JP2011041918A - Platinum group metal adsorbent, and method for separating and recovering platinum group metal using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solid-liquid type platinum group metal adsorbent having both of the extraction properties and selectively of a liquid-liquid platinum group metal extractant in a conventional solvent extraction method and dispensing with the use of an organic solvent, and a method for efficiently separating and recovering a platinum metal using the same. <P>SOLUTION: Palladium and/or platinum is selectively separated and recovered using a platinum metal adsorbent using the platinum group metal adsorbent having an amide-containing sulfur functional group represented by formula (1) (wherein R<SP>1</SP>and R<SP>2</SP>are each independently a hydrogen atom, a 1C-18C chain hydrocarbon group, a 3C-10C alicyclic hydrocarbon group or a 6C-14C aromatic hydrocarbon group and m and n are each independently an integer of 1-4) on the surface of a carrier. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a platinum group metal adsorbent having a specific amide-containing sulfur functional group on the surface of a carrier, and a method for separating and recovering a platinum group metal using the same.

  Platinum group metals such as platinum and palladium are used in industrial catalysts, automobile exhaust gas purification catalysts, and many electrical appliances. Since these platinum group metals are expensive and useful as resources, they have been conventionally collected and recycled after use. Recently, the importance of collecting and recycling in consideration of the conservation of resources has increased further.

  Many methods such as precipitation separation, ion exchange, electrolytic deposition, and solvent extraction have been developed to recover platinum group metals. Of these, solvent extraction is economical and easy to use. Widely adopted. For example, a method is known in which palladium ions in an aqueous solution are contacted with an organic solvent in which an oil-soluble extractant is dissolved in a liquid-liquid contact to extract palladium ions to the organic phase side. As the extractant, a sulfur-containing organic compound such as dialkyl sulfide is used (for example, see Patent Document 1). In order to improve the extraction rate, a method of introducing an amide group in the vicinity of sulfur of a dialkyl sulfide has been proposed (see, for example, Patent Document 2).

  However, since the above-described solvent extraction method uses a large amount of organic solvent, it has problems in terms of safety and environmental load.

  For this reason, a specific thioether is used as a ligand, which is immobilized on a polymer of a styrene derivative (for example, polymethylstyrene) to form a water-insoluble solid polymer sulfide compound, which is directly added to an aqueous solution containing palladium ions. A method (adsorption method) in which palladium ions are adsorbed and added without using an organic solvent has been proposed (for example, see Patent Document 3).

  However, the adsorption method described in Patent Document 3 has a problem that the palladium adsorption amount of the adsorbent is as low as 4 mg (0.04 mmol) per 1 g of the adsorbent.

  As described above, in order to recover the platinum group metal, the solvent extraction method is widely adopted from the viewpoints of economy and operability, but has a problem that the use of an organic solvent is essential.

  On the other hand, the adsorption method using a water-insoluble polymer chelating agent or ion exchange resin has an advantage that metal separation can be performed without using an organic solvent, but the selectivity to a specific metal is often low. For example, Patent Document 3 does not disclose the knowledge that platinum or palladium is selectively separated from a solution in which a plurality of metals are mixed by the polymer sulfide type compound described in Patent Document 3.

  In addition, both the solvent extraction method and the adsorption method are often affected by the acidity of the solution to be treated, and there are many cases where a problem arises in the separation efficiency of the metal, particularly under strongly acidic conditions.

JP-A-9-279264 International Publication No. 2005/083131 Pamphlet JP-A-5-105973

  The present invention has been made in view of the above-described background art, and the object thereof is to combine the extraction performance and selectivity of a liquid-liquid type platinum group metal extractant in a conventional solvent extraction method, and an organic solvent. It is an object to provide a solid-liquid platinum group metal adsorbent that does not need to be used, and an efficient method for separating or recovering a platinum group metal using the same.

  As a result of intensive studies to solve the above problems, the present inventors have found an adsorbent having a specific amide-containing sulfur functional group on the surface of the carrier, and further, using this adsorbent, separation and recovery of platinum and palladium can be performed. As a result, it was found that the above-described problems can be solved, and the present invention has been completed.

