WO2022239843A1

WO2022239843A1 - In-liquid substance separation membrane using octosilicate material and production method for same

Info

Publication number: WO2022239843A1
Application number: PCT/JP2022/020111
Authority: WO
Inventors: 敬三中川; 卓司新谷; 朋久吉岡; 裕丈北川; 紀之高熊
Original assignee: 国立大学法人神戸大学; 日産化学株式会社
Priority date: 2021-05-13
Filing date: 2022-05-12
Publication date: 2022-11-17
Also published as: JPWO2022239843A1; TW202337552A

Abstract

[Problem] To provide: an in-liquid substance separation membrane molded body that is made of highly chemical-resistant components, has a high membrane solvent permeation speed, and efficiently separates the substances (e.g., the ionic organic substances) in a liquid; and a production method for the in-liquid substance separation membrane molded body. [Solution] According to the present invention, an in-liquid substance separation membrane molded body includes: lamellar particles (A) that include a quaternary ammonium ion (a) that has a total of 15–45 carbon atoms and has one or two alkyl groups that have 10–20 carbon atoms and an anion surfactant (b) that has an ammonium ion, have an average thickness of 0.7–100 nm, an average length of 50–10,000 nm, and a (maximum length/width orthogonal to maximum length) ratio of 1.0–10.0, and are a separated layer substance formed by separating the layers of a layered compound; and a base material (B). The lamellar particles (A) are an aqueous dispersion of the lamellar particles (A) that includes (a) and (b) for the separation of the layers of the layered compound. The 90% cumulative particle size value for a laser diffraction particle size distribution of the lamellar particles (A) of the aqueous dispersion is 1.5–10 times the average value for the particle size distribution.

Description

Submerged substance separation membrane using octosilicate material and its manufacturing method

The present invention relates to a liquid-substance separation membrane compact using plate-like particles, which is a release layer material due to delamination of a layered compound, and a method for producing the same.

Attempts have been made to use membrane technology to selectively remove substances (eg, ionic components) in solution. It is attracting attention from the viewpoint of environmental technology and resource reuse.
For example, it has been disclosed to remove heavy metal ions from an aqueous solution using a metal ion separation membrane containing a metal ion transporting ligand (see Patent Document 1). The polymer membrane is a cellulose derivative, and kemp acid derivatives such as kemp acid decylamide and kemp acid dodecylamide are used as ligands to transport copper ions, lead ions, mercury ions, magnesium ions, calcium ions, etc. through the membrane. It is stated that he has the ability.
Further, a dispersion of a plate-like material formed from a peeling layer material by delamination of a layered compound and a gas separation membrane using the dispersion have been disclosed (see Patent Document 2).

JP-A-10-290927 WO 2020/153352 pamphlet

The present invention relates to a separation membrane made of an octosilicate material that can efficiently remove substances (eg, ionic substances) in liquids. In addition, the present invention has high chemical resistance due to the separation membrane component, high solvent permeation rate of the solution containing the substance to be separated in the membrane, and efficiently separates substances in the liquid (for example, ionic organic substances). An object of the present invention is to provide a separation membrane molded article and a method for producing the same.

As a first aspect of the present invention, a quaternary ammonium ion (a) having a total of 15 to 45 carbon atoms and 1 to 2 alkyl groups having 10 to 20 carbon atoms and an ammonium ion-containing anion and an ionic surfactant (b), having an average thickness of 0.7 to 100 nm, an average major axis of 50 to 10,000 nm, and (maximum major axis/width perpendicular to the maximum major axis) = 1.0 to 10.0 and a liquid-substance separation membrane containing a plate-like particle (A) that is a delamination substance due to delamination of a layered compound, and a substrate (B) that supports the liquid-substance separation membrane. molding,
As a second aspect, the molded article for separating substances in liquid according to the first aspect, wherein the layered compound is ilaite;
As a third aspect, the submerged substance separation membrane is a composite film of ilaite and graphene oxide. The film is formed from an aqueous dispersion of the plate-like particles (A) containing (a) and (b) used for delamination of the layered compound, and the plate-like particles (A) in the aqueous dispersion are Separation of substances in liquid according to any one of the first aspect to the third aspect, wherein the 90% cumulative particle size value in the laser diffraction particle size distribution is 1.5 to 10 times the average value of the particle size distribution. membrane molded body,
As a fifth aspect, the liquid-substance separation membrane is formed from an aqueous dispersion of plate-like particles (A) containing the above (a) and (b) used for delamination of the layered compound, and the aqueous dispersion A plate having an average particle size of 10 to 10,000 nm as measured by a liquid dynamic light scattering method, and having the above (a) and (b) both in the range of 0.01 to 50.0% by mass with respect to (A). The liquid-substance separation membrane compact according to any one of the first to fourth aspects, which is the shaped particles (A),
As a sixth aspect, any one of the first to fifth aspects, wherein the substrate (B) is at least one porous substrate selected from the group consisting of cellulose, synthetic polymers, and ceramics. The liquid-substance separation membrane molded product described above,
As a seventh aspect, the submerged substance separation membrane molded article according to the sixth aspect, wherein the cellulose is nitrocellulose, carboxymethyl cellulose, or hydroxyethyl cellulose;
As an eighth aspect, in liquid according to the sixth aspect, wherein the synthetic polymer is polyethersulfone, polysulfone, polyvinylidene fluoride, polyvinylidene chloride, polyethylene vinyl alcohol, polyvinyl alcohol, polyacrylic acid, or polymethacrylic acid. material separation membrane molded body,
As a ninth aspect, the liquid-submerged substance separation membrane compact according to the sixth aspect, wherein the ceramic is silica, alumina, or mullite;
As a tenth aspect, the first aspect to the ninth aspect, wherein the liquid-substance separation membrane is formed on the surface of the substrate (B), and the liquid-substance separation membrane has a thickness of 1.5 nm to 10 μm. The liquid-submerged substance separation membrane molded article according to any one of
As an eleventh aspect, any one of the first aspect to the tenth aspect, wherein the solvent permeation rate of the solution containing the substance to be separated is 0.1 to 100 L·m ⁻² ·hr ⁻¹ ·bar ⁻¹ The liquid-substance separation membrane molded product described above,
As a twelfth aspect, the molded body for separating substances in liquid according to any one of the first aspect to the eleventh aspect, wherein the substance removal rate of the solution containing the substance to be separated is 15 to 99%;
As a thirteenth aspect, the submerged substance separation membrane compact according to any one of the first to twelfth aspects, wherein the substance to be separated is an ionic compound;
As a thirteenth aspect, the molded article for separating substances in liquid according to the twelfth aspect, wherein the ionic compound is an organic compound having at least a sulfonate ion or a carboxylate ion;
As a fifteenth aspect, the solution containing the substance to be separated is a solution containing the substance to be separated and at least one or more solute molecules having a molecular weight different from that of the substance to be separated, and the substance to be separated in the solution is concentrated. The liquid-substance separation membrane compact according to any one of the first to fourteenth aspects for
As a sixteenth point of view,
The following steps (i) to (vi):
(i) Step: An aqueous dispersion of a silicic acid compound is hydrothermally treated at a temperature of 90 to 150° C., and the resulting layered compound is separated and washed with water. the process of
(ii) step: adding to the aqueous dispersion obtained in step (i) a total carbon atom number of 15 to 45 and a carbon atom number of 10, which is 1 to 3 times the ion exchange capacity of the layered compound; adding a quaternary ammonium ion (a) having 1 to 2 alkyl groups of ∼20 and heating at 40 to 100°C for 12 to 48 hours;
(iii) step: adding pure water to the liquid obtained in step (ii), and removing the sodium ion-containing liquid from the system so that the sodium ion concentration in the liquid is 100 ppm or less;
(iv) step: after dispersing the wet gel included in step (iii) in an anionic surfactant (b) aqueous solution containing ammonium ions at a concentration of 0.01 to 1% by mass, ammonia is further added; adding to adjust the pH in the liquid to 9.0 to 12.0;
(v) step: a step of heating the liquid obtained in step (iv) at 40 to 90° C. for 12 to 48 hours to obtain a dispersion of plate-like particles (A);
(vi) Step: A first aspect including a step of forming a liquid-substance separation membrane on the surface of the substrate (B) using the dispersion of the plate-like particles (A) obtained in the (v) step. A method for producing a liquid-substance separation membrane molded product according to any one of the 15th aspects,
As a seventeenth aspect, the step (vi) forms a plate-like particle (A) layer on the surface of the substrate (B) using the dispersion liquid of the plate-like particles (A) obtained in the step (v). and laminating a graphene oxide layer on the layer using an aqueous dispersion of graphene oxide. A method for producing a material separation membrane molded article.
As an eighteenth aspect, the step (vi) of forming a film on the surface of the substrate (B) using the dispersion of the plate-like particles (A) obtained in the step (v) is performed by suction filtration or pressure filtration. The method for manufacturing the liquid-substance separation membrane molded article according to the sixteenth or seventeenth aspect,
As a nineteenth aspect, between the (v) step and the (vi) step, further (v-0) step,
(v-0) step: The dispersion containing the plate-like particles (A) obtained in step (v) is Both the quaternary ammonium ions (a) having ~2 and the anionic surfactant (b) having ammonium ions are reduced to the range of 0.01 to 15.0% by mass with respect to the plate-like particles (A) The method for producing a molded article for separating a substance in liquid according to the sixteenth or seventeenth aspect, which adds a step of obtaining a dispersion containing the plate-like particles (A), and as a twentieth aspect, (v-0) The step is the following (v-1) step,
(v-1) step: the dispersion containing the plate-like particles (A) obtained in step (v) is subjected to ultracentrifugation at 20,000 to 60,000 G, and the total number of carbon atoms is 15 to 45, and Both the quaternary ammonium ion (a) having 1 to 2 alkyl groups of number 10 to 20 and the anionic surfactant (b) having an ammonium ion are 0.01 to 15.0 masses relative to (A). % of the plate-like particles (A).

