JPH0466112A - Determination of transportation condition in membrane transport - Google Patents

Abstract

PURPOSE:To determine transportation conditions by forming a monomolecular film of a water-insoluble amphiphilic compound having a functional group which interacts with specific substance on the surface of water and obtaining the mutual relation between a limiting area formed by compressing the film and pH of said water. CONSTITUTION:A membrane is used to determine the conditions under which specific substances, e.g. Ga, In, Sc, etc., are selected and distributed from a plurality of substances contained in water, in which a monomolecular film of an amphiphilic compound, which has, in its one molecule, both functional group which interacts with said specific substances, e.g. chelate formation group, and hydrophobic group such as phenyl group or alkyl group, is formed on the surface of said water. The monomolecular film is compressed to obtain a limiting area, so that said conditions are determined based on the mutual relation between said area and pH of said water. As a result, interactions between specific substances such as valuable metal etc., and amphiphilic compound can be obtained precisely, also making it possible to determine transportation and separation conditions with a high degree of reliability.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention describes a method for determining conditions for selectively transporting substances using a membrane, and more specifically, a method for determining conditions for selectively transporting substances using a membrane. The present invention relates to a method for determining transport conditions for selectively transporting and separating and recovering a specific metal ion, and for predicting the selectivity of a specific metal ion.

[Conventional techniques and problems to be solved by the invention] With the development of science and technology and with the increase in the diversity of substance use, there is a need for selective separation techniques to obtain target substances. Demand is increasing and technology is becoming more sophisticated. In particular, valuable metals such as gallium, indium, and scandium are attracting attention as key materials that will support the next generation electronics and optical industries, and demand is expected to increase significantly in the future. However, these metal ions do not exist as individual ores, but are widely distributed in small amounts contained in raw ores such as aluminum, zinc, iron, etc. Therefore, various metal ions can be selectively separated and recovered. A method has been proposed.

For example, methods for selectively separating and recovering the above-mentioned valuable metals from the hydrosphere using artificial membranes include conventional solvent extraction methods,
Compared to the sedimentation method, mercury amalgam method, and adsorption method, it is cleaner because there is no environmental pollution caused by solvents, mercury, etc., it has excellent recovery efficiency and selectivity of valuable metals, and the process is simple and energy-saving. Because it is a separation and recovery method,
It has been attracting attention in recent years. Currently, the artificial membranes used for the separation and recovery of valuable metals include hydrophilic functional groups (chelate-forming groups) that form chelates with metals,
Examples include a membrane containing an amphipathic compound having both a hydrophobic group such as a phenyl group and an alkyl group in one molecule, or a hydrophobic polymer membrane to which a chelate-forming group is chemically bonded.

In the process of selectively transporting metal ions from the hydrosphere using the above-mentioned artificial membrane to separate and recover the metal ions, in order to transport the target metal ions with high selectivity and high efficiency, it is necessary to It is necessary to accurately understand the interaction between chelate-forming groups and metal ions in the membrane at the interface with water, and to set appropriate transport conditions.

Therefore, the conventional method for accurately determining the interaction between a chelate-forming group and a metal ion is to use an amphipathic compound having a chelate-forming group or a solution prepared by dissolving this in a hydrophobic organic solvent, Aqueous solutions of various pH levels containing metal ions to be separated and recovered are brought into contact with each other and stirred vigorously for a predetermined period of time to bond the metal ions to chelate-forming groups, and changes in the concentration of metal ions in the aqueous solutions are measured. The presence or absence of interaction between metal ions and chelate-forming groups was determined from the obtained equilibrium adsorption rate or distribution coefficient.

However, the conventional methods have the following problems, for example.

■The concentration of metal ions in an aqueous solution must be measured.

(2) It is necessary to prepare at least 4 types of aqueous solutions with different pH, and an average of 6 types.

(2) It takes at least 4 hours for each stirring time to reach equilibrium, and 8 hours on average, and it is necessary to measure the metal ion concentration of at least 6 types of samples, and an average of 8 types of samples, until equilibrium is reached.