  That is, the present invention is a platinum group metal adsorbent as shown below, and a platinum group metal separation method or recovery method using the same.

  [1] The following general formula (1)

（式中、Ｒ^１、Ｒ^２は各々独立して、水素原子、炭素数１〜１８の鎖式炭化水素基、炭素数３〜１０の脂環式炭化水素基、又は炭素数６〜１４の芳香族炭化水素基を表し、ｍ、ｎは各々独立して、１〜４の整数を表す。）
で示されるアミド含有硫黄官能基を担体表面に有する白金族金属吸着剤。

(Wherein R ¹ and R ² are each independently a hydrogen atom, a chain hydrocarbon group having 1 to 18 carbon atoms, an alicyclic hydrocarbon group having 3 to 10 carbon atoms, or a group having 6 to 14 carbon atoms. Represents an aromatic hydrocarbon group, and m and n each independently represents an integer of 1 to 4.)
A platinum group metal adsorbent having an amide-containing sulfur functional group represented by

  [2] The following general formula (2)

（式中、Ｒ^１、Ｒ^２は各々独立して、水素原子、炭素数１〜１８の鎖式炭化水素基、炭素数３〜１０の脂環式炭化水素基、又は炭素数６〜１４の芳香族炭化水素基を表し、ｍ、ｎは各々独立して、１〜４の整数を表す。）
で示される硫黄含有ジアミド化合物が担体に固定化された白金族金属吸着剤。

(Wherein R ¹ and R ² are each independently a hydrogen atom, a chain hydrocarbon group having 1 to 18 carbon atoms, an alicyclic hydrocarbon group having 3 to 10 carbon atoms, or a group having 6 to 14 carbon atoms. Represents an aromatic hydrocarbon group, and m and n each independently represents an integer of 1 to 4.)
A platinum group metal adsorbent in which a sulfur-containing diamide compound represented by the formula is immobilized on a support.

[3] In General Formula (1) or General Formula (2), R ₁ and R ₂ are chain hydrocarbon groups having 1 to 4 carbon atoms, m = 2, and n = 1 or 2. The platinum group metal adsorbent according to [1] or [2] above, wherein

  [4] The platinum group metal adsorbent according to any one of [1] to [3], wherein the carrier is a styrene polymer.

  [5] The platinum group metal adsorbent according to any one of [1] to [4] is brought into contact with an aqueous solution containing a platinum group metal to adsorb palladium and / or platinum on the platinum group metal adsorbent. A method for separating platinum group metals.

  [6] The platinum group metal adsorbent according to any one of [1] to [4] is brought into contact with an aqueous solution containing a platinum group metal to adsorb palladium and / or platinum on the platinum group metal adsorbent. Then, palladium and / or platinum adsorbed on the platinum group metal adsorbent is eluted with an eluent to obtain an aqueous solution containing palladium and / or platinum.

  The platinum group metal adsorbent of the present invention has a high affinity for the platinum group metal, and particularly has a feature of selectively adsorbing palladium and platinum. The platinum group adsorbent of the present invention can adsorb 2 mmol or more per 1 g of adsorbent with respect to palladium, and has a higher palladium adsorbing ability than the adsorbent described in Patent Document 3.

  Further, the platinum group metal adsorbent of the present invention can adsorb platinum group metals (particularly palladium and platinum) without any problem even if the solution to be adsorbed is strongly acidic such as concentrated hydrochloric acid solution.

  On the other hand, according to the separation method or recovery method of the platinum group metal of the present invention, the platinum group metal can be efficiently and selectively adsorbed to the platinum group metal adsorbent of the present invention from the aqueous solution containing the platinum group metal. In addition, by using the eluent, the platinum group metal adsorbed on the adsorbent can be efficiently recovered. Since the platinum group metal adsorbent of the present invention has a feature of selectively adsorbing palladium and platinum, palladium and platinum can be recovered particularly efficiently.

  Further, according to the separation method or recovery method of the platinum group metal of the present invention, it is possible to efficiently and selectively adsorb and recover the platinum group metal in industrial catalysts and automobile exhaust gas purification catalysts without using an organic solvent. it can.

