Modifier Selection Support Device, Modifier Selection Support Method, and Program

Abstract

To support selection of a modifying agent in a solvent extracting method.SOLUTION: A modifying agent selection support device, which supports selection of a modifying agent in a solvent extracting method, comprises: a molecular information obtaining part that obtains molecular information about a diluent molecule, about an extracting agent molecule and about a plurality of modifying agent molecules which become candidates; a modifying agent candidate selecting part that calculates an HLB value of a complex of the extracting agent molecule and each of the plurality of modifying agent molecules and narrows down the modifying agent molecules which become candidates on the basis of the calculated HLB value; a molecular dynamics calculating part that performs molecular dynamics calculation in a three-dimensional model including an organic phase and a water phase in a case where each of the narrowed-down extracting agent molecules is used, so as to calculate pressure tensor in an interface between the organic phase and the water phase; and an interface tension calculating part that calculates interface tension in the interface on the basis of the calculated pressure tensor of each of the narrowed-down modifying agent molecules.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a modifier selection support device, a modifier selection support method, and a program.

Background Art

[0002] One method for selectively extracting metal ions contained in an aqueous solution is the solvent extraction method (SX: Solvent Extraction). In the solvent extraction method, two immiscible phases are used, and a combination of an organic phase (organic solvent) and an aqueous phase (aqueous solution) is widely used. Metal ions bind to an extractant added to the organic phase near the two-phase interface and move into the organic phase. Therefore, the stability of the interface (phase separability) greatly affects the extraction equilibrium and extraction rate of metal ions.

[0003] When an extractant with strong surface activity is used, the interfacial tension decreases and an emulsified phase is formed, making phase separation difficult. In such a case, a new surfactant is added to suppress the emulsified phase. The surfactant at this time is called a modifier and plays a role in increasing the interfacial tension.

[0004] The phase separability changes depending on the combination of the organic solvent (also called a diluent) and the modifier, and the specific gravity, interfacial tension, and viscosity of the diluent have a great influence. It is also related to the temperature of the system. In particular, when the interfacial tension is large, the phase separability is good.

[0005] Therefore, a method for selecting a modifier used in solvent extraction based on the interfacial tension has been studied. For example, Patent Document 1 discloses an apparatus for measuring the interfacial tension by the centrifugal liquid membrane method, which consists of measuring an ultrathin film in a phase-separated state.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] However, when experimentally measuring the interfacial tension using the above-described conventional technology to select a modifier, there is a problem that it takes time and cost as the number of candidate modifiers increases.

[0008] The present invention has been made in view of the above circumstances, and an object thereof is to assist in the selection of a modifier in a solvent extraction method.

Means for Solving the Problems

[0009] To achieve the above object, a modifier selection support device according to an aspect of the present invention is a modifier selection support device for assisting in the selection of a modifier in a solvent extraction method, a molecular information acquisition unit that acquires molecular information of diluent molecules, extractant molecules, and a plurality of candidate modifier molecules; a modifier candidate selection unit that calculates the HLB (Hydrophilic-Lipophilic Balance) value of a complex of each of the extractant molecules and the plurality of modifier molecules, and narrows down candidate modifier molecules based on the calculated HLB value; a molecular dynamics calculation unit that performs molecular dynamics calculations on a three-dimensional model including an organic phase and an aqueous phase when each of the narrowed-down modifier molecules is used, and calculates a pressure tensor at the interface between the organic phase and the aqueous phase; an interfacial tension calculation unit that calculates the interfacial tension at the interface based on the pressure tensor calculated for each of the narrowed-down modifier molecules.

Advantages of the Invention

[0010] It is possible to assist in the selection of a modifier in a solvent extraction method.

Brief Description of the Drawings

[0011]

Figure 1

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Embodiments for Carrying Out the Invention

[0012] Hereinafter, embodiments of the present invention (the present embodiments) will be described with reference to the drawings.

[0013] (Functional Configuration of Modifier Selection Support Device) FIG. 1 is a diagram showing an example of the functional configuration of the modifier selection support device.

[0014] The modifier selection support device 1 according to the present embodiment is a device that supports the selection of a modifier in the solvent extraction method. The modifier is Specifically, the modifier selection support device 1 includes a molecular information acquisition unit 11, a modifier candidate selection unit 12, a molecular dynamics calculation unit 13, an interfacial tension calculation unit 14, a display unit 15, and a modifier selection unit 16.

