JP4693123B2 - Gold adsorbent and method for selective separation and recovery of gold - Google Patents

Description

  The present invention relates to a gold adsorbent and a method for selectively separating and recovering gold using the same.

  In recent years, with the remarkable development of industrial technology such as electronics / electric field, organic synthesis field, etc., metals such as gold, silver, palladium, platinum, rhodium are not only decorative items but also semiconductors, substrates, cathode ray tubes, etc. It is widely used as an electronic industrial material and a catalyst for organic chemical reaction. However, on the other hand, it is a well-known fact that the amount of production of these metals is small compared to other metals, and it is a major issue to efficiently recover and reuse these metals.

  As a method for recovering gold from wastewater containing gold, several methods are known. For example, heating concentration, activated carbon, solvent extraction, and electrolysis use. However, these methods are applicable when the gold concentration in the wastewater is high, but when the gold concentration in the wastewater is dilute, the amount of gold remaining in the solution without being recovered increases. There is a problem that the recovery rate decreases. Moreover, it was difficult to selectively collect gold from waste water containing a plurality of metals (see Non-Patent Document 1).

  The method of concentrating and recovering gold using an ion exchange resin is known to have a relatively high recovery rate. However, when recovering gold from a resin that has adsorbed gold, the gold can be desorbed from the resin. In addition, gold must be recovered after ashing the expensive resin, or even if it can be desorbed, the desorption rate is low and the gold recovery rate is reduced, making it impossible to reuse the resin. There is a problem such as.

  In addition, gold-containing solutions for recovery often contain a large amount of metals such as palladium, platinum, iron, nickel, copper, lead, zinc, tin, and cobalt in addition to gold. However, there is a problem that these metals are mixed into gold during the gold recovery, a high quality product cannot be obtained, and there are many steps for the subsequent purification of gold (see Patent Document 1).

Functional materials, 26, 5 (2006) Japanese Patent Laid-Open No. 1-111824

  An object of the present invention is to provide an adsorbent for easily and efficiently recovering gold from a liquid containing gold and a method for selectively separating and recovering gold using the same.

  That is, the present invention provides the following general formula (1):

(In the formula, R ¹ and R ² are the same or different and each independently represent a hydrogen atom or an alkyl group having 1 to 10 carbon atoms. R ³ and R ⁴ are the same or different and each independently represent A hydrogen atom, an alkyl group having 1 to 10 carbon atoms, a monocyclic carbocyclic group which may have a substituent, a condensed polycyclic carbocyclic group which may have a substituent, or a substituent. A monocyclic heterocyclic group or a condensed polycyclic heterocyclic group which may have a substituent.) And a polyaniline system having a number average molecular weight in the range of 500 to 1,000,000. The present invention relates to a gold adsorbent containing a resin as an active ingredient.

The present invention relates to a gold adsorption method, wherein the adsorbent is brought into contact with a liquid containing gold.
Further, the present invention is directed to selective separation of gold, wherein the adsorbent is brought into contact with a liquid containing gold under acidity, and gold is desorbed from the adsorbent that has adsorbed gold using a desorbent. It relates to a collection method.

According to the present invention, there is provided a method for easily and efficiently selectively recovering gold from a liquid containing gold.
By the selective separation and recovery method of the present invention, only gold can be selectively adsorbed and separated from a liquid in which metals such as palladium, platinum, iron, nickel, copper, lead, zinc, tin, and cobalt are mixed. Further, by using an acidic solution containing a thiourea derivative, it is possible to desorb and recover the gold separated by adsorption in a high yield.

Hereinafter, the present invention will be described in detail.
The gold adsorbent of the present invention has the following general formula (1):

(In the formula, R ¹ and R ² are the same or different and each independently represent a hydrogen atom or an alkyl group having 1 to 10 carbon atoms. R ³ and R ⁴ are the same or different and each independently represent A hydrogen atom, an alkyl group having 1 to 10 carbon atoms, a monocyclic carbocyclic group which may have a substituent, a condensed polycyclic carbocyclic group which may have a substituent, or a substituent. A monocyclic heterocyclic group or a condensed polycyclic heterocyclic group which may have a substituent.) And a polyaniline system having a number average molecular weight in the range of 500 to 1,000,000. Resin is the active ingredient.