It is a figure which shows the relationship between the palladium ion density | concentration in Example 2, and a metal adsorption amount. It is a figure which shows the relationship between the hydrochloric acid concentration in Example 4, and a metal adsorption rate.

  The platinum group metal adsorbent of the present invention (hereinafter sometimes referred to as “adsorbent of the present invention”) has an amide-containing sulfur functional group represented by the above general formula (1) on the surface of the carrier, or the above The compound represented by the general formula (2) is immobilized on a carrier.

In the general formula (1), R ¹ and R ² are each independently a hydrogen atom, a chain hydrocarbon group having 1 to 18 carbon atoms (these groups may be branched), carbon. An alicyclic hydrocarbon group having 3 to 10 carbon atoms or an aromatic hydrocarbon group having 6 to 14 carbon atoms is represented. Among these, a hydrogen atom, a C1-C8 chain hydrocarbon group, a C5-C8 alicyclic hydrocarbon group, and a C6-C8 aromatic hydrocarbon group are preferable.

  Examples of the chain hydrocarbon group having 1 to 18 carbon atoms include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, and dodecyl. Group, tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group, isopropyl group, isobutyl group, s-butyl group, t-butyl group, isopentyl group, neopentyl group, t-pentyl group, 2-ethylhexyl Group, vinyl group, allyl group, 1-propenyl group, isopropenyl group, 1-butenyl group, 2-butenyl group, 2-methylallyl group, 1-heptynyl group, 1-hexenyl group, 1-heptenyl group, 1-octenyl Group, 2-methyl-1-propenyl group and the like.

  Examples of the alicyclic hydrocarbon group having 3 to 10 carbon atoms include cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group, cyclononyl group, cyclodecyl group, cyclohexenyl group, and cyclohexadi group. Examples include an enyl group, a cyclohexatrienyl group, a cyclooctenyl group, and a cyclooctadienyl group.

  Examples of the aromatic hydrocarbon group having 6 to 14 carbon atoms include phenyl group, naphthyl group, anthryl group, tolyl group, xylyl group, cumenyl group, benzyl group, phenethyl group, styryl group, cinnamyl group, biphenylyl group, phenanthryl. Groups and the like.

The R ^1, R ² in the above-mentioned general formulas (1) and (2), more preferably chain hydrocarbon group having 1 to 4 carbon atoms, further the chain hydrocarbon group having 1 to 2 carbon atoms Preferably, an ethyl group is particularly preferable.

In the above general formula (1) and general formula (2), the methylene numbers between the carbonyl group and the sulfur atom represented by m and n are each independently an integer of 1 to 4, In the present invention, the carrier is not particularly limited as long as it is insoluble in water.

  Examples of such carriers include styrene polymers such as polystyrene and crosslinked polystyrene; polyolefins such as polyethylene and polypropylene; poly (halogenated olefins) such as polyvinyl chloride and polytetrafluoroethylene; and nitrile polymers such as polyacrylonitrile. ; Polymer carriers such as (meth) acrylic polymers such as polymethyl methacrylate and polyethyl acrylate, and inorganic carriers such as activated carbon, silica gel, diatomaceous earth, hydroxyapatite, alumina, titanium oxide, magnesia, and polysiloxane. .

  Here, cross-linked polystyrene means monovinyl aromatic compounds such as styrene, vinyl toluene, vinyl xylene, vinyl naphthalene, and divinyl benzene, divinyl toluene, divinyl xylene, divinyl naphthalene, trivinyl benzene, bis vinyl diphenyl, bis vinyl phenyl ethane, etc. The main component is a cross-linked copolymer with a polyvinyl aromatic compound, and methacrylic acid esters such as glycerol methacrylate and ethylene glycol dimethacrylate may be copolymerized with these copolymers.

  In the present invention, as the crosslinked polystyrene, those obtained by introducing a haloalkyl group into the crosslinked polystyrene are particularly preferable. The method for introducing a haloalkyl group into the crosslinked polystyrene is not particularly limited. For example, as a monovinyl aromatic compound, haloalkyl styrene such as chloromethyl styrene, chloroethyl styrene, bromomethyl styrene, and bromobutyl styrene is used. The method of copolymerizing this and a polyvinyl aromatic compound is mentioned.

