Extractant and Method for Separating Metals with High Economic Value from Wastewater

Abstract

The present application provides an extractant and a method for separating highly economically valuable metals from wastewater, belonging to the technical field of wastewater purification. The extractant uses a binary heterocycle as the molecular backbone. The large spatial volume of the binary cyclic molecule can ensure that the molecular structure of the extractant presents a unique spatial structure, guaranteeing the selective extraction of target metals; by chemically derivatizing the binary heterocycle, the length of the molecular chain segment can be directionally regulated, the chemical activity of the functionalized functional groups can be changed, and the dimension of the spatial extension of the main chain of the extractant molecule can be regulated; by carrying out an esterification reaction with an aliphatic cyclic mercaptan to form a thioester group, the introduction of an activation site of the extractant is realized, achieving the purpose of selectively chelating / complexing with target metal ions, avoiding the interference of other impurity metal ions in the wastewater solution system, and at the same time being applicable to solution systems with various complex anionic species.

Description

Technical Field

[0001] The present invention relates to the technical field of wastewater purification, and particularly relates to an extractant and a method for separating highly economically valuable metals from wastewater. Background Art

[0002] Highly economically valuable metals (such as gold, platinum, palladium, etc.) are indispensable raw materials for the national economy and national defense construction, with an industrial correlation of over 90%, supporting the development of high-tech emerging industries, and playing an irreplaceable strategic role. Currently, due to the low concentration of highly economically valuable metals in industrial wastewater, traditional treatment methods can be divided into: chemical precipitation method, redox method, solvent extraction method, membrane separation method, ion exchange method, etc. Among them, the premise for the separation, purification, and enrichment of highly economically valuable metals by the chemical precipitation method and the redox method is that the concentration of target metal ions in the solution is high, while it is difficult to achieve the expected separation purpose in a low-concentration system; the membrane separation method and the ion exchange method can achieve the separation, purification, and enrichment of highly economically valuable metals at low concentrations, but they have problems such as long process flow, long working cycle, high initial equipment investment, and high energy consumption, which restrict their application fields.

[0003] The solution extraction method can achieve the separation and enrichment of target metals at different concentrations and the purification of water bodies. Based on ion exchange reactions, the core of the solution extraction method mainly focuses on the selection of extractant types. Since the chemical properties of functionalized functional groups are affected by the types of anions in the solution, it is difficult to achieve effective separation, purification, and enrichment when dealing with complex solution systems, such as a mixed solution system of gold ions and thiosulfate ions, or a mixed solution system of gold ions, platinum ions, palladium ions, and glutamate anions.

[0004] In view of this, it is necessary to design an improved extractant and a method for separating highly economically valuable metals from wastewater to solve the above problems. Summary of the Invention

[0005] In view of the technical problems existing in the background art, the present application provides an extractant and a method for separating highly economically valuable metals from wastewater, aiming to solve the technical problem that it is difficult to effectively separate, purify, and enrich highly economically valuable metals in complex solution systems.

[0006] In the first aspect, the present application provides an extractant, and the structural formula of the extractant is as follows:

[0007] .

[0008] In the second aspect, the present application provides a method for separating highly economically valuable metals from wastewater using the extractant. The extraction is carried out using the extractant described in the first aspect, and the method includes the following steps:

[0009] Mix and dissolve the extractant with a diluent to obtain an extractant diluent;

[0010] Add the diluent of the extractant to the wastewater containing the target metal to achieve selective extraction of the target metal in the solution.

[0011] As a further improvement of the present application, the diluent is sulfonated kerosene.

[0012] As a further improvement of the present application, the mass ratio of the extractant to the diluent is 1:(9 - 59).

[0013] As a further improvement of the present application, the volume ratio of the diluent of the extractant to the wastewater containing the target metal is 1:(1 - 10).

[0014] As a further improvement of the present application, the target metal is one or more of gold, palladium, and platinum.