Currently, ultrafiltration membranes are widely used, and ultrafiltration membranes filter out molecules with a certain molecular weight using the pores in the membrane, allowing the solvent to pass out of the system, thereby filtering out substances in the liquid. It is a system that separates However, the principle of ultrafiltration membranes limits the amount of liquid that can pass through the pores, limiting the amount of liquid that can be filtered.
On the other hand, filtering out substances from liquids is also widely practiced. However, although the filter has a high liquid flow rate, it has a coarse mesh diameter and cannot remove ionic substances dissolved in the liquid.

INDUSTRIAL APPLICABILITY The present invention is a liquid-substance separation membrane molded article, and is a separation membrane molded article capable of removing a substance (eg, an ionic component) from a solution.
The liquid-substance separation membrane molded article of the present invention has a liquid-substance separation membrane in which a substance having a function of separation is contained in a structure in which one or more layers are laminated on a base material that serves as a coarse support. Submerged substance separation membranes are required to play a role in preventing substances contained in a solution (such as ionic components) from crawling between separated substances and reaching the base material. a molecular sieve effect, and when the substance to be separated is an ionic substance, such as an ionic substance having negative ions, the separation membrane substance having negative ions is used to prevent passage between the separation membrane substances due to the electrical repulsion, so that only the solution (or solvent) that does not contain the substance to be separated passes through and the substance to be separated (e.g., ionic substance) It is removed.

In the present invention, the material having a separation function (separation membrane material) is plate-like particles that are peeled layer material by delamination of a layered compound (e.g., octosilicate material). By controlling the thickness of the layer, it is easy to control the interlayer. Therefore, it is possible not only to electrically eliminate substances (e.g. ionic substances), but also to eliminate (separate) substances with different molecular diameters (e.g. ionic substances) according to the size of the molecular diameter according to the size between layers. is.

A layered compound is a laminate of plate-like substances, and alkali metal ions are inserted between the layers of the plate-like substances to electrically connect the plate-like substances. By spreading the layers of this plate-like material with a bulky compound, such as quaternary ammonium ions, the electrical bonding force is rapidly reduced. Delamination of the material takes place, resulting in a single sheet of platy material. This plate-like substance can be called plate-like particles, and is formed into a dispersion liquid of plate-like particles by exfoliating the layers while being dispersed in the medium or by dispersing the plate-like particles in the medium. Here, the anionic surfactant during delamination is also used to improve the dispersibility when dispersing in the medium. When plate-like particles (e.g., octosilicate material) contain silanol groups, this is sufficient when a dispersion liquid is formed due to the repulsive force between the negative charges of the silanol groups and the negative charges of the anionic surfactant. This is to obtain good dispersibility.

Plate-like particles, which are exfoliated plate-like substances, are also called nanosheets, and the thickness of a single layer is several nanometers. Nanosheets obtained by exfoliating layered silicates, such as ilaite, are thin silicates, and the silanol groups are negatively charged and highly hydrophilic. It is possible to separate substances (for example, ionic substances) mainly by passing only the solvent of the solution through electrical repulsion and elimination.

In the present invention, plate-like particles having a narrow particle size distribution and a uniform particle size can be obtained by dispersing in an anionic surfactant aqueous solution in a wet gel state after delamination by a quaternary ammonium compound. was formed on a substrate to obtain a liquid-substance separation membrane molding having high separation performance and high solution-permeability.

FIG. 1 is a schematic diagram showing the process of forming a liquid-substance separation membrane containing plate-like particles (A) on a substrate (supporting membrane) by suction filtration. FIG. 2 is a schematic diagram showing a water permeability test of a separation membrane molded body and an evaluation test method for separation performance. 3 is a scanning electron micrograph of the surface of the separation membrane molded product obtained in Example 1. FIG. The magnification is 10,000 times. FIG. 4 is a scanning electron micrograph of a cross section of the separation membrane molded product obtained in Example 1. FIG. The magnification is 50,000 times. FIG. 5 shows the results of X-ray diffraction measurement of the separation membrane molded product obtained in Example 1. In FIG. FIG. 6 is a graph showing the water permeability and pigment rejection of EB (Evans Blue) and Acid Red 265 of the separation membrane molded articles obtained in Example 1 and Comparative Example 1. FIG. FIG. 7 shows the water permeability and dye rejection of two types of separation membrane molded bodies formed by using the aqueous dispersion of the Ialite nanosheets obtained in Example 1 before and after ultracentrifugation. graph. FIG. 8 shows a separation membrane molded article containing Iialite nanosheets obtained in Example 1, a separation membrane molded article containing niobic acid (HNb ₃ O ₈ ) nanosheets, and a separation membrane molded article containing GO (graphene oxide) nanosheets. It is a graph showing each water permeability and dye blocking rate. X-ray diffraction of the Ialite nanosheet laminate after immersing the separation membrane molded product obtained in Example 1 in an aqueous solution adjusted to pH 3 with hydrochloric acid or in an aqueous solution adjusted to pH 11 with sodium hydroxide for 2 weeks. The figure which shows a measurement result. 1 is a diagram showing the blocking performance of an anionic dye using the separation membrane molded article obtained in Example 1. FIG. 1 is a diagram showing the results of molecular weight cut-off measurement of polyethylene glycol, which is a non-polar molecule, using the separation membrane molded article obtained in Example 1. FIG. 4 is a graph showing the water permeability evaluation using the molded body for separating substances in liquid containing ialite and graphene oxide obtained in Example 2 at a mass ratio of 1:1, and the salt blocking rate of a salt-containing aqueous solution. 2 is a graph showing the water permeability evaluation using a molded body for separating substances in liquid containing ialite and graphene oxide obtained in Example 2 at a mass ratio of 1:0.1 and the salt blocking rate of a salt-containing aqueous solution. .

The present invention provides a quaternary ammonium ion (a) having 15 to 45 carbon atoms in total and 1 to 2 alkyl groups having 10 to 20 carbon atoms and an anionic surfactant having an ammonium ion ( b), having an average thickness of 0.7 to 100 nm, an average major axis of 50 to 10,000 nm, and (maximum major axis/width perpendicular to the maximum major axis) = 1.0 to 10.0, of a layered compound It is a liquid-substance separation membrane molded article including a liquid-substance separation membrane containing plate-like particles (A) that are delamination substances due to delamination, and a substrate (B) that supports the liquid-substance separation membrane.
The submerged substance separation membrane molded product of the present invention is a submerged substance separation membrane molded product for separating a substance to be separated from a solution containing the substance to be separated, or for obtaining a solution in which the substance to be separated is concentrated or diluted. be.

In the present invention, the liquid-substance separation membrane molded product is a membrane that can separate a substance dissolved in a solvent (a polar solvent or a non-polar solvent, such as an aqueous solvent or an organic solvent) into a solvent and a substance. It means a molded body with a separation that allows separation, concentration or dilution of substances in the solution. The present invention includes completely separating the substance to be separated and the solvent from the solution containing the substance to be separated. This means that two types of solutions are obtained, one with increasing substance concentration. Further, by optionally changing the membrane permeation speed of the solution containing the substance to be separated in the separation and concentration step, it is possible to obtain a plurality of solutions in which the concentration of the substance to be separated in the solvent changes stepwise.

The plate-like particles (A), which are the component (A) used in the present invention, can be used in the form of a dispersion. The plate-like particles (A) are dispersed in a dispersion medium containing a liquid medium, a quaternary ammonium ion (a), and an anionic surfactant (b) having ammonium ions, and the above (a) and (b) at least partly covered or adsorbed by one or both of (A), or one or both of (a) and (b) interposed between plate-like particles (A). state.

The liquid-substance separation membrane containing the plate-like particles (A) or the aqueous dispersion forming the same has a Na ion concentration of 0.1% by mass (1000 ppm) or less, or 0.01% by mass (100 ppm) or less. It is preferably a membrane or an aqueous dispersion.
Further, the concentration of the plate-like particles (A) in the dispersion can be 30% by mass or less, 0.01 to 30% by mass, or 0.1 to 30% by mass.

The average major axis and the width perpendicular to the maximum major axis of the plate-like particles (A) can be measured by transmission electron microscope observation. The value of [maximum length (nm)/width (nm) perpendicular to the maximum length] of the plate-like particles (A) can be called an aspect ratio, and is in the range of 1.0 to 10.0. The width (nm) perpendicular to the maximum major axis of the plate-like particles (A) can be 50 to 10,000 nm, 50 to 5,000 nm, or 50 to 3,000 nm on average.

Further, the average thickness of the plate-like particles (A) can be measured by observing the coated surface of the substrate when the dispersion is applied using an AFM (atomic force microscope). The plate-like particles (A) have an average thickness of 0.7 to 100 nm, or 0.7 to 40 nm. For AFM observation, a sample obtained by dropping a dispersion having a tabular particle concentration of 1% by mass or less onto a substrate such as mica and drying it can be used. Natural drying is preferable for drying the sample, but heating may be used. In addition, a sample coated on a substrate using the Langmuir-Blodgett method can also be used for AFM measurement.
Furthermore, the average particle size of the plate-like particles (A) can be measured as the average particle size of the plate-like particles (A) in the dispersion by a dynamic light scattering method. At this time, the concentration of the dispersion liquid (concentration of plate-like particles) at the time of measurement can be 30% by mass or less.

For the plate-like particles (A), a release layer material obtained by delamination of a layered compound can be used. Layered compounds include, for example, layered polysilicates, clay minerals, manganates, titanates, niobic acid, niobates, GO (graphene oxide), and the like. Examples of clay minerals include smectite and vermiculite. Examples of layered polysilicates include kanemite, macatite, kenyaite, and ilaite (Ilerite is also called ialite, ailite, and ailaite).