  In the present invention, among these carriers, styrene polymers such as polystyrene and crosslinked polystyrene are preferable.

  As the shape of the carrier used in the present invention, it is generally a separating group such as spherical (eg, spherical particles), granular, fibrous, granular, monolithic column, hollow fiber, membrane (eg, flat membrane), etc. Although the shape used as a material can be utilized and it does not specifically limit, A spherical shape, a film | membrane form, a granular form, and a fibrous form are preferable among these. Spherical particles can be used particularly preferably because the volume of use can be set freely when used in the column method or batch method.

  When spherical particles are used as the carrier, the average particle size is usually in the range of 1 μm to 10 mm, preferably in the range of 2 μm to 1 mm, and the average pore size is usually in the range of 1 nm to 1 μm, preferably in the range of 1 nm to 300 nm. .

  In this case, the method for immobilizing the amide-containing sulfur functional group represented by the general formula (1) on the carrier is not particularly limited. For example, the sulfur-containing diamide compound represented by the general formula (2) is used. And a method in which the sulfur-containing diamide compound represented by the general formula (2) is physically adsorbed and supported on the carrier.

  The adsorbent of the present invention is represented by, for example, polychloromethylstyrene (PCMS), which is a crosslinked polystyrene of chloromethylstyrene and divirbenzene, when the carrier is a crosslinked polystyrene, and the general formula (2). This can be produced by reacting with a sulfur-containing diamide compound under basic conditions.

  In addition, for example, the sulfur-containing diamide compound represented by the general formula (2) is dissolved in a solvent such as THF, and then the above-described carrier is added, the compound is impregnated in the carrier, and the solvent is further distilled off. By doing so, the adsorbent of the present invention can be produced.

  In the adsorbent of the present invention, the amount of the amide-containing sulfur functional group represented by the general formula (1) contained in the adsorbent can be arbitrarily adjusted according to the purpose, and is not particularly limited. The adsorbent of the present invention preferably contains the amide-containing sulfur functional group represented by the general formula (1) in the range of 1 to 90% by weight, and more preferably in the range of 5 to 80% by weight.

  In addition, when the sulfur-containing diamide compound represented by the general formula (2) is immobilized (supported) on a carrier, the immobilization rate (support rate) of the compound on the carrier can be arbitrarily adjusted according to the purpose. Although not particularly limited, the sulfur-containing diamide compound represented by the general formula (2) is immobilized (supported) in the range of 1 to 90% by weight with respect to the adsorbent of the present invention. Is preferable, and the range of 5 to 80% by weight is more preferable.

  Although it does not specifically limit as a manufacturing method of the sulfur containing diamide compound shown by the said General formula (2), The following formula (A)

（式中、Ｒ^１、Ｒ^２、ｎは上記と同じ定義である。）
で示されるクロロアミドに、塩基性条件下でチオ安息香酸を反応させて、下記式（Ｂ）

(Wherein R ¹ , R ² and n have the same definitions as above)
Is reacted with thiobenzoic acid under basic conditions to give the following formula (B):

（式中、Ｂｚはベンゾイル基を表し、Ｒ^１、Ｒ^２、ｎは上記と同じ定義である。）
で示されるチオエステルを得、次に、チオエステルを塩基性条件下で下記式（Ｃ）

(In the formula, Bz represents a benzoyl group, and R ¹ , R ² , and n have the same definitions as above.)
And then the thioester is subjected to the following formula (C) under basic conditions:

（式中、Ｒ^１、Ｒ^２、ｎは上記と同じ定義である。）
で示されるチオラートを得、さらに、このチオラートと下記一般式（Ｄ）

(Wherein R ¹ , R ² and n have the same definitions as above)
In addition, this thiolate and the following general formula (D)

（式中、ｍは上記と同じ定義である。）
で示されるビス（２−クロロアルキル）アミンと反応させることにより、上記一般式（２）で示される硫黄含有ジアミド化合物を得ることができる。

(In the formula, m has the same definition as above.)
The sulfur-containing diamide compound represented by the general formula (2) can be obtained by reacting with the bis (2-chloroalkyl) amine represented by formula (2).

