Low molecular weight polymer extractant and method for treating copper and nickel-containing acidic wastewater

Abstract

The present application provides a low molecular weight polymeric extractant and a method for treating copper and nickel-containing acidic wastewater, which belongs to the field of wastewater purification. The polymeric molecular skeleton of the extractant is low molecular weight polymerized isosorbide terephthalate. By regulating the molecular skeleton structure, the type of functional groups, the distribution of functionalized sites, and the synergistic effect of the functionalized functional groups of the spatially specific molecular skeleton and the chelation extraction, the selective chelation effect of metal ions of a specific size is achieved, and the targeted capture of the target metal is realized. The low molecular weight polymeric extractant expands the types of extractants and provides a new solution for the enrichment and purification of heavy metals in wastewater. At the same time, the extractant has a good service life and regeneration ability. Because its molecular skeleton is a low molecular weight polymer, it is extremely difficult for the polymeric compound to enter the water phase through the transfer between the phase interfaces, which effectively avoids the secondary pollution problem caused by the traditional extractant that may be dissolved in the water phase.

Description

Technical Field

[0001] The invention relates to the technical field of wastewater purification, and in particular to a low molecular weight polymer extractant and a method for treating copper- and nickel-containing acidic wastewater using the extractant. Background Art

[0002] In modern chip integrated circuit production lines, copper and nickel-containing waste liquids generated during the production process mainly come from etching, electroplating and cleaning processes. These waste liquids are classified as hazardous wastes because they contain heavy metal components, posing a serious threat to the environment and human health. In order to treat this type of heavy metal-containing wastewater, the industry mainly uses the extraction process. The extraction process has the characteristics of simple operation and strong applicability. It is one of the mainstream processes for treating copper and nickel-containing wastewater generated by the etching process. The core of the extraction process is the research and development of the type of extractant. While achieving efficient extraction, it is necessary to take into account the targeted selective extraction effect.

[0003] At present, the research and development of extractants mainly focuses on small molecule compounds, such as traditional organic extractants and ion exchange liquids, etc. However, these traditional extractants have the disadvantages of short cycle life, easy decomposition under strong acidic conditions, and easy to cause secondary pollution of water bodies during use.

[0004] In view of this, it is necessary to design an improved low molecular weight polymer extractant and a method for treating copper and nickel-containing acidic wastewater to solve the above problems. Summary of the invention

[0005] In view of the technical problems existing in the background technology, the present application provides a low molecular weight polymer extractant and a method for treating copper and nickel-containing acidic wastewater, aiming to solve the technical problems of short recycling service life of the extractant and easy secondary pollution of water bodies.

[0006] In the first aspect, the present application provides a low molecular weight polymeric extractant, wherein the polymeric molecular skeleton of the low molecular weight polymeric extractant is a low molecular weight polymerized isosorbide terephthalate, and the structural formula thereof is:

[0007]

[0008] Among them, 2≤n≤10.

[0009] As a further improvement of the present application, the molecular weight of the low molecular weight polymeric extractant is 850 to 3100 Da.

[0010] In a second aspect, the present application provides a method for treating copper- and nickel-containing acidic wastewater using a low molecular weight polymeric extractant, wherein the low molecular weight polymeric extractant described in the first aspect is used for extraction, comprising the following steps:

[0011] The low molecular weight polymer extractant is mixed with a diluent, and ultrasonically dissolved to obtain a diluted solution;

[0012] A pH regulator is added to the acidic wastewater containing copper and nickel to adjust the pH value of the solution to 1-5, and then the diluted solution is added and the solution is oscillated in a water bath for a predetermined time to achieve selective extraction of copper and nickel in the solution.

[0013] As a further improvement of the present application, the copper- and nickel-containing acidic wastewater contains one or more of sulfate anions, chloride ions, fluoride ions, nitrate anions, and methanesulfonate ions.

[0014] As a further improvement of the present application, the diluent is a mixture of chloroform and sulfonated kerosene.

