CN110394152A - A kind of preparation method and product of selective separation palladium ion adsorption material - Google Patents

Abstract

The invention discloses the preparation methods and product of a kind of Selective Separation palladium ion adsorbent material, the method first activates silica gel using acid, silica gel reaction after reusing gamma-aminopropyl-triethoxy-silane, aniline and activation, realizes that Silica Surface has amino, that is, SiO₂‑NH₂, then further to SiO₂‑NH₂Carry out area load graphene oxide, then composite material surface is introduced by double bond and sulfydryl by chemical grafting method, material is finally subjected to the processing steps such as palladium ion absorption, polymerization and palladium ion elution, obtains the palladium ion imprinted polymer to the selective absorption of palladium ion.Show preparation gained adsorbent material to palladium ion with significant evident characteristics and affinity as experimental verification.

Description

A kind of preparation method and product of selective separation palladium ion adsorption material

technical field

The invention belongs to the field of separation, recovery and utilization of palladium ions, and in particular relates to a preparation method and a product of an adsorption material for selectively separating palladium ions.

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 carboxyl adsorption properties, 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 purpose of the present invention is to provide a preparation method and product for selectively separating palladium ion adsorption materials. The present invention combines silica gel with graphene oxide, and further introduces the surface of the composite material into dual Bonds and mercapto groups, and then the material is subjected to palladium ion adsorption, polymerization and palladium ion elution and other process steps, and the prepared material realizes memory selective separation of palladium ions.

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

1, a kind of preparation method of selective separation palladium ion adsorption 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 composite material containing amino groups, which was labeled as SiO ₂ -NH ₂ ;

2) Disperse graphene oxide in N,N-dimethylformamide and sonicate for 30 minutes to obtain mixture A, and further add SiO ₂ -NH ₂ obtained in step 1) and catalyst N,N-dicyclohexylcarbodiene to mixture A For imine, keep the reactant heated to 40-80°C for 20-35h, and further filter to obtain a solid, then dry the solid under vacuum at 30-60°C for 8-12h to obtain graphene oxide-loaded silica gel Composite material, labeled SiO ₂ @GO;

3) Disperse SiO ₂ @GO obtained in step 2) in toluene to obtain mixture B, and add N-aminoethyl-γ-aminopropyltriethoxysilane and γ-mercapto to mixture B under stirring Propyltrimethoxysilane, heated to 80-120°C and refluxed for 15-17h, suction filtered the resulting solid and dried at 110°C for 12h to obtain a silica gel/graphene oxide-based composite material containing both amino groups and mercapto groups, marked as SiO ₂ @ GO-NH ₂ -SH;

4) Disperse the SiO ₂ @GO-NH ₂ -SH obtained in step 3) in the acetic acid solution to obtain a mixture C, further add maleic anhydride to the mixture C, stir and react at room temperature for 8-24 hours, and filter the obtained solid with washing liquid Washing several times, and drying at 60-90°C for 8-12 hours, a silica-graphene material with double bonds and mercapto groups was obtained, which was marked as SiO ₂ @A;

5) Put the SiO ₂ @A obtained in step 4) into a palladium-containing solution to obtain a mixture D, let the mixture D stand for adsorption and saturation, and further filter the obtained solid with suction and dry it for 8-12 hours at a temperature of 80-110°C to obtain the adsorbed Materials with palladium ions, marked as SiO ₂ @A-Pd;

6) Disperse the SiO ₂ @A-Pd obtained in step 5) in an acetonitrile solvent to obtain a mixture E, add AIBN and EGDMA to the mixture E in turn, and then carry out the whole reaction system under the N ₂ atmosphere, at 60°C The reaction was stirred for 10-24 hours under the conditions of the suction filtration, and the solid obtained by suction filtration was washed with washing liquid for several times, and dried in a vacuum oven at 40-60 °C for 8-12 hours;

7) All the palladium ions adsorbed in the product obtained in step 6) are eluted with an eluent to obtain an imprinted polymer material that selectively adsorbs palladium ions, and the eluent is composed of HCl, sulfuric acid, nitric acid One or more of them are composed of thiourea, wherein the concentrations of HCl, sulfuric acid and nitric acid are 0.05-2 mol/L, and the mass fraction of thiourea is 25-50%.

Preferably, 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, and heat it to 60-120°C , stirred and reacted for 3-24 hours, then filtered with suction, washed with deionized water until neutral, and dried in a drying oven at 110°C for 12 hours to obtain activated silica gel.

Preferably, the mass volume ratio (g/mL) of the activated silica gel to toluene in step 1) is 4% to 40%, 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 volume ratio (g/mL) of graphene oxide and N,N-dimethylformamide in the mixture A in step 2) is 0.1% to 1%, and the graphene oxide and SiO ₂ -NH The mass ratio of ₂ is 0.01-0.5:1.