Among these layered compounds, octosilicate materials such as ilaite can be preferably used. Ilayite has a chemical formula of Na ₂ O.8SiO ₂ .nH ₂ O, has a planar silicic acid skeleton, and has silanol groups between the layers. The layered compound, ilaite, does not exist in nature, so it is artificially synthesized. Ilayite is prepared, for example, by placing an aqueous solution of colloidal silica and sodium hydroxide mixed (SiO ₂ /Na ₂ O molar ratio is, for example, 4.0) or water glass in a hermetically sealed container and subjecting it to a hydrothermal reaction of about 90 to 150°C. By performing, it is possible to synthesize.

The Na ions in the dispersion are Na ions released from the layered compound (interlayers) when the Na ions present between the layers of the layered silicate are ion-exchanged with quaternary ammonium ions (a), In the state as it is, it will be present in a large amount in the dispersion liquid, but it is discharged out of the system by the method described later. A low concentration of Na ions in the dispersion is desirable to prevent re-layering of the release layer material. For example, the Na ion concentration in the dispersion can be 1000 ppm or less, or 100 ppm or less, such as 0.1-1000 ppm, 1-1000 ppm, 0.1-100 ppm, or 1-100 ppm.

Since the quaternary ammonium ion has a role as a release agent that spreads the interlayers of the layered compound, it preferably has a bulky organic group, and on the other hand, it preferably has high solubility. Therefore, in the present invention, the total number of carbon atoms is 13 to 45, or 13 to 23, or 15 to 45, or 15 to 25, and has 1 to 2 alkyl groups having 10 to 20 carbon atoms. A quaternary ammonium ion (a) is used.

Examples of such quaternary ammonium ions (a) include hexadecyltrimethylammonium ion, didecyldimethylammonium ion, dimethyldioctadecylammonium ion, and lauryltrimethylammonium ion. In particular, lauryltrimethylammonium ion can be preferably used. Counter ions for the ammonium ion include chloride ion and bromide ion.

The concentration of the quaternary ammonium ion (a) in the dispersion liquid is 30% by mass or less, or 10% by mass or less, and is 0.001 to 30% by mass, 0.001 to 20% by mass, or 0.001 It can be up to 10% by mass.

The anionic surfactant (b) having an ammonium ion is a surfactant composed of a hydrophobic group and a hydrophilic group, and is a compound in which the hydrophilic group portion is composed of a pair of an anion and an ammonium ion. It is preferable to use a compound that does not contain sodium ions or potassium ions. The anionic surfactant (b) having an ammonium ion is preferably a compound containing, for example, a relatively long-chain alkyl group having about 8 to 12 carbon atoms as a hydrophobic group, and also contains an aromatic ring. It is preferably a compound that does not have

Examples of the anionic surfactant (b) having an ammonium ion include ammonium octanoate, ammonium decanoate, ammonium laurate, ammonium stearate, ammonium hexanesulfonate, ammonium octanesulfonate, ammonium decanesulfonate, and dodecanesulfone. ammonium phosphate, ammonium lauryl sulfate (ammonium dodecyl sulfate), ammonium myristyl sulfate, ammonium lauryl phosphate, ammonium tripolyphosphate and the like. Among them, ammonium lauryl sulfate (ammonium dodecyl sulfate) can be preferably used.

The concentration of the anionic surfactant (b) containing ammonium ions in the dispersion can be 0.01 to 20% by mass.

In the present invention, a quaternary ammonium ion (a) having 1 to 2 alkyl groups with 10 to 20 carbon atoms and an anionic surfactant (b) having an ammonium ion are essentially used. When the anionic surfactant (b) having ammonium ions is not added, when an anionic surfactant having sodium ions or an anionic surfactant having potassium ions is used instead of ammonium ions, the interlayer Peeling does not proceed, or the peeling layer material that has been delaminated tends to form a layered structure again, so that the transparency of the dispersion decreases (that is, the absorbance of the dispersion does not decrease). In addition, when the delamination does not progress, the labyrinth for separating the substances in the liquid (for example, the ions in the liquid) becomes insufficient, and the sufficient separation of the substances in the liquid (for example, the ions in the liquid) does not occur. can also occur.

The dispersion of the present invention is characterized by high transparency. For example, in a dispersion having a tabular particle concentration of 0.1% by mass, the absorbance is 0.1 under the conditions of an optical path length of 1 cm and a wavelength of 620 nm. or less, and in particular can be 0.015 or less.
The layered compound can usually be produced as a dispersion liquid in which the concentration of the plate-like particles (A) is in the range of 30% by mass or less.

In the dispersion of the present invention, the dispersion medium (liquid medium) for the plate-like particles (A) may be an aqueous medium such as water or an organic solvent. can also do When producing the dispersion of the present invention, the aqueous medium can be replaced with an organic solvent. Solvent replacement can be performed by an evaporation method or an ultrafiltration method.

Examples of the organic solvent include methanol, ethanol, n-propanol, isopropanol, butanol, diacetone alcohol, propylene glycol, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monobutyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl. ether acetate, propylene glycol monopropyl ether acetate, propylene glycol monobutyl ether acetate, toluene, xylene, methyl ethyl ketone, cyclopentanone, cyclohexanone, ethyl 2-hydroxypropionate, ethyl 2-hydroxy-2-methylpropionate, ethyl ethoxyacetate, ethyl hydroxyacetate, methyl 2-hydroxy-3-methylbutanoate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, ethyl 3-ethoxypropionate, methyl 3-ethoxypropionate, methyl pyruvate, ethyl pyruvate, Ethylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monopropyl ether acetate, ethylene glycol monobutyl ether acetate , diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dipropyl ether, diethylene glycol dibutyl ether, propylene glycol dimethyl ether, propylene glycol diethyl ether, propylene glycol dipropyl ether, propylene glycol dibutyl ether, ethyl lactate, propyl lactate, isopropyl lactate, butyl lactate, lactic acid isobutyl, methyl formate, ethyl formate, propyl formate, isopropyl formate, butyl formate, isobutyl formate, amyl formate, isoamyl formate, methyl acetate, ethyl acetate, amyl acetate, isoamyl acetate, hexyl acetate, methyl propionate, ethyl propionate, propionate Propyl Acid, Isopropyl Propionate, Butyl Propionate, Isobutyl Propionate, Methyl Butyrate, Ethyl Butyrate, Propyl Butyrate, Isopropyl Butyrate, Butyl Butyrate, Isobutyrate Chill, methyl 3-methoxy-2-methylpropionate, methyl 2-hydroxy-3-methylbutyrate, ethyl methoxyacetate, 3-methoxybutyl acetate, 3-methoxypropyl acetate, 3-methyl-3-methoxybutyl acetate, 3 -methyl-3-methoxybutyl propionate, 3-methyl-3-methoxybutyl butyrate, methyl acetoacetate, methyl propyl ketone, methyl butyl ketone, 2-heptanone, 3-heptanone, 4-heptanone, N, N- Examples include dimethylformamide, N-methylacetamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, 4-methyl-2-pentanol, and γ-butyrolactone. These solvents can be used alone or in combination of two or more.

The liquid-substance separation membrane of the present invention may be in the form of a composite membrane including a multi-layer body in which a plurality of layers of exfoliated material (plate-like particles (A)) are laminated by delamination of a layered compound. The layers to be laminated may be layers of the same release layer material or layers of other release layer materials.
For example, a composite film including a laminate in which a layer of graphene oxide is laminated on a layer of release layer material of an octosilicate material such as ilaite. In the case of the shape of a composite film including a multilayer body, the content of the layered compound (or peeling layer substance) contained in each layer is 1 in mass ratio when the plate-like particles (A) contained in the bottom layer is 1. :0.01 to 1:10, preferably 1:0.05 to 1:5, more preferably 1:0.1 to 1:1.

The present invention provides the following steps (i) to (vi):
(i) Step: An aqueous dispersion of a silicic acid compound is hydrothermally treated at a temperature of 90 to 150° C., and the resulting layered compound is separated and washed with water. the process of
(ii) step: adding to the aqueous dispersion obtained in step (i) a total carbon atom number of 15 to 45 and a carbon atom number of 10, which is 1 to 3 times the ion exchange capacity of the layered compound; adding a quaternary ammonium ion (a) having 1 to 2 alkyl groups of ∼20 and heating at 40 to 100°C for 12 to 48 hours;
(iii) step: adding pure water to the liquid obtained in step (ii), and removing the sodium ion-containing liquid from the system so that the sodium ion concentration in the liquid is 100 ppm or less;
(iv) step: after dispersing the wet gel included in step (iii) in an anionic surfactant (b) aqueous solution containing ammonium ions at a concentration of 0.01 to 1% by mass, ammonia is further added; adding to adjust the pH in the liquid to 9.0 to 12.0;
(v) step: a step of heating the liquid obtained in step (iv) at 40 to 90° C. for 12 to 48 hours to obtain a dispersion of plate-like particles (A);
(vi) step: forming a liquid-substance separation membrane on the substrate (B) surface using the dispersion of the plate-like particles (A) obtained in the (v) step. This is a method for manufacturing a separation membrane molded article.

The above step (i) will be described by exemplifying ilaite as the layered compound used here. Ilayite is a layered compound that does not exist in nature, and can be synthesized, for example, by subjecting an aqueous solution of a silicic acid compound to a hydrothermal reaction at 90 to 150°C. Silicic acid compounds include silicates such as sodium silicate and potassium silicate. The silicic acid compound aqueous solution has a SiO ₂ /M ₂ O molar ratio of 3.5 to 4.0 (where M represents Na and K), and a silicic acid compound concentration of about 10 to 30% by mass. An aqueous sodium silicate solution is preferred. The hydrothermal conditions are preferably 90 to 150° C., particularly 90 to 130° C. Ilaite can be synthesized by static heating for 1 to 24 days, or 1 to 12 days.