[0015] The molecular information acquisition unit 11 acquires molecular information of diluent molecules, extractant molecules, and a plurality of modifier molecules as candidates. The molecular information is information indicating the chemical structure of the molecule, and includes the number and type of atoms constituting the molecule, data indicating the relationship between atoms, and the like. The data indicating the relationship between atoms is data including the size of the atoms, the angle of the bond with the bonded atoms, and the like.

[0016] The modifier candidate selection unit 12 performs a simulation of molecular docking (a method of obtaining a stable complex structure by randomly arranging each of the extractant molecule and a plurality of candidate modifier molecules and comparing the energies of their structures) between the extractant molecule and each of the plurality of candidate modifier molecules, and generates information indicating a complex of the extractant molecule and the modifier molecule. Then, the modifier candidate selection unit 12 calculates the HLB value of the complex, and narrows down the candidate modifier molecules based on the calculated HLB value. Specifically, the modifier candidate selection unit 12 calculates the three-dimensional structure based on the molecular information of the complex, and calculates the HLB value of the complex by the Griffin method or the like. Then, the modifier candidate selection unit 12 narrows down the candidate modifier molecules by comparing the difference between the HLB value and a preset reference value with a threshold value.

[0017] The molecular dynamics calculation unit 13 generates a three-dimensional model of a system having an organic phase and an aqueous phase for each of the narrowed-down modifier molecules, performs molecular dynamics calculations on the generated three-dimensional model, and calculates the pressure tensor. The three-dimensional model is data indicating the arrangement of each molecule. The organic phase contains diluent molecules and modifier molecules, and the aqueous phase contains water molecules (counter ions if necessary).

[0018] Specifically, for each of the narrowed-down modifier molecules, the molecular dynamics calculation unit 13 generates, as a three-dimensional model, data indicating the arrangement of each molecule in a system having an organic phase and an aqueous phase based on the molecular information acquired by the molecular information acquisition unit 11. Here, the molecular dynamics calculation unit 13 generates a three-dimensional model in which the complex of the extractant molecule and each modifier molecule is dispersed in space and randomly arranged. Then, the molecular dynamics calculation unit 13 performs molecular dynamics calculations and calculates the pressure tensor for each of the narrowed-down modifier molecules.

[0019] The interfacial tension calculation unit 14 calculates the interfacial tension at the interface between the two phases based on the pressure tensor calculated for each of the narrowed-down modifier molecules.

[0020] The display unit 15 displays, on a screen such as a display, information indicating the interfacial tension when each of the narrowed-down modifier molecules is used. Note that the display unit 15 may display the information on another device, such as a terminal operated by the user.

[0021] Based on the interfacial tension value, the modifier selection unit 16 selects an optimal modifier. Furthermore, the display unit 15 may display information indicating the selected modifier.

[0022] (Operation of the modifier selection support device) Next, the operation of the modifier selection support device 1 will be described with reference to the drawings. FIG. 2 is a flowchart showing an example of the flow of the modifier selection support process.

[0023] Upon receiving a user operation, the molecular information acquisition unit 11 acquires the molecular information of the diluent molecule, the extractant molecule, and a plurality of candidate modifier molecules (step S11).

[0024] Next, the modifier candidate selection unit 12 selects one from the candidate modifier molecules (step S12), calculates the HLB value of the complex composed of the extractant and the selected modifier (step S13), and then the modifier candidate selection unit 12 determines whether the difference between the HLB value and the reference value is less than or equal to the threshold (step S14). Here, the reference value is a value set in advance as a value indicating an appropriate HLB value for the complex. For example, the reference value is 7, 8, etc.

[0025] When the modifier candidate selection unit 12 determines that the difference between the HLB value and the reference value is not less than the threshold value (step S14: NO), it returns to the process of step S12 to select a modifier molecule that has not been selected. Also, when the modifier candidate selection unit 12 determines that the difference between the HLB value and the reference value is less than the threshold value (step S14: YES), the molecular dynamics calculation unit 13 generates a three-dimensional model of a system having an organic phase and an aqueous phase based on the molecular information of the diluent molecule and the selected modifier molecule (step S15). Here, the molecular dynamics calculation unit 13 may perform a structure optimization calculation such as a molecular mechanics (MM: Molecular Mechanics) calculation, a molecular dynamics (MD: Molecular Dynamics) calculation, or a quantum chemistry (QM: Quantum Mechanics) calculation.