Examples of the alkyl group having 1 to 10 carbon atoms represented by R ¹ and R ² include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert. -Butyl group, n-pentyl group, isopentyl group, neopentyl group, n-hexyl group, isohexyl group, n-octyl group, n-decyl group and the like.

Examples of the alkyl group having 1 to 10 carbon atoms represented by R ³ and R ⁴ are the same as those described above.
Examples of the monocyclic carbocyclic group that may have a substituent include a phenyl group that may have a substituent, a 2-cyclohexen-1-yl group that may have a substituent, and a substituent. Examples thereof include a 3-cyclohexen-1-yl group which may have, a cyclopropyl group which may have a substituent, and a cyclohexyl group which may have a substituent.

  Examples of the condensed polycyclic carbocyclic group which may have a substituent include a naphthyl group which may have a substituent, an anthryl group which may have a substituent, and a substituent. A pyrenyl group, a pentarenyl group which may have a substituent, an indenyl group which may have a substituent, an azulenyl group which may have a substituent, a heptalenyl group which may have a substituent, and a substituent. Acenaphthyl group which may have, fluorenyl group which may have substituent, phenalenyl group which may have substituent, phenanthryl group which may have substituent, fluor which may have substituent Oranthenyl group, triphenylenyl group which may have a substituent, perylenyl group which may have a substituent, chrysenyl group which may have a substituent, picenyl group which may have a substituent, substituent A pentacenyl group which may have Good ovalenyl group and the like have also good coronenyl group and substituent.

  Examples of the monocyclic heterocyclic group which may have a substituent include a pyridyl group which may have a substituent, a pyrimidyl group which may have a substituent, and a furyl which may have a substituent. Group, a thiophenyl group which may have a substituent, a thiopyrenyl group which may have a substituent, a pyrazinyl group which may have a substituent, and a pyridazinyl group which may have a substituent.

  Examples of the condensed polycyclic heterocyclic group that may have a substituent include a quinolyl group that may have a substituent, a benzofuryl group that may have a substituent, and a substituent. Isobenzofuryl group, 1-benzothiophenyl group which may have a substituent, 2-benzothiophenyl group which may have a substituent, carbazoyl group which may have a substituent, An optionally substituted xanthenyl group, an optionally substituted isoquinolyl group, an optionally substituted acridinyl group, an optionally substituted quinoxalyl group, and an optionally substituted comarinyl group Etc.

In addition, as said substituent, a C1-C10 alkyl group, an alkoxy group, an alkanoyl group, a carbamoyl group, a cyano group etc. are mentioned, for example.
Specific examples of the alkyl group having 1 to 10 carbon atoms are the same as the alkyl group having 1 to 10 carbon atoms represented by R ¹ and R ² .
Examples of the alkoxy group include a methoxy group and an ethoxy group.
Examples of the alkanoyl group include a methanoyl group and an ethanoyl group.
Also, such substituents in the monocyclic carbocyclic group, condensed polycyclic carbocyclic group, monocyclic heterocyclic group and condensed polycyclic heterocyclic group may be one or more substituents.