In other words, in the conventional method, the selective transport ability of a membrane impregnated with an amphiphilic compound is predicted by recognizing the interaction between a metal ion and an amphiphilic compound based on the adsorption rate and partition coefficient. was. For example, just by determining the conditions for transporting and separating and recovering the target metal ion with the highest selectivity from a mixed aqueous solution of two types of metal ions, metal ion detection for at least 48 types of samples, and an average of 96 types of samples, can be carried out with the highest selectivity. It is necessary to measure the concentration, and determining transportation conditions requires a lot of effort and time.

Furthermore, valuable metals such as gallium, indium, and scandium for the purpose of separation and recovery generally exist at a low concentration of about one hundred bones of the coexisting metal ions, so this aqueous solution is When this is brought into contact with a solution dissolved in a hydrophobic organic solvent, the concentration of the metal ions to be separated and recovered will further decrease, making it difficult to measure the concentration of the metal ions to be obtained. The reliability of the value will further decline. Therefore, the adsorption rate and partition coefficient of the target metal ion determined from such measured values are extremely ambiguous, and it is difficult to determine whether these adsorption rates and partition coefficients exist at low concentrations in the solution for separation and recovery. It is difficult to say that the value accurately reflects the interaction between the metal ion present and the amphiphilic compound at the membrane interface. In other words, when a membrane is used to selectively transport and separate and recover target metal ions from a solution system that is closer to the actual situation, the membrane selectivity and membrane transport conditions are mutually adjusted based on the results obtained by the above method. Conventional methods for predicting and determining effects are hardly suitable for determining membrane transport conditions.

Therefore, an object of the present invention is to be able to accurately grasp the interaction between specific substances such as valuable metals and amphiphilic compounds, and to determine transport and separation conditions with high reliability. The object of the present invention is to provide a method for determining transport conditions in membrane transport.

(!!!Means for Solving the Problem) The present inventors have determined a conventional method for predicting selectivity and determining accurate transport conditions in selective transport of specific substances in water using membranes. As a result of intensive studies to establish a new method that overcomes the We found that it accurately reflects the interaction with

The present invention has been made based on the above findings, and includes a method for determining transportation conditions for a specific substance when selectively transporting and separating the specific substance from a plurality of substances contained in water using a membrane. A monomolecular film of a water-insoluble amphiphilic compound having a functional group that interacts with the specific substance is formed on the water surface, then the monomolecular film is compressed to determine the ultimate area, and the ultimate area and the water The present invention provides a method for determining transport conditions in membrane transport, characterized in that the transport conditions are determined based on the correlation with the pH of the membrane transport.

The present invention will be explained in detail below.

The form of the membrane used in the present invention is not particularly limited as long as it has a functional group that chemically or physicochemically interacts with a specific substance in water. Examples of specific substances to be interacted with here include rare substances such as valuable metals that can exist in the hydrosphere, such as gallium, indium, and scandium, and the above-mentioned functional groups include: Conventionally known materials can be mentioned, but when the specific substance is a metal ion such as gallium, indium, scandium, etc., it is preferable to use a material that forms a chelate with the metal ion. In addition, the above film includes:
Examples include impregnated membranes, emulsion membranes, polymer blend membranes, and hydrophobic membranes.

The above-mentioned impregnated membrane is amphiphilic, which has both a hydrophilic functional group (chelate-forming group) that interacts with a specific metal ion such as a chelate bond, and a hydrophobic group such as a phenyl group or an alkyl group in one molecule. It is a membrane in which a compound is dissolved in a hydrophobic organic solvent and impregnated into a hydrophobic polymer porous membrane.The above emulsion membrane is a membrane stabilized by a surface active side, and the above polymer blend membrane is , is a blend membrane prepared by puncturing the above amphiphilic compound into a polymer and forming this into a membrane, and the above hydrophobic membrane is a membrane in which chelate-forming groups are chemically bonded. be. The above membrane only needs to have selectivity, which is the most important function of a membrane, through the interaction between an amphiphilic compound having a chelate-forming group and a metal ion; An impregnated membrane is preferable in consideration of ease of handling, simplicity of operation, etc.

