Modified silica gel as well as preparation method and adsorption application method thereof

Abstract

The invention provides modified silica gel as well as a preparation method and an adsorption application method thereof, the modified silica gel is prepared from the following raw materials: silica gel, ionic liquid, an inorganic acid aqueous solution, a solvent, triethylamine and # imgabs0, n is selected from an integer of 0-6, and R1 is selected from C1-C10 alkyl. The prepared modified silica gel is high in surface functional group content and has good adsorption selectivity on metal ions.

Description

Technical Field

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

[0002] Metal residues in industrial wastewater not only cause environmental pollution, but also pose a potential threat to human health if left in medicines. Therefore, the removal, adsorption and recovery of metals 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. As China gradually becomes a leader in the global manufacturing industry, its consumption of precious metals has jumped to the first place in the world. In this context, the recovery and recycling or adsorption of metals is of great significance for reducing corporate production costs and promoting environmental protection, and has 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 uses the hydroxyl groups on the surface of silica gel to react with certain active groups 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., to achieve the adsorption of heavy metals.

[0005] However, the modified silica gel in the prior art still has the problem of low activity and limited metal adsorption capacity. This limits its application effect and efficiency in the field of metal recovery or adsorption to a certain extent. Therefore, it is of far-reaching significance to develop a modified silica gel with higher activity and stronger metal adsorption capacity and its preparation method and adsorption application method.

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

[0007] The purpose of the present invention is to provide a modified silica gel and 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 invention provides a modified silica gel, wherein the raw materials for preparation include silica gel, ionic liquid, inorganic acid aqueous solution, solvent, triethylamine and wherein n is selected from an integer of 0-6, and R1 is selected from C1-C 10 of alkyl.

[0009] Furthermore, the silica gel, ionic liquid, inorganic acid aqueous solution, solvent, triethylamine and The dosage ratio 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] Furthermore, n is selected from 0, 1, 2 or 3; R1 is selected from methyl, ethyl, propyl or butyl.

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

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

[0014] In another aspect, the present invention provides a method for preparing modified silica gel, comprising the steps of:

[0015] (1) Silica gel pretreatment: Mix silica gel and ionic liquid evenly, add inorganic acid aqueous solution and stir at 100-150° C.; cool to room temperature, filter, wash with water until neutral, and dry to obtain pretreated silica gel;

[0016] (2) The pretreated silica gel is neutralized in a solvent The reaction is carried out to obtain modified silica gel.

[0017] Furthermore, the silica gel, ionic liquid, inorganic acid aqueous solution, solvent, triethylamine and The dosage ratio 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] Furthermore, n is selected from 0, 1, 2 or 3; R1 is selected from methyl, ethyl, propyl or butyl.

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

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

[0022] Furthermore, the reaction is stirred for 1.5-2.5 hours in step (1).

[0023] Furthermore, in step (2), the reaction is carried out under heating reflux, and the reaction time is 18-22 hours.

[0024] On the other hand, the modified silica gel of the present invention is used for adsorption of metal ions.

[0025] The beneficial effects of the present invention are:

[0026] The present invention uses ionic liquid and inorganic acid for activation during the silica gel pretreatment process, thereby improving the number and distribution of hydroxyl groups on the silica gel surface, so that the modified silica gel prepared by subsequent reaction of the pretreated silica gel has good adsorption selectivity for metal ions. DETAILED DESCRIPTION

[0027] The technical solution of the present invention is described clearly and completely below. Obviously, the described embodiments are only 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.

[0028] The present invention provides a method for preparing modified silica gel, the steps comprising:

[0029] (1) Silica gel pretreatment: Mix silica gel and ionic liquid evenly, add inorganic acid aqueous solution and stir at 100-150° C.; cool to room temperature, filter, wash with water until neutral, and dry to obtain pretreated silica gel;

[0030] (2) The pretreated silica gel is neutralized in a solvent The modified silica gel is obtained by reaction, wherein n is selected from an integer of 0-6, and R1 is selected from C1-C 10 of alkyl.

[0031] Wherein, the silica gel, ionic liquid, inorganic acid aqueous solution, solvent, triethylamine and The dosage ratio 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-methylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium bromide, 1-butyl-3-methylimidazolium chloride and 1-ethyl-3-methylimidazolium trifluoroacetate; the inorganic acid is any one of hydrochloric acid, nitric acid and sulfuric acid.

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

[0033] Example 1

[0034] This embodiment provides a modified silica gel.

[0035] 100 g of 1-ethyl-3-methylimidazolium tetrafluoroborate, 100 g of 200-300 mesh silica gel, and 100 g of 5% sulfuric acid were mixed and stirred evenly, 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 g of ionic liquid-modified silica gel carrier.

[0036] Under nitrogen protection, the above silica gel carrier, 500 ml of toluene, 5 g of triethylamine, and 3-mercaptopropyltrimethoxysilane were added into a three-necked flask. 60 g, heated to reflux reaction 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 g of modified silica gel.

[0037] Example 2

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

[0039] Example 3

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

[0041] Example 4

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

[0043] Example 5

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

[0045] Example 6

[0046] Referring to the preparation method of Example 1, 99 grams of modified silica gel was prepared by replacing 100 grams of 1-ethyl-3-methylimidazolium tetrafluoroborate with 50 grams of 1-ethyl-3-methylimidazolium tetrafluoroborate.

