CN110354800A - One kind modifying SiO with ghiourea group2Preparation method of composite material and products thereof and application - Google Patents

Abstract

The invention discloses a preparation method for modifying _SiO2 composite material with thiourea group and its product and application. The silica gel composite material containing amino group is obtained by amination of activated silica gel, and the silica gel containing amino group is further modified with allylthiourea The composite material is the composite material of silica gel modified with thiourea groups. The composite material of the thiourea-modified silica gel prepared by the invention has a high adsorption rate for palladium ions, good selectivity for ions in solution, and the material can be repeatedly used, and the adsorption performance is basically unchanged.

Description

A kind of preparation method of SiO2 composite material modified with thiourea group and its product and application

technical field

The invention belongs to the field of separation, recovery and utilization of palladium ions, and in particular relates to a preparation method for modifying _SiO2 composite materials with thiourea groups and its products and applications.

Background technique

Palladium is a platinum group metal that can be used in electroplating, catalysts, dental alloys, brazing alloys and various contact materials. It has unique physical and chemical properties and is widely used in chemical catalysis, aerospace, microelectronics, exhaust gas purification It plays a key and central role in cutting-edge science and modern industries such as petrochemical, electrical and electronic, environmental protection, biopharmaceuticals, and national defense. With the increasing importance of environmental protection and the in-depth development and application of catalysts, the demand for metal palladium is growing rapidly. Facing the sustainable utilization of resources and the rising price of metal palladium, the recycling of palladium has significant economic and social benefits.

The main source of palladium-containing waste liquid is electroplating waste liquid such as activation and passivation in the process production of various electronic industries. The waste liquid is weakly acidic and the palladium content is ~50ppm. Palladium, gold and other precious metal production waste liquid contains ~ 10ppm of palladium. The workpiece cleaning wastewater after the metallization of printed circuit board holes, plastic electroplating and various non-metallic electroplating activation also contains a certain amount of palladium, and its content is ~ 1ppm. The study found that a large amount of palladium-containing waste liquid in the electroplating industry is discharged as ordinary wastewater, which not only increases the difficulty of subsequent wastewater treatment, but also causes a waste of resources. According to statistics, about 3 tons of metal palladium in the palladium-containing waste liquid produced by my country's electroplating and circuit board industries cannot be effectively recovered. In addition, the accumulation of palladium emissions in the environment will endanger human health, such as causing diseases such as asthma, allergies and rhinitis. In order to improve the recovery rate of palladium in the printed circuit board waste liquid, researchers at home and abroad have carried out different degrees of research on techniques such as extraction method, ion exchange method and resin adsorption method. Although these studies have made some progress in some aspects, there are still some shortcomings. Better treatment technology can only reduce the palladium content to 3-4ppm. The different forms of palladium in palladium-containing waste liquid is one of the important reasons for the decrease of palladium recovery.

CN107130114A discloses a method for separating and recovering palladium in palladium-containing waste liquid, which uses chitosan derivatives and palladium waste liquid to form flocs to realize the separation of palladium and waste liquid, and the above method is relatively cumbersome. CN 109438719 A discloses a modified metal-organic framework composite material and a preparation method. This patent proposes the concept of using a metal-organic framework modified material as an adsorption material, but the modification operation of the metal-organic framework material used in this technical solution Complex, with a wide variety of raw materials.

Contents of the invention

In view of the technical defects that still exist in the prior art scheme, the object of the present invention is to provide a preparation method and product for modifying _SiO2 composite material with thiourea groups. The product prepared according to the method is very effective for adsorbing palladium ions. significantly.

Concrete technical scheme of the present invention is:

1, a kind of with thiourea group modification SiO _The preparation method of composite material, comprises the steps:

1) Disperse the activated silica gel in toluene, continue to add γ-aminopropyltriethoxysilane and aniline under stirring conditions, heat and keep the reactant at 100-120°C, stir and reflux for 3-24 hours, and wait for the reaction to complete After suction filtration, the solid was obtained to obtain a silica gel material containing an amino group, which was labeled as SiO ₂ -NH ₂ ;

2) Prepare a sodium ethoxide solution with a mass fraction of 1-20%, add allylthiourea and SiO ₂ -NH ₂ to the sodium ethoxide solution in sequence, heat the reactant to 50-100° C. and stir for 8-24 hours, After the reaction is finished, the solid is obtained by suction filtration, and the SiO ₂ composite material modified with thiourea groups is obtained.

Further, the preparation method of the activated silica gel described in step 1) is: disperse the chromatography silica gel in one or more of 1-10 mol/L hydrochloric acid, sulfuric acid, nitric acid or sulfonic acid, heat to 60-120°C, After stirring and reacting for 3-24 hours, it was suction-filtered, washed with deionized water until neutral, and dried in a drying oven at 110° C. for 12 hours to obtain activated silica gel.