The chelate-forming group constituting the amphiphilic compound is not particularly limited, and may include conventionally known functional groups that form a chelate with a metal ion. Further, examples of the hydrophobic group include saturated aliphatic hydrocarbons, unsaturated aliphatic hydrocarbons, alicyclic hydrocarbons, aromatic hydrocarbons, etc., and saturated aliphatic hydrocarbons having 8 to 30 carbon atoms. hydrogen,
Unsaturated aliphatic hydrocarbons are preferred. The hydrophobic organic solvent used in preparing the impregnated film and emulsified film has extremely low solubility in water, and examples of the organic solvent include kerosene, xylene, toluene, diethylbenzene, carbon tetrachloride, Tetrachloroethane, 1-
Examples include octatool, 1-decanol, diphenyl ether, and organic compounds having hydrophobicity equivalent to these. Further, the hydrophobic polymer porous membrane is a membrane-like polymer material having a large number of fine through-holes, and examples of the membrane-like polymer material include polyethylene,
Polypropylene, polybutadiene, polymethyl acrylate, polystyrene, polyacrylonitrile, polyvinyl chloride, polyvinylidene chloride, polyvinylidene fluoride,
Examples include Teflon and silicone rubber. The shape of the membrane may be either a flat membrane or a hollow fiber membrane.

The monomolecular film of an amphipathic compound in the present invention is an amphipathic compound formed of a monomolecular film formed on the water surface by dropping the amphipathic compound dissolved in an organic solvent onto the water surface and evaporating the organic solvent. It is a membrane of

Furthermore, the ultimate area of the amphiphilic compound in the present invention can be determined by compressing a monomolecular film formed on the water surface. Specifically, it is performed as follows. A trough made of a highly water-repellent material such as a tetrafluoroethylene resin or a metal coated with a tetrafluoroethylene resin is filled with metal ions and the like for the purpose of transport from 0.5 to 2 cm above the top of the trough. Aqueous solutions of various pHs containing metal ions that are considered to coexist are added, and this is used as a subphase. After spreading a solution of the amphipathic compound on this water surface and evaporating the solvent in the solution,
Compress the monomolecular film on the water surface along the top of the trough at a constant speed, measure the area (A) and surface pressure (π) of the film on the water surface, and calculate the relationship as the π-A-line. obtain.

The minimum area (limit area) that one molecule of the amphiphilic compound occupies on the water surface at the measurement temperature is determined from the obtained πA convex curve, and the determined limit area is plotted against PH. At this time, if there are no metal ions in the subphase, the π to 8 line does not change even if the pH changes, and the limit area shows a constant value. However, when the subphase is an aqueous solution containing metal ions, the ultimate area begins to increase from a certain pH, continues to increase in a certain pH range, and remains unchanged as the pH increases and becomes a constant value. The reproducibility of this measurement is extremely high, and the required ultimate area value is within ±3%. Further, the range of change in pH value from when the ultimate area begins to increase until it reaches a constant value is approximately 0.5 and is approximately constant regardless of the type of metal ion. Furthermore, the ultimate area and the pH range in which the ultimate area changes exhibit specific values depending on the metal ions of the subphases. On the other hand, even when the subphase is a mixed aqueous solution of metal ions, the metal ions do not interfere with each other through certain operations, and the above relationships are established independently. In other words, in the relationship between the ultimate area and pH of an amphiphilic compound obtained as a subphase of a single aqueous solution of each metal ion, the pH at which the ultimate area changes
If the regions are separated by 0.5 or more, the above relationship holds true regardless of the concentration and concentration ratio of metal ions in the subphase.

Therefore, when the subphase is a single aqueous solution of metal ions in which the ultimate area changes from a low pH range in the π-A-line, the π-A-line corresponds to that of each of the metal ions in the mixed solution, The increase in the ultimate area is not affected by the coexisting metal ions from the high pH range, and therefore, the lower the pH value at which the increase in the ultimate area begins, the more the amphiphilic compounds developed on the water surface and in the subphase. interaction with metal ions increases. That is, by creating a π-octaconvex curve of an amphipathic compound using a single or mixed aqueous solution of various metal ions at various pH as a subphase, and finding the relationship between the limit area and pH, Interaction between chelate-forming groups and metal ions in water when transporting and separating metal ions using a membrane or a hydrophobic polymer membrane with chemically bonded chelate-forming groups constituting an amphiphilic compound. judge the effect,
It becomes possible to predict selectivity and accurately determine transport conditions in selective separation and recovery of metal ions using a membrane.