Preferably, the mass volume ratio (g/ml) of SiO ₂ @GO and toluene in the mixture B in step 3) is 2% to 40%, and the SiO ₂ @GO and N-aminoethyl-γ-aminopropyl The mass volume ratio (g/mL) of triethoxysilane is 1:0.1～1, and the mass volume ratio (g/mL) of SiO ₂ @GO and γ-mercaptopropyltrimethoxysilane is 1:0.2～2 .

Preferably, the mass fraction of SiO ₂ @GO-NH ₂ -SH in the mixture C in step 4) is 3%-8%, and the mass ratio of maleic anhydride to SiO ₂ @GO-NH ₂ -SH is 4～ 6:1.

Preferably, the concentration of the palladium-containing solution in step 5) is 100-2000 mg/L, and the mass fraction of SiO ₂ @A in the mixture D is 2%-8%.

Preferably, the mass fraction of SiO ₂ @A-Pd in the mixture E in step 6) is 4%-25%, the mass ratio of SiO ₂ @A-Pd to AIBN is 20-60:1, and the SiO ₂ @A-Pd The mass volume ratio (g/mL) to EGDMA is 1~2:2~1.

Preferably, the washing solution in step 4) and step 6) is absolute ethanol.

2. The selective separation palladium ion adsorption material obtained according to the preparation method described in any one of the above.

In the above technical scheme, AIBN is azobisisobutyronitrile, and EGDMA is ethylene glycol dimethacrylate.

The beneficial effects of the present invention are:

1) 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, so that the surface of the silica gel has amino groups, that is, SiO ₂ -NH ₂ , and then the SiO ₂ - Grafting graphene oxide on the surface of NH ₂ . 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 higher the adsorption capacity. big. 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. The selectivity is poor, so for the separation of certain specific metal ions, especially the separation of precious metal (palladium) ions, it is necessary to combine its own characteristics and introduce specific functional groups, so the present invention adopts further surface sulfhydryl groups and double bonds, and then The material is subjected to process steps such as adsorption of palladium and elution of palladium, that is, the effect of the prepared material having memory selective separation of palladium ions is realized.

2) The material disclosed in the present invention has a high adsorption rate for palladium ions and good selectivity for palladium ions in the solution, and the material can be reused many times without substantially changing the adsorption performance.

Detailed ways

The present invention will be further described below in conjunction with specific embodiment;

Example 1

A preparation method for selectively separating palladium ion adsorption materials, comprising the steps of:

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 Dry for 12h to obtain 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 5mL of aniline, and stir and reflux for 24 hours under the condition of heating to 110°C. After filtration, the solid was dried in a drying oven at 110°C for 12 hours to obtain amino silica gel;

3) Disperse 0.85g of graphene oxide in 350mL, N,N dimethylformamide solution, ultrasonically disperse graphene oxide for 30min, then add 25g of amino silica gel and 2.0g of DCC, and place in a 60°C oil bath Heating and stirring at medium temperature for 3 days, after the reaction was completed, repeated washing and suction filtration with absolute ethanol, and drying in a vacuum oven at 60°C for 12 hours to obtain SiO ₂ @GO;

4) Disperse 5g of SiO ₂ @GO in 350mL of toluene solution, add 5mL of N-aminoethyl-γ-aminopropyltriethoxysilane and 10mL of γ-mercaptopropyltrimethoxysilane into a small beaker to prepare a mixed solution, Slowly add the mixed solution under the condition of stirring, heat to 100°C and reflux for 15 hours, then filter with suction, dry in a vacuum oven at 50°C for 12 hours, and the SiO ₂ @GO-NH ₂ -SH composite material is prepared;

5) Add 2.0g SiO ₂ @GO-NH ₂ -SH to the round bottom flask, then add 10g maleic anhydride, and finally add 50mL HAC, stir and react at room temperature for 24h, after the reaction is completed, wash with absolute ethanol several times The solid was obtained by suction filtration, and the solid was dried in a 90°C drying oven for 12 hours to obtain a silica gel graphene material containing double bonds and mercapto groups

6) Put this material into a solution containing palladium ions with a concentration of 1000 mg/L, wait for it to absorb palladium ions to saturation, and dry at 110°C for 12 hours;

7) Then add 3g of the adsorption material that has adsorbed palladium ions into the three-necked flask, add 120mL acetonitrile as a solvent, add 150mgAIBN, 1mLEGDMA in turn, and then fill the three-necked flask with _N2 , so that the entire reaction system is carried out under anaerobic conditions. , and finally placed in an oil bath at 60°C and stirred for 24 hours. After the reaction, wash with absolute ethanol several times, and dry in a vacuum oven at 60°C for 24 hours. After drying, prepare 0.16mol/LHCl+50wt % thiourea eluent, all the palladium ions adsorbed in the material are eluted, and a palladium ion cavity is formed, that is, a palladium ion-imprinted polymer selectively adsorbing palladium ions is obtained.

