Water treatment system, water treatment method and amine solution

Abstract

To provide a water treatment system, a water treatment method, and an amine solution that treat water with low energy.SOLUTION: An apparatus has means 11 for introducing treated water A into a first container B, means 12 for introducing an amine solution C into the first container to obtain a first mixture D, and means 14 for separately separating a supernatant phase F and a concentrated phase G of a second mixture E in which the first mixture is phase separated. The amine solution contains tertiary amine compounds of chemical formula (1) or / and chemical formula (2), in which R1 and R2 are linear alkyl chains, and R3 and R4 are linear or branched alkyl groups.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] SUMMARY OF THE INVENTION Embodiments of the present invention relate to a water treatment system, a water treatment method, and an amine solution. [Background technology]

[0002] As the global population grows, demand for water is expected to grow significantly, creating a need for low-energy desalination technologies. Common desalination methods include thermal evaporation and reverse osmosis (RO) membranes, with the RO membrane method, which consumes relatively little energy, coming into widespread use in recent years. The reverse osmosis membrane method desalinates by applying pressure to an osmotic membrane in the opposite direction to the osmotic pressure. [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] Environ.Sci.Technol. 2020, 54 9124-9131 Summary of the Invention [Problem to be solved by the invention]

[0004] Embodiments provide a water treatment system, a water treatment method, and an amine solution that treat water with low energy. [Means for solving the problem]

[0005] The water treatment system of the embodiment includes: Contains water and solutes a means for introducing the water to be treated into a first container; and a means for introducing an amine solution into the first container. The treated water and the amine solution were mixed. The method includes a means for obtaining a first mixture, and a means for separating the supernatant phase and the concentrated phase into a second mixture obtained by phase separation of the first mixture. The first mixture obtained by the means for obtaining a first mixture is miscible with the water to be treated at a temperature of 3°C or higher and 40°C or lower. The miscibility of the amine solution with the water to be treated causes phase separation into a supernatant phase, which is a mixed liquid containing the amine solution and the water to be treated, and a concentrated phase, which is a precipitate of the solute, a slurry of the solute, or a liquid in which the solute of the water to be treated is concentrated. The amine solution contains a tertiary amine compound of chemical formula (1) or / and chemical formula (2). 1 is a linear alkyl chain containing 2 to 4 carbon atoms. 2is a linear alkyl chain containing 2 to 4 carbon atoms. 3 is a linear alkyl group having 1 to 4 carbon atoms or a branched alkyl group having 3 to 4 carbon atoms. 4 is a linear alkyl group having 1 to 4 carbon atoms or a branched alkyl group having 3 to 4 carbon atoms. [Brief explanation of the drawings]

[0006] [Figure 1] 1 is a schematic diagram of a water treatment system according to an embodiment. [Figure 2] 1 is a flowchart of a water treatment method according to an embodiment. [Figure 3] 1 shows the chemical formula of a tertiary amine compound according to an embodiment. [Figure 4] 1 shows the chemical formula of a tertiary amine compound according to an embodiment. [Figure 5] 1 is a schematic diagram of a water treatment system according to an embodiment. [Figure 6] 1 is a flowchart of a water treatment method according to an embodiment. [Figure 7] 1 is a schematic diagram of a water treatment system according to an embodiment. [Figure 8] 1 is a flowchart of a water treatment method according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0007] DETAILED DESCRIPTION OF THE INVENTION

[0023] An embodiment of the present invention will now be described with reference to the accompanying drawings. Unless otherwise specified, values ​​obtained by pH and other measurements are values ​​measured at atmospheric pressure and 25°C.

[0008] Water treatment embodiments relate to the concentration and recovery (including precipitation) and / or production (eg, desalination) of water from target water.

[0009] (First embodiment) The first embodiment relates to a water treatment system and method that are applied to non-evaporative extraction and separation by concentration using a tertiary amine compound whose hydrophobicity and hydrophilicity change with temperature. Fig. 1 shows a schematic diagram of a water treatment system 100 according to the first embodiment. The schematic diagram of the water treatment system 100 in Fig. 1 includes a means 11 for introducing water A to be treated into a first container B, a means 12 for introducing an amine solution C into the first container B to obtain a first mixture D, a temperature control means 13 for controlling the temperature, and a means 14 for separating a supernatant phase F (liquid phase) from a concentrated phase G (liquid phase, solid phase, or slurry phase) of a second mixture E, which is a phase-separated version of the first mixture D containing the water A to be treated and the amine solution C. The second mixture E undergoes phase separation at low temperatures.

[0010] In the schematic diagram of Figure 1, means 11 for introducing the water to be treated A into the first container B, means 12 for introducing the amine solution C into the first container B to obtain a second mixture E, temperature control means 13 for controlling the temperature, and means 14 for separating the supernatant phase F and concentrated phase G of the second mixture E obtained by phase separation of the first mixture D containing the water to be treated A and the amine solution C are provided outside the first container B, but these means may also be provided inside the first container B.

[0011] FIG. 2 shows a flowchart of a water treatment method according to a first embodiment. The water treatment method according to the embodiment preferably includes the steps of: obtaining a first mixture D by mixing water to be treated A and an amine solution C; phase-separating the first mixture D at a low temperature to obtain a phase-separated second mixture E; and separating a supernatant phase F from a concentrated phase G of the phase-separated second mixture E. The step of mixing water to be treated A and amine solution C to obtain the first mixture D is performed by means 11 for introducing water to be treated A into a first container B and means 12 for introducing amine solution C into the first container B to obtain the second mixture E. By storing the first mixture D at a low temperature in the first container B, the first mixture D undergoes phase separation, resulting in the phase-separated second mixture E. The first container B, which mixes water to be treated A and amine solution C, and the container which contains the first mixture D when the first mixture D undergoes phase separation may be the same container or different containers. The step of separating the supernatant phase F and concentrated phase G of the phase-separated second mixture E is performed by means 14 for separating the supernatant phase F and concentrated phase G of the second mixture resulting from phase separation of the first mixture D containing the water to be treated A and the amine solution C. The water treatment system 100 will be described below, and the description of the water treatment system 100 also includes a description of the water treatment method.

[0012] The means 11 for introducing the water to be treated A into the first container B introduces the water to be treated A into the first container B. The means 11 for introducing the water to be treated A into the first container B includes, for example, a pipe leading to the first container B, and instruments for determining the properties of the water to be treated A, such as a water quality measuring instrument such as a pH meter or a conductivity meter, a thermometer, and valves, cocks, and pumps for controlling the flow rate of the water to be treated A flowing through the pipe.

[0013] The water to be treated A contains water and inorganic salts soluble in water and / or organic matter soluble in water. The inorganic salts soluble in water and / or organic matter soluble in water are separated by the water treatment system 100 of the embodiment. The inorganic salts and / or organic matter in the water to be treated A can be separated by phase separation. The separated inorganic salts and / or organic matter can also be recovered. The inorganic salts are dissolved in the water to be treated A and exist as ions in the water to be treated A. When the organic matter is a water-soluble salt, the water to be treated A contains ionized organic matter and counterions of the ionized organic matter. The organic matter contained in the water to be treated A (organic matter recovered by precipitation) is preferably a water-soluble compound that is solid or liquid at the treatment temperature. The water to be treated A can be treated even if it contains substantially no salts and only organic matter. When "water to be treated A" is written alone, it refers to the water to be treated A before the water treatment of the embodiment.

[0014] The water to be treated A is an aqueous solution. The total mass of the inorganic salts and / or organic substances and the water is preferably 5 wt% to 300 wt% of the water in the water to be treated A. In addition to the inorganic salts and / or organic substances and water, the water to be treated A may contain 0.0 wt% to 5 wt% of one or more selected from the group consisting of water-insoluble organic substances, water-soluble organic substances that are liquid at the treatment temperature, metals, and metal oxides.

[0015] There are no particular limitations on the concentration of inorganic salts and / or organic matter contained in the water to be treated A. In the embodiment, the inorganic salts and / or organic matter can be separated regardless of the concentration of inorganic salts and / or organic matter contained in the water to be treated A.

[0016] Specifically, the ions contained in the water to be treated A are preferably one or more selected from the group consisting of sodium ions, potassium ions, lithium ions, magnesium ions, calcium ions, manganese ions, iron ions, fluoride ions, sulfate ions, nitrate ions, nitrite ions, chloride ions, bromide ions, iodide ions, cyanide ions, acetate ions, bicarbonate ions, thiocyanate ions, hydrogen sulfide ions, hydrogen oxalate ions, chlorate ions, perchlorate ions, hypochlorite ions, hydroxide ions, silver ions, copper ions, iron ions, cobalt ions, tin ions, lead ions, manganese ions, ammonium ions, aluminum ions, chromium ions, various complex ions, phosphate ions, strontium ions, barium ions, cadmium ions, nickel ions, zinc ions, mercury ions, ionic silica, etc. The water to be treated A may also contain non-ionized organic matter, silica, and colloidal silica.