[0026] Next, the molecular dynamics calculation unit 13 calculates the pressure tensor at the interface by molecular dynamics calculation (step S16). The pressure tensor is represented as a tensor (Pxx, Pyy, Pzz) by the XYZ axes defined in advance in the space where the diluent molecules exist.

[0027] Specifically, the molecular dynamics calculation unit 13 executes a temperature increase calculation that simulates a state in which the temperature is gradually increased to room temperature in the generated three-dimensional model. Next, the molecular dynamics calculation unit 13 performs an NVT calculation that simulates so that the number of atoms, volume, and temperature are each maintained at a specified value. Subsequently, the molecular dynamics calculation unit 13 performs an NPT calculation that simulates so that the number of atoms, pressure, and temperature are each maintained at a specified value, and calculates the pressure tensor at the interface based on the data of the last 0.1 ns in the NPT calculation.

[0028] Next, the interfacial tension calculation unit 14 calculates the interfacial tension based on the pressure tensor (step S17). Specifically, the interfacial tension calculation unit 14 calculates the interfacial tension σ by the following formula (1).

[0029] σ = (L / 2) × {Pzz - (1 / 2) × (Pxx + Pyy)} ··· (1) Here, (Pxx, Pyy, Pzz) is the pressure tensor, and L is the cell size in the normal direction of the interface.

[0030] Next, the modifier selection support device 1 determines whether all modifiers have been calculated (step S18). When the modifier selection support device 1 determines that there is a modifier that has not been calculated (step S18: NO), it returns to step S12, selects one from the modifiers that have not been calculated yet, and executes the process.

[0031] When the modifier selection support device 1 determines that all modifiers have been calculated (step S18: YES), the display unit 15 displays the calculation result of the interfacial tension (step S19).

[0032] Subsequently, the modifier selection unit 16 selects a modifier, and the display unit 15 displays information indicating the selected modifier (step S20). Specifically, the modifier selection unit 16 stores information serving as a criterion for selecting a modifier based on the interfacial tension in advance, and selects a modifier based on the information. For example, the modifier selection unit 16 may select a modifier whose interfacial tension is close to a reference value (e.g., 20 [mN / m]). Also, the modifier selection unit 16 may select one modifier, or may select a plurality of modifiers, and may also be determined based on the ranking of the recommended modifiers as a criterion.

[0033] Note that the modifier selection support device 1 may not include the modifier selection unit 16, and may not execute the processes of step S19 and step S20. In that case, the user may select a modifier based on the displayed calculation result of the interfacial tension.

[0034] Next, the hardware configuration of the modifier selection support device 1 will be described. FIG. 3 is a diagram showing an example of the hardware configuration of the modifier selection support device.

[0035] The modifier selection support device 1 is configured by a computer and includes, for example, a CPU (Central Processing Unit) 101, a main memory device 102, an auxiliary storage device 103, an input device 104, a display device 105, a communication interface device 106, and a drive device 107. These devices are connected by a bus.

[0036] The CPU 101 is a main control unit that controls the operation of the modifier selection support device 1. By reading and executing the program stored in the main memory device 102, it realizes various functions described later.

[0037] The main memory device 102 reads and stores the program from the auxiliary storage device 103 when the modifier selection support device 1 is started. The auxiliary storage device 103 stores the installed program and also stores files, data, etc. necessary for various functions described later.

[0038] The input device 104 is a device for inputting various kinds of information and is realized by, for example, a keyboard, a pointing device, etc. The display device 105 is for displaying various kinds of information and is realized by, for example, a display, etc. The communication interface device 106 includes a LAN card, etc. and is used for connection with other devices, etc.

[0039] The program according to this embodiment is at least a part of various programs that control the modifier selection support device 1. The program is provided, for example, by distribution of a storage medium 108 or download from a network. The storage medium 108 recording the program can use various types of storage media such as a storage medium that optically, electrically, or magnetically records information like a CD-ROM, a flexible disk, a magneto-optical disk, etc., a semiconductor memory that electrically records information like a ROM, a flash memory, etc.

[0040] Also, when the storage medium 108 storing the program is set in the drive device 107, the program is installed from the storage medium 108 via the drive device 107 into the auxiliary storage device 103. A program downloaded from a network is installed into the auxiliary storage device 103 via the communication interface device 106.