Example 2

A preparation method for selectively separating palladium ion adsorption materials, comprising the steps of:

1) The preparation of the activated silica gel is the same as described in step 1) of Example 1.

2) The preparation of the amino silica gel is the same as described in step 2) of Example 1.

3) Disperse 0.85g of graphene oxide in 350mL N,N dimethylformamide solution, ultrasonically disperse graphene oxide for 30min, then add 85g of amino silica gel and 2.0g of DCC, heat in an oil bath at 60°C Stir for 3 days. After the reaction is completed, wash and filter repeatedly with absolute ethanol, and dry in a vacuum oven at 60°C for 12 hours to obtain SiO ₂ @GO;

4) Disperse 5g of SiO ₂ @GO in 250mL of toluene solution, add 2.5mL of N-aminoethyl-γ-aminopropyltriethoxysilane and 5mL of γ-mercaptopropyltrimethoxysilane into a small beaker to prepare a mixed solution , slowly add the mixed solution under the condition of stirring, heat to 120°C and reflux for 15 hours, then filter with suction, and dry in a vacuum oven at 50°C for 12 hours, and the SiO ₂ @GO-NH ₂ -SH composite material is prepared;

5) Add 2.0g SiO ₂ @GO-NH ₂ -SH to the round bottom flask, then add 2g maleic anhydride, and finally add 50mL HAC, stir and react at room temperature for 24h, after the reaction is completed, wash with absolute ethanol several times The solid was obtained by suction filtration, and the solid was dried in a 90°C drying oven for 12 hours to obtain a silica gel/graphene oxide-based composite material containing double bonds and mercapto groups;

6) Put this material into a solution containing palladium ions with a concentration of 1000 mg/L, wait for it to absorb palladium ions to saturation, and dry at 110°C for 12 hours;

7) Then add 3g of the adsorption material that has adsorbed palladium ions into the three-necked flask, add 120mL of acetonitrile as a solvent, add 50mgAIBN, 3mL of EGDMA in turn, and then fill the three-necked flask with N ₂ to make the entire reaction system under anaerobic conditions Finally, place it in an oil bath at 60°C and stir for 24 hours. After the reaction is over, wash it with absolute ethanol several times, and dry it in a vacuum oven at 60°C for 24 hours. After drying, prepare 0.16mol/L HCl+ The eluent of 50wt% thiourea elutes all the palladium ions adsorbed in the material, forming a palladium ion cavity, that is, obtaining a palladium ion-imprinted polymer selectively adsorbing palladium ions.

Selective adsorption palladium ion performance test:

Selectivity experiment was carried out with the material obtained in Example 1: Weigh 2.0 g of palladium ion-imprinted polymer, put it into a fixed bed (diameter 6 mm, height 100 mm), pass the palladium-containing waste liquid through the fixed bed at a flow rate of 1 mL/min, The palladium-containing waste liquid also contains various other metal ions (as shown in the subscript of FIG. 1 ), and finally the adsorption capacity of various metal ions is calculated. The calculation formula of adsorption capacity:

Wherein in the formula: m represents the quality (g) of palladium ion imprinted polymer, c ₀ represents the initial concentration (mg/L) of various metal ions, c _f represents the concentration (mg/L) of various metal ions in the fixed bed effluent L), V represents the volume (L) of the effluent.

After adsorption, various metal ions were measured and calculated, and the adsorption capacity diagram shown in Figure 1 was obtained. The experimental results in Figure 1 show that the adsorption material has significant recognition characteristics and affinity for palladium ions. The material prepared in Example 2 was further tested for the selective adsorption of palladium ions, which also showed that it had significant recognition characteristics and affinity for palladium ions.