[0017] The first container B is a container for containing the water to be treated A and the amine solution. The first container B is preferably provided with a means 11 for introducing the water to be treated A into the first container B, a means 12 for introducing the amine solution C into the first container B to obtain a first mixture D, a temperature control means 13, and a means 14 for separating the supernatant phase F and the concentrated phase G. The means 14 for separating the supernatant phase F and the concentrated phase G may also be provided in a container separate from the first container B.

[0018] The total pressure in the first container B is preferably 700 Pa or more and 1 MPa or less. The gas in the first container B includes carbon dioxide, argon, oxygen, nitrogen, etc. A portion of the gas contained in the first container B is contained in one or more selected from the group consisting of the water to be treated A, the amine solution C, the first mixture D, the second mixture E, and the supernatant phase F.

[0019] The means 12 for introducing the amine solution C into the first container B to obtain a first mixture D introduces the amine solution C into the first container B. The means 12 for introducing the amine solution C into the first container B to obtain a first mixture D includes, for example, a pipe leading to the first container B, and instruments for determining the properties of the amine solution C, such as a pH meter, a conductivity meter, and a thermometer, as well as a valve, a cock, a pump, and the like for controlling the flow rate of the amine solution C flowing through the pipe.

[0020] The temperature adjustment means 13 can adjust the temperatures of the water to be treated A, the first container B, the amine solution C, the first mixture D, the phase-separated second mixture E, the supernatant phase F, and the concentrated phase H. Temperature adjustment by the temperature adjustment means 13 is not performed when it is not necessary. As the temperature adjustment means 13, a heat medium such as a heater or hot water and / or a refrigerant such as a cooling coil or the atmosphere (air cooling) is used. It is preferable to use exhaust heat as the temperature adjustment means 13.

[0021] Whether or not the temperature control means 13 is used, the temperature of the first mixture D in the first container B is preferably 3°C or higher and 40°C or higher. If the temperature of the first mixture D is too low, a lot of energy is required for cooling, and the viscosity of the solution increases, making it difficult to handle. If the temperature of the first mixture D is high, a lot of energy is required for heating, the amine compound may volatilize, and it may be difficult to form each phase. The temperature of the first mixture D is more preferably 5°C or higher and 35°C or lower. By maintaining the first mixture D and the phase-separated second mixture E at the above low temperatures, the concentrated phase H can be recovered.

[0022] Amine solution C contains a tertiary amine whose solubility changes in response to temperature. The liquid properties of a solution containing amine solution C change depending on the temperature in the solution. By mixing amine solution C with water to be treated A at a low temperature, the solutes contained in water to be treated A precipitate, or the water containing the solutes contained in water to be treated A undergoes phase separation from the amine.

[0023] The tertiary amine compound used in the embodiment is liquid at room temperature.

[0024] When mixed with water, the tertiary amine compound used in the embodiments forms a homogeneous phase with water or undergoes phase separation into an aqueous phase and an organic phase, depending on the temperature. In the first embodiment, water treatment is performed by utilizing the property of the tertiary amine compound used, which easily absorbs water at low temperatures. In the second and subsequent embodiments, reuse of the tertiary amine compound is described by utilizing the property of phase separation into an aqueous phase and an organic phase at high temperatures. Compounds with low boiling points emit a distinctive ammonia odor, so compounds with high boiling points are more preferable. Furthermore, phase separation properties vary depending on the compound, and some are soluble in water to a certain extent even at high temperatures. Using amines that are easily soluble in water increases the amount of amine contained in the supernatant phase F, so compounds with high phase separation properties that are less soluble in water at high temperatures are more preferable. Using amine compounds with high solubility at room temperature, a high boiling point, and high phase separation properties when heated enables efficient separation. Furthermore, amine compounds that allow efficient precipitation operations with a small amount of amine compound are preferred.

[0025] Figures 3 and 4 show the chemical formulas of tertiary amine compounds according to embodiments. Amine solution C preferably contains a tertiary amine compound represented by chemical formula (1) and / or (2) shown in Figures 3 and 4. Amine solution C preferably contains a tertiary amine compound represented by chemical formula (1) or (2) shown in Figures 3 and 4. Amine solution C preferably contains a tertiary amine compound represented by chemical formula (1) or (2) shown in Figures 3 and 4. Hereinafter, the tertiary amine compound represented by chemical formula (1) or (2) may be referred to as the amine compound according to embodiments. The amine compound according to embodiments has high compatibility with water at low temperatures. Due to its high compatibility with water, many amine compounds according to embodiments dissolve in water. When the amine compound according to embodiments is dissolved in water at a volume of 7 times or more, substances dissolved in the water to be treated A become less soluble in the water to be treated. Substances that are no longer soluble in the water to be treated A become concentrated phase H. The compatibility of the amine compound according to embodiments with water decreases when heated. Concentrated phase H in second mixture E is maintained at a low temperature. The state in which concentrated phase H and supernatant phase F are separated is maintained at a low temperature. In the embodiment, supernatant phase F undergoes phase separation when heated. When heated, the solution containing the amine compound of the embodiment exceeds the lower critical solution temperature of the amine compound, causing a change in liquid properties. In the first embodiment, the high compatibility with water at low temperatures of the amine compound of the first embodiment is utilized.

[0026] The amine compound of the embodiment has a high dissolution rate in water, and therefore, the concentrated phase H appears quickly. The rapid appearance of the concentrated phase H improves the efficiency of the water treatment process. The amine compound of the embodiment has a high vapor pressure at 25°C, and therefore does not easily volatilize during the water treatment process.

[0027] The amine compound of the embodiment appears in a relatively small amount to produce concentrated phase H. This means that the amount of the amine compound of the embodiment required to produce concentrated phase H may be small. It is preferable that the use of the amine compound of the embodiment results in high utilization efficiency of the amine compound used to produce concentrated phase H.

[0028] The vapor pressure of the amine compound of the embodiment at 25°C is 1.0 x 10 -10[Torr] or more 1.0×10 -1 It is preferable that the pressure is 1 Torr or less.

[0029] When water treatment was carried out at 10°C, the amine compound of the embodiment was confirmed to have high solubility in the water to be treated A and to produce a concentrated phase H.

[0030] From the viewpoint of high solubility at room temperature, high boiling point, and high phase separation property when heated, R 1 is preferably a linear alkyl chain having 2 to 4 carbon atoms. 1 is preferably a linear alkyl chain having 2 or 3 carbon atoms. 1 is preferably a linear alkyl chain having 3 carbon atoms.

[0031] From the viewpoint of high solubility at room temperature, high boiling point, and high phase separation property at elevated temperature, R 2 is preferably a linear alkyl chain having 2 to 4 carbon atoms.

[0032] From the viewpoint of high solubility at room temperature, high boiling point, and high phase separation property at elevated temperature, R 3 is preferably a linear alkyl group having 1 to 4 carbon atoms or a branched alkyl group having 3 to 4 carbon atoms.

[0033] From the viewpoint of high solubility at room temperature, high boiling point, and high phase separation property at elevated temperature, R 4 is preferably a linear alkyl group having 1 to 4 carbon atoms or a branched alkyl group having 3 to 4 carbon atoms.

[0034] R in chemical formula (2) 2 is a linear alkyl chain with 2 to 4 carbon atoms, and R 3 and R 4 are preferably the same and are a linear alkyl group having 1 to 4 carbon atoms or a branched alkyl group having 3 to 4 carbon atoms.

[0035] R in chemical formula (2) 2 is a linear alkyl chain having 2 or 3 carbon atoms, and R3 and R 4 are preferably the same and are a linear alkyl group having 1 to 3 carbon atoms or a branched alkyl group having 3 to 4 carbon atoms.

[0036] R in chemical formula (2) 2 is a linear alkyl chain having 2 or 3 carbon atoms, and R 3 and R 4 are preferably the same and are a linear alkyl group having 1 to 3 carbon atoms or a branched alkyl group having 3 carbon atoms.

[0037] R in chemical formula (2) 2 is a linear alkyl chain with 3 carbon atoms, and R 3 and R 4 are preferably the same and are linear alkyl groups having 1 to 3 carbon atoms.

[0038] R in chemical formula (2) 2 is a linear alkyl chain with 3 carbon atoms, and R 3 and R 4 are preferably the same and are linear alkyl groups having one carbon atom.

[0039] R in chemical formula (2) 2 is a linear alkyl chain with 3 carbon atoms, and R 3 and R 4 are preferably the same and are linear alkyl groups having two carbon atoms.

[0040] R in chemical formula (2) 2 is a linear alkyl chain with 3 carbon atoms, and R 3 and R 4 are preferably the same and are linear alkyl groups having 3 carbon atoms.

[0041] Amine solution C preferably contains 80 wt% or more and 100 wt% or less, more preferably 90 wt% or more and 100 wt% or less, and more preferably 95 wt% or more and 100 wt% or less, of a tertiary amine compound whose solubility changes in response to heat.

[0042] Amine solution C preferably contains 80 wt% or more and 100 wt% or less of the tertiary amine compounds of chemical formula (1) and / or chemical formula (2), more preferably 90 wt% or more and 100 wt% or less, and more preferably 95 wt% or more and 100 wt% or less.