[0015] As a further improvement of the present application, the wastewater containing the target metal is one or more of mine cyanide solution, petrochemical catalyst waste liquid, metallurgical waste liquid, and electroplating waste liquid.

[0016] As a further improvement of the present application, the anion system in the wastewater containing the target metal is one or more of chloride ion, cyanide ion, thiosulfate anion, glutamate anion, and glycine anion.

[0017] The beneficial effects of the present application are as follows:

[0018] The present application provides an extractant and a method for separating high - economic - value metals from wastewater. The extractant has a binary heterocycle as the molecular skeleton. The large spatial volume of the binary cyclic molecule can ensure that the molecular structure of the extractant presents a unique spatial structure, guaranteeing the selective extraction of the target metal; by chemically derivatizing the binary heterocycle, the length of the molecular chain segment can be directionally regulated, the chemical activity of the functionalized functional group can be changed, and the dimension of the spatial extension of the main chain of the extractant molecule can be regulated; by esterifying with aliphatic cyclic thiol to form a thioester group, the introduction of the activation site of the extractant is realized, achieving the purpose of selectively chelating / complexing with the target metal ions, avoiding the interference of other impurity metal ions in the wastewater solution system, and at the same time being applicable to solution systems with various complex anion species.

[0019] The extractant of the present application presents a structure with dual activation sites, that is, each end of 1 mol of extractant molecules contains 1 mol of thioester groups, which can react with the target metal ions to the greatest extent, ensuring the high - efficiency chelating / complexing effect of the extractant.

[0020] The extractant of the present application realizes synergistic enhancement by regulating factors such as the spatial structure of the molecular skeleton, the length of the molecular chain segment, and the number of activation sites, ensuring the effect of selective and efficient extraction of the target metal, and ultimately achieving the resource utilization of metals with high economic value and the environmental protection and purification of wastewater.

[0021] The above description is only an overview of the technical solution of the present application. In order to be able to understand the technical means of the present application more clearly, it can be implemented according to the content of the specification. And in order to make the above and other purposes, features and advantages of the present application more obvious and understandable, the specific embodiments of the present application are specifically given below. Brief Description of the Drawings

[0022] In order to more clearly illustrate the technical solution of the present application, the drawings used in the present application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0023] Figure 1 It is a physical picture before and after liquid-liquid extraction of the gold glycine system solution in Example 18 of the present application;

[0024] Figure 2 It is a synthetic route diagram of the extractant in Example 58 of the present application;

[0025] Figure 3 It is a nuclear magnetic resonance hydrogen spectrum diagram of the extractant in Example 58 of the present application. Detailed Description of the Embodiments

[0026] The embodiments of the technical solution of the present application will be described in detail below with reference to the drawings. The following embodiments are only used to illustrate the technical solution of the present application more clearly, so they are only examples and cannot be used to limit the protection scope of the present application.

[0027] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above description of the drawings are intended to cover non-exclusive inclusion.

[0028] In the description of the embodiments of the present application, technical terms such as "first" and "second" are only used to distinguish different objects and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity, specific order or primary-secondary relationship of the indicated technical features. In the description of the embodiments of the present application, "a plurality" means more than two unless otherwise specifically defined.

[0029] References to "embodiments" in this application mean that the specific features, structures, or characteristics described in connection with the embodiments can be included in at least one embodiment of the present application. The phrase appears in various places in the specification and does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art will explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments.

[0030] In the description of the embodiments of the present application, the term "plurality" means two or more (including two). Similarly, "multiple groups" means two or more groups (including two groups), and "multiple pieces" means two or more pieces (including two pieces).

[0031] The prior art has the following problems in dealing with highly economically valuable metals in low-concentration industrial wastewater: chemical precipitation and redox methods are difficult to achieve effective separation and enrichment in low-concentration systems; membrane separation and ion exchange methods can handle low-concentration metals, but have long process flows, long cycles, high equipment investment, and high energy consumption, restricting their applications; although solvent extraction can achieve the separation and enrichment of metals at different concentrations, it is difficult to achieve effective separation, purification, and enrichment in dealing with complex solution systems due to the influence of anion types. These problems have restricted the development and application of highly economically valuable metal recovery technologies.

