CN110394153A - A kind of composite material preparation method and product thereof for adsorbing palladium ions - Google Patents

Abstract

The invention discloses a kind of for adsorbing the composite material and preparation method thereof of palladium ion, is activated first using acid to silica gel, and the silica gel reaction after reusing gamma-aminopropyl-triethoxy-silane, aniline and activation realizes that SiO is prepared with amino in Silica Surface₂‑NH₂, graphene oxide is then introduced into SiO₂‑NH₂Surface of graphene oxide is modified finally by γ-mercaptopropyl trimethoxysilane in surface, and silica gel/graphene oxide based composites are prepared.The present invention takes full advantage of silica gel and the respective characteristic of graphene oxide, in conjunction with the characteristics of the two itself, introduce specific functional group, realize that prepared composite material is big to the adsorption capacity of palladium ion, it is selectively good to palladium ion in solution, and the material can be realized and be repeatedly used, and absorption property is basically unchanged.

Description

A kind of composite material preparation method and product thereof for adsorbing palladium ions

technical field

The invention belongs to the field of separation, recovery and utilization of palladium ions, and in particular relates to a method for preparing a composite material for adsorbing palladium ions and a product thereof.

Background technique

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 printed circuit board waste liquid, researchers at home and abroad have successively carried out different researches on technologies 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.

Some composite materials for adsorption and separation of palladium have also been synthesized in the existing technology, but the use effect is limited. For example, CN102009983A discloses a mercapto-modified SBA-15 molecular sieve and its preparation and use method. It utilizes adding SBA-15 molecular sieve into the prepared mercapto-modifier ethanol aqueous solution and stirring at room temperature for 36-48 hours to obtain mercapto-modified SBA -15 molecular sieve product. It uses ethanol as a medium, and the reaction time is too long, and the final product efficiency is also unsatisfactory. CN1136960C discloses a method for preparing sulfhydryl functionalized MCM-48 mesoporous molecular sieve. It is prepared by using MCM-48 mesoporous molecular sieve and mercaptopropyltrimethoxysilane toluene solution to reflux for 12 to 24 hours, but it adopts the reaction method of direct reflux of mesoporous molecular sieve and mercaptopropyltrimethoxysilane toluene solution to prepare the Product adsorption is limited. CN201510379076.4 discloses a carboxyl-terminated dendritic polymer adsorption material and a preparation method thereof. The disclosed technical scheme is to dissolve cyanuric chloride in acetone or tetrahydrofuran and add it to the acetone solution of dibasic alcohols to obtain The crude product of the first-generation hydroxyl-terminated dendritic polymer is purified to obtain the first-generation hydroxyl-terminated dendritic polymer; the second-generation and third-generation hydroxyl-terminated dendritic polymers are obtained by using cyanuric chloride as the core and the first-generation hydroxyl-terminated dendritic polymer as the branch unit The crude product is purified again; the hydroxyl-terminated dendritic polymer is dispersed in water, and maleic anhydride and p-toluenesulfonic acid are added to obtain a crude carboxyl-terminated dendritic polymer, which is purified to obtain a carboxyl-terminated dendritic polymer adsorption material. This patent utilizes the adsorption properties of carboxyl groups, but its disclosed technical solutions all use polymer materials, which have high cost and complicated process conditions.

Contents of the invention

In view of this, the object of the present invention is to provide a method for preparing a composite material for adsorbing palladium ions and products thereof, by combining silica gel with graphene oxide and introducing a composite material prepared by a functional group, the adsorption of palladium ions can be achieved. The effect is significantly improved.

In order to realize the above-mentioned purpose of the invention, the following technical solutions are specifically provided:

1. A composite material preparation method for adsorbing palladium ions, comprising the steps of:

1) Disperse the chromatographic silica gel in the acid solution, heat it to 60-120°C, stir and reflux for 3-12h, filter the solid with suction, wash the solid with deionized water until it is neutral, and place it in a drying oven at 110°C Dry for 12 hours to obtain activated silica gel;

2) Disperse the activated silica gel obtained in step 1) in toluene, continue to add γ-aminopropyltriethoxysilane and aniline under stirring conditions, heat and keep the reactant at a temperature of 100-120°C, and stir and reflux for 3-24 hours , after the reaction was finished, the solid was obtained by suction filtration, and the silica gel composite material containing amino groups was obtained, which was marked as SiO ₂ -NH ₂ ;

3) Disperse graphene oxide in N,N-dimethylformamide, then add SiO ₂ -NH ₂ and catalyst DCC obtained in step 2), wherein the mass ratio of graphene oxide to SiO ₂ -NH ₂ Between 0.01 and 0.5:1, heat and stir in an oil bath at 60°C for 5h-120h, after the reaction is completed, wash and filter the solid product repeatedly with absolute ethanol, and dry it in a vacuum oven at 60°C for 8-24h , to obtain a silica gel material loaded with graphene oxide, marked as SiO ₂ @GO;

4) Disperse the SiO ₂ @GO material obtained in step 3) in toluene, the mass volume ratio (g/ml) of SiO ₂ @GO to toluene is 1-20:50, and slowly add γ-mercaptopropyl under uniform stirring Trimethoxysilane was heated to 60-80°C and stirred and refluxed for 3-15 hours, and the solid was obtained by suction filtration, that is, the silica gel/graphene oxide-based composite material was obtained, which was marked as SiO ₂ @GO-SH.