[0041] (Example) An example of the modifier selection support device 1 according to the present embodiment will be described. The diluent molecules are cyclohexane (C6H 12 ), the extractant molecules are LIX63, and the candidate modifier molecules are (a) 1-octanol, (b) 2-ethylhexanol, and (c) tributyl phosphate. The results of the implementation are shown below.

[0042] FIG. 4 is a diagram showing an example of a three-dimensional model. The three-dimensional model generated by the molecular dynamics calculation unit 13 may be arranged such that, for example, boxes 20 including an organic phase 21 and an aqueous phase 22 are arranged side by side in the XY direction. Further, the length Lx in the X direction and the length Ly in the Y direction of the box 20 are, for example, 50 angstroms each, and the length Lz in the Z direction of the box 20 is, for example, 100 angstroms.

[0043] The molecular dynamics calculation unit 13 generates, for example, two phases in the box 20: an organic phase in which about 25 extractant molecules (LIX63) and about 25 modifier molecules are arranged in a box containing about 600 diluent molecules (cyclohexane), and an aqueous phase containing about 4300 water molecules.

[0044] FIG. 5 is a diagram showing an example of a molecular model of a modifier. (a) shows the molecular model of the modifier molecule 1-octanol, (b) shows the molecular model of the modifier molecule 2-ethylhexanol, and (c) shows the molecular information (information indicating the arrangement of each atom and the relationship of bonds) acquired by the molecular information acquisition unit 11 as the molecular model of the modifier molecule tributyl phosphate.

[0045] FIG. 6 is a diagram showing an example of an interfacial tension calculation result screen. The interfacial tension calculation result screen 30 is an example of a screen displayed on the display unit 15 in step S19 of the modifier selection support process. On the interfacial tension calculation result screen 30, the name of each modifier and the interfacial tension calculated for each modifier are displayed in association with each other.

[0046] Further, in step S20 of the modifier selection support process, the display unit 15 displays information indicating the modifier selected by the modifier selection unit 16. For example, the modifier selection unit 16 selects tributyl phosphate having a value close to a reference value (for example, 20 [mN / m]). The display unit 15 may display the selected tributyl phosphate on the interfacial tension calculation result screen 30 in a different character color from the others.

[0047] According to the modifier selection support device 1 according to the present embodiment, by calculating the interfacial tension by molecular dynamics calculation and using it as an index of phase separability, efficient selection of a modifier can be supported.

[0048] In addition, the modifier selection support device 1 calculates the HLB value of the complex of each of the extractant molecule and a plurality of modifier molecules, and narrows down the candidate modifier molecules based on the calculated HLB value, thereby reducing the number of modifier molecules to be calculated by molecular dynamics calculation by a simple method and reducing the calculation cost. In particular, since the modifier acts at the interface, the function of activating the interface can be predicted by the HLB value, so that the modifier molecules can be appropriately narrowed down.

[0049] The modifier candidate selection unit 12 may narrow down to the modifier molecules constituting the complex in which the difference between the preset reference value and the calculated HLB value is equal to or less than the threshold value. Thereby, it is possible to narrow down to the modifier molecules constituting the complex having an appropriate HLB value.

[0050] The modifier selection support device 1 may further include a modifier selection unit 16 that selects a modifier based on the calculated interfacial tension. Thereby, the variation among users in the selection of the modifier can be suppressed, and selection based on a uniform criterion becomes possible.

[0051] Further, the modifier selection unit 16 may select a modifier having an interfacial tension close to a preset reference value. If a modifier with too large an interfacial tension is selected, it is too stable to mix, so the interface is not activated. Conversely, if the interfacial tension is too small, it is not stable and mixes, so it does not separate into two phases. Therefore, based on the reference value considering such a trade-off, the selection of an appropriate modifier can be supported.

[0052] Further, the molecular dynamics calculation unit 13 may generate a three-dimensional model in which complexes of extractant molecules and modifier molecules are randomly arranged by structure optimization calculation. As a result, in creating the three-dimensional model, it is not necessary to specify the arrangement of all molecules, so the generation of the three-dimensional model can be realized by a simple operation.

[0053] Further, the molecular dynamics calculation unit 13 may perform at least any one of heating calculation, NVT calculation, and NPT calculation to calculate the pressure tensor. This makes it possible to attempt calculations for a large number of candidates, reducing costs and labor.

[0054] The modifier selection support device 1 may further include a display unit 15 that displays, in association with each other, the name indicating the modifier for each candidate modifier molecule and the information indicating the calculated interfacial tension. Thereby, information for supporting the selection can be presented to the user.