The solid material obtained by the hydrothermal reaction can be separated, washed with water and dried to recover ilaite. In order to facilitate delamination and dispersion, the solid substance obtained by the hydrothermal reaction may be separated, washed with water, and then recovered as an aqueous slurry suspended in water without drying. During the hydrothermal reaction, the reaction system may be stirred at the beginning of the reaction to make the reaction system uniform, but static heating is preferred for particle growth of ilaite.
Fine islayite can be synthesized by adding fine seed crystals (seed particles) of islayite itself to an aqueous sodium silicate solution.

The layered compound in step (i) is produced by pulverizing the layered material as a raw material, as in the synthesis of fine ailaite described above, and adding the pulverized layered material as seed particles to an aqueous silicate solution, A layered compound produced by hydrothermal treatment at 90 to 130° C. for 6 to 72 hours can be used. These layered compounds are fine layered compounds unlike layered substances. Furthermore, by adjusting the concentration of the fine layered compound to 30% by mass or less, an aqueous dispersion of the layered compound can be produced.

After the above hydrothermal treatment, unreacted sodium silicate is removed from the hydrothermal reaction medium, and the layered compound obtained by standing still is separated and washed with water to obtain a wet gel, which is added to water. An aqueous dispersion of the layered compound in step (i) can also be obtained by dispersing at a concentration of 30% by mass or less.

The fine layered compound (especially ilaite) is specifically the aqueous silicate solution, or a suspension obtained by adding unpulverized or pulverized layered substances as seed crystals (seed particles) to the aqueous silicate solution. , 90 to 150° C., particularly 90 to 130° C. for 1 to 24 days, and particularly 110° C. for 1 to 12 days in a static state for hydrothermal reaction. The seed crystals (seed particles) added to the silicate aqueous solution when producing the fine layered compound are not limited in particle diameter, and are 0.1 to 10% by mass, or 0.1 to 10% by mass, based on the mass of the silicate. It is preferably added in the range of 1 to 5% by mass, or 0.1 to 2% by mass.

The pulverized layered material added as seed crystals (seed particles) has a particle size of 30 to 60 nm according to the dynamic light scattering method, and its [(2θ = 6.9 to 8.4 ° diffraction peak (sum of integrated intensities of diffraction peaks up to 2θ=5 to 40°)/(sum of integrated intensities of diffraction peaks up to 2θ=5 to 40°)]×100.
The particle size of the (fine) layered compound (especially ilaite) obtained by hydrothermal reaction with the addition of seed crystals (seed particles) has an average major axis of 100 nm to 100000 nm, (maximum major axis/width perpendicular to the maximum major axis)=1. .0 to 10.0, and the width (nm) perpendicular to the maximum length (nm) is on average 50 nm to 10000 nm, 50 nm to 5000 nm, or 50 nm to 3000 nm. The average major axis (nm) and the width (nm) perpendicular to the maximum major axis (nm) can be measured by observation with a transmission electron microscope.
Further, the average particle size of the fine layered compound as measured by a dynamic light scattering method can be 10 nm to 500000 nm, 20 nm to 300000 nm, 100 nm to 10000 nm, or 200 nm to 5000 nm.

Seed crystals (seed particles) (Ilayite here) can be obtained by pulverizing a layered material (Ilayite here) as a raw material. Grinding can be carried out, for example, by ball milling.
Grinding is carried out, for example, using a planetary ball milling device. A planetary ball mill can grind a container containing hard balls (for example, zirconia balls) and ilaite by rotating and revolving. This planetary ball milling can perform two stages of pulverization, and preliminary pulverization is performed first, and then fine pulverization is performed to obtain ilaite as seed crystals (seed particles). Grinding can be wet or dry, but dry grinding is preferably used.
Islayite obtained separately can be used as the seed crystal (seed particle), or a part of the previous batch can be added, or the material remaining in the reaction vessel can be used for continuous batch production. .

In the step (ii), the aqueous dispersion of the layered compound obtained in the step (i) has a total number of carbon atoms of 15 to 45 and 1 to 2 alkyl groups of 10 to 20 carbon atoms. In this step, quaternary ammonium ions (a) are added in an amount that is 1 to 20 times the ion exchange capacity of the layered compound, and heated at 40 to 100° C. for 1 to 100 hours.

The above (iii) step is a step of adding pure water to the liquid obtained in the (ii) step and removing the sodium ion-containing liquid out of the system so that the sodium ion concentration in the liquid is 1000 ppm or less. In the step (ii), the sodium ions present between the layers of the layered compound are replaced with quaternary ammonium ions, and the sodium ions released in the liquid are removed from the system to prevent re-substitution with sodium ions, The interlayers are expanded with quaternary ammonium ions, allowing layered compounds to be delaminated. Methods for removing sodium ions include ultrafiltration, decantation, and solid-liquid separation using a filter.

The above step (iv) disperses the wet gel contained in the one obtained in step (iii) in an anionic surfactant (b) aqueous solution having an ammonium ion concentration of 0.01 to 20% by mass, After that, there is a step of adding ammonia so that the pH in the liquid becomes 9.0 to 12.0. Addition of the anionic surfactant (b) having ammonium ions coats the release layer material caused by delamination, or the anionic surfactant (b) intervenes between the release layer materials. In this way, it is possible to prevent the release layer material caused by the delamination occurring in the subsequent step (v) from returning to the form of the stratified compound.
This step (iv) can be carried out under ultrasonic irradiation or stirring in order to sufficiently coat the surface of the release layer material (here, ilaite) with the anionic surfactant (b) having ammonium ions. .

The above step (v) is a step of heating the liquid obtained in the step (iv) at 40 to 100° C. for 1 to 100 hours.
The plate-like particles (A) obtained here have an average thickness of 0.7 to 100 nm, an average major axis of 50 to 10,000 nm, and (maximum major axis/width perpendicular to the maximum major axis)=1.0 to 10.0. The plate-like particles (A) which are delamination substances due to delamination of a layered compound, wherein the laser diffraction particle size distribution of the plate-like particles (A) in the aqueous dispersion shows a 90% cumulative particle size value is 1.5 to 10 times, or 1.5 to 6.0 times, or 1.5 to 5.0 times, or 1.5 to 3.0 times the mean value of the particle size distribution. The plate-like particles (A) have a particle size range of 0.1 μm to 10 μm as measured by a laser diffraction method, the particle size distribution is narrow, and aggregates do not exist.
In addition, the average particle size of the aqueous dispersion measured by dynamic light scattering is 10 to 10,000 nm, and the above (a) and (b) are both 0.01 to 3.0% by mass with respect to (A). plate-like particles (A) or a dispersion thereof.

In the method for producing a molded article for separating substances in liquid of the present invention, between the step (v) and the following step (vi), the plate-like particles (A ) containing a quaternary ammonium ion (a) having a total number of carbon atoms of 15 to 45 and having 1 to 2 alkyl groups of 10 to 20 carbon atoms and an anionic surfactant having an ammonium ion a step of forming a film on a substrate (B) from plate-like particles (A) in which the content of the agent (b) is both reduced to a range of 0.01 to 15.0% by mass relative to (A); can be added.

Examples of methods for reducing the contents of (a) and (b) above to within the range of 0.01 to 15.0% by mass relative to (A) include centrifugation and ultrafiltration.

In the method for producing a molded article for separating substances in liquid of the present invention, between step (v) and step (vi) below, step (v-1),
(v-1) Step: A dispersion of plate-like particles (A) is subjected to ultracentrifugation at 20000 to 60000 G, and 1 alkyl group having a total number of carbon atoms of 15 to 45 and 10 to 20 carbon atoms. Reduce the content of both the quaternary ammonium ion (a) having two and the anionic surfactant (b) having an ammonium ion to the range of 0.01 to 15.0% by mass with respect to (A) A step of obtaining a dispersion of plate-like particles (A) can be added.

Using a dispersion of plate-like particles (A) in which the surfactant has been reduced by ultracentrifugation and a base material (B), the total number of carbon atoms is 15 to 45 and The content of both the quaternary ammonium ion (a) having 1 to 2 alkyl groups and the anionic surfactant (b) having an ammonium ion is 0.01 to 15.0% by mass based on (A), Alternatively, liquid-substance separation comprising a liquid-substance separation membrane containing plate-like particles (A) in a range of 0.01 to 5.0% by mass and a substrate (B) supporting the liquid-substance separation membrane It can be made into a film molding.

The (vi) step is a step of forming a film on the surface of the substrate (B) using the dispersion liquid of the plate-like particles (A) obtained in the (v) step. When step (v-0) or (v-1) is included between step (v) and step (vi), step (vi) is a dispersion of plate-like particles (A) obtained in step (v) Instead, the dispersion of plate-like particles (A) obtained in step (v-0) or (v-1) is used.

When forming a liquid-substance separation membrane containing a laminate on the surface of the substrate (B), the step of forming the liquid-substance separation membrane in the above step (vi) includes, on the substrate (B) surface, (v) forming a plate-like particle (A) layer using the dispersion of the plate-like particles (A) obtained in step; and laminating the layer of release layer material using.
When step (v-0) or (v-1) is included between step (v) and step (vi), step (vi) is a dispersion of plate-like particles (A) obtained in step (v) Instead, the dispersion of plate-like particles (A) obtained in step (v-0) or (v-1) is used.
As the dispersion of the release layer material obtained by delamination of the stratiform compound, the dispersion of the plate-like particles (A) obtained in the above step (v), (v-0) or (v-1) may be used. Alternatively, a dispersion containing a release layer material obtained by delamination of the layered compounds described above, either commercially available or prepared by known methods, can be used.
The layer to be stacked is preferably a graphene oxide layer using a graphene oxide dispersion.