  Specific examples of the polyaniline-based resin include, for example, poly (o-aniline), poly (3-n-hexyl-o-aniline), poly (3-n-octyl-o-aniline), poly (4-n -Hexyl-o-aniline), poly (4-n-octyl-o-aniline), poly (imino (3-n-hexyl-1,2-phenylene) imino (3-n-octyl-1,2-phenylene) )), Poly (imino (3-n-hexyl-1,2-phenylene) imino (4-n-octyl-1,2-phenylene)), poly (imino (4-n-hexyl-1,2-phenylene) ) Imino (3-n-octyl-1,2-phenylene)), poly (imino (4-n-hexyl-1,2-phenylene) imino (4-n-octyl-1,2-phenylene)), poly (M-aniline), poly ( -N-hexyl-m-aniline), poly (2-n-octyl-m-aniline), poly (4-n-hexyl-m-aniline), poly (4-n-octyl-m-aniline), poly (Imino (2-n-hexyl-1,3-phenylene) imino (2-n-octyl-1,3-phenylene)), poly (imino (2-n-hexyl-1,3-phenylene) imino (4 -N-octyl-1,3-phenylene)), poly (imino (4-n-hexyl-1,3-phenylene) imino (2-n-octyl-1,3-phenylene)), poly (imino (4 -N-hexyl-1,3-phenylene) imino (4-n-octyl-1,3-phenylene)), poly (p-aniline), poly (2-n-hexyl-p-aniline), poly (2 -N-octyl-p-aniline), poly (3-n-hexyl-p-aniline), poly (3-n-octyl-p-aniline), poly (imino (2-n-hexyl-1,4-phenylene) imino (2-n-octyl-1) , 4-phenylene)), poly (imino (2-n-hexyl-1,4-phenylene) imino (3-n-octyl-1,4-phenylene)), poly (imino (3-n-hexyl-1) , 4-phenylene) imino (2-n-octyl-1,4-phenylene)), poly (imino (3-n-hexyl-1,4-phenylene) imino (3-n-octyl-1,4-phenylene) )), Poly (imino (3-n-hexyl-1,2-phenylene) imino (2-n-octyl-1,3-phenylene)), poly (imino (3-n-hexyl-1,2-phenylene) ) Imino (4-n-octyl-1) , 3-phenylene)), poly (imino (4-n-hexyl-1,2-phenylene) imino (2-n-octyl-1,3-phenylene)), poly (imino (4-n-hexyl-1) , 2-phenylene) imino (4-n-octyl-1,3-phenylene)), poly (imino (3-n-hexyl-1,2-phenylene) imino (2-n-octyl-1,4-phenylene) )), Poly (imino (3-n-hexyl-1,2-phenylene) imino (3-n-octyl-1,4-phenylene)), poly (imino (4-n-hexyl-1,2-phenylene) ) Imino (2-n-octyl-1,4-phenylene)), poly (imino (4-n-hexyl-1,2-phenylene) imino (3-n-octyl-1,4-phenylene)), poly (Imino (2-n-hexyl- , 3-phenylene) imino (2-n-octyl-1,4-phenylene)), poly (imino (2-n-hexyl-1,3-phenylene) imino (3-n-octyl-1,4-phenylene) )), Poly (imino (4-n-hexyl-1,3-phenylene) imino (2-n-octyl-1,4-phenylene)), poly (imino (4-n-hexyl-1,3-phenylene) ) Imino (3-n-octyl-1,4-phenylene)), poly (N-phenyl-o-aniline), poly (N-2-pyridyl-m-aniline), poly (N-1-naphthyl-p) -Aniline), poly (N-1-anthryl-p-aniline), poly (N-1-acridinyl-p-aniline) and the like. Among these, poly (m-aniline) is preferably used from the viewpoint of being inexpensive and having a large gold adsorption capacity.

  Examples of the method for producing a polyaniline resin include a method of oxidative polymerization of aniline. Polymerization can be carried out using various oxidizing agents, but the usual method is to prepare a 1N hydrochloric acid aqueous solution of ammonium peroxodisulfate and an aqueous hydrochloric acid solution of aniline in separate containers, cooled to 0 ° C. and stirred. The polyaniline-based resin can be obtained by mixing both solutions (Journal of Chemical Society of Japan, 10, 1791 (1989)).