Therefore, in order to obtain the π-octaconvex curve in the present invention, the device for measuring the surface pressure (π) of the amphiphilic compound and the area (A) of the monomolecular film may be a trough, a surface pressure measuring device, or an automatic device. Any device may be used as long as it is composed of a water surface compressor, or a device prepared by appropriately combining each of these may be used, but a known commercially available Langmuir-Prodgett film manufacturing device is preferably used. It will be done. A solution containing an amphiphilic compound having a chelate-forming group that develops on the water surface is composed of the amphiphilic compound and an organic solvent, and the organic solvent contains the amphiphilic compound at a temperature of 0 or 1 m+go.
l ·dm−' or more, and S=γ1−γ.

The expansion coefficient (S) defined by T1 (where T is the surface tension of water, γ is the surface tension of the organic solvent, and T1 is the interfacial tension between water and the organic solvent) is 3 to 40. Organic solvents are preferably used. Examples of the organic solvent include hydrophobic organic solvents such as benzene, toluene, xylene, hexane, cyclohexane, chloroform, diethyl ether, and petroleum ether, mixtures thereof, or combinations thereof with methanol, ethanol, isopropano, and the like. acetonitrile, N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-
Examples include mixtures with hydrophilic organic solvents such as pyrrolidone and dimethyl sulfoxide. Among them, organic solvents having an expansion coefficient of 5 to 30 and containing hydrophobic organic solvents as a main component, such as benzene, toluene, xylene, cyclohexane, chloroform, and petroleum ether, are preferably used.

In addition, the concentration of the solution is 0.1 to 20IIIlo1・d1
3 is preferable, more preferably 0.5 to 5 mmol・d
It is m-'. The amount of the solution spread onto the water surface is selected appropriately depending on the area of the trough and the concentration of the solution, but the surface pressure is O before compression, and the water surface on the trough is compressed by about 1/2 to 4/5. The amount is preferably such that the surface pressure shows a maximum during this time and a π-A curve representing the collapse of the monomolecular film on the water surface can be measured. The compression rate of the monolayer on the water surface is 1 to 10
0 cd-Ilin-' is preferred, more preferably 5
~80 cd-sin-', particularly preferably 10-60
cii-sin-'. The metal ion concentration in the subphase is preferably 10 to 500,000 times the molar ratio of the amphiphilic compound developed on the water surface, more preferably 2
0 to 300,000 times, particularly preferably 50 to 20,000 times
It is 0 times. The temperature at which the surface pressure (π) and the area (A) are measured can be adjusted by the temperature of the subphase, and the preferred measurement temperature is 2 to 50°C, more preferably 5 to 30°C. The measurement time for the surface pressure (1t) and the area (A) is preferably 40 to 60 minutes.

Furthermore, in order to clarify the interaction between the amphipathic compound and the metal ion, only 7 to 8 samples are required for measurement.

Therefore, according to the method for determining transport conditions in membrane transport of the present invention, compared to conventional methods, the measurement time is shorter, the number of measurements is smaller, and the amount of amphipathic compound used can be reduced. I can do it.

Furthermore, when membrane transport is carried out under the conditions given by the interaction between the amphipathic compound and a specific substance such as a metal ion, evaluated by the method of the present invention, the membrane containing the amphipathic compound exhibits a low pH as predicted. If an increase in the ultimate area occurs from 0.
In a mixed system with metal ions where the ultimate area increases from a pH higher than 5, selective transport can be achieved without being affected by the metal ion concentration ratio. Therefore, the method of the present invention is a method for determining transport conditions extremely effectively to efficiently separate and recover metal ions in water using a membrane, and selectively removes specific valuable substances other than metal ions. It can also be applied to determining transportation conditions during transportation.
This is an extremely valuable decision method.

[Effect]

According to the present invention, specific substances in water, particularly valuable metals such as gallium, indium, and scandium, are transported using a membrane, and when determining transport conditions and predicting selectivity when separating and recovering, A monomolecular film of a water-insoluble amphiphilic compound having a functional group that interacts with a substance is formed on the water surface, the monomolecular film is then compressed to determine the ultimate area, and the ultimate area and the pH of the water are Transport conditions with high reliability can be determined with high precision based on the correlation between

〔Example〕

Hereinafter, the present invention will be explained in more detail based on the following examples. It goes without saying that the present invention is not limited to the following examples.