[0043] Amine solution C preferably contains 80 wt% or more and 100 wt% or less of the tertiary amine compound of chemical formula (1) or chemical formula (2), more preferably 90 wt% or more and 100 wt% or less, and more preferably 95 wt% or more and 100 wt% or less.

[0044] The tertiary amine compound of the embodiment preferably has high solubility in water. Because the tertiary amine compound of the embodiment has high solubility, the time required for phase separation can be shortened. By shortening the time required for phase separation, the treatment speed of the water to be treated A can be increased. When the tertiary amine compound dissolves in water (water to be treated), it undergoes phase separation with a slurry containing a high concentration of solute, or the solute precipitates, so high solubility also contributes to improving the recovery rate.

[0045] The solubility of the tertiary amine compound of the embodiment is preferably 35 [g / L] or more. Although there is no particular upper limit to the solubility, for example, the solubility of the tertiary amine compound of the embodiment is preferably 1000 [g / L] or less.

[0046] Phase separation can also be achieved using diisopropylamine, propylbutylamine, dibutylamine, 2-ethylhexylamine, N-ethylbenzylamine, heptylamine, and octylamine. However, these amine compounds have high boiling points and vapor pressures, making them less practical in terms of solvent loss and odor.

[0047] The tertiary amine compound of the embodiment preferably has a high boiling point. Tertiary amine compounds with low boiling points are prone to volatilization. Because amines have a distinctive odor, it is preferable to use amines that are less prone to volatilization for water treatment. In addition, the use of a tertiary amine compound that is less prone to volatilization is also preferable because it increases the amine recovery efficiency, as described in the second and subsequent embodiments.

[0048] The boiling point of the tertiary amine compound of the embodiment at 1 atmosphere is preferably 100° C. or higher, more preferably 150° C. or higher, and even more preferably 200° C. or higher. The upper limit of the boiling point is not particularly limited, but the boiling point of the tertiary amine compound of the embodiment at 1 atmosphere is, for example, 500° C. or lower.

[0049] Phase separation can also be achieved using diisopropylamine, propylbutylamine, dibutylamine, 2-ethylhexylamine, N-ethylbenzylamine, heptylamine, and octylamine. However, these amine compounds have boiling points below 200°C and high vapor pressures of over 1 Torr at room temperature. These amines are not very practical due to solvent loss and odor.

[0050] If a small amount of amine solution C is used, the amount of inorganic salts and / or organic matter precipitated in the water to be treated A will be small, so it is preferable to use an appropriate amount of amine solution C depending on the amount of inorganic salts and / or organic matter contained in the water to be treated A. The total number of moles of tertiary amines whose solubility changes with temperature is preferably equal to or greater than the total number of moles of inorganic salts and / or organic matter contained in the water to be treated A, more preferably equal to or greater than twice the total number of moles of inorganic salts and / or organic matter contained in the water to be treated A, and even more preferably equal to or greater than five times the total number of moles of inorganic salts and / or organic matter contained in the water to be treated A.

[0051] In chemical formulas, hydrogen may be omitted. For example, when three of the four carbon bonds are shown in the chemical formulas of Figures 3 and 4, the remaining carbon bond is a hydrogen bond, and the hydrogen bond is omitted. Also, for example, an ethyl group may be abbreviated as Et, a propyl group may be abbreviated as Pr, and a methyl group may be abbreviated as Me.

[0052] Specific examples of amine compounds of chemical formula (1) are shown in Figure 3. A method for synthesizing compounds of chemical formula (1) is briefly explained below. For example, pyrrolidine and 1,3-dibromopropane (alternatively, dibromomethane or 1,2-dibromoethane may be used depending on the number of carbon atoms in the alkyl chain) are heated and stirred in a solvent, and pyrrolidine is bonded to the bromine atoms on both sides of the 1,3-dibromopropane through a nucleophilic reaction. The resulting compound can be purified to obtain the tertiary amine of chemical formula (1).

[0053] The amine compound of chemical formula (1) is preferably one or more of the tertiary amine compounds of chemical formula (1-1), tertiary amine compounds of chemical formula (1-2), and tertiary amine compounds of chemical formula (1-3).

[0054] The tertiary amine compound of chemical formula (1-1) in FIG. 3 is a compound that has high solubility at room temperature, a high boiling point, a low vapor pressure at room temperature, and high phase separation upon heating. Furthermore, the tertiary amine compound of chemical formula (1-1) has a high vapor pressure at 25°C. When water treatment is performed using the tertiary amine compound of chemical formula (1-1) at 10°C, a concentrated phase H appears. Furthermore, since the lower critical solution temperature of chemical formula (1-1) is within the range of 35°C to 90°C, the amines of the second and subsequent embodiments can be regenerated by gentle heating.

[0055] When using an amine solution C containing 50 wt % or more of a tertiary amine compound of chemical formula (1-1), the temperatures of the first mixture D and the second mixture E are preferably kept at room temperature or lower, preferably between 5°C and 38°C, inclusive, where the present invention is carried out. If the process is carried out at a location above room temperature, the temperature in the uncontrolled area of ​​the apparatus will be lower than that of the first container, and solids may precipitate from the second mixture E or the liquid phase F, causing the piping to clog.

[0056] The tertiary amine compound of chemical formula (1-2) in FIG. 3 is a compound that has high solubility at room temperature, a high boiling point, and high phase separation upon heating. Furthermore, the tertiary amine compound of chemical formula (1-2) has a high vapor pressure at 25°C. When water treatment is performed using the tertiary amine compound of chemical formula (1-2) at 10°C, a concentrated phase H appears. Furthermore, since the lower critical solution temperature of chemical formula (1-2) is within the range of 35°C to 90°C, the amines of the second and subsequent embodiments can be regenerated by gentle heating.

[0057] When an amine solution C containing 50 wt % or more of the tertiary amine compound of chemical formula (1-2) is used, the temperature of the first mixture D and the temperature of the second mixture E are preferably 5°C or more and 38°C or less.

[0058] The tertiary amine compound of chemical formula (1-3) in FIG. 3 is a compound that has high solubility at room temperature, a high boiling point, and high phase separation upon heating. Furthermore, the tertiary amine compound of chemical formula (1-3) has a high vapor pressure at 25°C. When water treatment is performed using the tertiary amine compound of chemical formula (1-3) at 10°C, a concentrated phase H appears. Furthermore, since the lower critical solution temperature of chemical formula (1-3) is within the range of 35°C to 90°C, the amines of the second and subsequent embodiments can be regenerated by gentle heating.

[0059] When an amine solution C containing 50 wt% or more of the tertiary amine compound of chemical formula (1-3) is used, the temperature of the first mixture D and the temperature of the second mixture E are preferably 5°C or more and 38°C or less.

[0060] Specific examples of amine compounds of chemical formula (2) are shown in Figure 4. A method for synthesizing compounds of chemical formula (2) is briefly explained below. For example, pyrrolidine and 1,3-dibromopropane (alternatively, dibromomethane or 1,2-dibromoethane may be used depending on the number of carbon atoms in the alkyl chain) are heated and stirred in a solvent, and pyrrolidine is bonded to the bromine atoms on both sides of the 1,3-dibromopropane through a nucleophilic reaction. The resulting compound can be purified to obtain the tertiary amine of chemical formula (2).

[0061] The amine compound of chemical formula (2) is preferably one or more of the tertiary amine compounds of chemical formula (2-1), tertiary amine compounds of chemical formula (2-2), and tertiary amine compounds of chemical formula (2-3).

[0062] The tertiary amine compound of chemical formula (2-1) in FIG. 4 is a compound with high solubility at room temperature, a high boiling point, and high phase separation upon heating. Furthermore, the tertiary amine compound of chemical formula (2-1) has a high vapor pressure at 25°C. When water treatment is performed using the tertiary amine compound of chemical formula (2-1) at 10°C, a concentrated phase H appears. Furthermore, since the lower critical solution temperature of chemical formula (2-1) is within the range of 35°C to 90°C, the amines of the second and subsequent embodiments can be regenerated by gentle heating.

[0063] When an amine solution C containing 50 wt % or more of the tertiary amine compound of chemical formula (2-1) is used, the temperature of the first mixture D and the temperature of the second mixture E are preferably 5°C or more and 38°C or less.

[0064] The tertiary amine compound of chemical formula (2-2) in FIG. 4 is a compound with high solubility at room temperature, a high boiling point, and high phase separation upon heating. Furthermore, the tertiary amine compound of chemical formula (2-2) has a high vapor pressure at 25°C. When water treatment is performed using the tertiary amine compound of chemical formula (2-2) at 10°C, a concentrated phase H appears. Furthermore, since the lower critical solution temperature of chemical formula (2-2) is within the range of 35°C to 90°C, the amines of the second and subsequent embodiments can be regenerated by gentle heating.