[0015] Furthermore, the mass ratio of the low molecular weight polymer extractant to the chloroform and the sulfonated kerosene is 1:(5-10):(10-100).

[0016] As a further improvement of the present application, the pH adjuster is one or more of hydrochloric acid, sulfuric acid, nitric acid, and a hydrochloric acid / ammonium fluoride mixture.

[0017] As a further improvement of the present application, the volume ratio of the copper-nickel acid wastewater to the diluted dissolving solution is 5:(1-2). The temperature of the water bath oscillation is 25-28° C., and the time is 5-10 min.

[0018] As a further improvement of the present application, the copper- and nickel-containing acidic wastewater is one or more of acidic catalyst waste liquid, acidic metallurgical waste liquid, acidic electronic waste leaching solution, acidic photovoltaic module etching liquid, and acidic waste circuit board electroplating liquid.

[0019] The beneficial effects of this application are:

[0020] The present application provides a low molecular weight polymer extractant and a method for treating copper and nickel-containing acidic wastewater. By regulating the molecular skeleton structure, the type of functional groups, the distribution of functionalized sites, and the synergistic effect of the functionalized functional groups of the spatially specific molecular skeleton and chelation extraction, the selective chelation of metal ions of a specific size (ionic radius) is achieved, and the targeted capture of the target metal is realized. The low molecular weight polymer extractant expands the types of extractants and provides a new solution for the enrichment and purification of heavy metals in wastewater. In addition, the extractant has a good service life and regeneration ability. The extractant uses a low molecular weight polymer as a molecular skeleton, and it is extremely difficult for the polymer compound to enter the water phase through the transfer between the phase interfaces, which can avoid the secondary pollution caused by the traditional extractant dissolving in the water phase.

[0021] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solution of the present application, the following is a brief introduction to the drawings used in the present application. Obviously, the drawings described below are only some embodiments of the present application, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0023] Figure 1 A schematic diagram of the synthesis route of the low molecular weight polymeric extractant provided in this application;

[0024] Figure 2 This is the hydrogen nuclear magnetic resonance spectrum of the molecular skeleton of the low molecular weight polymeric extractant provided in Example 15 of the present application. DETAILED DESCRIPTION

[0025] The following embodiments of the technical solution of the present application are described in detail in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present application.

[0026] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians 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" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0027] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0028] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0029] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of the associated objects, indicating that there may be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

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

[0031] At present, the research and development of extractants mainly focuses on small molecule compounds, such as traditional organic extractants and ion exchange liquids, etc. However, these traditional extractants have the disadvantages of short cycle life and are prone to secondary water pollution during use.

[0032] In order to solve the technical problems of short recycling service life of extractants and easy secondary pollution of water bodies, the present application provides a low molecular weight polymer extractant and a method for treating copper- and nickel-containing acidic wastewater, wherein the low molecular weight polymer extractant achieves the effect of selective chelation of metal ions of specific sizes through the synergistic effect of spatially specific molecular skeleton and functional functional groups of chelation extraction, thereby realizing the targeted capture of target metals.

[0033] In a first aspect, the present invention provides a low molecular weight polymeric extractant, wherein the polymeric molecular skeleton of the low molecular weight polymeric extractant is low molecular weight polymerized isosorbide terephthalate, and the structural formula thereof is:

[0034]

[0035] Among them, 2≤n≤10.

[0036] In the technical scheme of the embodiment of the present application, the polymeric molecular skeleton of the extractant is a low molecular weight polymerized isosorbide terephthalate. Since the isosorbide molecular skeleton presents a spatial "V"-shaped structure, the hydroxyl chemical activity presenting endo is poor, and the polymerization effect with dibasic acid is poor during the polymerization process, the polymer molecular weight is low, and the end groups of the polymer exist mostly in the form of endo, which is conducive to the derivatization of low molecular weight high molecular polymers and the introduction of functional functional groups of chelate extraction. At the same time, the overall molecular skeleton of the low molecular weight polymer is affected by the spatial structure of isosorbide and is difficult to stretch linearly, presenting spatial distortion, and finally the overall molecular skeleton presents a spatial specific type. The spatially specific molecular skeleton cooperates with the functional functional groups of chelate extraction to achieve the effect of selective chelation of metal ions of a specific size (ionic radius), and realizes the targeted capture of target metals.