When forming a film consisting of a laminate, the content of the release layer substance contained in each layer is
The mass ratio is 1:0.01 to 1:10, preferably 1:0.05 to 1:5, and more preferably 1:0.1 when the plate-like particles (A) contained in the lowermost layer are taken as 1. to 1:1.

At least one porous substrate selected from the group consisting of cellulose, synthetic polymers, and ceramics can be used as the substrate (B).
Examples of cellulose include nitrocellulose, carboxymethyl cellulose, hydroxyethyl cellulose, and the like.
Synthetic polymers include polyethersulfone, polysulfone, polyvinylidene fluoride, polyvinylidene chloride, polyethylene vinyl alcohol, polyvinyl alcohol, polyacrylic acid, polymethacrylic acid, and the like.
Ceramics include silica, alumina, mullite, and the like.

When a liquid-substance separation membrane is formed on the surface of the substrate (B) using a dispersion containing the plate-like particles (A), suction filtration or pressure filtration is preferably performed.
The substrate (B) is a material that becomes a support film (support). The substrate (B) is set in a filtration device, and the plate-like particles (A) obtained in the step (v) are dispersed from above. Liquid is injected and suction filtration or pressure filtration is performed. The dispersibility of the plate-like particles (A) is preferably enhanced before it is poured into a filtering device. For example, ultrasonic irradiation and stirring can be performed for about 0.1 to 1 hour. A liquid-substance separation membrane can be similarly formed by using the dispersion liquid of the plate-like particles (A) obtained in the step (v-0) or (v-1).
When the liquid-substance separation membrane includes a composite membrane, the substrate (B) surface is coated using the dispersion liquid of the plate-like particles (A) obtained in the step (v), (v-0) or (v-1) After forming a layer of plate-like particles (A) on top, drying if necessary, injecting a dispersion containing a release layer material from above, performing suction filtration or pressure filtration, and laminating the release layer material. can be done. It is preferable to enhance the dispersibility of the dispersion of the release layer material before injecting it into the filtering device. For example, ultrasonic irradiation and stirring can be performed for about 0.1 to 1 hour.

In addition, when the substrate (B) is an organic material such as cellulose, polyethersulfone, or synthetic polymer, it is immersed in pure water for about 0.1 to 12 hours to impart hydrophilicity and filtered. It is preferable to set it in the device.
Substrate (B) can be formed on one side or both sides thereof with a liquid-substance (for example, ion) separation membrane containing plate-like particles (A). The base material (B) is a support, and the film thickness of the base material (B) itself can be arbitrarily set from several μm to several mm. For example, it can be set to about 1 μm to 10 mm, or about 10 μm to 1 mm.

The liquid-substance separation membrane that functions as a separation layer formed on the surface of the substrate (B) can be set to the following values as the film thickness of the liquid-substance separation membrane itself. The film thickness of the submerged substance (eg, ion) separation membrane on the substrate (B) surface can be set to the following values on one side. In order for the molecular sieving effect caused by stacking the plate-like particles (A) in the liquid-substance separation membrane to function effectively, the plate-like particles (A) constituting the liquid-substance separation membrane must be formed in multiple layers (for example, It is preferable that two or more layers are formed, and the film thickness can be set to 1.5 nm or more, for example. The lower limit of the film thickness of the liquid-substance separation membrane can be set to, for example, 1.5 nm, 40 nm, and 50 nm, and the upper limit of the film thickness can be set to 100 nm, 500 nm, 1 μm, and 10 μm. Therefore, the film thickness can be set to, for example, 1.5 nm to 10 μm, 40 nm to 1 μm, 50 nm to 500 nm, 1.5 nm to 100 nm, 1.5 nm to 500 nm, 50 nm to 10 μm, 50 nm to 1 μm, 50 nm to 100 nm, etc. .

In the present invention, the solvent that dissolves the substance (the substance to be removed or the substance to be concentrated) is a polar solvent or a non-polar solvent, and can be an aqueous solvent or an organic solvent.

In the present invention, the permeation rate of the solvent (aqueous solvent or organic solvent) containing the substance is 0.1 to 100 L·m ⁻² ·hr ⁻¹ ·bar ⁻¹ , or 5 to 25 L·m ⁻² ·hr ⁻¹ · bar ⁻¹ .
In the present invention, the substance removal rate of the solvent (aqueous solvent or organic solvent) containing the substance to be separated can be 15 to 99%, 15 to 99%, or 80 to 99%.

Also, the substance to be separated can be an ionic compound in a solvent (aqueous solvent or organic solvent).
A case where the substance to be separated is an ionic compound in an aqueous solvent will be described below. Examples of ionic compounds include organic compounds having at least sulfonate ions or carboxylate ions.

For example, in the case of an ionic substance, a liquid-substance separation membrane containing the plate-like particles (A) and its support is separated from a tank containing an aqueous solution containing a water-soluble ionic organic compound using a pump. The liquid was poured into a cell loaded with a submerged substance (ion) separation membrane molded body containing the base material (B), and passed through the submerged substance (ion) separation membrane to reduce the water-soluble ionic organic compound. It is possible to separate the aqueous solution and the aqueous solution in which the water-soluble ionic organic compound is concentrated without passing through the submerged substance (ion) separation membrane. Therefore, it is also a method for removing water-soluble ionic organic compounds in an aqueous solution and a method for concentrating water-soluble ionic organic compounds.

As a typical example, when the effective membrane area is 2.54×10 ⁻⁴ m ² , the pump pressure is 1.0 to 5.0 atmospheres, and the liquid flow rate is 1.0 ml/min. Water-soluble ionic organic compounds can be concentrated to 10 ppm. Even with the above pump pressure of 5 to 15 atm, the aqueous solvent permeation rate is 6 to 8 L·m ⁻² ·hr ⁻¹ ·bar ⁻¹ , and stable water permeation can be carried out for 13 hours. When the film area is 9.6×10 ⁻⁴ m ² , the film thickness is 100 nm, and the plate-like particles (A) at that time have a lamination amount of 1 mg on the substrate (B).

Examples of the water-soluble ionic organic compounds include organic compounds having at least sulfonate ions or carboxylate ions, and these can have a dye structure.
Compounds having a sulfonate structure include Evans Blue and Acid Red 265, which have the following structures.

Under the above conditions, Evans Blue has a blocking rate of 96%, and Acid Red 265 has a blocking rate of 15-40%.

According to the present invention, it is possible to obtain a liquid-substance separation membrane molded article capable of concentrating one kind of solute molecule from a solution containing two or more kinds of solute molecules having different molecular weights. For example, in a solution in which two types of molecules with different molecular weights are dissolved as solutes, it is possible to concentrate molecules with large molecular weights by preventing passage of molecules with large molecular weights through the membrane and allowing molecules with small molecular weights to pass through the membrane. A compact liquid-substance separation membrane molded product can be obtained. For example, by using two or more kinds of solute molecules having a molecular weight difference of 1.3 times or more, or 1.5 times or more, the solute molecule having the largest molecular weight among them can be concentrated.
Typically, a quaternary ammonium ion (a) having 15 to 45 carbon atoms in total and 1 to 2 alkyl groups having 10 to 20 carbon atoms and an anionic surfactant having an ammonium ion agent (b), having an average thickness of 0.7 to 100 nm, an average major axis of 50 to 10000 nm, and (maximum major axis/width perpendicular to the maximum major axis) = 1.0 to 10.0, In a liquid-substance separation membrane molded article containing a liquid-substance separation membrane containing plate-like particles (A), which are delamination substances due to delamination, and a substrate (B) supporting the liquid-substance separation membrane,
The plate-like particles (A) are in the form of an aqueous dispersion of the plate-like particles (A) containing the above (a) and (b) used for delamination of the layered compound, and the plate-like particles of the aqueous dispersion ( The 90% cumulative particle size value in the laser diffraction particle size distribution of A) is 1.5 to 10 times the average value of the particle size distribution,
The plate-like particles (A) are in the form of an aqueous dispersion of the plate-like particles (A) containing (a) and (b) used for delamination of the layered compound, and dynamic light scattering of the aqueous dispersion The above containing plate-like particles (A) having an average particle diameter of 10 to 10,000 nm according to the method, and both (a) and (b) being in the range of 0.01 to 15.0% by mass with respect to (A) The liquid-substance-separating membrane molded article is used to concentrate one kind of solute molecule from two or more kinds of solute molecules in a liquid.

(Evaluation method)
Dynamic light scattering method: Measured with Zetasizer Nano S (trade name, manufactured by Spectris Co., Ltd.).
Laser diffraction particle size distribution measurement: Measured with SALD-7500 manufactured by Shimadzu Corporation.
Transmission electron microscope: JEM-1010 (trade name) manufactured by JEOL Ltd. was used.
Average major axis: From 200 particle images taken using a transmission electron microscope JEM-1010 manufactured by JEOL Ltd., the average major axis and the maximum major axis/width perpendicular to the maximum major axis were calculated.
Ultraviolet-visible-near-infrared spectrophotometer: V630 manufactured by JASCO Corporation was used.
X-ray diffraction: D2 PHASER manufactured by Buruker was used.
(Method for evaluating water permeability of separation membrane)
S. Kawada et al. , Colloids and Surfaces A: Physicochem. Eng. Aspects, 2014, vol. 451, p. 33-37, evaluation was made using a cross-flow water permeation device. Ultrapure water purified by an ultrapure water production device (“milli-Q (registered trademark) manufactured by Direct Merck) is passed through a water permeation device under conditions of a primary side (supply side) pressure of 0.1 to 0.5 MPa. The water permeation rate was obtained by dividing the water permeation rate per unit time by the effective membrane area and pressure.
(Solute blocking performance test)
An aqueous solution in which Evans Blue (EB) or Acid Red 265 (AR) was dissolved at a concentration of 10 ppm was used for the solute inhibition test. (Method for evaluating water permeability of separation membrane) The above aqueous solution (40 mL) is allowed to pass through, and the concentration of solute in the permeated liquid is measured with an ultraviolet-visible-near-infrared spectrophotometer. Calculated.
(Salt inhibition performance test)
An aqueous solution in which 500 ppm of sodium sulfate or sodium chloride was dissolved was used for the salt inhibition test. (Method for evaluating water permeability of separation membrane) The above aqueous solution (40 mL) is allowed to permeate, and the salt concentration in the permeate is measured with a compact sodium ion meter LAQUAtwin-Na-11 (HORIBA). was calculated.