[0065] When the amine solution C containing 50 wt % or more of the tertiary amine compound of chemical formula (2-2) is used, the temperature of the first mixture D and the temperature of the second mixture E are preferably 5°C or more and 38°C or less.

[0066] The tertiary amine compound of chemical formula (2-3) in FIG. 4 is a compound with high solubility at room temperature, a high boiling point, and high phase separation upon heating. Furthermore, the tertiary amine compound of chemical formula (2-3) has a high vapor pressure at 25°C. When water treatment is performed using the tertiary amine compound of chemical formula (2-2) at 10°C, a concentrated phase H appears. Furthermore, the lower critical solution temperature of chemical formula (2-3) is within the range of 35°C to 90°C, so that the amines of the second and subsequent embodiments can be regenerated by gentle heating.

[0067] When the amine solution C containing 50 wt % or more of the tertiary amine compound of chemical formula (2-3) is used, the temperature of the first mixture D and the temperature of the second mixture E are preferably 5°C or more and 38°C or less.

[0068] The supernatant phase F is a mixture of the treated water A and amine solution C, from which the solute and solvent (in the case of a slurry) have been partially removed. Raising the temperature changes the liquid nature of amine solution C from hydrophilic to hydrophobic. When the supernatant phase F is heated, the LCST (Lower Critical Solution Temperature) of amine solution C causes phase separation into an amine-rich phase and a water-rich phase. The tertiary amine compounds contained in amine solution C can then be reused.

[0069] A first mixture D containing water to be treated A and an amine solution C is contained in a first container B.

[0070] In the embodiment, water treatment is carried out using the water to be treated A and the amine solution. By the water treatment of the embodiment, inorganic salts and / or organic substances contained in the water to be treated A are separated (concentrated).

[0071] The pH of the water to be treated A (measured at 25°C) is preferably 6 or more and 13 or less, more preferably 10 or more and 12 or less. If the pH of the first mixture D is less than 6, the alkaline amines will likely form salts, dissolve in water, and become unrecoverable, which is undesirable. If the pH of the water to be treated A is greater than 13, this is undesirable because it makes the equipment more susceptible to corrosion. An alkaline solution is preferably used to adjust the pH. At least one alkaline solution selected from the group consisting of sodium hydroxide, potassium hydroxide, potassium carbonate, and sodium bicarbonate is practical for use in adjusting the pH. To adjust the pH of the first mixture D, it is preferable to adjust the pH of the water to be treated A.

[0072] The water to be treated A and the amine solution C are mixed to obtain a first mixture D. Vigorous stirring may be performed during mixing. Regarding the ratio of the water to be treated A to the amine solution C, when the volume of the water to be treated A is taken as 1, the volume of the amine solution C (Solvent / Feed) is preferably 1 to 200, more preferably 1 to 50, and even more preferably 1 to 25. Regarding the ratio of the water to be treated A to the amine solution C, when the volume of the water to be treated A is taken as 1, the volume of the amine solution C (Solvent / Feed) is preferably 4 to 200, more preferably 4 to 50, and even more preferably 4 to 25. Regarding the ratio of the water to be treated A to the amine solution C, when the volume of the water to be treated A is taken as 1, the volume of the amine solution C (Solvent / Feed) is preferably 7 to 100, more preferably 7 to 50, and even more preferably 7 to 25. It is preferable to perform separation using a small amount of amine compound, thereby increasing the amine utilization efficiency. Regarding the ratio of water to be treated A to amine solution C, if the volume of water to be treated A is 1, the volume of amine solution C can be 4 to 20 or 4 to 15.

[0073] The first mixture D, which contains the water to be treated A and the amine solution C contained in the first container B, is placed in a low-temperature environment, whereby the first mixture D undergoes phase separation into a supernatant phase F and a concentrated phase G. The temperature of the first mixture D during phase separation is preferably 3°C to 40°C, more preferably 5°C to 35°C. Furthermore, it is desirable to leave the first mixture D in the first container B for 5 minutes to 3 hours until the first mixture D separates into the supernatant phase F and the concentrated phase G (the time during which the first mixture D is being phase separated), or to perform a mechanical separation operation that utilizes the density difference between the supernatant phase F and the concentrated phase G. Heating the first mixture D here increases the salt solubility in the supernatant phase F, thereby decreasing the salt concentration in the concentrated phase G.

[0074] When the water to be treated A and the amine solution C are mixed, the tertiary amine compound dissolves in the water to be treated A, making the inorganic salts and / or organic substances dissolved in the water to be treated A less soluble, and making it easier for the inorganic salts and / or organic substances to be concentrated. This phase separation allows the inorganic salts and / or organic substances to be concentrated without utilizing the polarity reversal property.

[0075] The phase-separated second mixture E contains a supernatant phase F and a concentrated phase G. The concentrated phase G in the phase-separated second mixture E is a precipitate consisting of sediment or a liquid containing a high concentration of solute. If the separation of the supernatant phase F and the concentrated phase G is insufficient, the phase-separated second mixture E may be stirred, an amine solution C may be added, or the mixture may be cooled, or the phase-separated second mixture E from the first mixture D may be centrifuged.

[0076] The means 14 for separating the supernatant phase F and the concentrated phase G separates the supernatant phase F and the concentrated phase G. The means 14 for separating the supernatant phase F and the concentrated phase G includes a mechanism for discharging either or both of the supernatant phase F and the concentrated phase G from the first container B from the second mixture E obtained by phase separation of the first mixture D. An example of the means 14 for separating the supernatant phase F and the concentrated phase G is a pump that extracts the supernatant phase F from the upper side of the first container B. Another example of the means 14 for separating the supernatant phase F and the concentrated phase G is a filter at the bottom of the first container B through which the concentrated phase G is filtered and an opening that can be controlled to open and close using a cock or the like. The concentrated phase G remains in the filter, and the supernatant phase F can be discharged from the opening to separate the supernatant phase F and the concentrated phase G. The concentrated phase G remaining in the filter can then be recovered, allowing the supernatant phase F and the concentrated phase G to be separately discharged from the first container B. Alternatively, the second mixture E obtained by phase separation of the first mixture D can be transferred to another container and then similarly separated into a supernatant phase F and a concentrated phase G. The mesh size of the filter is appropriately selected depending on the substance contained in the concentrated phase G.

[0077] In the water treatment system 100 and water treatment method of the embodiment, a tertiary amine whose liquid properties change in response to temperature is used, and inorganic salts and / or organic substances contained in the water to be treated A can be efficiently separated. In the water treatment system 100 and water treatment method, inorganic salts and / or organic substances contained in the water to be treated A can be efficiently recovered under low-temperature conditions. This can be done with much less energy than concentrating the water to be treated A by evaporating the water contained in the water to be treated A.

[0078] (Second embodiment) The second embodiment relates to a water treatment system and method that are applied to non-evaporative extraction and separation by concentration using a tertiary amine compound whose hydrophobicity and hydrophilicity change in response to heat. The second embodiment is an application example of the first embodiment. In the second embodiment, water treatment is performed by utilizing the LCST (Lower Critical Solution Temperature) phenomenon of the tertiary amine compound of the embodiment, which is hydrophilic at low temperatures.

[0079] FIG. 5 shows a schematic diagram of a water treatment system 200 according to a second embodiment. The schematic diagram of the water treatment system 200 in FIG. 5 includes a means 11 for introducing water to be treated A into a first container B, a means 12 for introducing an amine solution C into the first container B to obtain a second mixture E, a temperature control means 13 for controlling the temperature, a means 14 for separating a supernatant phase F from a concentrated phase G of the second mixture E obtained by phase separation of a first mixture D containing the water to be treated A and the amine solution C, and a means 15 for separating the supernatant phase F into an aqueous phase H and an organic phase (amine phase) J to separate and recover the tertiary amine (organic phase J). A filter 20 is preferably provided between the means 14 for separating the supernatant phase F from the concentrated phase G and the means 15 for separating and recovering the tertiary amine compound. The mesh size of the filter 16 is appropriately selected depending on the substance to be filtered by the filter.

[0080] The water treatment system 200 of the second embodiment has a means 15 for separating a supernatant phase F into an aqueous phase H and an organic phase J to separate and recover a tertiary amine (organic phase J), ​​and the separated and recovered tertiary amine (organic phase J) is mixed with the amine solution C via a means 12 for introducing an amine solution C into a first container B to obtain a first mixture D. In the second embodiment, a description of the contents common to the first embodiment will be omitted.

[0081] FIG. 6 shows a flowchart of a water treatment method according to a second embodiment. The water treatment method of the embodiment preferably includes the steps of: obtaining a first mixture D by mixing water to be treated A and an amine solution C; phase-separating the first mixture D at a low temperature to obtain a phase-separated second mixture E; separating a supernatant phase F from a concentrated phase G of the phase-separated second mixture E; and heating the supernatant phase F to separate it into an aqueous phase H and an organic phase J, thereby separating and recovering the tertiary amine compound. The water treatment method of the second embodiment includes the steps of: separating the supernatant phase F into an aqueous phase H and an organic phase J using a means 15 for separating the supernatant phase F into the aqueous phase H and the organic phase J, thereby separating and recovering the tertiary amine compound. Hereinafter, the water treatment system 200 will be described, and the description of the water treatment system 200 also includes the description of the water treatment method.