Example 1 pH is 1.57.1.85.2.06.2.31.2.
At 96.3.15.3.16 and 4.10, G a ”
Aqueous solutions with a concentration of I x 10-' + mol dII +-3 were prepared respectively, and a trough of HBM-AP3 type (inner dimensions, 715 m, 140 mm x 6 m, manufactured by Kyowa Interface Science Co., Ltd.)
), and the aqueous solution that rises from the top of the trough is swept with an aluminum plate (240mm x 29m x 5.6cm) coated with tetrafluoroethylene resin, and the water surface is approximately 0.5cm from the top of the trough. Adjust to a height of ~1.0 m. An aluminum plate (barrier) coated with tetrafluoroethylene resin was installed on the water surface compressor installed at one end of the trough (240 m
29m x 5.6m5) so that it is in contact with the water surface and straddles the short side of the trough, and immerses the glass Tilhelmy plate in the water near the other end of the trough to reduce the surface pressure to 0. do. Subsequently, on the water surface surrounded by a barrier and one end of the trough near which the Wilhelmy plate is immersed, a 2 X 10-"mol-da-"Hensen's solution of N-octadecanoyl-N-phenylhydroxyamine is added to the water surface. Gently develop 0.1cj using a microsyringe at precisely l/lI. After evaporating Hensen from above the water surface for about 10 minutes, 14.0c4- +n1n
The barrier movement is started at a speed of -' and the monolayer on the water surface is compressed at 23°C. While compressing, the accompanying surface pressure (π) and the area (A) of the monomolecular film on the water surface were continuously measured, and in about 40 minutes one π-A as shown in Figure 1 was obtained.
get a curve. From the obtained π-A curve, the linear portion where the surface pressure rises rapidly is extrapolated to the surface pressure of 0 (see FIG. 1), and the ultimate area is determined. Similar operation was carried out at pH 3,77,3,99.
, 4, 15, 4, 49, 5, 02 and 5, 61, A2
3゛Concentration is I x 10-'s.

1-da-' aqueous solution as a subphase,
The limit area at each pH was determined. Obtained ultimate area and pH
Figure 2 shows the relationship between Also, the pH is 3
．． 02 and the concentration is I x 10-'+s.

The π-A curve obtained when the above operation is performed using a Ga"-Al" mixed aqueous solution with a pH of 1-dm-3 as a subphase, It almost coincides with the measured π-8 line.

From these results, p of the mixed aqueous solution on the metal ion supply side is
By setting H to 2.5 to 3.5 and pH on the transport side to 1 or less, a hydrophobic film containing N-octadecanoyl-N phenylhydroxyamine can be formed by Ga"-Aj2" (1:
I, molar ratio) selectively transport Ga'' from the mixed aqueous solution,
This shows that it can be separated. Based on this prediction, N-octadecanoyl-N-phenylhydroxyamine in 1-decanol-kerosene (1:2.58,
Volume ratio) solution (1 degree I x 10-2 mol-d1')
Polypropylene porous II impregnated with 6.88 Xl 0-3cd! (Average pore diameter 0.27 μm, porosity 73%,
On the left side (Lside) of the film thickness 30 μm), a mixed aqueous solution of Ga "/l" with a pH of 3.0 (5X10-5
X 10-! s.

1-dm-”) and 100 cd of water with a pH of 0°5 on the right side (R31de), membrane transport was started at 23°C, and the changes in metal ion concentration of Lside and R51de over time are shown in Figure 3. Indicated.

According to the results shown in FIG. 3, G a ”1 of Lside
As the degree increases over time, R51de's ca ”
While the a degree is decreasing over time, the Lside Al”
.

The concentration hardly changes, indicating that Ga'' is selectively transported and separated from ACo by the impregnated membrane.

From this fact, it is clear that the monomolecular film of N-octadecanoyl-N-phenylhydroxyamine formed on the water surface and Ga"
Information regarding the interaction between Ga and Affi'' is extremely useful in determining the pH conditions and predicting the selectivity of metal ions at that pH when selectively transporting Ga'' using the above-mentioned impregnated membrane and separating and recovering it. It turns out to be useful.

Comparative Example I PH is 1.50.2.00.2.50.3.00.3.
50.4.00.4.80.5.38 and 5.90,
Six samples of 20C were each prepared with an aqueous solution having a Ga concentration of I x 10-3 mol-da-. 'l-Deca/-ノL/-ke.