  Here, the thiolate (C) may be once isolated and then reacted with bis (2-chloroalkyl) amine (D), but the thioester (B) is represented by the above general formula (2) in one pot. A method for converting to a sulfur-containing diamide compound is simpler.

  The platinum group metal separation method of the present invention is characterized in that the adsorbent of the present invention is brought into contact with an aqueous solution containing a platinum group metal to adsorb palladium and / or platinum on the adsorbent.

  Further, the platinum group metal recovery method of the present invention comprises contacting the adsorbent of the present invention with an aqueous solution containing a platinum group metal, adsorbing palladium and / or platinum to the adsorbent, and then adsorbing to the adsorbent. The obtained palladium and / or platinum is eluted with an eluent to obtain an aqueous solution containing palladium and / or platinum.

  In the platinum group metal separation method or recovery method described above, the solution to be treated in the present invention is, for example, an aqueous solution in which an automobile exhaust gas treatment catalyst is dissolved, or a solution after acid leaching in a platinum group metal wet refining process. be able to. These target solutions contain platinum group metals such as palladium, platinum, and rhodium, but it is sufficient that palladium and / or platinum is contained, and other components are not essential. .

  In order to adsorb palladium and / or platinum with the adsorbent of the present invention, first, the adsorbent of the present invention is added to the target solution. At this time, it is desirable to stir the solution. Further, the target solution is preferably acidic, and more preferably acidic with hydrochloric acid. As the hydrochloric acid concentration of the target solution, the adsorbent of the present invention can be used in a wide range of hydrochloric acid concentration, and is not particularly limited, but is preferably in the range of 0.1 to 5 mol / L. At a hydrochloric acid concentration within this range, both palladium and platinum can be adsorbed without impairing the adsorption efficiency.

  Further, in the above-described method for separating or recovering palladium, the amount of the adsorbent of the present invention is not particularly limited. For example, the adsorbent of the present invention is added to the above-mentioned general It is preferable to use an equimolar amount or more in terms of the sulfur-containing diamide compound represented by the formula (2).

  By the above operation, the platinum group metal adsorbed on the adsorbent of the present invention is eluted with the eluent to obtain an aqueous solution containing the platinum group metal, thereby recovering the platinum group metal. As the platinum group metal eluate, for example, ammonia water, thiourea aqueous solution, a mixed aqueous solution of thiourea aqueous solution and hydrochloric acid can be suitably used, and among them, a mixed aqueous solution of thiourea aqueous solution and hydrochloric acid is most preferable. When palladium and platinum are adsorbed using the adsorbent of the present invention, palladium and platinum can be recovered as an aqueous solution by using the eluate.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention should not be construed as being limited to these examples.

Synthesis Example 1
A platinum group metal adsorbent having an amide-containing sulfur functional group represented by the above general formula (1) on the support surface (or a platinum group metal obtained by immobilizing a sulfur-containing diamide compound represented by the above general formula (2) on a polymer carrier As a synthesis example of the adsorbent), a method for synthesizing the adsorbent represented by the following formula (3) is described below.

なお、本合成例で使用したポリクロロメチルスチレン（ＰＭＣＳ）は、クロルメチルスチレンとジビニルベンゼンとの架橋ポリスチレンであって、分級による粒子径が５〜１０μｍの範囲にある網目状の球状ポリマーである。

The polychloromethylstyrene (PMCS) used in this synthesis example is a cross-linked polystyrene of chloromethylstyrene and divinylbenzene, and is a network-like spherical polymer having a particle diameter by classification in the range of 5 to 10 μm. .

Synthesis of thioester (E).
To a 200 mL eggplant-shaped flask, 15.20 g (110 mmol) of potassium carbonate and 80 g of water were weighed, and 15.20 g (110 mmol) of thiobenzoic acid was added thereto, followed by stirring at room temperature for 30 minutes. To this were added 14.96 g (100 mmol) of 2-chloro-N, N-diethylacetamide and 20 g of tetrahydrofuran (THF), and the mixture was stirred at room temperature for 3 hours. The reaction solution was transferred to a separatory funnel to separate the organic layer and the aqueous layer, and then the aqueous layer was extracted with ethyl acetate. The organic layers were combined, washed successively with water and saturated brine, dehydrated with sodium sulfate, the solvent was distilled off, and the thioester compound represented by the above formula (E) (hereinafter referred to as “thioester compound (E)”). Was obtained as an orange oil in a yield of 25.67 g and a yield of 100%.