Electrochemically, when a working electrode and a counter electrode platinum plate are placed in a mixed aqueous solution of aniline and hydrochloric acid and a voltage of 1 to 2 V is applied to both electrodes, a polyaniline resin is obtained on the working electrode (Synth. Met. 36, 139 (1990)).
In addition, a method of reacting dihalogenobenzenes and phenylenediamine in the presence of a catalyst containing a palladium compound and a phosphine compound and a base (Polym. J., 31, 206 (1999), JP-A-2005-200618) ) Etc. are known.

The number average molecular weight of the polyaniline resin used in the present invention is 500 to 1,000,000, preferably 1,000 to 100,000. When the number average molecular weight of the polyaniline resin is less than 500, the polyaniline resin may be dissolved in a liquid containing gold. Moreover, when the number average molecular weight exceeds 1,000,000, the mechanical stability of the polyaniline resin in the liquid may be lowered.
Gold can be adsorbed by bringing the adsorbent of the present invention into contact with a liquid containing gold.
Gold-containing liquid includes gold extracted from gold-containing scrap, waste liquid containing gold discharged from the process of using gold, and a small amount of gold discharged from the process of gold recovery and purification There are many things such as waste liquid.

The adsorbent of the present invention can selectively adsorb gold from a liquid containing metals such as palladium, platinum, iron, nickel, copper, lead, zinc, tin, and cobalt as impurities.
The liquid containing gold may be any solution such as an aqueous solution or an organic solution.

  In order to efficiently adsorb gold to the adsorbent of the present invention, it is desirable to add hydrochloric acid, nitric acid, mineral acid of sulfuric acid or the like to the liquid containing gold in advance to make the liquid containing gold acidic. Specifically, the hydrogen ion concentration is preferably adjusted within the range of pH = 1 to 5.5, and more preferably adjusted within the range of pH = 1 to 4.0.

The method for adsorbing gold using the adsorbent of the present invention is not particularly limited, and examples thereof include a method of adsorbing gold by immersing the adsorbent in a liquid containing gold.
The contact temperature between the liquid containing gold and the adsorbent is generally 0 to 100 ° C, preferably 10 to 60 ° C. When temperature is lower than 0 degreeC, there exists a possibility that the viscosity of a liquid may become high or a solid substance may precipitate. Moreover, when temperature is higher than 100 degreeC, since the expense which heating requires increases, it is unpreferable.
The contact time between the gold-containing liquid and the adsorbent is not particularly limited, but is usually several seconds or more, preferably 1 minute to 48 hours.

The shape of the adsorbent of the present invention is not particularly limited. For example, a cartridge in which a polyaniline-based resin is chemically modified and supported on an appropriate synthetic resin can be used as a cartridge. By doing in this way, it can install in the drainage channel from which a waste liquid is discharged | emitted, or can be used in the container filled with the waste liquid, stirring easily. Moreover, it is also possible to attach to an underwater moving body (for example, hull) and to use it. By using in this way, gold present in the liquid is collected by the adsorbent.
The gold thus adsorbed on the adsorbent is selectively separated and recovered by desorbing the gold using the desorbent.

Since the gold adsorbed on the polyaniline resin adsorbent has a relatively strong bond, it is difficult to desorb with mineral acids such as hydrochloric acid, nitric acid, and sulfuric acid generally used for resin regeneration. It is necessary to use a desorbent.
As the desorbing agent, an acidic aqueous hydrochloric acid solution containing a thiourea derivative such as thiourea, N-methylthiourea, N, N′-dimethylthiourea, N-ethylthiourea, N, N′-diethylthiourea is preferably used. In particular, thiourea is preferably used from the viewpoint of low cost and excellent desorption effect.

Contact between the adsorbent adsorbing gold and the desorbent is generally performed at a temperature of 0 to 100 ° C, preferably 10 to 60 ° C. When temperature is lower than 0 degreeC, there exists a possibility that the detachment | desorption property of gold may fall. Moreover, when temperature is higher than 100 degreeC, since the expense which heating requires increases, it is unpreferable.
The contact time between the adsorbent adsorbed with gold and the desorbent is not particularly limited, but is usually several seconds or longer, preferably 1 minute to 48 hours.