[0082] The supernatant phase F separated by the means 14 for separating the supernatant phase F and the concentrated phase G is treated by the means 15 for separating the supernatant phase F into an aqueous phase H and an organic phase J to separate and recover the tertiary amine compound. The supernatant phase F is an aqueous solution in which a tertiary amine is dissolved. The supernatant phase F may contain trace amounts of inorganic salts and / or organic matter. A filter 16 is preferably provided on the path from the means 14 for separating the supernatant phase F and the concentrated phase G to the means 15 for separating and recovering the tertiary amine compound. The supernatant phase F may contain some precipitated solid inorganic salts and / or organic matter. It is preferable to provide the filter 16 to remove the solid inorganic salts and / or organic matter contained in the supernatant phase F, thereby reducing the amount of solid inorganic salts and / or organic matter flowing into the means 15 for separating the supernatant phase F into an aqueous phase and an organic phase to separate and recover the tertiary amine compound.

[0083] The means 15 for separating and recovering the tertiary amine compound by phase separation of the supernatant phase F into an aqueous phase H and an organic phase J separates and recovers the tertiary amine compound contained in the supernatant phase F. As the means 15 for separating and recovering the tertiary amine compound by phase separation of the supernatant phase into an aqueous phase H and an organic phase J, a mechanism for heating the supernatant phase F is preferred. For example, the supernatant phase F is placed in a second container (not shown) and heated in the second container. As the temperature of the supernatant phase F increases, the compatibility of the tertiary amine compound of the embodiment with water changes, causing separation into an organic phase and an aqueous phase. The supernatant phase separates into an aqueous phase H and an organic phase J at a temperature higher than that at which the first mixture D phase separates. It is preferable to heat the supernatant phase F to a temperature higher than that of the first mixture D (the temperature at which the first mixture D phase separates (the temperature at which the supernatant phase F and the concentrated phase G are separated)). It is preferable to heat the supernatant phase F to a temperature at least 5°C higher than the first mixture D (the temperature at which the first mixture D is phase separated (the temperature at which the supernatant phase F and the concentrated phase G are separated)). It is preferable to heat the supernatant phase F to a temperature at least 10°C higher than the first mixture D (the temperature at which the first mixture D is phase separated (the temperature at which the supernatant phase F and the concentrated phase G are separated)). It is preferable to heat the supernatant phase F to a temperature at least 20°C higher than the first mixture D (the temperature at which the first mixture D is phase separated (the temperature at which the supernatant phase F and the concentrated phase G are separated)). It is preferable to heat the supernatant phase F to a temperature at least 20°C higher than the first mixture D. It is preferable to heat the supernatant phase F to a temperature at least 30°C higher than the first mixture D (the temperature at which the first mixture D is phase separated (the temperature at which the supernatant phase F and the concentrated phase G are separated)). The supernatant phase F is preferably heated to a temperature of 35°C or higher and 90°C or lower, more preferably 35°C or higher and 75°C or lower from the viewpoint of reducing energy consumption. The supernatant phase F preferably undergoes phase separation at a temperature of 35°C or higher and 90°C or lower. From the viewpoint of reducing energy consumption, the supernatant phase F more preferably undergoes phase separation at a temperature of 35°C or higher and 75°C or lower. The supernatant phase F is preferably heated using waste heat generated in a plant or the like.

[0084] When supernatant phase F is heated, the compatibility of the tertiary amine compound with water changes, causing phase separation into aqueous phase H and organic phase J. Aqueous phase H contains the tertiary amine compound, inorganic salts, and / or organic substances dissolved in water. Organic phase J contains the tertiary amine whose compatibility with water changes in response to heat, and organic phase J is returned to amine solution C to reuse the tertiary amine compound whose compatibility with water changes in response to heat.

[0085] From the viewpoint of recovering the tertiary amine from the supernatant phase F, it is preferable to use the tertiary amine contained in the supernatant phase F, that is, the amine compound of the embodiment contained in the amine solution C.

[0086] The supernatant phase F containing the amine compound of the embodiment is confirmed to undergo phase separation at 90°C.

[0087] The tertiary amine compound contained in the amine solution C is preferably the tertiary amine compound of embodiment 1 shown in Figures 3 and 4 from two perspectives: recovering the tertiary amine from the supernatant phase F and extracting and separating inorganic salts and / or organic matter from the treated water A.

[0088] The water treatment system 200 and water treatment method of the embodiment use a tertiary amine whose liquid properties change in response to temperature, and can efficiently recover the amine from the supernatant phase F that is generated when inorganic salts and / or organic matter contained in the water to be treated A are separated. The water treatment system 200 and water treatment method gently heat the supernatant phase F to cause phase separation of the supernatant phase F, allowing the recovery of the amine used to precipitate the inorganic salts and / or organic matter. This can be done with much less energy than concentrating the supernatant phase F by evaporating the water contained in the supernatant phase F. Therefore, the water treatment system 200 can be operated with low energy consumption and a low environmental impact overall.

[0089] (Third embodiment) The third embodiment relates to a water treatment system and method applied to non-evaporative extraction separation (desalination) by concentration using a tertiary amine compound whose hydrophobicity and hydrophilicity change in response to heat. The third embodiment is an application example of the first and second embodiments. Fig. 7 shows a schematic diagram of a water treatment system 300 of the third embodiment. The schematic diagram of the water treatment system 300 in Fig. 7 includes means 11 for introducing water to be treated A into a first container B, means 12 for introducing an amine solution C into the first container B to obtain a second mixture E, temperature control means 13 for controlling the temperature, means 14 for separating a supernatant phase F and a concentrated phase G of the second mixture E obtained by phase separation of a first mixture D containing the water to be treated A and the amine solution C, means 15 for separating the supernatant phase F into an aqueous phase H and an organic phase J to separate and recover the tertiary amine (organic phase J), ​​and means 16 for treating the aqueous phase H with a reverse osmosis (RO) membrane. Depending on the characteristics of the amine molecule, an NF membrane (nanofiltration membrane) may be used instead of an RO membrane.

[0090] The water treatment system 300 of the third embodiment has a means 16 for treating the aqueous phase H with an RO membrane, and has the same structure as the water treatment system 200 of the second embodiment except that the obtained highly pure water M is discharged and the concentrated water L is returned to the first container B. In the third embodiment, a description of the contents common to the second embodiment will be omitted.

[0091] FIG. 8 shows a flowchart of a water treatment method according to a third embodiment. The water treatment method according to the embodiment preferably includes the steps of: obtaining a first mixture D by mixing water to be treated A and an amine solution C; subjecting the first mixture D to phase separation at a low temperature to obtain a phase-separated second mixture E; separating a supernatant phase F from a concentrated phase G of the phase-separated second mixture E; heating the supernatant phase F to separate it into an aqueous phase H and an organic phase J to separate and recover the tertiary amine compound; and treating the aqueous phase H with a reverse osmosis membrane (RO membrane). In the water treatment method according to the third embodiment, a step of treating the aqueous phase H with an RO membrane is performed in means 16 for treating the aqueous phase H with an RO membrane. Hereinafter, a water treatment system 300 will be described, and the description of the water treatment system 300 also includes a description of the water treatment method.

[0092] The resulting highly pure water M contains almost no impurities because it has been treated with an RO membrane, and can be released into rivers, etc., if the water quality conditions are met. Treating the untreated water A directly with an RO membrane would incur very high power costs, but by treating the aqueous phase H, which is much smaller in volume than the untreated water A, with an RO membrane, highly pure water L can be obtained efficiently.

[0093] The concentrated water L obtained by treatment with the RO membrane is preferably returned to the first container B through a return flow path and subjected to concentration treatment again. The concentrated water L contains the tertiary amine contained in the amine solution C, in addition to the inorganic salts and / or organic matter contained in the water to be treated A. Therefore, by performing water treatment in a cyclical manner, the amount that can be recovered in the concentrated phase G increases. The concentrated water L can also be returned to the first container B via the means 11 that introduces the water to be treated A into the first container B. Alternatively, the concentrated water L can be used as water to be treated in another water treatment process without being returned to the first container B.

[0094] When the water to be treated A contains a high concentration of salt, the osmotic pressure of the treated water is high and general RO membrane treatment technology cannot be applied. In any of the water treatment systems of the embodiments, the water to be treated A can be treated even with a high salt concentration, and high-purity water M can be obtained by finally subjecting the low-concentration aqueous phase H to RO membrane treatment.

[0095] In the water treatment system 300 and water treatment method of the embodiment, a tertiary amine whose liquid properties change in response to heat is used, and the supernatant phase F generated when the inorganic salts and / or organic matter contained in the water to be treated A is efficiently separated, thereby enabling further phase separation to obtain highly pure water M and concentrated water L. The water treatment system 300 and water treatment method can perform a circulatory water treatment that separates the water to be treated A into both the inorganic salts and / or organic matter in the concentrated phase G and the highly pure water M. As described for the water treatment system 100 of the first embodiment and the water treatment system 200 of the second embodiment, the water treatment system 200 can be operated with low energy and low environmental load overall, and can efficiently produce highly pure water M that can be discharged into rivers, etc.