Further, the mass volume ratio (g/mL) of the activated silica gel to toluene in step 1) is 4 to 40:100, and the mass volume ratio (g/mL) of the activated silica gel to γ-aminopropyltriethoxysilane ) is 1:0.3~2, and the mass volume ratio (g/mL) between activated silica gel and aniline is 100:0.1~5.

Further, in step 2), the mass volume ratio (g/mL) of the allylthiourea to sodium ethylate is 1.5-3:100, and the mass volume ratio (g/mL) of the SiO ₂ -NH ₂ to sodium ethylate For 4-15:100.

Further, the solid obtained in step 2) was further washed with ethanol for 3 to 5 times, and dried in a drying oven at 110° C. for 12 hours to obtain a thiourea-modified SiO ₂ composite material.

2. The _SiO2 composite material modified with thiourea groups prepared according to any one of the above methods.

3. Application of a _SiO2 composite material modified with thiourea groups in the field of palladium ion separation and recovery.

The beneficial effects of the present invention are:

1) In the present invention, an acid is used to activate the silica gel first, and then γ-aminopropyltriethoxysilane and aniline are used to react with the activated silica gel, so that the silica gel surface has amino groups, that is, SiO ₂ -NH ₂ , and then SiO 2 -NH 2 is further activated. ₂ -NH ₂ is modified with thiourea group, and the SiO ₂ composite material modified with thiourea group is prepared. This preparation process can realize the introduction of thiourea functional groups into the surface of silica gel, and prepare the _SiO2 composite material containing thiourea group modification, and then realize the adsorption material with high adsorption rate for palladium ions and good selectivity for ions in solution.

2) According to the Lewis acid-base theory, Pd ²⁺ belongs to soft acid, and thiourea group belongs to soft base, and they are easier to coordinate and combine to form complexes. The technical solution disclosed in the present invention is through chemical grafting The introduction of thiourea functional groups to the surface of silica gel can realize the adsorption of Pd ²⁺ on the surface of modified silica gel. Although this adsorption is a chemical adsorption process, the energy of the formed coordination bonds is low. It is easy to fall off under the action of groups with stronger coordination ability with Pd ²⁺ . Therefore, the thiourea-modified _SiO2 composite material of the present invention has a high adsorption rate to palladium ions, good selectivity to palladium ions in the solution, and the material can be reused many times after the elution process, and the adsorption performance is basically the same. Change.

Detailed ways

The present invention will be further described below in conjunction with specific embodiments.

Example 1

Modified _SiO2 composites with thiourea group were prepared as follows:

1) Add 60g of chromatographic silica gel and 500mL of 6mol/L hydrochloric acid solution into a 1000mL three-neck flask, heat to 110°C, stir and reflux for 8h, wash it with a large amount of deionized water until neutral after the reaction is completed, and place it at 110°C Drying for 12 hours under the hood to obtain activated silica gel.

2) Weigh 5.0g of activated silica gel in a 250mL three-neck flask, add 100mL of toluene as a solvent, add 5mL of γ-aminopropyltriethoxysilane under stirring conditions, and finally add 0.2mL of aniline, and heat Stir and reflux the reaction at 110°C for 24 hours. After suction filtration, dry the solid in a drying oven at 110°C for 12 hours. The dried product taken out is amino silica gel.

3) Weigh 1.5g of NaOH in a 250mL three-necked flask, add 120mL of absolute ethanol as a solvent, and dissolve it fully under heating and stirring to obtain a sodium ethoxide solution. After cooling to room temperature, add 2.5g of alkene Propylthiourea was dissolved completely, then 5.0 g of amino silica gel was added, heated to 80°C, stirred and refluxed for 15 hours, then suction filtered, the solid was washed with ethanol and dried in a 110°C drying oven for 12 hours. The product taken out is the composite material of _SiO2 modified with thiourea group.

Example 2

Modified _SiO2 composites with thiourea group were prepared as follows:

1) Add 60g of chromatographic silica gel and 500mL of 1mol/L sulfuric acid solution into a 1000mL three-neck flask, heat to 120°C, stir and reflux for 24h, wash it with a large amount of deionized water until neutral after the reaction is completed, and place it at 110°C Drying for 12 hours under the hood to obtain activated silica gel.

2) Weigh 5.0g of activated silica gel in a 250mL three-neck flask, add 100mL of toluene as a solvent, add 5mL of γ-aminopropyltriethoxysilane under stirring conditions, and finally add 0.2mL of aniline, and heat Stir and reflux at 110°C for 24 hours, and then dry in a drying oven at 110°C for 12 hours after suction filtration. The dried product taken out is amino silica gel.