(Example 1)
(Synthesis of Ilayite)
Water glass (SiO ₂ : Na ₂ O: H ₂ O molar ratio is 3.8: 1: 39.8: 1:39. 0, SiO ₂ concentration is 23.05% by mass, and Na ₂ O concentration is 6.25% by mass) was sealed in a 3L stainless steel (SUS316) sealed container and left to stand at 110°C for 12 days to heat ilaite in water. thermally synthesized. It was confirmed by XRD that the product was ilaite (PDF card No. 00-048-0655).
22.2 g of the obtained islaite was placed in a silicon nitride container (capacity: 500 ml) of a planetary ball mill (PM100, manufactured by Verder Scientific) together with 811.1 g of zirconia grinding balls having a diameter of 5 mm, and was rotated at a rotation speed of 160 rpm. Dry milling for 1 hour was performed in an air atmosphere. Subsequently, after replacing the grinding balls with a diameter of 5 mm with zirconia grinding balls with a diameter of 3 mm (811.1 g), the rotational speed was changed to 220 rpm and dry grinding was performed for 1 hour in an air atmosphere.
Using 24.0 g of the pulverized particles of the obtained ilaite as seed crystals (seed particles), water glass (SiO ₂ : _Na2O : _H2O molar ratio is 4.0:1:39.0, _SiO2 concentration is 23.85% by weight, _Na2O concentration is 6.12% by weight. By encapsulating in a SUS316 sealed container and heating at 120° C. for 24 hours, ilaite nanoparticles having a number-based median diameter of dynamic light scattering diameter of 832.8 nm were obtained. The obtained ilaite had a major axis of 845.0 nm, a width perpendicular to the maximum major axis of 686.6 nm, an average thickness of 38.1 nm, and a ratio of (maximum major axis/width perpendicular to the maximum major axis) of 1.2. It was confirmed by XRD that the product was ilaite (PDF card No. 00-048-0655).

(Production of aqueous dispersion of ilaite nanosheets)
A dispersion containing 0.8 g of the above ilaite nanoparticles and 0.96 g of lauryltrimethylammonium chloride were added to 78.2 g of water and heated at 100° C. for 24 hours to remove sodium ions between the silicate layers of ilaite. was replaced by the lauryltrimethylammonium ion. After the liberated sodium ions were removed from the system by filtration with a membrane filter, the wet powder was collected and dispersed again in water to obtain an ion-exchanged aqueous dispersion of ilaite. At this time, the concentration of lauryltrimethylammonium chloride in the islayite water dispersion was 1.2 wt %, and the solid content concentration (1000° C. firing residue) of the water dispersion was 1.6 wt %.
After adding 30 g of a 10 wt % ammonium dodecylsulfate aqueous solution to 37 g of the ion-exchanged aqueous dispersion of islayite, the mixture was diluted with 521 g of pure water so that the solid concentration of islayite was 0.1 wt % and the ammonium dodecyl sulfate concentration was 1.5 wt %. Aqueous ammonia was added thereto to adjust the pH to 10.1. The solution obtained here is heated at 60° C. for 24 hours under stirring with a stirrer to give a colloidal solution (aqueous dispersion of ilaite nanosheets) of nanosheets (plate-like particles A) in which the ilaite nanoparticles are delaminated. got
The average particle size of the resulting aqueous dispersion of ilaite nanosheets was 760 nm as determined by dynamic light scattering. The 90% cumulative particle size value of the obtained aqueous dispersion of ilaite nanosheets was 3.3 μm in the laser diffraction particle size distribution, and the average particle size was 1.3 μm in the laser diffraction particle size distribution. Therefore, (90% cumulative particle size value)/(average particle size value) was 2.5.
The average thickness of the exfoliated nanosheets (plate-like particles A) was 1.5 nm, measured by a method of applying the resulting aqueous dispersion onto a substrate, drying it, and then observing it with an AFM (atomic force microscope).
A sample obtained by drying the obtained aqueous dispersion at room temperature was dried at 100°C for 60 minutes, and then subjected to TG measurement (thermogravimetric measurement) to measure the weight change from 100°C to 800°C. From 220° C. to 500° C., the weight loss occurs in two stages, and is believed to be the first decomposition of the surfactant (20% decrease by mass) followed by the decomposition of the quaternary ammonium (14% decrease by mass). The weight ratio of nanosheets (plate-like particles A): quaternary ammonium ions (a): anionic surfactant (b) is 66:14:20, and the quaternary ammonium ions (a) are nanosheets (plate-like The content of the anionic surfactant (b) was 30.3% by mass based on the nanosheet (plate-like particles A).

(Preparation of Islayite Nanosheet Separation Membrane)
The resulting aqueous dispersion of islayite nanosheets was supplied onto a polyethersulfone (PES) supporting substrate and suction filtered to form an islayite nanosheet laminate on the supporting substrate. Even after the filtration of the aqueous dispersion of islayite nanosheets was completed, suction filtration (reduced pressure filtration) was continued to remove moisture contained in the laminate of islayite nanosheets, thereby enhancing the adhesion between the layers. The concentration and amount of the aqueous dispersion of islayite nanosheets to be supplied onto the supporting substrate are appropriately adjusted according to the thickness of the islayite nanosheet laminate to be formed. A solution obtained by mixing 1.25 mL of the above aqueous dispersion of islayite nanosheets with 50 mL of ultrapure water was supplied so that the solid content of the islayite nanosheets was 1 mg. In addition, separation membranes were also produced in which the solid content of the ilaite nanosheets in the laminate was adjusted to 0.5 mg or 2 mg.
A SEM (scanning electron microscope) image of the cross-sectional structure of a separation membrane having a solid content of 1 mg of islayite nanosheets revealed PES (polyethersulfone, molecular weight cutoff of 100 kDa, membrane area of 17.3×10 ⁻⁴ m ² ). ) and a nanosheet (NS) laminate (liquid-substance separation membrane) with a thickness of about 100 nm was observed.
FIG. 1 shows a process of forming a liquid-substance separation membrane containing ilaite nanosheets composed of plate-like particles (A) on a substrate (polyethersulfone support membrane) by suction filtration.
From the result of X-ray diffraction measurement of the obtained separation membrane, a diffraction peak was observed at 2θ=9.6° in the prepared separation membrane, which indicates that the interlayer distance of the ilaite nanosheet laminate was 0.92 nm. showing. Further, when the same separation membrane was immersed in ultrapure water for 72 hours and then X-ray diffraction was measured, a diffraction peak was observed at 2θ = 9.1°, which indicates the interlayer distance of the ilaite nanosheet laminate in a wet state. is 0.97 nm. Since the interlayer distances measured in the dry state and the wet state are approximately the same, the separation membrane according to the present invention can be said to have high structural stability in water.

(Example 2)
An aqueous dispersion of graphene oxide (GO) (manufactured by Sigma-Aldrich, product name: Graphene oxide, 4 mg/mL) was supplied onto the ilaite nanosheet laminate obtained in Example 1 above, followed by suction filtration to obtain ilaite. A graphene oxide (GO) layer was laminated on the nanosheet to prepare a liquid-substance separation membrane, which is a composite membrane of the ilaite nanosheet and graphene oxide (GO), on the substrate (B). Even after the filtration of the aqueous dispersion of graphene oxide (GO) is completed, suction filtration (reduced-pressure filtration) is continued to remove moisture contained in the laminate containing graphene oxide (GO) and increase the adhesion between the layers. rice field. Graphene oxide (GO) was laminated at a mass ratio of 1:1 to 1:1, and a liquid-borne substance separation membrane compact was laminated at a mass ratio of 1:0.1. did.

(Comparative example 1)
In the process of producing the aqueous dispersion of islayite nanosheets in Example 1, free sodium ions were removed from the system by filtration with a membrane filter, and then the wet powder was dried at 40° C. to obtain an islayite powder. An aqueous dispersion of ilaite nanosheets was obtained in the same manner as in Example 1 except that 12 g of the obtained powder was added to 1174 g of water together with 14 g of lauryltrimethylammonium chloride.
The obtained aqueous dispersion had a 90% cumulative particle size value of 45.8 μm in the laser diffraction particle size distribution, and an average particle size value of 3.6 μm in the laser diffraction particle size distribution. Cumulative particle size value)/(average particle size value) was 12.7.
Separation membranes were obtained in the same manner as in Example 1, except that the solid content of the exfoliated ilaite nanoparticles contained in the laminate was adjusted to 5 mg, 7.5 mg, and 10 mg.