[0037] Furthermore, in some embodiments, the molecular weight of the low molecular weight polymeric extractant is 850-3100 Da.

[0038] In the technical solution of the embodiment of the present application, the low molecular weight polymeric extractant has good solubility and fluidity, and can contact the target substance more effectively, thereby improving the extraction efficiency. After the extraction process, the low molecular weight extractant is easier to separate from the mixture by simple physical methods, which is convenient for recycling and reuse.

[0039] The low molecular weight polymer extractant provided in the present application is prepared by direct esterification using terephthalic acid and isosorbide as raw materials. Figure 1 As shown, the specific preparation method comprises the following steps:

[0040] S1. Add terephthalic acid and isosorbide in a molar ratio of 1: (2-5) into a reaction vessel, add 0.001-0.01 g of tetrabutyl titanate as a catalyst, replace the air in the container with nitrogen at room temperature, raise the temperature to 120-160°C, stir for 20-40 minutes when the raw materials are in a slurry state, raise the temperature of the reaction system to 250-300°C, stir for 2-4 hours, and the esterification is completed, and collect product A.

[0041] S2. Dissolve 0.5-1 mol of product A in dichloromethane, transfer to an ice-water bath, and slowly drip 50-200 ml of a Dess-Martin periodic acid mixed solution with a molar concentration of 0.01-0.05 mol / L under a nitrogen atmosphere. Stir the reaction for 4-6 hours, filter, collect the liquid, and remove the solvent to obtain an oily brown solid B.

[0042] S3. Add 0.2-0.5 mol of solid B, 0.3-0.6 mol of hydroxylamine hydrochloride and 1 L of anhydrous ethanol into a container, drop pyridine under nitrogen protection, add 30-100 ml of saturated sodium ethoxide, stir for 20-30 min, heat under reflux for 6-8 h, extract, dry, filter and concentrate the reaction solution under reduced pressure to obtain product C, i.e., a low molecular weight polymer extractant.

[0043] In a second aspect, the present invention provides a method for treating copper- and nickel-containing acidic wastewater using a low molecular weight polymeric extractant, wherein the low molecular weight polymeric extractant described in the first aspect is used for extraction, comprising the following steps:

[0044] Mixing a low molecular weight polymer extractant with a diluent, dissolving by ultrasonication, and obtaining a diluted solution;

[0045] A pH regulator is added to the acidic wastewater containing copper and nickel to adjust the pH value of the solution to 1-5, and then a diluent is added, and the solution is oscillated in a water bath for a predetermined time to achieve selective extraction of copper and nickel in the solution.

[0046] Among them, through ultrasonic dissolution and dilution, the low molecular weight polymer extractant can be more evenly distributed in the wastewater, increasing the contact area with copper and nickel ions, thereby achieving efficient extraction. Adjusting the pH of the wastewater to 1-5 can optimize the existence form of copper and nickel ions, making them easier to combine with the extractant, while other interfering ions are not easily extracted, thereby achieving selective separation. Due to its specific molecular structure, the low molecular weight polymer extractant is not easily soluble in the aqueous phase, which reduces the residue of organic matter in the water body and reduces the risk of secondary pollution. At the same time, the extractant is not easy to decompose in a strong acidic environment and has good stability.

[0047] Furthermore, in some embodiments, the copper- and nickel-containing acidic wastewater contains one or more of sulfate anions, chloride ions, fluoride ions, nitrate anions, and methanesulfonate ions.