3) Weigh 1.5g of NaOH in a 250mL three-neck flask, add 120mL of absolute ethanol as a solvent, and dissolve it fully under heating and stirring to obtain a sodium ethoxide solution. After cooling to room temperature, add 3.6g of alkene Propylthiourea was dissolved completely and then 7.0 g of amino silica gel was added, heated to 80°C, stirred and refluxed for 15 hours, then suction filtered, and the solid was washed with ethanol and dried in a drying oven at 110°C for 12 hours. The product taken out is the composite material of _SiO2 modified with thiourea group.

Adsorption palladium ion performance test:

The composite material that embodiment 1 and embodiment 2 obtains is weighed 3.0g respectively, packs in the fixed bed (diameter 6mm, height 100mm), will contain the waste water that palladium initial concentration is 100mg/L to pass through the fixed bed, the penetration volume respectively The maximum dynamic saturated adsorption capacity can reach 6.0L and 6.2L respectively, and the maximum dynamic saturated adsorption capacity can reach 200mg/g and 206.7mg/g respectively, and the enrichment factor can reach 500 and 517 respectively.

The adsorbed composite material was then eluted with a mixed solution composed of 12mL, 6mol/L hydrochloric acid and 30g/L thiourea. The palladium ion concentration in the eluent was as high as 50g/L and 51.7g/L respectively. After three times, the maximum dynamic saturated adsorption capacity and enrichment factor of the composite material did not decrease significantly, and the complete separation and recovery of palladium ions in the wastewater solution could be realized. The above examples further demonstrate that the composite material disclosed in the present invention has a high adsorption rate for palladium ions, good selectivity for palladium ions in solution, and the material can be reused many times, and the adsorption performance is basically unchanged.

Finally, it is noted that the specific embodiments of the present invention have been described in detail above, but the present invention is not limited to the above-mentioned embodiments. Make various changes below.

Claims (7)

1. a kind of modify SiO with ghiourea group₂The preparation method of composite material, which comprises the steps of:

1) it disperses activated silica gel in toluene, continuously adds gamma-aminopropyl-triethoxy-silane and aniline under stirring condition, add Under the conditions of heat keeps 100~120 DEG C of temperature of reactant, it is stirred at reflux reaction 3~for 24 hours, to filter to obtain solid after reaction, is obtained To the material silica gel composite containing amino, and it is labeled as SiO₂-NH₂；

2) alcohol sodium solution that mass fraction is 1-20% is prepared, allylthiourea and SiO are successively added into alcohol sodium solution₂- NH₂, heating reactant to being stirred to react 8-24h under the conditions of 50-100 DEG C, to filter after reaction solid to get with thiocarbamide Base modifies SiO₂Composite material.

2. a kind of according to claim 1 modify SiO with ghiourea group₂The preparation method of composite material, which is characterized in that step 1) activated silica gel described in the preparation method comprises the following steps: dispersing chromatographic silica gel in hydrochloric acid, sulfuric acid, nitric acid or the sulfonic acid of 1-10mol/L One or more of, it is heated to 60-120 DEG C, is filtered after being stirred to react 3-24h, is washed with deionized water to neutrality, in Dry 12h, obtains activated silica gel in 110 DEG C of drying boxes.

3. a kind of according to claim 1 modify SiO with ghiourea group₂The preparation method of composite material, which is characterized in that step 1) mass volume ratio (g/mL) of the activated silica gel and toluene is 4~40:100, the activated silica gel and three second of γ-aminopropyl The mass volume ratio (g/mL) of oxysilane is 1:0.3~2, and the mass volume ratio (g/mL) between activated silica gel and aniline is 100:0.1~5.

4. a kind of according to claim 1 modify SiO with ghiourea group₂The preparation method of composite material, which is characterized in that step 2) mass volume ratio (g/mL) of the allylthiourea and sodium ethoxide is 1.5-3:100, the SiO₂-NH₂With the matter of sodium ethoxide Measuring volume ratio (g/mL) is 4-15:100.

5. a kind of according to claim 1 modify SiO with ghiourea group₂The preparation method of composite material, which is characterized in that step 2) obtained solid is further used ethanol washing 3~5 times, and dries 12h at 110 DEG C in drying box, is able to ghiourea group modification SiO₂Composite material.

6. what any one of -5 the methods were prepared according to claim 1 modifies SiO with ghiourea group₂Composite material.

7. one kind is with thiourea modified SiO₂Composite material is in palladium ion separation, the application of recycling field.