A modified silica gel, its preparation method and adsorption application method

Abstract

The application provides a modified silica gel, a preparation method and an adsorption application method thereof, and the preparation raw materials of the modified silica gel include silica gel, an ionic liquid, an inorganic acid aqueous solution, a solvent, triethylamine, and wherein, n is an integer selected from 0-6, and R1 is selected from C1-C 10 alkyl. The modified silica gel prepared by the application has high surface functional group content and good adsorption selectivity for metal ions.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of organic synthesis, in particular to a modified silica gel, a preparation method and an adsorption application method thereof. BACKGROUND

[0002] Metal residues in industrial waste liquid not only cause environmental pollution, but also pose a potential threat to human health if left in drugs. Therefore, metal removal, adsorption and recycling have become an indispensable industrial process in the fields of economy, health and environmental protection.

[0003] Metal adsorbents are considered one of the most promising methods due to their high efficiency, stability, low cost and simple process. With China gradually becoming a global manufacturing leader, its consumption of precious metals has risen to the top of the world. Under this background, metal recycling and recycling or adsorption are of great significance to reduce production costs and promote environmental protection, and have become a hot research field of common concern in academia and industry in recent years.

[0004] Currently, modified silica gel is a commonly used adsorbent in metal recovery and adsorption technology. Modified silica gel reacts with certain active groups on the surface of silica gel to bond specific organic groups to the surface of silica gel. With the support of the silica gel skeleton, these bonded organic groups can complex metal ions including palladium, gold, platinum, rhodium, potassium, sodium, calcium, magnesium, etc., thereby achieving heavy metal adsorption.

[0005] However, the modified silica gel in the prior art still has the problems of low activity and limited metal adsorption capacity. This to some extent limits its application effect and efficiency in the field of metal recovery or adsorption. Therefore, it is of great significance to develop a modified silica gel with higher activity and stronger metal adsorption capacity, as well as a preparation method and an adsorption application method thereof.

[0006] Based on this, the present application provides a modified silica gel, a preparation method and an adsorption application method thereof. SUMMARY

[0007] The purpose of the present application is to provide a modified silica gel, a preparation method and an adsorption application method thereof, which solve the problems of low activity and weak metal adsorption capacity of the modified silica gel in the prior art.

[0008] In one aspect, the present application provides a modified silica gel, and the preparation raw materials include silica gel, ionic liquid, inorganic acid aqueous solution, solvent, triethylamine and wherein n is an integer selected from 0-6, R1 is selected from C1-C 10 alkyl.

[0009] Further, the silica gel, ionic liquid, inorganic acid aqueous solution, solvent, triethylamine and The amount ratio of the silica gel, the ionic liquid, the aqueous inorganic acid solution, the solvent, the triethylamine and the modifier is (90-110) g:(90-110) g:(90-100) g:(450-550) mL:(4.5-5.5) g:(50-70) g.

[0010] Further, the ionic liquid includes any one of 1-ethyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium bromide, 1-butyl-3-methylimidazolium chloride and 1-ethyl-3-methylimidazolium trifluoroacetate.

[0011] Further, n is selected from 0, 1, 2 or 3; and R1 is selected from methyl, ethyl, propyl or butyl.

[0012] Further, the inorganic acid includes any one of hydrochloric acid, nitric acid and sulfuric acid.

[0013] Further, the mass concentration of the inorganic acid is 4-6%.

[0014] In another aspect, the present application provides a preparation method of modified silica gel, the steps comprising:

[0015] (1) silica gel pretreatment: uniformly mixing the silica gel and the ionic liquid, and adding the aqueous inorganic acid solution to stir at 100-150℃; cooling to room temperature, filtering, washing with water until neutral, and drying to obtain the pretreated silica gel;

[0016] (2) reacting the pretreated silica gel in the solvent and to obtain the modified silica gel.

[0017] Further, the amount ratio of the silica gel, the ionic liquid, the aqueous inorganic acid solution, the solvent, the triethylamine and the modifier is (90-110) g:(90-110) g:(90-100) g:(450-550) mL:(4.5-5.5) g:(50-70) g.

[0018] Further, the ionic liquid includes any one of 1-ethyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium bromide, 1-butyl-3-methylimidazolium chloride and 1-ethyl-3-methylimidazolium trifluoroacetate.

[0019] Further, n is selected from 0, 1, 2 or 3; and R1 is selected from methyl, ethyl, propyl or butyl.

[0020] Further, the inorganic acid includes any one of hydrochloric acid, nitric acid and sulfuric acid.

[0021] Further, the mass concentration of the inorganic acid is 4-6%.​

[0022] Further, the stirring in the step (1) is performed for 1.5-2.5h.

[0023] Further, the reaction in the step (2) is a heating reflux reaction, and the reaction time is 18-22h.