[0048] In the technical solution of the embodiment of the present application, the low molecular weight polymer extractant can adapt to complex wastewater systems containing different anions and has good versatility. In wastewater containing multiple anions, the extractant can work stably and is not easy to decompose or inactivate, thereby extending its service life. By effectively extracting copper and nickel ions, harmful components in wastewater are reduced, making subsequent wastewater treatment simpler and more cost-effective.

[0049] Furthermore, in some embodiments, the diluent is a mixture of chloroform and sulfonated kerosene. The mass ratio of the low molecular weight polymer extractant to chloroform and sulfonated kerosene is 1:(5-10):(10-100).

[0050] In the technical scheme of the embodiment of the present application, chloroform has good solubility and stability, and can be mixed with many organic substances and some inorganic substances. Sulfonated kerosene has good hydrophilicity, can increase the contact area with the aqueous phase, and is helpful for the extraction process. The mixed solution of chloroform and sulfonated kerosene can increase the solubility of low molecular weight polymer extractant in the aqueous phase, help to form a stable extraction system, and prevent the extractant from decomposing or failing during the extraction process. The difference in density and polarity of the diluent and the aqueous phase helps to form a good two-phase separation, which is convenient for subsequent extraction agent recovery and metal ion recovery. By accurately controlling the proportion of the diluent, the amount of organic solvent used can be reduced while ensuring the extraction effect, reducing costs and environmental impact.

[0051] Furthermore, in some embodiments, the pH adjuster is one or more of hydrochloric acid, sulfuric acid, nitric acid, and a hydrochloric acid / ammonium fluoride mixture.

[0052] In the technical solution of the embodiment of the present application, according to the type and concentration of metal ions in the wastewater, the pH value of the wastewater itself and the chemical reactions that may occur during the treatment process, one or more of hydrochloric acid, sulfuric acid, nitric acid, and hydrochloric acid / ammonium fluoride mixture can be selected to adjust the pH value. By adjusting the pH value to a predetermined range, copper and nickel ions can be present in a specific form, such as Cu 2+ and Ni 2+ , these forms are more likely to combine with the functional groups in the extractant, thus achieving efficient and selective extraction.

[0053] Furthermore, in some embodiments, the volume ratio of the copper- and nickel-containing acidic wastewater to the diluted dissolving solution is 5:(1-2).

[0054] In the technical solution of the embodiment of the present application, the appropriate volume ratio can ensure that the extractant is in full contact with the metal ions in the wastewater to form a stable complex, thereby improving the extraction efficiency. By accurately controlling the volume ratio, excessive use of the extractant can be avoided, the processing cost can be reduced, and the subsequent separation and metal recovery process can be made simpler, reducing the processing difficulty.

[0055] Furthermore, in some embodiments, the temperature of the water bath oscillation is 25-28° C., and the time is 5-10 min.

[0056] In the technical solution of the embodiment of the present application, at a temperature of 25 to 28°C, the fluidity of the extractant and the wastewater is good, which is conducive to the interaction between the metal ions and the extractant, thereby improving the extraction efficiency. The appropriate temperature can avoid the damage of the extractant to the high temperature and extend the service life of the extractant. Oscillation can enhance the mass transfer between the two phases, so that the metal ions are more effectively transferred from the aqueous phase to the organic phase.

[0057] Furthermore, in some embodiments, the copper- and nickel-containing acidic wastewater is one or more of acidic catalyst waste liquid, acidic metallurgical waste liquid, acidic electronic waste leaching solution, acidic photovoltaic module etching solution, and acidic waste circuit board electroplating solution.

[0058] In the technical solution of the embodiment of the present application, the low molecular weight polymer extractant has good selectivity and can efficiently extract the target metal ions from complex waste liquids. The low molecular weight polymer extractant is used to treat the acidic wastewater from these specific sources, which can achieve efficient and environmentally friendly metal ion removal and resource recovery.

[0059] 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 limiting the present application. If specific techniques or conditions are not specified in the embodiments, the techniques or conditions described in the literature in this area or the product specifications are used. The reagents or instruments used without specifying the manufacturer are all conventional products that can be obtained commercially.

