JPS594181B2 - metal ion collector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a metal ion collector, and more particularly to a metal ion collector that can extremely selectively collect specific metal ions.

Traditionally, metal ion collectors include various surfactants used in foam separation methods such as ion flotation and foam fractionation, fatty acids, water-soluble organic compounds such as sodium alkylxanthate, bentonite, and iron hydroxide. Particulate inorganic compounds such as ion exchange resins, chelate resins, and other polymeric compounds used in column separation methods are known.

However, since the collection of metal ions by these collectors is carried out through electrostatic bonds or coordinate bonds between the collector and the metal ions, these metal ions with similar properties do not interact with each other. There is almost no difference in binding, and therefore it is impossible to selectively collect only a specific metal ion from a solution in which metal ions with similar properties coexist without any pretreatment. .

In addition, when a metal ion is bound by the above-mentioned bond between a certain atomic group in the collector and an ion, no further binding of metal ions occurs, and therefore, the metal ion is not bound by the collector. The amount of trapping was determined by the number of atomic groups 5 in the collector that can form bonds with metal ions.

Therefore, the present invention aims to eliminate the drawbacks of such conventional metal ion collectors, and has a collection mechanism that is completely different from that of conventional metal ion collectors, and can achieve similar properties without special pretreatment. It has the characteristic that only specific metal ions can be collected extremely selectively and in large quantities from a solution in which 10 metal ions coexist.

In order to achieve this objective, the present invention focuses on the fact that membrane structures that constitute living cells, that is, biological membranes, extremely selectively take in specific substances into cells etc. through a certain type of carrier. It is made by forming an oil film of an organic solvent containing a metal chelating agent and a nonionic surfactant on the surface of a polymer constituting a porous microcapsule containing water as a core material20. It is an ion collector.

The porous microcapsules containing water as the core material used in the metal ion collector of the present invention are made of a high molecular weight polymer and can be easily prepared by ordinary interfacial polymerization. may be any type of microcapsule, preferably polyamide microcapsules.

For example, a water-soluble diamine compound is dissolved in water, an organic solvent containing an oil-soluble surfactant (for example, a mixed solution of chloroform and cyclohexane) 30 is added thereto, and the mixture is stirred to form a water/organic solvent emulsion (hereinafter referred to as W10 emulsion). .

) can be adjusted by adding an oil-soluble polybasic acid halide dissolved in the same solvent. Furthermore, the metal chelate 35 agent constituting the collector of the present invention is
It plays an important role in collecting metal ions and satisfies the following conditions. In other words, metal chelating agents are hardly soluble in water, are oil-soluble, and combine with the metal to be collected to form a chelate compound, but they do not create a chelate compound with very strong bonds, and are effective in collecting metal ions. It should not bind to the fat-soluble anion of the chelate compound counterion added during the process.

Metal chelating agents that meet these conditions include, for example, 4,7-diphenyl-2,9-dimethyl-1,1 for copper ions.
0-phenanthroline, and the lead ion is dicyclohexyl-18-crown 6. The concentration of this chelating agent added to the oil film may be at any level, but it is preferably at a concentration similar to that of the metal ions to be collected, so that metal ions can be efficiently collected. be able to.

Furthermore, the organic solvent used as the oil film constituting the collector of the present invention is used in order to facilitate the permeation of fat-soluble anions, which are counter ions of the chelate compound added when collecting metal ions, through the oil film. , an organic solvent that is relatively polar and insoluble in water, such as dichloroethane and dichloromethane.

Furthermore, as for the surfactant added to the oil film, 1 to 2% by weight of a nonionic surfactant is added to the organic solvent in consideration of the dispersibility of the microcapsules in an aqueous metal ion solution as described below.

The metal ion collector of the present invention is prepared by first preparing porous microcapsules containing water as a core material by a conventional method as described above, and then placing the microcapsules in an organic solvent containing a metal chelating agent and a nonionic surfactant. After immersion in water, excess organic solvent is removed by filtration or centrifugation to form an oil film of organic solvent containing a metal chelating agent and a nonionic surfactant on the surface of the polymer constituting the microcapsules. Manufactured by forcing.

When the metal ion collector thus obtained is placed in water containing metal ions, the microcapsules containing water as a core substance are dispersed by the action of the nonionic surfactant present in the oil film, and then this When fat-soluble anions, such as nitrate ions and perchlorate ions, which serve as counterions to the chelate compound formed from the collector and metal ions are added to the solution, the metal ions are incorporated into the microcapsules.

That is, metal ions combine with the chelating agent on the surface of the oil film formed on the surface of the microcapsule containing the metal chelating agent to form a chelate compound, which further combines with a fat-soluble anion to form an ion pair. The metal ions move to the inner surface of the oil film, and then dissociate at the interface between the oil film and the solution inside the microcapsule, releasing metal ions into the capsule. Therefore, collection of metal ions by the metal ion collector of the present invention continues as long as there is a difference in concentration between the inside and outside of the capsule of the fat-soluble anions added for ion pair formation.