Add 30cj of Syn (1:2.5B, volume ratio) solution to each, stir vigorously at 23°C, and add 0.5, 1, 2.5.
The concentration of Ga'' in the aqueous solution was measured every 6 and 8 hours.

On the other hand, the pH is 2.50.3.00.3.50.4.00.
4.80.5.38 and 5.90, AN” concentration is 1×
10-3++ol-dn+-' The same operation as above was performed for the aqueous solution, and the distribution coefficient was calculated from the concentration measurement value of each of the 9th degree of Affi "4 degrees in the aqueous solution.
It was plotted against the pH of the aqueous solution (see Figure 4).

From this FIG. 4, it is possible to predict the selectivity of a hydrophobic membrane containing N-octadecanoyl-N-phenylhydroxyamine and to determine the conditions for selective transport.

However, as is clear from the results shown in Table 1 below, in this comparative example, the concentration must be measured for each sample, and furthermore, the number of experiments, measurement time, and amount of chelating agent consumed were all lower than those in Example 1. This shows that the method of determining transport conditions using a monomolecular film in Example 1 is extremely useful.

Example 2 pH is 2.81.2.99.3.12.3.39.3.
87.4.27 and 5.15, the concentration is 3.88X10
The surface pressure and area of the monomolecular film were measured under the same conditions and operating methods as in Example 1, except that the A11 aqueous solution of ``mol-d++-'' was used as the subphase, and the π-A curve was obtained. The limit area was obtained from the π-Affi curve.The obtained limit area was plotted against the pH in the aqueous solution along with the limit area when the Ga''° aqueous solution of Example 1 was used as a subphase, and the relationship between pH and limit area was calculated. The relationship is shown in Figure 5. Also, when the pH is 2.40, the concentrations of Ga3゛ and A23゛ are I x 10-' and 3゜88 x 1O-1-o, respectively.
The same operation as in Example 1 was carried out using a mixed aqueous solution of Ga"-AIV, 3+, which is l-ds+-3, as a subphase. The π-A curve obtained here is as shown in FIG.
Ga” aqueous solution with H of 2.40 (fi degree: I
I O-'mo1. It agrees well with the π-A curve measured with dm-3) as a subphase. Also, the pH is 2.4
A13゛ aqueous solution of 0 (concentration, 3.88 x 10-”m
The πA curve measured with ol-d13) as a subphase is the chain double-dashed line in FIG.

5 and 6, the pH of the metal ion aqueous solution on the supply side is 2.3 to 2.7, and the pH of the transport side is 1.3 to 2.7, respectively.
By setting it to 0 or less, N-octadecanoyl-N
-A hydrophobic membrane containing phenylhydroxyamine is Affi
"is 388 times more molar than Ga" (150 times more by weight)
This shows that it is possible to selectively transport and separate Ga'' even from an aqueous solution in which it coexists in excess. Based on this prediction, the left side (
G a ”-A j1 with a pH of 2.40 on Lside)
! "Mixed aqueous solution (l x l O-'-5x lO-
”, lXl0-3-IXIO, 1 x 10-'-2
x 10-', I x 10-'-3X 10'-'m
100c+j of ol・d1') and 100d of water with a pH of 0.5 on the right side (Rside), membrane transport was started at 23°C, and the metal ion concentration of R51de was measured after 24 hours. Table 2 shows the Lside metal ion concentration and separation coefficient.