[0024] In another aspect, the modified silica gel of the present application is applied to the adsorption of metal ions.

[0025] The present application has the following beneficial effects:

[0026] The present application improves the number and distribution of the hydroxyl groups on the surface of the silica gel by simultaneously using an ionic liquid and an inorganic acid for activation in the above-mentioned pretreatment process of the silica gel, and thus the modified silica gel prepared by the subsequent reaction of the pretreated silica gel has good adsorption and selection performance for metal ions. DETAILED DESCRIPTION

[0027] The technical solutions of the present application will be described clearly and completely below. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the present application.

[0028] The present application provides a preparation method of modified silica gel, and the steps include:

[0029] (1) silica gel pretreatment: uniformly mix the silica gel and the ionic liquid, and add the inorganic acid aqueous solution to stir at 100-150℃; cool to room temperature, filter, wash with water until neutral, and dry to obtain the pretreated silica gel;

[0030] (2) react the pretreated silica gel in a solvent and to obtain the modified silica gel, and n is an integer selected from 0-6, and R1 is an alkyl group selected from C1-C 10 .

[0031] The amount ratio of the silica gel, the ionic liquid, the inorganic acid aqueous solution, the solvent, the triethylamine and is (90-110)g:(90-110)g:(90-100)g:(450-550)mL:(4.5-5.5)g:(50-70)g; the ionic liquid is any one of 1-ethyl-3-methylimidazole tetrafluoroborate, 1-butyl-3-methylimidazole tetrafluoroborate, 1-butyl-3-methylimidazole bromide, 1-butyl-3-methylimidazole chloride and 1-ethyl-3-methylimidazole trifluoroacetate; and the inorganic acid is any one of hydrochloric acid, nitric acid and sulfuric acid.

[0032] The silica gel used in the present application is commercially available silica gel.

[0033] Example 1

[0034] The present example provides a modified silica gel,

[0035] 100 grams of 1-ethyl-3-methylimidazole tetrafluoroborate, 100 grams of silica gel with a particle size of 200-300 mesh, 100 grams of sulfuric acid with a mass concentration of 5% were mixed and stirred uniformly, heated to 100°C and stirred for 2 hours, cooled to room temperature, filtered, washed with water, and dried at 80°C under reduced pressure for 6 hours to obtain 96 grams of ion liquid modified silica gel carrier.

[0036] Under nitrogen protection, the above silica gel carrier, 500 milliliters of toluene, 5 grams of triethylamine, 60 grams of 3-mercaptopropyltrimethoxysilane were added to a three-necked flask, heated to reflux for 20 hours, cooled to 25°C, filtered, washed with toluene, ethanol, and water, and dried at 80°C under reduced pressure for 12 hours to obtain 98 grams of modified silica gel.

[0037] Example 2

[0038] Referring to the preparation method of Example 1, except that 100 grams of sulfuric acid with a content of 5% was replaced by 100 grams of nitric acid with a content of 5%, 99 grams of modified silica gel was prepared.

[0039] Example 3

[0040] Referring to the preparation method of Example 1, except that 100 grams of sulfuric acid with a content of 5% was replaced by 100 grams of nitric acid with a content of 5%, 99 grams of modified silica gel was prepared.

[0041] Example 4

[0042] Referring to the preparation method of Example 1, except that 100 grams of sulfuric acid with a content of 5% was replaced by 50 grams of sulfuric acid with a content of 5%, 97 grams of modified silica gel was prepared.

[0043] Example 5

[0044] Referring to the preparation method of Example 1, except that 100 grams of sulfuric acid with a content of 5% was replaced by 150 grams of sulfuric acid with a content of 5%, 97 grams of modified silica gel was prepared.

[0045] Example 6

[0046] Referring to the preparation method of Example 1, except that 100 grams of 1-ethyl-3-methylimidazole tetrafluoroborate was replaced by 50 grams of 1-ethyl-3-methylimidazole tetrafluoroborate, 99 grams of modified silica gel was prepared.

[0047] Example 7

[0048] Referring to the preparation method of Example 1, except that 100 grams of 1-ethyl-3-methylimidazole tetrafluoroborate is replaced by 150 grams of 1-ethyl-3-methylimidazole tetrafluoroboric acid, modified silica gel 98 grams is prepared.

[0049] Example 8

[0050] Referring to the preparation method of Example 1, except that 100 grams of 1-ethyl-3-methylimidazole tetrafluoroboric acid is replaced by 100 grams of 1-ethyl-3-methylimidazole trifluoroacetic acid, modified silica gel 97 grams is prepared.

[0051] Comparative Example 1

[0052] 100 grams of 1-ethyl-3-methylimidazole tetrafluoroboric acid, 100 grams of 200-300 mesh silica gel are mixed and stirred uniformly, heated to 100℃ and stirred for 2 hours, cooled to room temperature, filtered, washed with water, and dried to obtain 96 grams of ion liquid modified silica gel carrier.