[0060] Example 1

[0061] Example 1 provides a method for treating copper- and nickel-containing acidic wastewater using a low molecular weight polymeric extractant, comprising the following steps:

[0062] S1. Mixing a low molecular weight polymer extractant with chloroform and sulfonated kerosene in a mass ratio of 1:10:50, and dissolving by ultrasonication to obtain a diluted solution;

[0063] S2. Add hydrochloric acid to the copper- and nickel-containing acidic wastewater to adjust the pH value of the solution to 1;

[0064] S3. At room temperature, take 10 ml of the above diluted solution and put it into 50 ml of copper- and nickel-containing acidic wastewater. After shaking in a water bath oscillator at 25°C for 5 minutes, separate the organic phase and use ICP-OES (inductively coupled plasma emission spectrometer) to detect the concentration of copper and nickel in the inorganic liquid phase solution, thereby calculating the extraction rate of the low molecular weight polymer extractant, wherein the detection error of ICP-OES is ±2%.

[0065] Embodiment 2-5

[0066] Examples 2-5 respectively provide a method for treating copper- and nickel-containing acidic wastewater using a low molecular weight polymeric extractant. Compared with Example 1, the only difference is that the pH value of the solution is adjusted differently, as shown in Table 1. Other experimental parameters and conditions are basically the same as those in Example 1 and will not be repeated here.

[0067] Comparative Examples 1-4

[0068] Comparative Examples 1-4 respectively provide a method for treating copper- and nickel-containing acidic wastewater using a low molecular weight polymer extractant. Compared with Example 1, the only difference is that sodium hydroxide is used to adjust the pH value of the solution. Other experimental parameters and conditions are basically the same as those in Example 1 and will not be repeated here.

[0069] Table 1 Extraction effect of Examples 1-5 and Comparative Examples 1-4

[0070]

[0071] - represents below the detection limit of ICP-OES.

[0072] As can be seen from Table 1, the low molecular weight polymer extractant provided by the present application has an efficient extraction capacity for copper and nickel, and the extraction effect is more than 90% in the pH range (1 to 5). The low molecular weight polymer extractant is suitable for strong acid systems, is not easy to decompose, and has good stability. When the pH value is 6, the leaching rate of copper is not affected, while the leaching rate of nickel is reduced to 77%. The main reason is that the nickel ions are partially converted into nickel hydroxide precipitation and separated from the waste water solution phase, and the extraction principle of the extractant is the ion exchange between the organic phase and the inorganic aqueous phase. The metal ions in the solid phase are difficult to transfer to the solution phase, which leads to the loss of some nickel ions in the wastewater, resulting in a low leaching rate of nickel. When the pH value is 8, nickel is completely converted into nickel hydroxide precipitation and cannot be effectively extracted. At this time, the extraction rate of copper is only 45%, because under alkaline conditions, the hydroxyoxime functional group in the low molecular weight polymer extractant begins to decompose, causing the extractant to fail. When the pH rises to 12, the extractant is completely ineffective and no longer has extraction ability. At the same time, the copper and nickel ion precipitations are separated from the aqueous phase.

[0073] Embodiment 6-9

[0074] Examples 6-9 respectively provide a method for treating copper- and nickel-containing acidic wastewater using a low molecular weight polymeric extractant. Compared with Example 1, the only difference is that the pH adjuster and the pH value of the solution are different, as shown in Table 2. The other experimental parameters and conditions are basically the same as those in Example 1 and will not be repeated here.

[0075] Table 2 Extraction effect of Examples 6-9

[0076]

[0077] As can be seen from Table 2, the low molecular weight polymer extractant provided in the present application maintains a high efficiency in extracting copper and nickel in a complex solution system containing a variety of anion species. At the same time, the extractant is not easily decomposed in a strong acidic environment and has good stability.