  The concentration of the acidic solution containing the thiourea derivative used as the desorbing agent is preferably 0.001 mol / L to 10 mol / L, and the hydrogen ion concentration should be adjusted within the range of pH <4. preferable.

The contact method between the adsorbent that has adsorbed gold and the desorbent is not particularly limited. For example, a method of immersing an adsorbent that has adsorbed gold in the desorbent, a tower packed with an adsorbent that has adsorbed gold For example, a method of passing a desorbing agent is employed.
The gold desorbed and recovered by the above method is then recovered as a high-quality gold metal or gold compound by a known method such as concentration, purification, or electrolysis, and used for industrial use, decoration, or the like.
The adsorbent after desorbing gold can be reused after being washed with water and regenerated.

When using an adsorbent used when recovering conventional gold, metal ions such as palladium, platinum, iron, copper, nickel, cobalt may be adsorbed simultaneously, but the polyaniline resin used in the present invention By using an adsorbent as an active ingredient, it is possible to selectively adsorb only gold substantially from a solution containing palladium, platinum or the like, for example, 100 times the amount of gold.
In addition, the polyaniline resin has a large gold adsorption capacity, and for example, 1 mol of gold can be adsorbed per repeating unit represented by the general formula (1). This corresponds to, for example, adsorbing as much as 2.2 g of gold to 1.0 g of polyaniline resin.

EXAMPLES The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to these examples.
The number average molecular weight of the polyaniline-based resin obtained in the examples is N, N- containing LiBr (0.01 mol / L) using gel permeation chromatography (Tosoh Corporation, trade name: HLC-8020). Measured in dimethylformamide at 30 ° C. and calculated with reference to standard polystyrene.

  The metal contained in the solution was measured using an atomic absorption analyzer (Hitachi, Ltd., trade name: 180-80 polarization Zeeman atomic absorption photometer). Moreover, the total organic carbon concentration contained in the solution was measured using a total organic carbon analyzer (Shimadzu Corporation, trade name: TOC-500).

Production Example 1
Into a 1 L four-necked flask equipped with a condenser and a thermometer, 20.45 g (86.7 mmol) of 1,3-dibromobenzene, 9.38 g (86.7 mmol) of 1,3-phenylenediamine, Tris (Dibenzylideneacetone) dipalladium (0) 1.98 g (2.16 mmol), 2,2′-bis (diphenylphosphino) -1,1′-binaphthyl 4.05 g (6.50 mmol), sodium 25.00 g (260.1 mmol) of tert-butoxide and 800 mL of toluene were charged. Subsequently, it heated up to 100 degreeC under nitrogen atmosphere, and was made to react at 100 degreeC for 12 hours. After completion of the reaction, the reaction solution was cooled to 25 ° C. and filtered to obtain crude poly (m-aniline). The obtained crude poly (m-aniline) was washed with 2 L of 28 wt% aqueous ammonia / methanol mixed solvent (volume ratio 1/4), further washed with methanol, and then dried under reduced pressure to obtain a poly ( m-aniline) (15.50 g) was obtained (yield 98.0%). The number average molecular weight of the obtained poly (m-aniline) was 14500.

Production Example 2
In a 1 L four-necked flask equipped with a condenser and a thermometer, 20.45 g (86.7 mmol) of 1,4-dibromobenzene, 9.38 g (86.7 mmol) of 1,4-phenylenediamine, Tris (Dibenzylideneacetone) dipalladium (0) 1.98 g (2.16 mmol), 2,2′-bis (diphenylphosphino) -1,1′-binaphthyl 4.05 g (6.50 mmol), sodium 25.00 g (260.1 mmol) of tert-butoxide and 800 mL of toluene were charged. Subsequently, it heated up to 100 degreeC under nitrogen atmosphere, and was made to react at 100 degreeC for 12 hours. After completion of the reaction, the reaction solution was cooled to 25 ° C. and filtered to obtain crude poly (p-aniline). The obtained crude poly (p-aniline) was washed with 2 L of 28 wt% ammonia water / methanol mixed solvent (volume ratio 1/4), further washed with methanol, and then dried under reduced pressure to obtain a blue-purple powder of poly (p 15.58 g of p-aniline) was obtained (yield 98.5%). In addition, the number average molecular weight of the obtained poly (p-aniline) was 15500.