[0032] To solve the technical problem of the difficult effective separation, purification, and enrichment of highly economically valuable metals in complex solution systems, the present application provides an extractant and a method for separating highly economically valuable metals from wastewater. By preparing an extractant with a specific structure, the technical effects of resource utilization of highly economically valuable metals and environmental protection purification of wastewater can be achieved.

[0033] In a first aspect, an embodiment of the present application provides an extractant, the structural formula of which is as follows:

[0034] 。

[0035] In the technical solution of the embodiment of the present application, the extractant has a binary heterocycle as the molecular backbone. The large spatial volume of the binary cyclic molecule can ensure that the molecular structure of the extractant presents a unique spatial structure, guaranteeing the selective extraction of target metals. By chemically derivatizing the binary heterocycle, the length of the molecular chain segment can be directionally regulated, which can change the chemical activity of the functionalized functional group (carboxyl group), and can also regulate the dimension of the spatial extension of the main chain of the extractant molecule. By esterifying with aliphatic cyclic thiol to form a thioester group, the introduction of the activation site of the extractant is realized, achieving the purpose of selectively chelating / complexing with target metal ions. The extractant presents a structure with dual activation sites, that is, each end of 1 mol of extractant molecules contains 1 mol of thioester groups, totaling 2 mol of thioester groups, which can react with target metal ions to the greatest extent, ensuring the high-efficiency chelating / complexing effect of the extractant.

[0036] In a second aspect, the embodiment of the present application provides a method for separating high-economic-value metals from wastewater by using an extractant. The extractant described in the first aspect is used for extraction, including the following steps:

[0037] S1. Mix and dissolve the extractant with a diluent to obtain an extractant diluent;

[0038] S2. Add the extractant diluent to the wastewater containing the target metal to achieve selective extraction of the target metal in the solution.

[0039] In the technical solution of the embodiment of the present application, by using a specific extractant, high-economic-value metals can be effectively separated from wastewater, improving resource utilization rate. Specifically, to accelerate the reaction rate, the reaction solution can be shaken in a water bath at 25 - 28 °C for 5 - 10 min to selectively extract the target metal in the solution. After the extraction is completed, the organic phase is separated, and the concentration of the target metal in the inorganic liquid phase solution is detected and the extraction rate is calculated. This method can selectively extract the target metal in the solution, reduce the interference of other impurities, and improve the purity of the metal. By recovering valuable metals from wastewater, environmental pollution is reduced, which is conducive to achieving sustainable development. This method has simple steps and is easy to operate, which is conducive to popularization and application in actual production.

[0040] Further, in some embodiments, the diluent is sulfonated kerosene.

[0041] In the technical solution of the embodiment of the present application, sulfonated kerosene has good compatibility, can be effectively mixed with the extractant to form a stable extraction system, and forms two-phase separation during the extraction process, facilitating the extraction and recovery of metals. Sulfonated kerosene has high chemical stability and is not easy to react with metal ions or other chemical substances in the wastewater, thus maintaining the effect of the extractant.

[0042] Further, in some embodiments, the mass ratio of the extractant to the diluent is 1:(9 - 59).

[0043] In the technical solution of the embodiments of the present application, by adjusting the ratio of the extractant to the diluent, the extractant can maximize its extraction ability and improve the recovery rate of metals. An appropriate diluent ratio helps to form a good two-phase separation system, making it easier to separate the extraction phase and the aqueous phase, facilitating subsequent processing steps.

[0044] Further, in some embodiments, the volume ratio of the extractant diluent to the wastewater containing the target metal is 1:(1 - 10).

[0045] In the technical solution of the embodiments of the present application, by adjusting the volume ratio of the extractant diluent to the wastewater, the extraction process can be optimized to ensure sufficient contact area and time to improve the extraction efficiency of metal ions. At the same time, a suitable volume ratio can reduce the usage amount of the extractant, ensuring the extraction effect while reducing the treatment cost.