Table 2: Concentration of chelating agent 2; I X 10-”mol-d
a-”1-decal/kerosene 1/2.58 (volume ratio)
・Solution; Initial pH5Rside: pH0.50, Ls
ide: p R2,40, Temperature of solution; 23°C a); Initial concentration of Lside b); Concentration of R51de after 24 hours c); Separation coefficient = ((Ga”) */ (Al”) *) /((Ga
3°] L/ (^+”) L) Comparative Example 2 pH is 2.50.3.00.3.50.4.00 and 4
80°, the concentration is 38 molar ratio of the Ga” concentration in Comparative Example 1.
8 times excess of 3,88 X 10-'sol・d+
++-'A 4.36 IM of N-octadecanoyl-N-phenylhydroxyamine in each 13° aqueous solution
5g was added and stirred vigorously at 23°C. In this comparative example, approximately 130 g of chelating agent was required to obtain the relationship shown in FIG. 4 in comparative example 1. To confirm interactions with high-concentration metal ions such as
The chelating agent was added as a solid because a very large amount (1164 d) was required when used with dm-'). In addition, since the interaction in this comparative example occurs in a non-uniform solid-liquid state,
The reliability of the information obtained is low, and furthermore, pl(is 2.OO
~3.50 Ga''-AI!,'' mixed aqueous solution (1x 1
When the above-mentioned chelate was adsorbed on 0-"-3,88X 10-'mol-dm-"), the concentration ratio (CGa
"]/(Al")) decreases, making it difficult to measure the concentration of Ga".

As mentioned above, when evaluating the interaction of Ga with a chelating agent in the coexistence of a large amount of Ga by the conventional adsorption method, it requires a large number of experiments, takes too much measurement time, and requires a large amount of Ga. In addition to the problem of requiring a chelating agent of G when selectively transporting and separating Ga'' from a Ga''-Al'' mixed aqueous solution in which a large amount of Al''+ coexists using an impregnated membrane containing
It is simply impossible to determine selective transport conditions for a.

Example 3 pH is 0.81.1.21.1.62.1.91.2.
45. At 2.98 and 3.26, the concentration is I X I Q
−'mol・dm−” of Ga” aqueous solution and pH is 1
．． 98.2.36.2.96.3.41.3.56 and 3.86 and the concentration is I X 10-'5ol-d+*-
3 Al! +Aqueous solution was used as the subphase and N-nitroso-1'J-p-octadecylphenylhydroxylamine ammonium salt was used as the chelating agent. Obtained.

According to this relationship, when Ga'' is used as a subphase, the ultimate area starts to increase from around PH1,2, and the
The increase ends around 2. On the other hand, when A13' is a subphase, the ultimate area starts increasing around pH 2.2 and ends around pH 3.

Based on these results, a solution of N-nitroso-N-p-octadecylphenylhydroxylamine ammonium salt in kerosene (concentration 2.46 x 10'mol-dm
Polypropylene porous flat membrane impregnated with 6.88 x 10-3 mol-dm-'
, porosity 73%, film thickness 30 μm) on the left side (Ls
Pour 100 cj of Ga"-AN" mixed aqueous solution (5X1 (I" 5 Membrane transport was carried out at C. As time passed, the concentration of Ga'' on the right side increased, and
The concentration of 34 decreases. On the other hand, the concentration of Al''° hardly changes.

Therefore, the above membrane transport conditions determined based on the PH dependence (relationship between ultimate area and pH) of the interaction between Ga3+ and Al'' and the chelating agent, respectively, selectively transport Ga'° and allow AI! , 3° is found to be suitable as conditions for separation from a mixed system.

Example 4 pH is 1.08.1.28.1.45.1.98.2.
46. At 3.01 and 3.76, In+3 aqueous solution with concentration lXl0-'haze o1-da-' and pH 3.16
．． 3.78.4.12.4.46.5.01 and 5,7
6, the concentration of Zn is I x 10-'5ol-da-'
``The relationship between the ultimate area and PH was obtained in the same manner as in Example 1 except that an aqueous solution was used as the subphase and N-nitroso-N-p-octadecylphenylhydroxylamine ammonium salt was used as the chelating agent. .

According to this relationship, when In3° is a subphase, the ultimate area starts to increase from around P H1,7, and p
It ends around H2.5. On the other hand, when Zn'' is used as a subphase, the ultimate area begins to increase around pH 3.8 and ends around pH 4.5.

Based on this result, a solution of N-nitroso-N-P octadecylphenylhydroxylamine ammonium salt in kerosene (2.46 x 10-3 m once) was prepared.

Polypropylene porous flat membrane impregnated with 6.80X I O-”c+I (average pore size 0.27 μm
, porosity 73%, film thickness 30 μm) on the left side (Lsid
e) an In”-Zn”° mixed aqueous solution with a pH of 3.50 (
5×10-' 5 X 10-'mol-dm-')
100c+a, 10M of water with a pH of 0.5 was charged on the right side (Rside), and membrane transport was performed at 23°C. As a result, as time passes, the In'' concentration on the right side increases and the In'' concentration on the left side decreases, while the Zn'' concentration hardly changes. Therefore, the interaction between In'° and Zn'' and the chelating agent The above membrane transport conditions determined based on the pH dependence of action (relationship between ultimate area and pH) are appropriate for selectively transporting In''!- and separating it from the mixed system with Zn''. I understand.