[0047] Example 7

[0048] Referring to the preparation method of Example 1, 98 grams of modified silica gel was prepared by replacing 100 grams of 1-ethyl-3-methylimidazolium tetrafluoroborate with 150 grams of 1-ethyl-3-methylimidazolium tetrafluoroborate.

[0049] Example 8

[0050] Referring to the preparation method of Example 1, 97 g of modified silica gel was prepared by replacing 100 g of 1-ethyl-3-methylimidazolium tetrafluoroborate with 100 g of 1-ethyl-3-methylimidazolium trifluoroacetate.

[0051] Comparative Example 1

[0052] 100 g of 1-ethyl-3-methylimidazolium tetrafluoroborate and 100 g of 200-300 mesh silica gel were mixed and stirred evenly, heated to 100° C. and stirred for reaction for 2 hours, cooled to room temperature, filtered, washed with water, and dried to obtain 96 g of ionic liquid-modified silica gel carrier.

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

[0054] Comparative Example 2

[0055] 100 g of 200-300 mesh silica gel and 100 g of 5% sulfuric acid were mixed and stirred evenly, heated to 100° C. and stirred for 2 hours, cooled to room temperature, filtered, washed with water, and dried to obtain 96 g of ionic liquid-modified silica gel carrier.

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

[0057] Comparative Example 3

[0058] 100 g of 200-300 mesh silica gel, 500 ml of toluene, 5 g of triethylamine, 3-mercaptopropyltrimethoxysilane 60 g, heated to reflux for reaction for 20 hours, cooled, filtered, washed with toluene, ethanol, water, and dried to obtain 90 g of modified silica gel.

[0059] Experimental study on the metal ion adsorption performance of modified silica gel in the embodiments and comparative examples of the present invention:

[0060] Take 100 ml of heavy metal aqueous solution (metal Pd 2+ Solution, initial concentration 20ppm, metal Cu 2+ Solution, initial concentration 20ppm, metal Na + Solution, initial concentration 20ppm), add 0.2g of modified silica gel prepared in the above examples or comparative examples as adsorbent, stir thoroughly for half an hour at 25°C, filter, and measure the metal content in the mother liquor. The experimental data are shown in the following table:

[0061]

[0062]

[0063] Comparing Example 1 with Example 8, the silica gel carrier prepared by 1-ethyl-3-methylimidazolium trifluoroacetate improves the number and distribution of hydroxyl groups on the surface of the silica gel, so that the modified silica gel prepared subsequently has a significantly improved adsorption performance for sodium ions.

[0064] Comparing Example 1 with Example 2, sulfuric acid is replaced with nitric acid to prepare a silica gel carrier, which improves the number and distribution of hydroxyl groups on the silica gel surface, so that the modified silica gel prepared subsequently has greatly improved adsorption performance for palladium ions.

[0065] Finally, it should be noted that the above embodiments are only used to illustrate the present invention and are not intended to limit the technical solutions described in the present invention. Those skilled in the art should understand that the present invention can still be modified or replaced by equivalents. All technical solutions and improvements that do not depart from the spirit and scope of the present invention should be included in the scope of the claims of the present invention.

Claims

1. A modified silica gel, characterized in that: The raw materials for preparation include silica gel, ionic liquid, inorganic acid aqueous solution, solvent, triethylamine and wherein n is selected from an integer of 0-6, and R1 is selected from C1-C 10 of alkyl.

2. A modified silica gel according to claim 1, characterized in that: The silica gel, ionic liquid, inorganic acid aqueous solution, solvent, triethylamine and The dosage ratio is (90-110) g: (90-110) g: (90-100) g: (450-550) mL: (4.5-5.5) g: (50-70) g.

3. A modified silica gel according to claim 1, characterized in that: 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.

4. The modified silica gel according to claim 1, characterized in that: The n is selected from 0, 1, 2 or 3; R1 is selected from methyl, ethyl, propyl or butyl.

5. The modified silica gel according to claim 1, characterized in that: The inorganic acid includes any one of hydrochloric acid, nitric acid and sulfuric acid.

6. The modified silica gel according to claim 1, characterized in that: The mass concentration of the inorganic acid is 4-6%.

7. A method for preparing the modified silica gel according to any one of claims 1 to 6, characterized in that the steps include: (1) Silica gel pretreatment: Mix silica gel and ionic liquid evenly, add inorganic acid aqueous solution and stir at 100-150° C.; cool to room temperature, filter, wash with water until neutral, and dry to obtain pretreated silica gel; (2) The pretreated silica gel is mixed with a solvent and triethylamine. The reaction is carried out to obtain modified silica gel.

8. The method for preparing modified silica gel according to claim 7, characterized in that: In the step (1), the reaction is stirred for 1.5-2.5 hours.

9. The method for preparing modified silica gel according to claim 7, characterized in that: The reaction in step (2) is carried out by heating under reflux, and the reaction time is 18-22 hours.

10. Use of the modified silica gel according to any one of claims 1 to 6 in the adsorption of metal ions.

Images