Preferably, the acid solution in step 1) is one or more of hydrochloric acid, sulfuric acid, nitric acid or sulfonic acid with a concentration of 1-10 mol/L.

Preferably, the mass volume ratio (g/mL) of the activated silica gel to toluene in step 2) is 1 to 10:25, and the mass volume ratio (g/mL) of the activated silica gel to γ-aminopropyltriethoxysilane mL) is 1:0.3~2, and the mass volume ratio (g/mL) between activated silica gel and aniline is 100:0.1~5.

Preferably, the mass ratio of graphene oxide to SiO ₂ —NH ₂ in step 3) is 0.01˜0.5:1.

Preferably, the mass volume ratio (g/mL) of SiO ₂ @GO and γ-mercaptopropyltrimethoxysilane added in step 4) is 1-2:0.3-1.

Preferably, the solid after suction filtration in step 4) is further dried in a vacuum oven at 50° C. for 12 hours.

2. The silica gel/graphene oxide-based composite material for adsorbing palladium ions obtained according to the above preparation method.

The beneficial effects of the present invention are:

1) The composite material disclosed in the present invention has a high adsorption rate for palladium ions and good selectivity for palladium ions in solution, and the material can be reused many times, and the adsorption performance is basically unchanged.

2) In the present invention, an acid is used to activate the silica gel, and then γ-aminopropyltriethoxysilane and aniline are used to react with the activated silica gel to realize that the silica gel surface has amino groups, that is, SiO ₂ -NH ₂ , and then further oxidized Graphene was introduced onto the surface of SiO ₂ -NH ₂ , and finally the surface of graphene oxide was modified by γ-mercaptopropyltrimethoxysilane to finally prepare a silica gel/graphene oxide-based composite material containing mercapto groups. Because graphene oxide has a large specific surface area (theoretically up to 2620m ² /g), there are a large number of hydroxyl groups on the surface, and more functional groups can be introduced. The more functional groups on the surface of the adsorption material, the greater the adsorption capacity. bigger. However, graphene oxide itself cannot be used as an adsorption material for the following reasons: 1. Graphene oxide is difficult to separate in aqueous solution, even with a high-speed centrifuge, so if graphene oxide is directly added to an aqueous solution, it itself is A pollutant that will cause water environmental pollution; 2. The functional groups on the surface of graphene oxide are hydroxyl, carboxyl and epoxy groups. These oxygen-containing groups can combine with most metal ions and select specific metal ions. Therefore, for the separation of certain specific metal ions, especially the separation of noble metal (palladium) ions, it is necessary to combine its own characteristics and introduce specific functional groups. The present invention uses further surface mercaptolation to obtain composite materials. The prepared material can realize effective adsorption and separation of palladium ions.

Detailed ways

The present invention will be further described below in conjunction with specific embodiments to demonstrate the technical effects of the present invention.

Example 1

A kind of preparation that is used to absorb the composite material of palladium ion comprises the steps:

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

2) Disperse 25g of activated silica gel in 400mL of toluene solution, add 25mL of γ-aminopropyltriethoxysilane under stirring conditions, and finally add 1mL of aniline, heat to reflux for 24h, suction filter and dry in a drying oven at 110°C for 12h to obtain Amino silica gel composite material, labeled SiO ₂ -NH ₂ ;

3) Disperse 0.85g of graphene oxide in 350mL, N,N dimethylformamide solution, ultrasonic 30min to completely disperse the graphene oxide in the solution, then add 25g of amino silica gel and 2.0g of DCC (N,N-bicyclic Hexylcarbodiimide) was heated and stirred in an oil bath at 60°C for 3 days. After the reaction was completed, it was repeatedly washed and filtered with absolute ethanol, and dried in a vacuum oven at 60°C for 12 hours. The obtained material was marked as SiO ₂ @ go;

4) Disperse 25g of SiO ₂ @GO in 400mL of toluene solution, add 25mL of γ-mercaptopropyltrimethoxysilane under the condition of stirring, heat, stir and reflux for 15h, then filter with suction, and dry in a vacuum oven at 50°C for 12h to prepare A composite material was obtained, labeled as SiO ₂ @GO-SH.