[0055] As described above, the present invention has been described based on the present embodiment, but the present invention is not limited to the requirements shown in the above embodiment. In these respects, it can be changed within the scope that does not deviate from the gist of the present invention, and can be appropriately determined according to the application form.

Industrial Applicability

[0056] The present invention can be applied to the selection of a modifier when selectively extracting metal ions contained in an aqueous solution by a solvent extraction method.

Description of Symbols

[0057] 1 Modifier Selection Support Device 11 Molecular Information Acquisition Unit 12 Modifier Candidate Selection Unit 13 Molecular Dynamics Calculation Unit 14 Interfacial Tension Calculation Unit 15 Display Unit 16 Modifier Selection Unit 20 Box 21 Organic Phase 22 Aqueous Phase 30 Interfacial Tension Calculation Result Screen 101 CPU 102 Main Memory Device 103 Auxiliary Memory Device 104 Input Device 105 Display Device 106 Communication Interface Device 107 Drive Device 108 Storage Medium

Claims

1. A modifier selection support device for supporting the selection of a modifier in a solvent extraction method, comprising: a molecular information acquisition unit that acquires molecular information of diluent molecules, extractant molecules, and a plurality of candidate modifier molecules; a modifier candidate selection unit that calculates the HLB value of a complex of each of the extractant molecules and the plurality of modifier molecules, and narrows down the candidate modifier molecules based on the calculated HLB value; a molecular dynamics calculation unit that performs molecular dynamics calculations on a three-dimensional model including an organic phase and an aqueous phase when each of the narrowed-down modifier molecules is used, and calculates a pressure tensor at the interface between the organic phase and the aqueous phase; an interfacial tension calculation unit that calculates the interfacial tension at the interface based on the pressure tensor calculated for each of the narrowed-down modifier molecules. Modifier selection support device.

2. The modifier candidate selection unit narrows down to modifier molecules that form a complex in which the difference between a preset reference value and the calculated HLB value is equal to or less than a threshold value. The modifier selection support device according to claim 1.

3. Further comprising a modifier selection unit that selects a modifier based on the calculated interfacial tension. The modifier selection support device according to claim 1 or 2.

4. The modifier selection unit selects the modifier that gives an interfacial tension having a value close to a preset reference value. The modifier selection support device according to claim 3.

5. The molecular dynamics calculation unit generates the three-dimensional model in which the complex of the extractant molecule and the modifier molecule is randomly arranged by a structural optimization calculation. The modifier selection support device according to any one of claims 1 to 4.

6. The molecular dynamics calculation unit calculates the pressure tensor by performing at least any one of a temperature increase calculation, an NVT calculation, and an NPT calculation. The modifier selection support device according to any one of claims 1 to 5.

7. Further comprising a display unit that associates and displays the name indicating the modifier for each of the candidate modifier molecules and the information indicating the calculated interfacial tension. The modifier selection support device according to any one of claims 1 to 6.

8. A method executed by a computer for supporting the selection of a modifier in a solvent extraction method, the method comprising: a step of acquiring molecular information of diluent molecules, extractant molecules, and a plurality of candidate modifier molecules; Calculating the HLB value of the complex of each of the extractant molecules and the plurality of modifier molecules, and narrowing down the candidate modifier molecules based on the calculated HLB value; Performing molecular dynamics calculations on a three-dimensional model including an organic phase and an aqueous phase when each of the narrowed-down modifier molecules is used, and calculating the pressure tensor at the interface between the organic phase and the aqueous phase; Calculating the interfacial tension at the interface based on the pressure tensor calculated for each of the narrowed-down modifier molecules. Modifier selection support method.

9. A computer for assisting in the selection of a modifier in a solvent extraction method, Obtaining molecular information of diluent molecules, extractant molecules, and a plurality of candidate modifier molecules; Calculating the HLB value of the complex of each of the extractant molecules and the plurality of modifier molecules, and narrowing down the candidate modifier molecules based on the calculated HLB value; Performing molecular dynamics calculations on a three-dimensional model including an organic phase and an aqueous phase when each of the narrowed-down modifier molecules is used, and calculating the pressure tensor at the interface between the organic phase and the aqueous phase; Calculating the interfacial tension at the interface based on the pressure tensor calculated for each of the narrowed-down modifier molecules; A program for causing the above to be executed.

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