[0096] (Fourth embodiment) The fourth embodiment relates to a tertiary amine compound. The tertiary amine compound of the fourth embodiment is the amine compound (2-3) in FIG. 4. The tertiary amine compound (2-3) is suitably used in the water treatment of the first to third embodiments. The amine compound (2-3) is contained in the amine solution C for the water treatment of the first to third embodiments.

[0097] The synthesis method of the amine compound (2-3) in Figure 4 is described below. Dibromopropane and THF (tetrahydrofuran) were mixed, and 4 equivalents of potassium carbonate relative to the dibromopropane were added. Furthermore, 4 equivalents of methyl-1-piperazinecarboxylate relative to the dibromopropane were added. After stirring at 70°C for 24 hours, the mixture was filtered under reduced pressure. The filtrate was concentrated to obtain a composition. The composition was purified by silica gel chromatography (chloroform / methanol) to obtain the compound of chemical formula 2-3.

[0098] Examples of the embodiment will be described below. (Example 1) Chemical Formula 1-2 (Salt Concentration) A 10 wt% aqueous solution of NaCl and the amine of formula (1-2) were placed in a stoppered measuring cylinder, the cylinder was closed, and the mixture was stirred at room temperature and then allowed to stand. The volume was adjusted so that the volume ratio of the solvent to the water to be treated (Solvent / Feed) was 4.0. Phase separation occurred, so the supernatant was transferred to another glass container. The Cl concentration of the supernatant was measured using ion chromatography, and it was found that the salt removal rate was 97%. The salt removal rate was calculated using the following formula. Salt removal rate = {(NaCl input amount) - (NaCl concentration in supernatant)} / (NaCl input amount) x 100

[0099] The salt concentration of the concentrated liquid that separated into the lower phase was measured and found to be 21.0 wt%, a saltwater concentration close to that of saturated salt water. The volume of the lower phase was 52% of the volume of the aqueous phase that was added.

[0100] The separated supernatant was heated in a constant temperature bath at 70°C, causing it to separate into an amine phase and an aqueous phase. When the amine phase was separated and used in a similar test, the salt removal rate was 97.5%, and the concentration of the separated lower phase was 21.2 wt%, the same results as in the first test.

[0101] (Example 2) Chemical Formula 1-2 (Salt Concentration) A 10 wt% NaCl aqueous solution and the amine of formula (1-2) were placed in a stoppered measuring cylinder, the cylinder was closed, and the mixture was stirred at room temperature and then allowed to stand. The volume was adjusted so that the volume ratio of the solvent to the water to be treated (Solvent / Feed) was 6.0. Phase separation occurred, so the supernatant was transferred to another glass container. The Cl concentration of the supernatant was measured using ion chromatography, and it was found that the salt removal rate was 98.7%.

[0102] The salt concentration of the concentrated liquid that separated into the lower phase was measured and found to be 25.9 wt%, a saltwater concentration close to that of saturated salt water. The volume of the lower phase was 54% of the volume of the aqueous phase that was added.

[0103] The separated supernatant was heated in a constant temperature bath at 70°C, causing it to separate into an amine phase and an aqueous phase. When the amine phase was separated and used in a similar test, the salt removal rate was 98.5%, and the concentration of the separated lower phase was 25.9 wt%, the same results as in the first test.

[0104] (Example 3) Chemical Formula 1-2 (Salt Precipitation) A 10 wt% aqueous solution of NaCl and the amine of formula (1-2) were placed in a measuring cylinder with a stopper, and after stirring at room temperature, the mixture was allowed to stand. The volume was adjusted so that the volume ratio of solvent to water to be treated (S / F) was 7.0. As salt precipitated, the supernatant was transferred to another glass container. The Cl concentration of the supernatant was measured using ion chromatography, and it was found that the salt removal rate was 99.0%.

[0105] The separated supernatant was heated in a thermostatic bath at 60°C, causing it to separate into an amine phase and an aqueous phase. When the amine phase was separated and used in a similar test, the salt removal rate was 99.2%, the same result as the first test.

[0106] (Example 4) Chemical Formula 1-2 (Salt Precipitation) A 10 wt% NaCl aqueous solution and the amine of formula (1-2) were placed in a stoppered measuring cylinder, the cylinder was closed, and the mixture was stirred at room temperature and then allowed to stand. The volume was adjusted so that the volume ratio of the solvent to the water to be treated (S / F) was 10.0. As salt precipitated, the supernatant was transferred to another glass container. The Cl concentration of the supernatant was measured using ion chromatography, and it was found that the salt removal rate was 99.0%.

[0107] The separated supernatant was heated in a constant temperature bath at 70°C, causing it to separate into an amine phase and an aqueous phase. When the amine phase was separated and used in a similar test, the salt removal rate was 99.0%, the same result as the first test.

[0108] (Example 5) Chemical Formula 2-1 The same test as in Example 1 was carried out, except that Chemical Formula 2-1 was used. The Cl concentration of the supernatant was measured by ion chromatography, and it was found that the salt removal rate was 96.5%. In addition, the salt concentration of the concentrated liquid separated into the lower phase was measured, and it was found to be 22.0 wt% salt water.

[0109] The separated supernatant was heated in a constant temperature bath at 70°C, causing it to separate into an amine phase and an aqueous phase. When the amine phase was separated and used in a similar test, the salt removal rate was 97.5%, and the concentration of the separated lower phase was 21.2 wt%, the same results as in the first test.

[0110] (Example 6) Chemical Formula 2-1 A test similar to that in Example 2 was carried out, except that Chemical Formula 2-1 was used. Phase separation occurred, so the supernatant was transferred to another glass container. The Cl concentration of the supernatant was measured by ion chromatography, and it was found that the salt removal rate was 98.3%.

[0111] The salt concentration of the concentrated liquid that separated into the lower phase was measured and found to be 25.5 wt%, a saltwater concentration close to that of saturated salt water. The volume of the lower phase was 50% of the volume of the aqueous phase that was added.

[0112] The separated supernatant was heated in a constant temperature bath at 70°C, causing it to separate into an amine phase and an aqueous phase. When the amine phase was separated and used in a similar test, the salt removal rate was 99.0%, and the concentration of the separated lower phase was 25.3 wt%, the same results as the first test were obtained.

[0113] (Example 7) Chemical Formula 2-1 A test similar to that in Example 3 was carried out using Chemical Formula 2-1, except that the temperature for separating amine and water was 50°C. Because salt precipitated, the supernatant was transferred to another glass container. The Cl concentration of the supernatant was measured by ion chromatography, and it was found that the salt removal rate was 98.3%.

[0114] The separated supernatant was heated in a constant temperature bath at 50°C, causing it to separate into an amine phase and an aqueous phase. When the amine phase was separated and used in a similar test, the salt removal rate was 99.2%, the same result as the first test.

[0115] (Example 8) Chemical Formula 2-1 A test similar to that in Example 4 was carried out, except that Chemical Formula 2-1 was used. Because salt precipitated, the supernatant was transferred to another glass container. The Cl concentration of the supernatant was measured by ion chromatography, and it was found that the salt removal rate was 99.0%.

[0116] The separated supernatant was heated in a constant temperature bath at 70°C, causing it to separate into an amine phase and an aqueous phase. When the amine phase was separated and used in a similar test, the salt removal rate was 99.0%, the same result as the first test.

[0117] (Comparative Example 1) A 10 wt% aqueous solution of NaCl and diisopropylamine were placed in a measuring cylinder with a stopper, and after stirring at room temperature, the mixture was allowed to stand. The volume was adjusted so that the volume ratio of solvent to water to be treated (Solvent / Feed) was 4.0. Phase separation occurred, so the supernatant liquid was transferred to another glass container. The salt concentration of the concentrated liquid that separated into the lower phase was measured, and it was found to be 15.0 wt% brine.

[0118] (Comparative Example 2) A 10 wt% aqueous solution of NaCl and diisopropylamine were placed in a measuring cylinder with a stopper, and after stirring at room temperature, the mixture was allowed to stand. The volume was adjusted so that the volume ratio of solvent to water to be treated (Solvent / Feed) was 10.0. Phase separation occurred, so the supernatant liquid was transferred to another glass container. The salt concentration of the concentrated liquid that separated into the lower phase was measured, and it was found to be 24.0 wt% brine.

[0119] (Comparative Example 3) A 10 wt% aqueous solution of NaCl and diisopropylamine were placed in a measuring cylinder with a stopper, and after stirring at room temperature, the mixture was allowed to stand. The volume was adjusted so that the volume ratio of solvent to water to be treated (Solvent / Feed) was 15.0. Phase separation occurred, so the supernatant liquid was transferred to another glass container. The salt concentration of the concentrated liquid that separated into the lower phase was measured, and it was found to be 25.9 wt% brine.