According to the metal ion collector of the present invention, metal ions collected as a chelate compound on the oil film on the outer surface of the microcapsule are released into the microcapsule as an ion pair of a metal ion and a fat-soluble anion. Since metal ions are collected by , it is possible to selectively collect only specific metal ions by appropriately selecting a metal chelating agent depending on the type of metal ion to be collected.

In addition, the amount of metals collected per collector is extremely high, and varies depending on the concentration of metal ions in the aqueous solution, but in the case of collecting metal ions from normal industrial wastewater, the amount of metals collected per 11 parts of the solution is extremely high.
1 to 10 salts containing fat-soluble anions and dispersing the collector of
When 7 is added, metal ions are rapidly collected within the microcapsules.

For example, in a solution containing 10-3 moles of metal ions,
90% of it is incorporated into the capsule within 15-30 minutes. Furthermore, it cannot absorb anything other than metals that have the same ionic radius as the metal ion.

Further, when collecting metal ions, no pretreatment is necessary at all, and the above-mentioned notable effects can be achieved simply by using the prepared metal ion collector as it is. Furthermore, since the metal ion collector of the present invention can selectively collect only specific metal ions in large quantities with simple operations, it is expected to be used in wastewater treatment, pharmaceutical, chemical, food industries, etc. and its industrial significance is great.

Next, examples of the present invention will be described.

Example 1 A: Production of metal ion collector In a 500 ml beaker, 0.4 mol of piperazine and 0.
．． Add 7.5 ml of an aqueous solution containing 45 mol of sodium carbonate and 7.5 ml of water, and add chloroform containing 5% by volume of sorbinone trioleate while cooling with ice water.
75 ml of a cyclohexane mixed solution (mixing ratio 1:3) was added and stirred for 5 minutes to prepare a W/O emulsion.

Next, add 75 chloroform-cyclohexane mixed solution (mixing ratio 1:3) containing 0.67 butalol chloride to this.
ml was added and stirred for an additional 3 minutes to form microcapsules.

In order to remove impurities from the obtained microcapsules, the supernatant was removed by centrifugation, and the microcapsules were further washed three times with ethanol.

Next, this microcapsule was added to 10-3 moles of 4.
The mixture was added to 100 ml of a 1,2-dichloroethane solution containing 7-diphenyl-2,9-dimethylphenanthroline and 1y polyoxyethylene sorbinone monolaurate, and stirred for 10 minutes.

Then centrifuge it to remove excess dichloroethane.
The obtained microcapsules were used as collectors of copper ions. The average diameter of these microcapsules is 5.
It was μ. B: Collection test 10ml (equivalent to 0.47) of the collection material obtained in A above was
Dispersed in 200 ml of a 10-3 molar copper sulfate solution at 5°C.

In order to measure changes in copper ion concentration, a copper ion electrode (manufactured by Orion, USA) was inserted, and 10 ml of 1 mol sodium perchlorate was added while stirring, and the electrode potential decreased by 30 mV after 23 minutes. This indicates that the copper ion concentration has decreased to one-tenth of the initial concentration, and during this time,
This means that 90% of the copper ions in the solution were incorporated into the microcapsules. Although similar measurements were made for iron (6), nickel, and ions, no collection of these ions was observed. Example 2 A: Preparation of collector In a 500 ml beaker, 7.5 ml of an aqueous solution containing 0.4 mol of 1,6-hexamethylenediamine and 0.45 mol of sodium carbonate and 7.5 ml of water were poured, and the mixture was poured with ice water. While cooling, 75 ml of a chloroform-cyclohexane mixed solution (mixing ratio 1:4) containing 5% by volume of sorbinone trioleate was added and stirred for 3 minutes to prepare a W/O emulsion.

Next, add 7 ml of a chloroform-cyclohexane mixed solution (mixing ratio 1:4) containing 0.67 butalol chloride to this solution.
5 ml was added and stirred for an additional 3 minutes to form microcapsules. In order to remove impurities, the obtained microcapsules were centrifuged to remove the supernatant, and then washed three times with ethanol. Next, the microcapsules were dissolved in 100 ml of a dichloromethane solution containing 10 −3 moles of dicyclohexyl-18-crown-6 and 27 moles of polyoxyethylene rubitan monolaurate.
1 and stirred for 10 minutes.

Thereafter, this was centrifuged to remove excess dichloromethane, and the resulting microcapsules were used as a lead ion collector. The diameter of this microcapsule is 4μ on average.
It was hot. B: Collection test 10ml (equivalent to 0.47) of the collection material obtained in A above was
Dispersed in 200 ml of a 10-3 molar lead nitrate solution at 5°C.

Claims (1)

[Claims] 1. A metal ion collector formed by forming an oil film of an organic solvent containing a metal chelating agent and a nonionic surfactant on the surface of a polymer constituting a porous microcapsule containing water as a core substance.