Production Example 3
Into a 1 L four-necked flask equipped with a condenser and a thermometer, 12.83 g (86.7 mmol) of 2,6-dichloropyridine, 9.46 g (86.7 mmol) of 2,6-diaminopyridine, Tris (Dibenzylideneacetone) dipalladium (0) 1.98 g (2.16 mmol), 2,2′-bis (diphenylphosphino) -1,1′-binaphthyl 4.05 g (6.50 mmol), sodium 25.00 g (260.1 mmol) of tert-butoxide and 800 mL of toluene were charged. Subsequently, it heated up to 100 degreeC under nitrogen atmosphere, and was made to react at 100 degreeC for 12 hours. After completion of the reaction, the reaction solution was cooled to 25 ° C. and filtered to obtain crude poly (2,6-pyridinediylimine). The obtained crude poly (2,6-pyridinediylimine) was washed with 2 L of 28 wt% aqueous ammonia / methanol solution (volume ratio 1/4), further washed with methanol, and then dried under reduced pressure to give an ocher powder. Of poly (2,6-pyridinediylimine) was obtained (yield 99.9%). Moreover, the number average molecular weight of the obtained polymer was 6900.

Example 1-4
Adsorption of gold (Au) (III) was examined using poly (m-aniline) (PmA).
5 mg of poly (m-aniline) was placed in a 10 mL sample bottle, 5 mL of 0.1 mmol / L aqueous gold solution was added, and the mixture was stirred at 25 ° C. for 16 hours using a magnetic stirrer under various acidic conditions. After stirring, the solution was filtered using a syringe equipped with a disposable filter (pore size 0.2 μm), and the filtrate was used as a solution after adsorption.
The gold concentration in the solution before and after adsorption was measured with an atomic absorption spectrometer to determine the adsorption rate. The results are shown in Table 1.

  The polyaniline-based resin obtained in Production Example 1 has an excellent adsorption capacity for Au (III) under acidic conditions.

Example 5-10
The adsorption rate was determined in the same manner as in Example 1 except that a 0.1 mmol / L aqueous gold solution adjusted to pH 2 was used and the stirring time was changed to 1, 3, 5, 10, 16, 25 hours. The results are shown in Table 2.

  Table 2 shows that the polyaniline resin obtained in Production Example 1 adsorbs Au (III) rapidly and 100% under acidic conditions and maintains its adsorption ability for a long time.

Examples 11-12
The adsorption rate was determined in the same manner as in Example 1 except that a 1 mmol / L aqueous gold solution adjusted to pH 2 or a 10 mmol / L aqueous gold solution was used. The results are shown in Table 3.

  Even in a gold solution containing a higher concentration of Au (III), the polyaniline resin obtained in Production Example 1 has an excellent adsorption capacity.

Examples 13-18
Gold and coexisting metals (M) (Pd (II), Pt (IV), Fe (III), Cu (II), Ni (II) or Co (II)) instead of 0.1 mmol / L gold aqueous solution) The adsorption rate was determined in the same manner as in Example 1 except that an aqueous solution (pH 2) having a concentration ratio of 1: 1 (0.1 mmol / L: 0.1 mmol / L) was used and the stirring time was 1 hour. The results are shown in Table 4.

（金の濃度は０．１ｍｍｏｌ／Ｌで一定である。）

(The gold concentration is constant at 0.1 mmol / L.)

  Table 3 shows that the polyaniline resin obtained in Production Example 1 adsorbs 100% of Au (III) and selectively adsorbs only gold in the presence of the co-metal.