[0120] Comparative Example 4 A 10 wt% NaCl aqueous solution and polypropylene glycol (average Mn ~ 725) were placed in a stoppered measuring cylinder, the cylinder was closed, and the mixture was stirred at room temperature and then allowed to stand. The volume was adjusted so that the volume ratio of the solvent to the water to be treated (Solvent / Feed) was 10.0. Phase separation occurred, so the supernatant liquid was transferred to another glass container. The salt concentration of the concentrated liquid that separated into the lower phase was measured, and it was found to be 10.0 wt% brine.

[0121] (Comparative Example 5) A 10 wt% NaCl aqueous solution and polypropylene glycol (average Mn ~ 725) were placed in a stoppered measuring cylinder, the cylinder was closed, and the mixture was stirred at room temperature and then allowed to stand. The volume was adjusted so that the volume ratio of the solvent to the water to be treated (Solvent / Feed) was 14.0. Phase separation occurred, so the supernatant liquid was transferred to another glass container. The salt concentration of the concentrated liquid that separated into the lower phase was measured, and it was found to be 14.0 wt% brine.

[0122] (Comparative Example 6) A 10 wt% NaCl aqueous solution and polypropylene glycol (average Mn ~ 725) were placed in a stoppered measuring cylinder, the cylinder was closed, and the mixture was stirred at room temperature and then allowed to stand. The volume was adjusted so that the volume ratio of solvent to water to be treated (Solvent / Feed) was 15.0. Phase separation occurred, so the supernatant liquid was transferred to another glass container. The salt concentration of the concentrated liquid that separated into the lower phase was measured, and it was found to be 22.0 wt% brine.

[0123] [Table 1]

[0124] These results demonstrate that salts in a salt-containing aqueous solution can be efficiently concentrated with a small amount of solvent by using a tertiary amine compound whose compatibility with water changes with heat. The salt concentration of the concentrated water, the amount of precipitated salt, and the amount of tertiary amine compound required for concentration varied depending on the dissolution of the tertiary amine compound in the treated water A. This is thought to depend on the structure, solubility, and polarity of the amine. The supernatant liquid after salt precipitation can be heated to separate the water and the tertiary amine compound, allowing the tertiary amine compound and water to be recovered. Since the aqueous phase after phase separation also contains amines, highly pure water can be obtained by RO membrane treatment. In examples using the amine compound of the embodiment, a concentrated phase (liquid phase (concentrated in the table) or solid phase (precipitated in the table)) was obtained from a small amount. Even when the S / F ratio was 7 or less, the salt removal rate was high, making the amine compound of the embodiment highly practical. In the examples, some unmeasured results are indicated with a hyphen.

[0125] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, modifications, and combinations can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, as well as the inventions described in the claims and their equivalents.

[0126] The technical solutions of the embodiments are described below. Technical proposal 1 a means for introducing water to be treated into the first container; means for introducing an amine solution into said first vessel to provide a first mixture; and means for separating the supernatant phase and the concentrated phase of the second mixture resulting from the phase separation of the first mixture; The amine solution contains a tertiary amine compound represented by chemical formula (1) or / and chemical formula (2), R of the chemical formula (1) 1 is a linear alkyl chain having 2 to 4 carbon atoms, R of the above chemical formula (2) 2 is a linear alkyl chain having 2 to 4 carbon atoms, R of the above chemical formula (2) 3 is a linear alkyl group having 1 to 4 carbon atoms or a branched alkyl group having 3 to 4 carbon atoms, R of the above chemical formula (2) 4 is a linear alkyl group having 1 to 4 carbon atoms or a branched alkyl group having 3 to 4 carbon atoms. Technical proposal 2 R of the above chemical formula (2) 2 is a linear alkyl chain having 2 to 4 carbon atoms, R of the above chemical formula (2) 3 and R 4 The water treatment system according to Technical Scheme 1, wherein the alkyl groups are the same and are linear alkyl groups having 1 to 4 carbon atoms or branched alkyl groups having 3 to 4 carbon atoms. Technical proposal 3 R of the above chemical formula (2) 2 is a linear alkyl chain having 2 or 3 carbon atoms, R of the above chemical formula (2) 3 and R 4 The water treatment system according to Technical Scheme 1 or 2, wherein the alkyl group is a linear alkyl group having 1 to 3 carbon atoms or a branched alkyl group having 3 to 4 carbon atoms. Technical proposal 4 R of the above chemical formula (2) 2 is a linear alkyl chain having 2 or 3 carbon atoms, R of the above chemical formula (2) 3 and R 4 The water treatment system according to any one of Technical Schemes 1 to 3, wherein the alkyl group is a linear alkyl group having 1 to 3 carbon atoms or a branched alkyl group having 3 carbon atoms. Technical proposal 5 R of the above chemical formula (2) 2 is a linear alkyl chain with 3 carbon atoms, R of the above chemical formula (2) 3 and R 4 The water treatment system according to any one of Technical Schemes 1 to 4, wherein the alkyl group is the same and has a carbon number of 1 to 3. Technical plan 6 The water treatment system according to any one of Technical Schemes 1 to 5, wherein the tertiary amine compound of chemical formula (1) is one or more of a tertiary amine compound of chemical formula (1-1), a tertiary amine compound of chemical formula (1-2), and a tertiary amine compound of chemical formula (1-3). Technical proposal 7 The water treatment system according to any one of Technical Schemes 1 to 6, wherein the tertiary amine compound of chemical formula (2) is one or more of a tertiary amine compound of chemical formula (2-1), a tertiary amine compound of chemical formula (2-2), and a tertiary amine compound of chemical formula (2-3). Technical proposal 8 A water treatment system according to any one of technical proposals 1 to 7, wherein the amine solution contains 80 wt% or more and 100 wt% or less of a tertiary amine compound represented by the chemical formula (1) and / or the chemical formula (2). Technical proposal 9 The water treatment system according to any one of Technical Schemes 1 to 8, wherein the volume of the amine solution is 4 or more and 100 or less when the volume of the water to be treated is 1. Technical proposal 10 10. The water treatment system according to any one of Technical Schemes 1 to 9, wherein the volume of the amine solution is 4 or more and 25 or less when the volume of the water to be treated is 1. Technical proposal 11 A water treatment system according to any one of technical proposals 1 to 10, wherein the first mixture undergoes phase separation at a temperature between 3°C and 40°C. Technical proposal 12 a step of mixing the water to be treated and the amine solution to obtain a first mixture; phase-separating the first mixture to obtain a phase-separated second mixture; separating the supernatant and concentrated phases of the phase-separated second mixture; The amine solution contains a tertiary amine compound represented by chemical formula (1) or / and chemical formula (2), R of the chemical formula (1) 1 is a linear alkyl chain having 2 to 4 carbon atoms, R of the above chemical formula (2) 2 is a linear alkyl chain having 2 to 4 carbon atoms, R of the above chemical formula (2) 3 is a linear alkyl group having 1 to 4 carbon atoms or a branched alkyl group having 3 to 4 carbon atoms, R of the above chemical formula (2) 4 The water treatment method is characterized in that the alkyl group is a linear alkyl group having 1 to 4 carbon atoms or a branched alkyl group having 3 to 4 carbon atoms. Technical proposal 13 R of the above chemical formula (2) 2 is a linear alkyl chain having 2 to 4 carbon atoms, R of the above chemical formula (2) 3 and R 4 The water treatment system according to Technical Scheme 12, wherein the alkyl groups are the same and are linear alkyl groups having 1 to 4 carbon atoms or branched alkyl groups having 3 to 4 carbon atoms. Technical proposal 14 R of the above chemical formula (2) 2 is a linear alkyl chain having 2 or 3 carbon atoms, R of the above chemical formula (2) 3 and R 4The water treatment system according to Technical Scheme 12 or 13, wherein the alkyl group is the same and is a linear alkyl group having 1 to 3 carbon atoms or a branched alkyl group having 3 to 4 carbon atoms. Technical proposal 15 R of the above chemical formula (2) 2 is a linear alkyl chain having 2 or 3 carbon atoms, R of the above chemical formula (2) 3 and R 4 The water treatment system according to any one of Technical Schemes 12 to 14, wherein the alkyl group is a linear alkyl group having 1 to 3 carbon atoms or a branched alkyl group having 3 carbon atoms. Technical proposal 16 R of the above chemical formula (2) 2 is a linear alkyl chain with 3 carbon atoms, R of the above chemical formula (2) 3 and R 4 The water treatment system according to any one of Technical Schemes 12 to 15, wherein the alkyl group is the same and has a carbon number of 1 to 3. Technical proposal 17 The water treatment system according to any one of Technical Schemes 12 to 16, wherein the tertiary amine compound of chemical formula (1) is one or more of a tertiary amine compound of chemical formula (1-1), a tertiary amine compound of chemical formula (1-2), and a tertiary amine compound of chemical formula (1-3). Technical proposal 18 The water treatment system according to any one of Technical Schemes 12 to 17, wherein the tertiary amine compound of chemical formula (2) is one or more of a tertiary amine compound of chemical formula (2-1), a tertiary amine compound of chemical formula (2-2), and a tertiary amine compound of chemical formula (2-3). Technical proposal 19 A water treatment system according to any one of technical proposals 12 to 18, wherein the amine solution contains 80 wt% or more and 100 wt% or less of a tertiary amine compound represented by the chemical formula (1) and / or the chemical formula (2). Technical proposal 20 20. The water treatment system according to any one of Technical Schemes 12 to 19, wherein the volume of the amine solution is 4 or more and 100 or less when the volume of the water to be treated is 1. Technical proposal 21 21. The water treatment system according to any one of Technical Schemes 12 to 20, wherein the volume of the amine solution is 4 or more and 25 or less when the volume of the water to be treated is 1. Technical proposal 22 A water treatment system according to any one of technical proposals 12 to 21, wherein the first mixture undergoes phase separation at a temperature between 3°C and 40°C. Technical proposal 23 The method further comprises a means for separating the supernatant phase into an aqueous phase and an organic phase to separate and recover the tertiary amine, The water treatment system according to any one of Technical Schemes 1 to 11, wherein the supernatant phase separates into an aqueous phase and an organic phase at a temperature higher than that at which the first mixture separates into phases. Technical proposal 24 The water treatment system according to Technical Proposal 23, wherein the supernatant phase separates into an aqueous phase and an organic phase at a temperature of 35°C or higher and 90°C or lower. Technical proposal 25 The water treatment system according to Technical Proposal 23 or 24, wherein the supernatant phase separates into an aqueous phase and an organic phase at a temperature that is 10°C or more higher than the temperature at which the first mixture phase separates. Technical proposal 26 The method further comprises a step of heating the supernatant phase to separate it into an aqueous phase and an organic phase, and separating and recovering the tertiary amine compound; The water treatment method according to any one of Technical Schemes 12 to 22, wherein the supernatant phase separates into an aqueous phase and an organic phase at a temperature higher than that at which the first mixture separates into phases. Technical proposal 27 The water treatment method according to Technical Scheme 26, wherein the supernatant phase separates into an aqueous phase and an organic phase at a temperature of 35°C or higher and 90°C or lower. Technical proposal 28 A water treatment system according to Technical Proposal 26 or 27, wherein the supernatant phase separates into an aqueous phase and an organic phase at a temperature that is 10°C or more higher than the temperature at which the first mixture phase separates. Technical proposal 29 An amine solution containing a tertiary amine compound of chemical formula (2-3). [Explanation of symbols]