Example 2

A kind of preparation that is used to absorb the composite material of palladium ion comprises the steps:

1) The preparation of activated silica gel is as described in Example 1;

2) The preparation of amino silica gel is as described in Example 1;

3) Disperse 0.85g graphene oxide in 300mL N,N dimethylformamide solution, ultrasonically disperse graphene oxide for 30min in the solution, then add amino silica gel and 2.0g DCC(N,N -dicyclohexylcarbodiimide), heated and stirred in an oil bath at 60°C for 3 days, after the reaction was completed, repeatedly washed and filtered with absolute ethanol, dried in a vacuum oven at 60°C for 12 hours, the obtained material was marked as SiO ₂ @GO;

4) Disperse 25g of SiO ₂ @GO in 350mL of toluene solution, add 50mL of γ-mercaptopropyltrimethoxysilane under stirring conditions, heat and stir under reflux for 15h, then filter with suction, and dry in a vacuum oven at 50°C for 12h to prepare A composite material was obtained, labeled as SiO ₂ @GO-SH.

Adsorption palladium ion performance test:

The adsorption material that embodiment 1～2 obtains is weighed 3.0g respectively, is packed in the fixed bed (diameter 6mm, height 100mm) respectively, is that the waste water that contains palladium initial concentration is 100mg/L passes through fixed bed, embodiment 1～2 The prepared adsorption materials reached breakthrough volumes of 6.9L and 7.2L respectively, the maximum dynamic saturated adsorption capacities were 230.5mg/g and 240mg/g respectively, and the enrichment factors could reach 690 and 720 respectively.

The adsorbed composite material was then eluted with a mixed solution composed of 10mL, 6mol/L hydrochloric acid and 30g/L thiourea. The concentration of palladium ions in the eluent was as high as 69g/L and 72g/L. After repeated use for 6 times , the maximum dynamic saturated adsorption capacity and the enrichment factor of the composite material did not decrease significantly, and all the 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 for adsorbing the composite material and preparation method thereof of palladium ion, which comprises the steps of:

1) it disperses chromatographic silica gel in acid solution, is heated under the conditions of 60-120 DEG C of temperature, is stirred at reflux 3-12h, filter Solid is washed solid to neutrality with deionized water, and dry 12h, obtains activated silica gel in 110 DEG C of drying boxes；

2) it disperses activated silica gel obtained by step 1) in toluene, gamma-aminopropyl-triethoxy silicon is continuously added under stirring condition Alkane and aniline under the conditions of heating keeps 100~120 DEG C of temperature of reactant, are stirred at reflux reaction 3~for 24 hours, to take out after reaction Solid is filtered to obtain, obtains the material silica gel composite containing amino, and be labeled as SiO₂-NH₂；

3) it disperses graphene oxide in n,N-Dimethylformamide, adds obtained SiO in step 2)₂-NH₂With urge Agent DCC, wherein graphene oxide and SiO₂-NH₂Mass ratio between 0.01~0.5:1, heat and stir in 60 DEG C of oil bath pans 5h-120h is mixed, is washed repeatedly with dehydrated alcohol filter obtained solid product after the reaction was completed, be placed in 60 DEG C of vacuum ovens Dry 8~for 24 hours, the silica gel material of graphene oxide must have been loaded, SiO is labeled as₂@GO；

4) by SiO obtained by step 3)₂@GO material is scattered in toluene, SiO₂@GO and toluene addition mass volume ratio (g/ml) are 1 ~20:50 is slowly added to γ-mercaptopropyl trimethoxysilane under uniform stirring, is heated to stirring under the conditions of 60-80 DEG C of temperature Flow back 3~15h, filter solid to get to silica gel/graphene oxide based composites, be labeled as SiO₂@GO-SH。

2. a kind of for adsorbing the composite material and preparation method thereof of palladium ion according to claim 1, which is characterized in that step 1) The acid solution is one or more of hydrochloric acid, sulfuric acid, nitric acid or the sulfonic acid of concentration 1-10mol/L.

3. a kind of for adsorbing the composite material and preparation method thereof of palladium ion according to claim 1, which is characterized in that step 2) The mass volume ratio (g/mL) of the activated silica gel and toluene is 1~10:25, the activated silica gel and three ethoxy of γ-aminopropyl The mass volume ratio (g/mL) of base silane 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 for adsorbing the composite material and preparation method thereof of palladium ion according to claim 1, which is characterized in that step 3) Middle graphene oxide and SiO₂-NH₂Addition mass ratio be 0.01~0.5:1.

5. a kind of for adsorbing the composite material and preparation method thereof of palladium ion according to claim 1, which is characterized in that step 4) Described in SiO₂@GO and γ-mercaptopropyl trimethoxysilane addition mass volume ratio (g/mL) are 1~2:0.3~1.

6. a kind of for adsorbing the composite material and preparation method thereof of palladium ion according to claim 1, which is characterized in that further The filtered solid of step 4) is dried into 12h in 50 DEG C of vacuum ovens.

7. silica gel/graphite oxide alkenyl for adsorbing palladium ion that any one of claim 1~6 preparation method obtains is multiple Condensation material.