[0046] Further, in some embodiments, the target metal is one or more of gold, palladium, and platinum.

[0047] In the technical solution of the embodiments of the present application, the extractant has a high coordination ability for gold, palladium, and platinum, and can efficiently and selectively extract these precious metals during the wastewater treatment process.

[0048] Further, in some embodiments, the wastewater containing the target metal is one or more of mine cyanide solution, petrochemical catalyst waste liquid, metallurgical waste liquid, and electroplating waste liquid.

[0049] In the technical solution of the embodiments of the present application, the extractant can effectively extract metals with high economic value from different types of wastewater, while ensuring the environmental protection, safety, and economic benefits of the process.

[0050] Further, in some embodiments, the anion system in the wastewater containing the target metal is one or more of chloride ions, cyanide ions, thiosulfate anions, glutamic acid anions, and glycine anions.

[0051] In the technical solution of the embodiments of the present application, the extractant has high selectivity and can preferentially extract the target metal even in the presence of multiple anions. At the same time, different anion systems have different acid-base properties, and the extractant can maintain chemical stability in the environment where the above anions exist and is not easily decomposed or undergo side reactions.

[0052] Some specific embodiments are listed below. It should be noted that the embodiments described below are exemplary and are only used to explain the present application, and should not be construed as a limitation of the present application. For those without specific technologies or conditions indicated in the embodiments, the technologies or conditions described in the literature in the field or the product specifications shall be followed. For reagents or instruments without the manufacturer indicated, they are all conventional products that can be obtained through commercial purchase.

[0053] Example 1

[0054] This embodiment provides a method for separating highly economically valuable metals from wastewater using an extractant. The extractant used is ; Specifically, it includes the following steps:

[0055] S1. Mix and dissolve the extractant and sulfonated kerosene at a mass ratio of 1:9 to obtain a diluted extractant solution;

[0056] S2. Adjust the pH value of the industrial wastewater in the thiosulfate solution system containing gold ions to 8; at room temperature, weigh 10 mL of the above-mentioned diluted extractant solution and add it to 100 mL of the industrial wastewater in the thiosulfate system containing gold ions. After oscillating in a water bath oscillator at 25 °C for 5 min, separate the organic phase, and use ICP-OES (Inductively Coupled Plasma Optical Emission Spectrometer) to detect the concentration of gold ions in the inorganic liquid phase solution, so as to calculate the extraction rate of the extractant. Among them, the detection error of ICP-OES is ±2%.

[0057] Examples 2-7 and Comparative Examples 1-7

[0058] Examples 2-7 and Comparative Examples 1-7 respectively provide a method for separating highly economically valuable metals from wastewater. Compared with Example 1, the only difference is that the pH value of the wastewater is different, and sodium hydroxide or hydrochloric acid is used to adjust the pH value to a predetermined value, as shown in Table 1. Other experimental parameters and conditions are basically the same as those in Example 1 and will not be elaborated here.

[0059]

[0060] As can be seen from Table 1, for the thiosulfate solution system containing gold ions, the extractant provided by the present application has high extraction ability for gold within a specific pH range (8-14), and the extraction effect reaches more than 90%. The main reason can be attributed to the chemical properties of the anions (thiosulfate) in the solution system under different pH environments. When the pH value is less than 8, the thiosulfate in the liquid phase decomposes to produce S 2-, it forms gold sulfide precipitate with gold ions, and the gold ions are separated from the solution system. The gold ions in the solid phase cannot achieve the target ion interfacial migration, resulting in inability to extract. The extractant has a wide application window in the thiosulfate solution system, especially suitable for strong alkaline (pH value of 12 - 14) environments. In strong alkaline environments, the extraction rate of gold is greater than 95%.

[0061] Examples 8 - 21

[0062] Examples 8 - 21 respectively provide a method for separating highly economically valuable metals from wastewater by an extractant. Compared with Example 1, the only difference is that the wastewater to be treated is a glycine solution system containing gold, and sodium hydroxide or hydrochloric acid is used to adjust the pH value of the solution to a predetermined value. As shown in Table 2, other experimental parameters and conditions are basically the same as those in Example 1 and will not be elaborated here.