[0053] Under nitrogen protection, the above silica gel carrier, 500 milliliters of toluene, 5 grams of triethylamine, 3-mercapto propyl trimethoxysilane 60 grams are added to a three-necked flask, heated to reflux for 20 hours, cooled, filtered, washed with toluene, ethanol, and water, and dried to obtain 97 grams of modified silica gel.

[0054] Comparative Example 2

[0055] 100 grams of 200-300 mesh silica gel, 100 grams of 5% sulfuric acid are mixed and stirred uniformly, heated to 100℃ and stirred for 2 hours, cooled to room temperature, filtered, washed with water, and dried to obtain 96 grams of ion liquid modified silica gel carrier.

[0056] Under nitrogen protection, the above silica gel carrier, 500 milliliters of toluene, 5 grams of triethylamine, 3-mercapto propyl trimethoxysilane 60 grams are added to a three-necked flask, heated to reflux for 20 hours, cooled, filtered, washed with toluene, ethanol, and water, and dried to obtain 95 grams of modified silica gel.

[0057] Comparative Example 3

[0058] 100 grams of 200-300 mesh silica gel, 500 milliliters of toluene, 5 grams of triethylamine, 3-mercapto propyl trimethoxysilane 60 grams are added to a three-necked flask, heated to reflux for 20 hours, cooled, filtered, washed with toluene, ethanol, and water, and dried to obtain 90 grams of modified silica gel.

[0059] The modified silica gel of the examples and comparative examples of the present application has the following metal ion adsorption performance experiment:

[0060] Take 100 milliliters of heavy metal aqueous solution (metal Pd 2+ solution, initial concentration 20 ppm, metal Cu 2+ solution, initial concentration 20 ppm, metal Na + solution, initial concentration 20 ppm), respectively, 0.2 grams of the modified silica gel prepared in the above examples or comparative examples is added as an adsorbent, and the mixture is stirred at 25°C for half an hour, filtered, and the metal content in the mother liquor is determined. The experimental data are shown in the following table:

[0061]

[0062]

[0063] Comparing Example 1 and Example 8, the silica gel carrier prepared by using 1-ethyl-3-methyl imidazole trifluoroacetate has improved the number and distribution of the surface hydroxyl groups, and the modified silica gel prepared therefrom has greatly improved the adsorption performance for sodium ions.

[0064] Comparing Example 1 and Example 2, the silica gel carrier prepared by using nitric acid instead of sulfuric acid has improved the number and distribution of the surface hydroxyl groups, and the modified silica gel prepared therefrom has greatly improved the adsorption performance for palladium ions.

[0065] Finally, it should be noted that the above examples are only used to illustrate the present application and not to limit the technical solutions described in the present application; those skilled in the art should understand that the present application can still be modified or replaced equivalently; and all technical solutions and improvements that do not deviate from the spirit and scope of the present application should be covered in the scope of the claims of the present application.

Claims

1. A modified silica gel, characterized by, The preparation steps of the modified silica gel include: (1) silica gel pretreatment: 100 grams of 1-ethyl-3-methyl imidazole tetrafluoroborate, 100 grams of 200-300 mesh silica gel, 100 grams of 5% nitric acid are mixed and stirred uniformly, heated to 100°C and stirred for 2 hours, cooled to room temperature, filtered, washed with water, and dried at 80°C under reduced pressure for 6 hours; (2) Under nitrogen protection, the above silica gel carrier is added to a three-necked flask, 500 ml of toluene, 5 grams of triethylamine, and 60 grams of 3-mercaptopropyl trimethoxysilane are added, heated to reflux for 20 hours, cooled to 25°C, filtered, washed with toluene, ethanol, and water, and dried at 80°C under reduced pressure for 12 hours.

2. A method of preparing a modified silica gel according to claim 1, characterized by the steps of including: (1) silica gel pretreatment: 100 grams of 1-ethyl-3-methyl imidazole tetrafluoroborate, 100 grams of 200-300 mesh silica gel, 100 grams of 5% nitric acid are mixed and stirred uniformly, heated to 100°C and stirred for 2 hours, cooled to room temperature, filtered, washed with water, and dried at 80°C under reduced pressure for 6 hours; (2) Under nitrogen protection, the above silica gel carrier is added to a three-necked flask, 500 ml of toluene, 5 grams of triethylamine, and 60 grams of 3-mercaptopropyl trimethoxysilane are added, heated to reflux for 20 hours, cooled to 25°C, filtered, washed with toluene, ethanol, and water, and dried at 80°C under reduced pressure for 12 hours.

3. The modified silica gel of claim 1 is used in the adsorption of metal ions.

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