Synthesis of amine body (F).
In a 200 mL four-necked flask, weigh out 12.57 g (50 mmol) of the above thioester (E), 40 g of methanol, and 20 g of water. Stir for 2 hours. A solution prepared by dissolving 4.46 g (25 mmol) of bis (2-chloroethyl) amine hydrochloride in 25 g of water was added dropwise thereto at 40 ° C. over 2 hours, and the mixture was further stirred at 40 ° C. for 20 hours. The reaction solution was cooled to room temperature, transferred to a separatory funnel to separate an organic layer and an aqueous layer, and then the aqueous layer was extracted with ethyl acetate. The organic layers were combined, washed successively with saturated aqueous sodium hydrogen carbonate and saturated brine, dried over sodium sulfate, the solvent was evaporated, and the amine compound represented by the above formula (F) (hereinafter referred to as “amine compound ( F) ”) was obtained as a pale yellow oil in a yield of 7.24 g and a yield of 79.6%.

Synthesis of adsorbent (3).
In a 50 mL eggplant-shaped flask, 7.27 g (20 mmol) of the amine compound (F), 1.50 g of polychloromethylstyrene (chlorine content 9 mmol, divinylbenzene crosslinking degree 10 mol%), and 10 g of 1,4-dioxane were weighed, and nitrogen The mixture was heated to reflux for 20 hours at room temperature under an air stream. After cooling the reaction solution to room temperature, 5 g of 5% aqueous sodium hydroxide solution was added, and the mixture was stirred at room temperature for 30 minutes. The solid was collected by filtration, washed successively with water and methanol, and the adsorbent represented by the above formula (3) (hereinafter referred to as “adsorbent (3)”) as a pale yellow powder was obtained in a yield of 4.24 g. Got in. The amount of the amide-containing sulfur functional group represented by the general formula (1) (or the amount of the sulfur-containing diamide compound represented by the general formula (2)) in 1 g of the adsorbent (3) calculated from the elemental analysis result is 687 mg. Yes, the sulfur content in 1 g of the adsorbent (3) was 3.8 mmol.

Synthesis Example 2
A platinum group metal adsorbent having an amide-containing sulfur functional group represented by the above general formula (1) on the support surface (or a platinum group metal obtained by immobilizing a sulfur-containing diamide compound represented by the above general formula (2) on a polymer carrier As a synthesis example of the adsorbent), a synthesis example of the adsorbent represented by the following formula (4) will be described below.

なお、本合成例で使用したポリクロロメチルスチレンは、合成例１で使用したものと同じでものある。

The polychloromethylstyrene used in this synthesis example is the same as that used in synthesis example 1.

Synthesis of thioester (G).
To a 200 mL eggplant-shaped flask, 9.95 g (72 mmol) of potassium carbonate and 80 g of water were weighed, and 9.95 g (72 mmol) of thiobenzoic acid was added thereto, followed by stirring at room temperature for 30 minutes. To this were added 9.82 g (60 mmol) of 3-chloro-N, N-diethylpropanamide and 20 g of THF, and the mixture was stirred at 40 ° C. for 6 hours. The reaction solution was transferred to a separatory funnel to separate the organic layer and the aqueous layer, and then the aqueous layer was extracted with ethyl acetate. The organic layers were combined, washed successively with water and saturated brine, dehydrated with sodium sulfate, the solvent was distilled off, and the thioester compound represented by the above formula (G) (hereinafter referred to as “thioester compound (G)”). Was obtained as an orange oil in a yield of 14.93 g and a yield of 93.8%.