[0063]

[0064] As can be seen from Table 2, for the glycine solution system containing gold, the extractant provided in this application has high extraction ability for gold in the range of pH value from 1 to 14, and the extraction effect is above 80%. The extraction effect shows a trend of increasing first and then decreasing. The main reason can be attributed to the different existence forms of gold ions in the solution system under different pH environments. When the pH value is less than 9, the glycine solution system in the liquid phase exists in the form of glycine molecules or glycine acidic protonated forms, which has no chelating effect on gold ions. At this time, the gold ions exist in the form of AuCl4 - form, and the extractant undergoes a competitive chelation reaction with AuCl4 - to achieve the extraction of gold ions. When pH ≥ 9, the glycine solution system in the liquid phase exists in the form of glycine anions, which has a chelating effect on gold ions. The extractant undergoes a competitive chelation reaction with the glycine - gold chelate to achieve the extraction of gold ions. At the same time, due to the stability of the glycine - gold chelate being less than that of AuCl4 - , in this environment, the extraction effect of gold is high. The extraction effect diagram at pH = 11 is as shown in Figure 1 . It can be seen that the solution becomes clear and transparent after being extracted by the extractant. When pH ≥ 12, the extraction rate of gold decreases slightly. The main reason is that under strong alkaline conditions, part of the glycine - gold chelate hydrolyzes to form precipitate Au(OH)3, which is separated from the solution system and cannot be extracted across the interface, resulting in a slight reduction in the extraction efficiency, but still higher than 90%.

[0065] Examples 22 - 35

[0066] Examples 22 - 35 respectively provide a method for separating highly economically valuable metals from wastewater using an extractant. Compared with Example 1, the only difference is that the wastewater to be treated is a glycine solution system containing palladium, and sodium hydroxide or hydrochloric acid is used to adjust the pH value of the solution to a predetermined value. As shown in Table 3, other experimental parameters and conditions are basically the same as those in Example 1 and will not be elaborated here.

[0067]

[0068] As can be seen from Table 3, for the glycine solution system containing palladium, the extractant has high extraction ability for palladium in the pH range of 1 - 14, and the extraction effect reaches 85% or more. The extraction effect shows a trend of increasing first and then stabilizing. The main reason can be attributed to the different existence forms of palladium ions in the solution system under different pH environments. When pH < 9, the glycine anion in the liquid phase exists in the form of glycine molecules or glycine acid protonated forms, which has no chelating effect on palladium ions. At this time, palladium ions exist in the form of PdCl4 2- form, and the extractant undergoes a competitive chelation reaction with PdCl4 2- to achieve the extraction of palladium ions. When pH ≥ 12, the extraction rate of palladium remains stable. The main reason is that under strong alkaline conditions, the glycine - palladium chelate hydrolyzes incompletely and exists in the form of Pd(OH) x (Gly) y (palladium - hydroxy - glycine complex, where x and y represent the stoichiometric numbers of hydroxyl and glycine respectively). Its solubility is good and it will not separate from the solution system. Therefore, the extraction rate of palladium remains stable under strong alkaline conditions (pH ≥ 12).

[0069] Examples 36 - 49

[0070] Examples 36 - 49 respectively provide a method for separating highly economically valuable metals from wastewater using an extractant. Compared with Example 1, the only difference is that the wastewater to be treated is a glycine solution system containing platinum, and sodium hydroxide or hydrochloric acid is used to adjust the pH value of the solution to a predetermined value. As shown in Table 4, other experimental parameters and conditions are basically the same as those in Example 1 and will not be elaborated here.