(Performance evaluation of separation membrane)
FIG. 2 shows a schematic diagram showing a water permeability test of a separation membrane and an evaluation test method for separation performance. An aqueous solution containing the substance to be separated (Evans Blue or Acid Red 265 in Example 1) dissolved therein is supplied from the supply liquid tank to the separation membrane molded body unit through a pump, and the liquid-substance separation membrane is placed in the substance concentrate tank. A liquid in which the substance to be separated (Evans Blue or Acid Red 265 in Example 1) that did not pass through was concentrated (a solution with a darker color than the liquid to be separated, and the absorbance of the substance to be separated is high according to the ultraviolet-visible absorption spectrum. solution) and separated water that has passed through the submerged substance separation membrane in the separated water tank (a solution that is colorless or lighter in color than the liquid to be separated, and the absorbance of the substance to be separated cannot be detected by the ultraviolet-visible absorption spectrum or is low) were each stored. As a result, it was possible to separate the substances to be separated from the aqueous solution containing the substances to be separated, while concentrating the substances to be separated.
Further, the same test was conducted using the polyethersulfone (PES) support substrate used in Example 1 instead of the separation membrane molded product unit. Although the rejection rate of the substance to be separated was 0% (0%, the color of the aqueous solution containing the substance to be separated and the separated water stored in the separation water tank was the same) with only the support substrate, the aqueous dispersion of ilaite nanosheets was used. All of the laminated separation membrane molded bodies exhibited dye-blocking properties (substance-removing properties).

EB (Evans Blue) and AR (Acid Red 265, AR is the separation of Example 1 according to the results of calculating the water permeability rate according to the above water permeability evaluation method of the separation membranes of Example 1 and Comparative Example 1 and the above solute blocking performance test Table 1 and FIG. 6 show the results of calculating the rejection rate (%) of the film only test). In FIG. 6, the left axis indicates water permeability (L · m ⁻² · hr ⁻¹ · bar ⁻¹ ), which is indicated by vertical bars in the graph, the right axis indicates dye blocking rate, and the horizontal axis is indicated by *Δ in the graph. indicates the loading amount of nanosheets per support film area of 9.6×10 ⁻⁴ m ² .
In the graph of Example 1 shown on the left, * indicates the blocking rate of Evans Blue, and Δ indicates the blocking rate of Acid Red 265.
In the graph of Comparative Example 1 shown on the right side, * indicates the rejection rate of Evans blue.
The membrane prepared in Comparative Example 1 had a water permeability of 0.32 L·m ⁻² ·h ⁻¹ ·bar ⁻¹ when the nanosheet loading was 10 mg, and an EB (Evans blue) blocking property of 72%. rice field. On the other hand, in the separation membrane according to the present invention, although the concentration was 10 times lower than that of Comparative Example 1 and the loading amount of the nanosheet was 1 mg, the water permeability was 13 L·m ⁻² ·h ⁻¹ ·bar ⁻¹ . and EB (Evans blue) inhibition was 95%. In addition, AR (Acid Red 265), which has a molecular weight smaller than that of EB (Evans Blue), was inhibited by 30% in the present invention. As shown in FIG. 6, the separation membrane molded article of Example 1 exhibits higher water permeability and pigment blocking property (pigment separation property) than the separation membrane molded article of Comparative Example 1. Therefore, the separation membrane molded article of the present invention is excellent. It has excellent separation properties and high solvent permeability.

A scanning electron micrograph of the surface of the separation membrane on the substrate obtained in Example 1 is shown in FIG. The film surface was smooth and had a wavy pattern.
FIG. 4 shows a scanning electron micrograph of a cross section of the separation membrane (1 mg load) on the substrate obtained in Example 1. As shown in FIG. It was confirmed that a film containing 1 mg of laminated nanosheets made of plate-like particles (A) had a thickness of approximately 100 nm.

X-ray of the separation membrane formed after the aqueous dispersion of islayite nanosheets obtained in Example 1 was subjected to ultracentrifugation at 40,000 G to reduce the amount of quaternary ammonium and surfactant to 15% by mass or less relative to the amount of ialite. Diffraction measurement results are shown in FIG. In the measurement result of the separation membrane in a dry state (dry), a peak derived from stacking of nanosheets in the membrane was observed (marked ▼). In addition, compared to the measurement results (wet) obtained by adding water to the separation membrane, the peak position derived from lamination did not shift, indicating that the obtained separation membrane has high structural stability even in water. was done. FIG. 5 shows, in order from the top, the X-ray diffraction diagram of ilaite before delamination, which is the raw material of the present invention, the X-ray diffraction diagram when the separation membrane laminated with the nanosheets of delaminated ilaite of the present invention is in a wet state, and the present invention. X-ray diffractogram of a separation membrane laminated with delaminated ilaite nanosheets in a dry state, X-ray diffractogram of a substrate (polyethersulfone) in a wet state, substrate in a dry state (polyethersulfone ) shows an X-ray diffraction pattern. Ultracentrifugation removes the exfoliating agent component of the layered compound, and the peak derived from delaminated ialite becomes clear, and the structure of the separation membrane containing ialite nanosheets is stable even in a wet state (in water). I found out.

FIG. 7 shows the results showing the water permeability and the dye blocking rate of the dispersion film molded article produced using the aqueous dispersion of Iaryte nanosheets obtained in Example 1. In FIG. The right vertical axis of the graph indicates the dye blocking rate (%), the left vertical axis indicates the water permeability (L·m ⁻² ·hr ⁻¹ ·bar ⁻¹ ), and the horizontal axis represents the support membrane area 9.6×10 ⁻ Nanosheet loading (mg) per ⁴ m ² is shown. The graph on the left side of the dotted line is the test result using a separation membrane molded article formed on a support membrane (polyethersulfone) using an aqueous dispersion of Iaryte nanosheets that has not been subjected to ultracentrifugation, and the graph on the right side of the dotted line. It is a test result using a molecular film molded article formed on an indicator film (polyethersulfone) using an aqueous dispersion of Ialite nanosheets ultracentrifuged at 40,000 G. (*) in the graph indicates the rejection rate of Evans Blue, (Δ) in the graph indicates the rejection rate of Acid Red 265, and the bar graph indicates the water permeability. The left end of the graph shows the test results using only the support film (polyethersulfone) as a blank, the rejection rate of Evans Blue and Acid Red 265 is both zero, and the water permeability is 95 (L m ^-2 hr ^-1・bar ⁻¹ ).
From the results shown in FIG. 7, both the liquid-submerged substance separation membrane compacts produced using the aqueous dispersion of Iialite nanosheets before and after ultracentrifugation are capable of separating BE and AR. It can be used as a liquid-substance separation membrane because it can be used and has water permeability.
In addition, from the results shown in FIG. 7, the separation membrane formed by using the aqueous dispersion of Iaryte nanosheets before ultracentrifugation increases the performance of separating two types of substances as the loading capacity of the nanosheets increases. , the permeability (ie throughput) decreased. On the other hand, the separation membrane formed using the aqueous dispersion of Iaryte nanosheets after ultracentrifugation has a high performance in separating two types of substances despite a low loading capacity, and the water permeability (i.e., throughput) is also high. You can see that it is higher than the load amount. That is, nanosheets can be obtained by using an aqueous dispersion of ialite nanosheets that has been subjected to ultracentrifugation and the amount of quaternary ammonium and surfactant is set to 15% by mass or less (for example, 0.01 to 15.0% by mass) relative to ialite. It can be understood that even if the content is low, two kinds of substances having different molecular weights can be efficiently separated, and a membrane for separating substances in liquid having high water permeability to the solvent in which the solutes are dissolved can be obtained. That is, it is possible to more efficiently separate and concentrate the substances in the liquid from the treatment liquid containing the substances to be separated.

A separation membrane compact having a separation membrane obtained by using the Iialite nanosheets used in Example 1, niobic acid (HNb ₃ O ₈ ) nanosheets, which are other plate-like particles, and GO (graphene oxide) nanosheets. FIG. 8 shows the results of water permeability and dye blocking rate. The right vertical axis of the graph shows the dye blocking rate (%), the left vertical axis shows the water permeability (L m ^-2 hr ^-1 bar ^-1 ), and the horizontal axis shows the same loading amount per support membrane area. The type of each nanosheet produced is shown. (*) in the graph indicates the rejection rate of Evans Blue (EB), (Δ) in the graph indicates the rejection rate of Acid Red 265 (AR), and the bar graph indicates the water permeability.
Separation membrane molded articles containing Iialite nanosheets are two types of substances with different molecular weights than separation membrane molded articles containing niobic acid (HNb ₃ O ₈ ) nanosheets and separation membrane molded articles containing GO (graphene oxide) nanosheets. It can be seen that (EB and AR) are efficiently separated and that the liquid in which these solutes are dissolved has a high water permeability (that is, throughput). That is, it is possible to efficiently separate and concentrate the substances in the liquid from the treatment liquid containing the substances to be separated.

X-ray diffraction measurement of the Ialite nanosheet laminate after the separation membrane molded product obtained in Example 1 was immersed in an aqueous solution adjusted to pH 3 with hydrochloric acid or in an aqueous solution adjusted to pH 11 with sodium hydroxide for 2 weeks. The results are shown in FIG. The X-ray diffraction pattern shows no structural change before and after immersion in the above aqueous solution, indicating that it is stable in an aqueous solution of pH 3-11. FIG. 9 shows, in order from the top, the X-ray diffraction patterns of the ilaite nanosheets in a dry state, a state of storage at pH 7, a state of storage at pH 3, and a state of storage at pH 11. The characteristic peaks derived from each ilaite nanosheet are 2θ (degree) = 9.3°, 9.2°, 9.4°, 9.3°, and d (lattice spacing) is 0.95 nm, 0.96 nm, 0.94 nm, 0.95 nm, respectively. and confirmed that there was no structural change.

