18 to 0.85 mm; and / or, The drying comprises: firstly placing in an electric hot air drying oven for drying at 120-200° C. for 5-10 hours, and then placing in a vacuum drying oven for drying at 100-120° C. for 12-24 hours.

3. The method according to claim 1, characterized in that In step (2), the mixing ratio of the activated silica gel adsorbent, 3-ureidopropyltrimethoxysilane and toluene is 1 g: (0.3-0.5) mL: (10-20) mL.

4. The method according to claim 1, characterized in that In step (2) and / or step (3), the drying temperature is 60-70° C. and the drying time is 24-48 hours; and / or, In step (2) and / or step (3), the heating temperature is 75 to 85° C. and the heating time is 24 to 48 hours.

5. The method according to claim 1, characterized in that In step (3), the intermediate product, ethylenediaminetetraacetic acid dianhydride and N-methyl-2-pyrrolidone are mixed in a ratio of 1 g: (0.1-0.6) g: (8-20) mL.

6. A modified silica gel adsorbent, characterized in that: The method is prepared by any one of claims 1 to 5.

7. The modified silica gel adsorbent according to claim 1, characterized in that: The structure of the modified silica gel adsorbent is:

8. The modified silica gel adsorbent according to claim 6, characterized in that: The pore volume of the modified silica gel adsorbent is 0.80 to 0.95 cm 3 / g; and / or, Specific surface area is 210~350m 2 / g; and / or, The nitrogen content is 5.5 to 6.5 wt %; and / or, The carbon content is 20.7-24.4wt%.

9. A method for removing metal ions from methanol by adsorption, characterized in that: The adsorption comprises: loading the modified silica gel adsorbent according to any one of claims 6 to 8 into an adsorption column, and allowing the methanol solution containing metal ions to flow through the adsorption column to fully contact with the modified silica gel adsorbent.

10. The method according to claim 9, characterized in that The metal ions include: at least one of copper ions, iron ions and nickel ions; and / or, The concentration of the metal ions is 0.1 to 5 mmol / L; and / or, The liquid space velocity of the methanol solution is 1 to 50 h -1 and / or, The adsorption temperature is 20-40°C; and / or, The adsorption pressure is 0.5-1.5 bar.

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