After the adsorbed composite material was eluted with a mixed solution composed of 10mL, 6mol/L hydrochloric acid and 30g/L thiourea, the maximum dynamic saturated adsorption capacity and enrichment factor of the composite material did not decrease significantly, and the waste water solution could be realized All the separation and recovery of palladium ions in the medium. 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 (10)

1. a kind of preparation method of Selective Separation palladium ion adsorbent 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) n,N-Dimethylformamide is dispersed by graphene oxide and ultrasound 30min obtains mixture A, further to mixture A SiO obtained by middle addition step 1)₂-NH₂And catalyst n, N- dicyclohexylcarbodiimide keep reactant to be heated to 40-80 DEG C of temperature 20-35h is reacted under the conditions of degree, further filters to obtain solid, and solid is dried into 8-12h under the conditions of 30-60 DEG C of temperature of vacuum, is obtained The material silica gel composite of graphene oxide has been loaded, SiO is labeled as₂@GO；

3) by gained SiO in step 2)₂@GO be scattered in toluene mixture B is added under stirring into mixture B N- aminoethyl-gamma-aminopropyl-triethoxy-silane and γ-mercaptopropyl trimethoxysilane are heated to 80-120 DEG C and reflux 15 ~17h, it is compound that suction filtration obtained solid dry 12h at 110 DEG C obtains the silica gel simultaneously containing amino and sulfydryl/graphite oxide alkenyl Material is labeled as SiO₂@GO-NH₂-SH；

4) by SiO obtained by step 3)₂@GO-NH₂- SH is scattered in acetum and obtains mixture C, is further added into mixture C Maleic anhydride is stirred to react 8-24h at normal temperature, filters obtained solid and is repeatedly washed with cleaning solution, and in 60-90 DEG C of temperature strip Dry 8-12h under part, obtains the silica gel grapheme material simultaneous with double bond and sulfydryl, and be labeled as SiO₂@A；

5) by SiO obtained by step 4)₂@A, which is placed in palladium-containing solution, obtains mixture D, and mixture D standing adsorption is saturated, is further taken out Obtained solid dry 8-12h under the conditions of 80-110 DEG C of temperature is filtered, the material of palladium ion has been adsorbed, has been labeled as SiO₂@A- Pd；

6) by SiO acquired in step 5)₂@A-Pd, which is scattered in acetonitrile solvent, obtains mixture E, is successively added into mixture E AIBN and EGDMA, then by entire reaction system in N₂It is carried out under ambient conditions, is stirred to react 10- under conditions of 60 DEG C For 24 hours, it filters obtained solid repeatedly to be washed with cleaning solution, and the dry 8-12h in 40-60 DEG C of vacuum oven；

7) all being eluted the palladium ion adsorbed in product acquired in step 6) with eluent has selection to get to palladium ion The imprinted polymer material of property suction-operated, the eluent are made of one or more of HCl, sulfuric acid, nitric acid and thiocarbamide, Wherein HCl, sulfuric acid, concentration of nitric acid are 0.05~2mol/L, and thiocarbamide mass fraction is 25-50%.

2. a kind of preparation method of Selective Separation palladium ion adsorbent material according to claim 1, 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 preparation method of Selective Separation palladium ion adsorbent material according to claim 1, which is characterized in that step 1) mass volume ratio (g/mL) of the activated silica gel and toluene is 4%~40%, 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 preparation method of Selective Separation palladium ion adsorbent material according to claim 1, which is characterized in that step 2) graphene oxide and the mass volume ratio (g/mL) of n,N-Dimethylformamide are 0.1%~1% in the mixture A, institute State graphene oxide and SiO₂-NH₂Mass ratio be 0.01~0.5:1.

5. a kind of preparation method of Selective Separation palladium ion adsorbent material according to claim 1, which is characterized in that step 3) SiO in the mixture B₂@GO and toluene mass volume ratio (g/ml) are 2%~40%, the SiO₂@GO and N- aminoethyl- Gamma-aminopropyl-triethoxy-silane mass volume ratio (g/mL) is 1:0.1~1, the SiO₂@GO and γ-mercapto propyl trimethoxy Base silane mass volume ratio (g/mL) is 1:0.2~2.

6. a kind of preparation method of Selective Separation palladium ion adsorbent material according to claim 1, which is characterized in that step 4) SiO in the mixture C₂@GO-NH₂- SH mass fraction is 3%-8%, the maleic anhydride and SiO₂@GO-NH₂- SH's Mass ratio is 4~6:1.

7. a kind of preparation method of Selective Separation palladium ion adsorbent material according to claim 1, which is characterized in that step 5) the palladium-containing solution concentration is 100-2000mg/L, SiO in the mixture D₂@A mass fraction is 2%-8%.

8. a kind of preparation method of Selective Separation palladium ion adsorbent material according to claim 1, which is characterized in that step 6) SiO in the mixture E₂@A-Pd mass fraction is 4%-25%, SiO₂The mass ratio of@A-Pd and AIBN are 20-60:1, SiO₂The mass volume ratio (g/mL) of@A-Pd and EGDMA are 1~2:2~1.

9. a kind of preparation method of Selective Separation palladium ion adsorbent material according to claim 1, which is characterized in that step 4) and the step 6) cleaning solution is dehydrated alcohol.

10. the Selective Separation palladium ion adsorbent material that any one of -9 preparation methods obtain according to claim 1.