FIG. 10 shows the results of measuring the anionic dye-blocking performance of the separation membrane molded product obtained in Example 1. In FIG. Examples of anionic dyes include Methyl Orange (molecular weight 327), Acid Red 265 (molecular weight 636), Brilliant Blue FCF (molecular weight 793), Evans Blue (molecular weight 961), Rose Bengal ( Rose Bengal, molecular weight 974) was used. The loading amount of Ialite nanosheets per support film area of 9.6×10 ⁻⁴ m ² is 0.1 mg for black ▪, 05 mg for black ●, and 1.0 mg for black ▴. The removal rate of methyl orange is 0-10%, the removal rate of Acid Red 265 is 0-18%, the removal rate of brilliant blue FCF is 0-30%, and the removal rate of Evans blue is 75-99. % and the removal rate of Rose Bengal was 90-99%. In each of the molded articles in which the loading amount of the Iialite nanosheets was varied within the above range, the aqueous solution of the material to be separated comprising the anionic dye was separated or passed through at a molecular weight of around 800. Therefore, in the separation of anionic substances in the separation membrane molded article obtained in Example 1, high separation selectivity at a molecular weight of around 800 is expected.

FIG. 11 shows the results of measuring the molecular weight cut off of the polyethylene glycol aqueous solution using the separation membrane molded article obtained in Example 1. As shown in FIG. Nonionic substances were separated using an aqueous polyethylene glycol solution. The loading amount of Ialite nanosheets per support film area of 9.6×10 ⁻⁴ m ² is 0.1 mg for black ▪, 05 mg for black ●, and 1.0 mg for black ▴. Aqueous polyethylene glycol solutions having different molecular weights (200, 1000, 6000, 12000, 20000 and 35000) were passed through separation membrane molded bodies having different load capacities, and the respective removal rates were measured. Separation due to molecular weight difference was not sufficient with a loading of 0.1 mg. When the loading amount was 0.5 mg and 1.0 mg, the removal rate was 90% or more when the molecular weight was around 10,000, indicating separation. Therefore, it is considered that the molecular weight cut off of the separation membrane molded article obtained in Example 1 exists in the vicinity of 10,000 in the separation of nonionic substances.

Evaluation of water permeability of a salt-containing aqueous solution using a liquid-substance separation membrane molded body having a liquid-substance separation membrane in which a graphene oxide layer is laminated at a mass ratio of 1:1 on the ialite nanosheet obtained in Example 2, and The results of the salt component separation test are shown in FIG. In Table 12, the bar graph represents water permeability, black diamond represents sodium sulfate, and black x represents salt rejection of sodium chloride.

Permeability of a salt-containing aqueous solution using a liquid-substance separation membrane formed body containing a liquid-substance separation membrane in which a graphene oxide layer is laminated on the Ialite nanosheet nanosheet obtained in Example 2 at a mass ratio of 1:0.1 The results of the evaluation and the salt component separation test are shown in FIG. In Table 13, the bar graph represents water permeability, black diamond represents sodium sulfate, and black x represents salt rejection of sodium chloride.

12 and 13, in the case of the ialite single film, compared with the case of the graphene oxide (GO) single film, the compound film of ialite and graphene oxide improves the rejection rate of salts. Do you get it.

It is a separation membrane that can efficiently remove substances to be separated (e.g., ionic substances) in a liquid. Disclosed is a liquid-submerged substance separation membrane molded product that efficiently separates ionic organic substances or nonionic substances) and a method for producing the same.

Claims

A quaternary ammonium ion (a) having 15 to 45 carbon atoms in total and 1 to 2 alkyl groups having 10 to 20 carbon atoms and an anionic surfactant (b) having an ammonium ion having an average thickness of 0.7 to 100 nm, an average major axis of 50 to 10,000 nm, and (maximum major axis/width perpendicular to the maximum major axis) = 1.0 to 10.0, due to delamination of the layered compound A liquid-substance separation membrane molded article comprising a liquid-substance separation membrane containing plate-like particles (A) which are delamination substances, and a substrate (B) supporting the liquid-substance separation membrane.
2. The molded article for separating substances in liquid according to claim 1, wherein the layered compound is ilaite.
3. The molded article for separating substances in liquid according to claim 1, wherein the membrane for separating substances in liquid is a composite film of ilaite and graphene oxide.
The liquid-substance separation membrane is formed from an aqueous dispersion of plate-like particles (A) containing the above (a) and (b) used for delamination of the layered compound. 4. The method according to any one of claims 1 to 3, wherein the 90% cumulative particle size value in the laser diffraction particle size distribution of the particles (A) is 1.5 to 10 times the average value of the particle size distribution. Submerged substance separation membrane molding.
The liquid-substance separation membrane is formed from an aqueous dispersion of plate-like particles (A) containing the above (a) and (b) used for delamination of the layered compound. Plate-like particles (A) having an average particle diameter of 10 to 10,000 nm as determined by a scattering method, and having both (a) and (b) in the range of 0.01 to 50.0% by mass with respect to (A) 5. The molded article for separating substances in liquid according to claim 1, wherein
6. The submerged substance according to any one of claims 1 to 5, wherein the substrate (B) is at least one porous substrate selected from the group consisting of cellulose, synthetic polymers, and ceramics. Separation membrane compact.
7. The molded article for separating substances in liquid according to claim 6, wherein the cellulose is nitrocellulose, carboxymethyl cellulose or hydroxyethyl cellulose.
7. The liquid-submerged substance separation membrane molded article according to claim 6, wherein the synthetic polymer is polyethersulfone, polysulfone, polyvinylidene fluoride, polyvinylidene chloride, polyethylene vinyl alcohol, polyvinyl alcohol, polyacrylic acid, or polymethacrylic acid. .
7. The molded article for separating substances in liquid according to claim 6, wherein the ceramic is silica, alumina or mullite.
The liquid-substance separation membrane is formed on the surface of the substrate (B), and the liquid-substance separation membrane has a thickness of 1.5 nm to 10 μm. The liquid-substance separation membrane molded product described above.
The substance-in-liquid according to any one of claims 1 to 10, wherein the solvent permeation rate of the solution containing the substance to be separated is 0.1 to 100 L·m −2 ·hr −1 ·bar −1 . Separation membrane compact.
12. The molded product for separating substances in liquid according to any one of claims 1 to 11, wherein the substance removal rate of the solution containing the substance to be separated is 15 to 99%.
13. The molded product for separating substances in liquid according to any one of claims 1 to 12, wherein the substance to be separated is an ionic compound.
14. The molded article for separating substances in liquid according to claim 13, wherein the ionic compound is an organic compound having at least sulfonate ions or carboxylate ions.
A solution containing a substance to be separated is a solution containing a substance to be separated and at least one or more solute molecules having a molecular weight different from that of the substance to be separated, and for concentrating the substance to be separated in the solution. 15. The molded product for separating substances in liquid according to any one of claims 1 to 14.
The following steps (i) to (vi):
(i) Step: An aqueous dispersion of a silicic acid compound is hydrothermally treated at a temperature of 90 to 150° C., and the resulting layered compound is separated and washed with water. the process of
(ii) step: adding to the aqueous dispersion obtained in step (i) a total carbon atom number of 15 to 45 and a carbon atom number of 10, which is 1 to 3 times the ion exchange capacity of the layered compound; adding a quaternary ammonium ion (a) having 1 to 2 alkyl groups of ∼20 and heating at 40 to 100°C for 12 to 48 hours;
(iii) step: adding pure water to the liquid obtained in step (ii), and removing the sodium ion-containing liquid from the system so that the sodium ion concentration in the liquid is 100 ppm or less;
(iv) step: after dispersing the wet gel included in step (iii) in an anionic surfactant (b) aqueous solution containing ammonium ions at a concentration of 0.01 to 1% by mass, ammonia is further added; adding to adjust the pH in the liquid to 9.0 to 12.0;
(v) step: a step of heating the liquid obtained in step (iv) at 40 to 90° C. for 12 to 48 hours to obtain a dispersion of plate-like particles (A);
(vi) Step: Forming a liquid-substance separation membrane on the surface of the substrate (B) using the dispersion liquid of the plate-like particles (A) obtained in the (v) step. 16. The method for manufacturing a liquid-substance separation membrane molded product according to any one of claims 1 to 15.
The step (vi) is a step of forming a plate-like particle (A) layer on the surface of the substrate (B) using the dispersion liquid of the plate-like particles (A) obtained in the step (v); 17. The article for separating substances in liquid according to claim 16, which is a step of forming a substance separation membrane in liquid, comprising a step of laminating a graphene oxide layer on the layer using a graphene oxide dispersion. Production method.
16. The step (vi) of forming a film on the surface of the substrate (B) using the dispersion of the plate-like particles (A) obtained in the step (v) is performed by suction filtration or pressure filtration. Alternatively, the method for manufacturing a liquid-substance separation membrane molded article according to claim 17.
(v) Between the step and (vi) step, further (v-0) step,
(v-0) step: The dispersion containing the plate-like particles (A) obtained in step (v) is The content of the quaternary ammonium ions (a) having ~2 and the anionic surfactant (b) having ammonium ions are both in the range of 0.01 to 15.0% by mass based on the plate-like particles (A) 18. The method for manufacturing a liquid-submerged substance separation membrane molded product according to claim 16 or 17, further comprising a step of obtaining a dispersion containing the plate-like particles (A) reduced to .
(v-0) step is the following (v-1) step,
(v-1) step: the dispersion containing the plate-like particles (A) obtained in step (v) is subjected to ultracentrifugation at 20,000 to 60,000 G, and the total number of carbon atoms is 15 to 45, and The content of both the quaternary ammonium ion (a) having 1 to 2 alkyl groups of number 10 to 20 and the anionic surfactant (b) having an ammonium ion is 0.01 to 15 with respect to (A) 20. The method for manufacturing a liquid-submerged substance separation membrane molded product according to claim 19, which is a step of obtaining a dispersion liquid containing the plate-like particles (A) reduced to a range of 0.0% by mass.