Examples 19-22
Instead of the 0.1 mmol / L aqueous gold solution, an aqueous solution (pH 2) having a concentration ratio of gold and the coexisting metal (M) (Pd (II) or Pt (IV)) of 1:10 or 1: 100 is used and stirred. The adsorption rate was determined in the same manner as in Example 1 except that the time was 1 hour. The results are shown in Table 5.

（金の濃度は０．１ｍｍｏｌ／Ｌで一定である。）

(The gold concentration is constant at 0.1 mmol / L.)

  Even in a solution containing a higher concentration of the co-metal, the polyaniline resin obtained in Production Example 1 selectively adsorbs only 100% of Au (III).

Example 23- 25
Using poly (m-aniline) (PmA) and poly (p-aniline) (PpA), the adsorption performance and elution of the polymer into the liquid phase during the stirring operation were compared.
The adsorption rate was determined in the same manner as in Example 1 except that a 0.1 mmol / L aqueous gold solution, a 0.1 mmol / L aqueous Pd solution, or a 0.1 mmol / L aqueous Pt solution adjusted to pH 2 was used. Moreover, the total organic carbon concentration (TOC) of the filtrate was measured. The results are shown in Table 6.

  The polyaniline resins obtained in Production Examples 1 and 2 have no or very low polymer elution (TOC) into the liquid phase during the stirring operation, and selectively only Au (III). Adsorb.

Example 26
5 mg of poly (m-aniline) was placed in a 10 mL sample bottle, and 5 mL of 0.1 mmol / L aqueous gold solution adjusted to pH 2 was added thereto. After stirring for 1 hour, the mixture was filtered using a syringe equipped with a disposable filter (pore size 0.2 μm).
The filtered poly (m-aniline) is taken together with the filter in a sample bottle, added with 10 mL of 0.5 mol / L thiourea solution acidified with 0.5 mol / L hydrochloric acid, stirred for 30 minutes, and then filtered. The gold concentration was measured with an atomic absorption spectrometer and the desorption rate was determined. The desorption rate was 99.3%.

Comparative Example 4 - 6
Adsorption performance, polymer in liquid phase during stirring operation, except that poly (2,6-pyridinediylimine) was used instead of poly (m-aniline) and poly (p-aniline) The elution of was compared. The results are shown in Table 7.

From the test results in Tables 6 and 7, the polyaniline resins obtained in Production Examples 1 and 2 are poly (2,6-pyridinediylimine), which is an organic polymer compound conventionally known as a gold adsorbent. As compared with the above, it was found that the coexisting metal was not adsorbed, it had an excellent selective adsorption ability for Au (III), and the polymer elution (TOC) was also excellent.

Claims (5)

General formula (1):

(In the formula, R ¹ and R ² are the same or different and each independently represent a hydrogen atom or an alkyl group having 1 to 10 carbon atoms. R ³ and R ⁴ are the same or different and each independently represent A hydrogen atom, an alkyl group having 1 to 10 carbon atoms, a monocyclic carbocyclic group which may have a substituent, a condensed polycyclic carbocyclic group which may have a substituent, or a substituent. It consists good monocyclic heterocyclic group or substituted showing also good condensed polycyclic heterocyclic group.) represented by the meta by (m) position repeating units of number average molecular weight of 500 to 1,000,000 Gold adsorbent containing polyaniline resin in the range as an active ingredient.   A method for adsorbing gold, comprising bringing the adsorbent according to claim 1 into contact with a liquid containing gold.   A method for selectively separating and recovering gold, wherein the adsorbent according to claim 1 is contacted with a liquid containing gold under acidity, and gold is desorbed from the adsorbent adsorbed with gold using a desorbent.   The method for selectively separating and recovering gold according to claim 3, wherein the desorbing agent is an acidic solution containing a thiourea derivative.   The method for selectively separating and recovering gold according to claim 4, wherein the thiourea derivative is thiourea.