[0071]

[0072] As can be seen from Table 4, for the glycine solution system containing platinum, the extractant has high extraction ability for platinum in the pH range of 1 - 14, and the extraction efficiency is over 80% in all cases. The extraction efficiency shows a trend of increasing first and then stabilizing. The main reason can be attributed to the different existence forms of platinum ions in the solution system under different pH environments. When pH is less than 9, the glycine anion in the liquid phase exists in the form of glycine molecules or protonated glycine acid, and it has no chelating effect on platinum ions. At this time, platinum ions exist in the form of PtCl6 2- form, and the extractant undergoes a competitive chelation reaction with PtCl6 2- to achieve the extraction of platinum ions. When pH ≥ 10, the extraction rate of platinum remains stable. The main reason is that under strong alkaline conditions, the hydrolysis product of the glycine - platinum chelate exists in the form of Pt(OH) x (Gly) y (platinum - hydroxy - glycine complex, where x and y represent the stoichiometric numbers of hydroxyl and glycine respectively), and its solubility is good and it will not separate from the solution system. Therefore, the extraction rate of platinum remains stable under strong alkaline conditions (pH ≥ 10).

[0073] Comparative Examples 8 - 21

[0074] Comparative Examples 8 - 21 respectively provide a method for separating highly economically valuable metals from wastewater using an extractant. Compared with Example 1, the only difference is that the wastewater to be treated is a glycine solution system containing copper, and sodium hydroxide or hydrochloric acid is used to adjust the pH value of the solution to a predetermined value, as shown in Table 5. Other experimental parameters and conditions are basically the same as those in Example 1 and will not be elaborated here.

[0075]

[0076] As can be seen from Table 5, the extractant provided in this application has a certain extraction ability for copper, but it cannot achieve high - efficiency extraction effects in the whole pH range, indicating that this extractant only has a high - efficiency selective chelating effect on the target metal.

[0077] Examples 50 - 57

[0078] Examples 50 - 57 respectively provide a method for separating highly economically valuable metals from wastewater using an extractant. The extractant provided in Example 1 is used to separately extract and separate the target metal from a solution of multiple co - existing ions. The specific operation steps are as follows:

[0079] Prepare a series of glycine co - blended solution systems containing different concentrations of gold, platinum, palladium, copper, and cobalt, adjust the pH value of the solution to 10, take 50 mL of the diluted extractant and add it to 50 mL of the solution respectively. After shaking in a water bath oscillator at 25°C for 5 min, take the inorganic liquid phase, and use ICP - OES to detect the concentration of each metal ion in the solution and calculate the extraction rate.

[0080]

[0081] As can be seen from Table 6, the extractant provided by the present application has the effect of selectively extracting gold, platinum, and palladium. When the metal ion concentration ≥ 200 ppm, copper and cobalt metal ions will not be extracted. The unique spatial structure of the extractant molecules realizes the difference in the extraction rate between the activated functional groups in the extractant and the metals, ensuring the selective extraction of the target metals in the extraction solution. When the metal ion concentration < 200 ppm, the excess extractant reacts with the impurity metals. However, since the formed chelate has poor stability and is easy to decompose, the extraction rate of the impurity metals is less than 10%.

[0082] Example 58

[0083] This example provides a method for preparing the extractant in Example 1. The synthesis route diagram is as Figure 2 shown, and the specific steps are as follows:

[0084] S1. Put 0.5 mol of raw material A, 100 mL of pyridine, and 150 mL of dichloromethane into a 500 mL three-necked flask. Stir for 10 min under an ice-water bath and nitrogen atmosphere, and slowly add 0.7 mol of trifluoromethanesulfonic anhydride dropwise to the flask. React at room temperature for 1 h, add 100 mL of deionized water to quench to obtain a mixed solution. After standing, separate, collect the organic phase, dry over anhydrous magnesium sulfate, decolorize with activated carbon, filter by suction, and rotary evaporate to obtain the first solid intermediate product;

[0085] S2. Under an ice-water bath and nitrogen atmosphere, add 5 g of sodium hydride to 1 L of anhydrous tetrahydrofuran solution, stir for 30 min, and the solution is in a suspended state. Then, drop 0.5 mol of diethyl malonate into the above solution and react for 0.5 h to obtain a solution system;