[0127] 11: Means for introducing the water to be treated A into the first container B 12: Means for introducing amine solution C into first container B to obtain first mixture D 13: Temperature control means for controlling the temperature 14: Means for separating a supernatant phase F and a concentrated phase G of a second mixture E obtained by phase separation of a first mixture D containing the water to be treated A and an amine solution C. 15: A means for separating the supernatant phase F into an aqueous phase H and an organic phase J to separate and recover the tertiary amine compound (organic phase J). 16: Means for treating aqueous phase H with RO membrane (reverse osmosis membrane) 20: Filter 100: Water treatment system 200: Water treatment system 300: Water treatment system A: Water to be treated B: 1st container C: Amine solution D: 1st mixture E: Second mixture F: Supernatant phase G: Concentrated phase H: water phase J:Organic phase L: Concentrated water M: Water

Claims

1. A means for introducing water to be treated, which contains water and solutes, into a first container; a means for introducing an amine solution into the first container to obtain a first mixture by mixing the water to be treated with the amine solution; a means for separating the supernatant phase and the concentrated phase of the second mixture obtained by phase separation of the first mixture; The first mixture is such that the amine solution is compatible with the water to be treated at a temperature of 3°C or higher and 40°C or lower, As a result of the amine solution becoming compatible with the water to be treated, the first mixture is separated into a supernatant phase, which is a mixed liquid containing the amine solution and the water to be treated, and a concentrated phase, which contains a precipitate of the solute, a slurry of the solute, or a liquid in which the solute of the water to be treated is concentrated; The amine solution contains a tertiary amine compound represented by chemical formula (1) or / and chemical formula (2), R of the chemical formula (1) １ is a linear alkyl chain having 2 to 4 carbon atoms, R of the chemical formula (2) ２ is a linear alkyl chain having 2 to 4 carbon atoms, R of the chemical formula (2) ３ is a linear alkyl group having 1 to 4 carbon atoms or a branched alkyl group having 3 to 4 carbon atoms, R of the chemical formula (2) ４ is a linear alkyl group having 1 to 4 carbon atoms or a branched alkyl group having 3 to 4 carbon atoms. 【Chemistry 1】

2. R of the chemical formula (2) ２ is a linear alkyl chain having 2 to 4 carbon atoms, R of the chemical formula (2) ３ and R 4 The water treatment system according to claim 1 , wherein: are the same and are linear alkyl groups having 1 to 4 carbon atoms or branched alkyl groups having 3 to 4 carbon atoms.

3. R of the chemical formula (2) ２ is a linear alkyl chain having 2 or 3 carbon atoms, R of the chemical formula (2) ３ and R 4 The water treatment system according to claim 1 , wherein: are the same and are linear alkyl groups having 1 to 3 carbon atoms or branched alkyl groups having 3 to 4 carbon atoms.

4. R of the chemical formula (2) ２ is a linear alkyl chain having 2 or 3 carbon atoms, R of the chemical formula (2) ３ and R 4 The water treatment system according to claim 1 , wherein: are the same and are linear alkyl groups having 1 to 3 carbon atoms or branched alkyl groups having 3 carbon atoms.

5. R of the chemical formula (2) ２ is a linear alkyl chain having 3 carbon atoms, R of the chemical formula (2) ３ and R 4 The water treatment system according to claim 1 , wherein:

6. The tertiary amine compound of chemical formula (1) is any one or more of a tertiary amine compound of chemical formula (1-1), a tertiary amine compound of chemical formula (1-2), and a tertiary amine compound of chemical formula (1-3). The water treatment system according to claim 1. 【Chemistry 2】

7. The tertiary amine compound of chemical formula (2) is any one or more of a tertiary amine compound of chemical formula (2-1), a tertiary amine compound of chemical formula (2-2), and a tertiary amine compound of chemical formula (2-3). The water treatment system according to claim 1. 【Transformation 3】

8. 2. The water treatment system according to claim 1, wherein the amine solution contains 80 wt % to 100 wt % of a tertiary amine compound represented by the chemical formula (1) or / and the chemical formula (2).

9. 2. The water treatment system according to claim 1, wherein the volume of the amine solution is 4 or more and 100 or less, assuming that the volume of the water to be treated is 1.

10. 2. The water treatment system according to claim 1, wherein the volume of the amine solution is 4 to 25 times the volume of the water to be treated.

11. The water treatment system according to claim 1 , wherein the first mixture undergoes phase separation at a temperature of 3° C. or higher and 40° C. or lower.

12. The water treatment system according to claim 1 , wherein the amine solution contains both the chemical formula (1) and the chemical formula (2).

13. A step of obtaining a first mixture by mixing water to be treated containing water and a solute with an amine solution; phase separating the first mixture to obtain a phase-separated second mixture; separating the supernatant and concentrated phases of the phase-separated second mixture; The first mixture is such that the amine solution is compatible with the water to be treated at a temperature of 3°C or higher and 40°C or lower, As a result of the amine solution becoming compatible with the water to be treated, the first mixture is separated into a supernatant phase, which is a mixed liquid containing the amine solution and the water to be treated, and a concentrated phase, which is a precipitate of the solute, a slurry of the solute, or a liquid in which the solute of the water to be treated is concentrated, The water treatment method, wherein the amine solution contains a tertiary amine compound of the chemical formula (1) or / and the chemical formula (2) according to any one of claims 1 to 12.

14. The water treatment method according to claim 13, wherein the first mixture undergoes phase separation at a temperature of 3°C or higher and 40°C or lower.

15. The method further comprises a means for separating the supernatant phase into an aqueous phase and an organic phase to separate and recover the tertiary amine, 13. The water treatment system according to claim 1, wherein the supernatant phase separates into an aqueous phase containing water separated from the tertiary amine in the amine solution and the water in the treatment water at a temperature higher than that at which the first mixture phase separates, and an organic phase containing the tertiary amine compound.

16. The water treatment system according to claim 15, wherein the supernatant phase separates into an aqueous phase and an organic phase at a temperature of 35°C or higher and 90°C or lower.

17. The method further comprises a step of heating the supernatant phase to separate it into an aqueous phase and an organic phase, and separating and recovering the tertiary amine compound; 14. The water treatment method according to claim 13, wherein the supernatant phase separates into an aqueous phase and an organic phase at a temperature higher than that at which the first mixture phase separates.

18. The water treatment method according to claim 17, wherein the supernatant phase separates into an aqueous phase and an organic phase at a temperature of 35°C or higher and 90°C or lower.

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