Synthesis of amine body (H).
In a 200 mL four-necked flask, 4.60 g (17.3 mmol) of the thioester (G) and 25 g of methanol were weighed, and 8.67 g (43.3 mmol) of a 20% aqueous sodium hydroxide solution was added thereto. For 2 hours. A solution prepared by dissolving 1.55 g (8.7 mmol) of bis (2-chloroethyl) amine hydrochloride in 15 g of water was added dropwise thereto at 40 ° C. over 2 hours, and the mixture was further stirred at 40 ° C. for 18 hours. The reaction solution was cooled to room temperature, transferred to a separatory funnel to separate an organic layer and an aqueous layer, and then the aqueous layer was extracted with ethyl acetate. The organic layers were combined, washed successively with saturated aqueous sodium hydrogen carbonate and saturated brine, dried over sodium sulfate, the solvent was evaporated, and the amine compound represented by the above formula (H) (hereinafter referred to as “amine compound ( H) ") was obtained as a pale yellow oil in a yield of 3.30 g, 97.1%.

Synthesis of adsorbent (4).
In a 50 mL eggplant-shaped flask, 7.05 g (18 mmol) of the amine (H), 1.37 g of polychloromethylstyrene (8.2 mmol of chlorine content, 10% by weight of divinylbenzene crosslinking), and 10 g of 1,4-dioxane were weighed. The mixture was refluxed for 40 hours at room temperature under a nitrogen stream. After cooling the reaction solution to room temperature, 5 g of 5% aqueous sodium hydroxide solution was added, and the mixture was stirred at room temperature for 30 minutes. The solid was collected by filtration, washed successively with water and methanol, and the adsorbent represented by the above formula (4) (hereinafter referred to as “adsorbent (4)”) as a pale yellow powder was obtained in a yield of 2.80 g. Got in. The amount of the amide-containing sulfur functional group represented by the above general formula (1) (or the amount of the sulfur-containing diamide compound represented by the above general formula (2)) in 1 g of the adsorbent (4) calculated from the elemental analysis result is 684 mg. Yes, the sulfur content in 1 g of the adsorbent (4) was 3.5 mmol.

Example 1.
The adsorbent (3) was added to 10 mL of 1M hydrochloric acid solution containing 50 to 400 mg / L of palladium, and the mixture was stirred at room temperature for 24 hours. Then, it filtered using the membrane filter with the hole diameter of 0.45 micrometer, and the residual metal density | concentration in a filtrate was measured with the ICP emission spectrometer (product name: OPTIMA3300DV by Perkin Elmaer). From the residual palladium concentration and the initial concentration before stirring, the palladium adsorption rate was determined, and the palladium adsorption amount was further calculated. The results are shown in FIG. The palladium saturated adsorption amount of the adsorbent (3) determined from this result was 240 mg / g (2.3 mmol / g).

Example 2
10 mg of the adsorbent (3) or adsorbent (4) was added to 10 mL of a 1 mol / L hydrochloric acid solution containing 50 mg / L each of palladium, platinum, and rhodium, and stirred at room temperature for 1 hour. Then, it filtered using the membrane filter with the hole diameter of 0.45 micrometer, and the residual metal density | concentration in a filtrate was measured with the ICP emission spectrometer (product name: OPTIMA3300DV by Perkin Elmaer). The adsorption rate of each metal was determined from the residual metal concentration and the initial concentration before stirring. As shown in Table 1, palladium was preferentially adsorbed when any adsorbent was used, and rhodium was hardly adsorbed.

実施例３．
パラジウム、白金、及びロジウムを各々５０ｍｇ／Ｌ含む０．１〜５ｍｏｌ／Ｌの濃度の塩酸溶液１０ｍＬに、上記吸着剤（３）を１０ｍｇを添加して室温で１時間攪拌した。その後、孔径０．４５μｍのメンブレンフィルターを用いてろ過し、ろ液中の残存金属濃度をＩＣＰ発光分光器（Ｐｅｒｋｉｎ Ｅｌｍａｅｒ社製、製品名：ＯＰＴＩＭＡ３３００ＤＶ）にて測定した。残存金属濃度と攪拌前の初濃度とから、各金属の吸着率を求めた。結果を図２に示す。図２から明らかなように、いずれの塩酸濃度においても良好なパラジウムが吸着が見られ、白金とパラジウムに関しては塩酸濃度を増加することで吸着率が向上した。尚、ロジウムに関してはいずれの塩酸濃度においてもほとんど吸着が見られなかった。