Example 5 pH is 3.1O13,38,3,56,3,90,4,
13, 4, 32, 5,00 and 5.70 with a concentration of 1x
Sc” aqueous solution of lO-'sol・dm-'' and pH is 3.85.4.18.4.2L4.62.4.95.5
．． Fe''-L-ascorbic acid mixed aqueous solution (concentration: I x 10-'-2X 10-
3 mol-dm-') as the subphase, the same chelating agent as in Example 1, and the same procedure as in Example 1 to obtain the π-A curve. The relationship between the ultimate area and pH was obtained.

According to this relationship, when Sc'' is a subphase, the limit area begins to increase around P H3,3, and P
It ends around H3.8. On the other hand, when Fe"L-ascorbic acid mixed aqueous solution is used as a subphase, the ultimate area starts to increase around pH 3.85, and pH 4.3
Ends nearby.

Based on these results, N-octadecanoyl-N-
Phenylhydroxylamine in 1-decanol-kerosene (1:2.58, volume ratio) solution Cfi degree I X l
O-"mol・dm-") 6.88 X I 0-3
On the left side (Lside) of the aj-impregnated polypropylene porous flat membrane (average pore diameter 0°27 μm, porosity 73%, film thickness 30 μm), a mixture of Sc"-Fe3"-L-ascorbic acid with a pH of 3.90 was added. Aqueous solution (5X10-35X
10-31 x 10-'mo1-dm-3)
0c+il, 100 ctll of water with a pH of 1.5 was placed on the right side (Rside), and membrane transport was performed at 23°C. As time passes, the concentration of Sc” on the right side increases, and the concentration of Sc on the left side increases.
The concentration of "Fe" decreases. On the other hand, the concentration of "Fe" hardly changes. Therefore, the pH dependence (limit area and p
The above membrane transport conditions determined based on the relationship of Sc
"Fe with selective transport of L-ascorbic acid"
It can be seen that these conditions are suitable for separation from a mixed system with

〔Effect of the invention〕

According to the method for determining transport conditions in membrane transport of the present invention,
It is possible to accurately understand the interaction between specific substances such as valuable metals and amphiphilic compounds, and it is also possible to determine transport and separation conditions with high reliability.

[Brief explanation of the drawing]

Figure 1 shows the relationship between the surface pressure and the area of the monolayer (π-A curve) when compressing a monolayer of N-octadecanoyl-N-phenylhydroxylamine on the water surface to find the ultimate area. The graph shown in Figure 2 shows the PH and N-octadecanoyl-N- of subphases containing Ga'' and Al'', respectively.
Figure 3 is a graph showing the relationship between the ultimate area of phenylhydroxylamine and pH.
A graph showing the concentration changes of each ion when transporting and separating Ga'° in an Alm-mixed aqueous solution.
"Aqueous solution and Affi" Partition coefficient and p of Ga" and Affi" between the hydrophobic solution of the chelating agent and water in the aqueous solution
A graph showing the relationship with H, Figure 5 is a diagram equivalent to Figure 2 when the concentration of Ga'' is changed, and Figure 6 is a graph showing the relationship between N-octadecanoyl-N-phenylhydroxylamine in a mixed aqueous solution of Ga''-Al''. and π−, which indicates the interaction with each metal ion.
It is a graph showing an A curve.

Claims (2)

[Claims] (1) In a method for determining transport conditions for a specific substance when selectively transporting and separating a specific substance from multiple substances contained in water using a membrane, the membrane has a functional group that interacts with the specific substance. A monomolecular film of a water-insoluble amphiphilic compound is formed on the water surface, the monomolecular film is then compressed to determine the ultimate area, and the transport is carried out based on the correlation between the ultimate area and the pH of the water. A method for determining transport conditions in membrane transport, the method comprising determining the conditions. (2) The method for determining transport conditions in membrane transport according to claim (1), wherein the specific substance is a metal ion.