[0086] S3. Dissolve the first solid intermediate product obtained in step S1 in 500 mL of anhydrous tetrahydrofuran solution, and drop it into the solution system obtained in step S2. React for 2 h. After the reaction is completed, quench with 50 mL of deionized water, and then extract 3 times with 1 L of dichloromethane. Collect the organic phase, dry, filter by suction, and rotary evaporate to obtain the second solid intermediate product;

[0087] S4. Mix the second solid intermediate obtained in step S3 with 1 L of hydrochloric acid with a concentration of 1 mol / L, and heat under reflux for 24 h. After the reaction is completed, wash it 3 times with 0.5 L of ether, collect the aqueous layer, then add 0.5 L of pyridine and heat under reflux for 5 h. After the reaction ends, rotary evaporate to remove pyridine, collect the brownish-red oily substance, add the brownish-red oily substance to 1 L of 1 mol / L hydrochloric acid for acidification for 3 h, then extract with an excess of ethyl acetate, and finally dry, filter by suction, and rotary evaporate. After recrystallizing the obtained crude product 2 times with ether, perform column chromatography separation with a mixed solution of toluene and ethyl acetate (volume ratio 1:1), and rotary evaporate to obtain a white crystal product B with a yield of 21%;

[0088] S5. Add 0.05 mol of product B and raw material C in a molar ratio of 1:8 to a 500 mL mixed solution of dimethyl sulfoxide and acetonitrile (volume ratio 4:1). Add 1 mmol of tetrabutyl titanate solution to a 20 mL mixed solution of dimethyl sulfoxide and acetonitrile (volume ratio 4:1), and add it to the mixed solution of product B and raw material C in batches. React for 12 h. After the reaction ends, distill off the organic solvent under reduced pressure. Dissolve the oily substance in an excess of ethanol, ultrasonically dissolve it for 30 min, filter, and collect the undissolved substance. Finally, dissolve the undissolved substance in a small amount of mixed solution of dimethyl sulfoxide and acetonitrile. After complete dissolution, rotary evaporate to obtain a transparent oily product D, which is the extractant, with a yield of 43%. Its nuclear magnetic resonance hydrogen spectrum is as Figure 3 shown.

[0089] It should be noted that this application is not limited to the above embodiments. The above embodiments are only examples. Embodiments having the same constitution and the same function and effect as the technical idea within the technical solution scope of this application are all included in the technical scope of this application. In addition, within the scope not departing from the gist of this application, various modifications that those skilled in the art can think of to the embodiments, and other ways constructed by combining some constituent elements in the embodiments are also included in the scope of this application.

Claims

1. An extractant, characterized in that The structural formula of the extractant is as follows: 。 2. A method for separating metals of high economic value from wastewater using an extractant, wherein the extractant according to claim 1 is used for extraction, characterized in that: The following steps are involved: Mixing and dissolving an extractant and a diluent to obtain an extractant diluent; the diluent is sulfonated kerosene; The extractant diluent is added to wastewater containing target metals to achieve selective extraction of the target metals in the solution; the target metals are one or more of gold, palladium and platinum.

3. The method for separating high economic value metals from wastewater by an extractant according to claim 2, characterized in that: The mass ratio of the extractant to the diluent is 1:(9-59).

4. The method for separating high economic value metals from wastewater by an extractant according to claim 2, characterized in that: The volume ratio of the extractant diluent to the wastewater containing the target metal is 1:(1-10).

5. The method for separating high economic value metals from wastewater by an extractant according to claim 4, characterized in that: The wastewater containing the target metal is one or more of mining cyanide solution, petrochemical catalyst waste liquid, metallurgical waste liquid, and electroplating waste liquid.

6. The method for separating high economic value metals from wastewater by an extractant according to claim 5, characterized in that: The anion system in the wastewater containing the target metal is one or more of chloride ion, cyanide ion, thiosulfate anion, glutamate anion, and glycine anion.

Images