Example 3
10 mg of the adsorbent (3) was added to 10 mL of a 0.1 to 5 mol / L hydrochloric acid solution containing 50 mg / L each of palladium, platinum, and rhodium, and the mixture was stirred at room temperature for 1 hour. Then, it filtered using the membrane filter with the hole diameter of 0.45 micrometer, and the residual metal density | concentration in a filtrate was measured with the ICP emission spectrometer (product name: OPTIMA3300DV by Perkin Elmaer). The adsorption rate of each metal was determined from the residual metal concentration and the initial concentration before stirring. The results are shown in FIG. As can be seen from FIG. 2, good palladium was adsorbed at any hydrochloric acid concentration, and the adsorption rate of platinum and palladium was improved by increasing the hydrochloric acid concentration. For rhodium, almost no adsorption was observed at any hydrochloric acid concentration.

Example 4
Preparation of dissolution test sample:
100 mg of the adsorbent (3) was added to 10 mL of a 1 mol / L hydrochloric acid solution containing 250 mg / L each of palladium and platinum, and the mixture was stirred at room temperature for 1 hour. Then, it filtered using the membrane filter with the hole diameter of 0.45 micrometer, and the residual metal density | concentration in a filtrate was measured with the ICP emission spectrometer (product name: OPTIMA3300DV by Perkin Elmaer). The adsorption rate of each metal was determined from the residual metal concentration and the initial concentration before stirring, and the metal content adsorbed on the adsorbent (3) was calculated. The amount of palladium adsorbed per 1 g of the adsorbent (3) was 23.8 mg, and the amount of platinum adsorbed was 25.0 mg.

Metal dissolution test:
10 mg of the adsorbent (3) adsorbing palladium and platinum was stirred in 10 mL of various eluates at room temperature for 1 hour to elute these metals into the aqueous layer. Then, it filtered using the membrane filter with the hole diameter of 0.45 micrometer, and measured the elution metal density | concentration in a filtrate with the ICP emission spectrometer (the product name: OPTIMA3300DV by Perkin Elmaer). The elution rate of each metal was determined from the elution metal concentration and the initial concentration before stirring. As a result, as shown in Table 2, palladium and platinum were efficiently eluted when a 1 mol / L thiourea / 1 mol / L hydrochloric acid solution was used as an eluent.

Claims (6)

The following general formula (1)

(Wherein R ¹ and R ² are each independently a hydrogen atom, a chain hydrocarbon group having 1 to 18 carbon atoms, an alicyclic hydrocarbon group having 3 to 10 carbon atoms, or a group having 6 to 14 carbon atoms. Represents an aromatic hydrocarbon group, and m and n each independently represents an integer of 1 to 4.)
A platinum group metal adsorbent having an amide-containing sulfur functional group represented by The following general formula (2)

(Wherein R ¹ and R ² are each independently a hydrogen atom, a chain hydrocarbon group having 1 to 18 carbon atoms, an alicyclic hydrocarbon group having 3 to 10 carbon atoms, or a group having 6 to 14 carbon atoms. Represents an aromatic hydrocarbon group, and m and n each independently represents an integer of 1 to 4.)
A platinum group metal adsorbent in which a compound represented by is immobilized on a carrier. The general formula (1), wherein R ₁ and R ₂ are chain hydrocarbon groups having 1 to 4 carbon atoms, m = 2, and n = 1 or 2. The platinum group metal adsorbent according to claim 2. The platinum group metal adsorbent according to any one of claims 1 to 3, wherein the carrier is a styrene polymer. The platinum group metal adsorbent according to any one of claims 1 to 4 is brought into contact with an aqueous solution containing a platinum group metal, and palladium and / or platinum is adsorbed on the platinum group metal adsorbent. To separate platinum group metals. The platinum group metal adsorbent according to any one of claims 1 to 4 is contacted with an aqueous solution containing a platinum group metal to adsorb palladium and / or platinum on the platinum group metal adsorbent, and then A method for recovering a platinum group metal, comprising eluting palladium and / or platinum adsorbed on a platinum group metal adsorbent with an eluent to obtain an aqueous solution containing palladium and / or platinum.

Images