[0078] Examples 10-13

[0079] Examples 10-13 provide a method for treating copper- and nickel-containing acidic wastewater using a low molecular weight polymeric extractant, respectively, wherein the low molecular weight polymeric extractant is used to extract and separate copper and nickel from a variety of coexisting ion solutions, and the specific operation steps are as follows:

[0080] A series of mixed solutions containing copper, nickel and mercury, tin and molybdenum in different concentration ratios were prepared, and the pH value of the solution was adjusted to 1 with hydrochloric acid. 50 ml of the diluted solution of the low molecular weight polymer extractant prepared in Example 1 was taken and added to 100 mL of the solution respectively, and after shaking in a water bath oscillator at 25° C. for 5 minutes, the organic phase was separated, and the concentration of each metal ion in the inorganic liquid phase solution was detected by ICP-OES, thereby calculating the extraction rate, wherein the detection error of ICP-OES was ±2%, and the results are shown in Table 3.

[0081] Table 3 Extraction ability of low molecular weight polymer extractants for various metal ions in blended solutions

[0082]

[0083] - represents below the detection limit of ICP-OES.

[0084] As shown in Table 3, the low molecular weight polymer extractant has a selective extraction effect on copper and nickel, but does not extract mercury ions, tin ions, and molybdenum ions. The main reason is that the functionalized chelating fragments unique to the low molecular weight polymer extractant coordinate with the spatial structure of the molecular skeleton to achieve the effect of efficient selective chelating extraction of copper and nickel.

[0085] Embodiment 14

[0086] Example 14 provides a method for treating copper- and nickel-containing acidic wastewater using a low molecular weight polymeric extractant, comprising the following steps:

[0087] S1. Mixing a low molecular weight polymer extractant with chloroform and sulfonated kerosene in a mass ratio of 1:10:50, and dissolving by ultrasonication to obtain a diluted solution;

[0088] S2. Add hydrochloric acid to the copper- and nickel-containing acidic wastewater to adjust the pH value of the solution to 1;

[0089] S3. At room temperature, take 10 ml of the above diluted solution and put it into 50 ml of copper- and nickel-containing acidic wastewater. After shaking in a water bath oscillator at 25 ° C for 5 min, separate the organic phase, and use ICP-OES to detect the concentration of copper and nickel in the inorganic liquid phase solution. Calculate the extraction rate, and the number of cycles of the extractant is recorded as N 0 ;

[0090] S4. The organic phase was stripped with a saturated ammonium chloride solution, and the organic phase was collected. At room temperature, the stripped organic phase was put into 50 ml of copper- and nickel-containing wastewater with a pH value of 1, and oscillated in a water bath oscillator at 25°C for 5 minutes. The organic phase was separated, and the concentrations of copper and nickel in the inorganic liquid phase solution were detected by ICP-OES. The extraction rate was calculated, and the number of cycles of the extractant was recorded as N. 1 ;

[0091] S5. Repeat step S4, and the number of cycles of the extractant is recorded as N 2 , N 3 , N 4 .....N n The changes in the extraction effects of the low molecular weight polymer extractants were compared to determine the cycle life. The results are shown in Table 4.

[0092] Table 4 Recycling effect of low molecular weight polymer extractant

[0093]

[0094] As shown in Table 4, when the low molecular weight polymer extractant is recycled for the 8th time, the extraction rates of copper and nickel can still be maintained at 90% or above. When it is recycled for the 9th time, the extraction rate of copper is 90%, and the extraction rate of nickel drops to 82%, indicating that the extractant still maintains a high extraction efficiency after 8 cycles, and the extraction performance has not decreased significantly. This shows that the structure and function of the extractant are relatively stable during the recycling process, and it can effectively extract copper and nickel ions from wastewater.

[0095] Embodiment 15

[0096] Example 15 provides a method for preparing the low molecular weight polymeric extractant in Example 1, such as Figure 1 As shown, the specific steps include:

[0097] S1. Put terephthalic acid and isosorbide in a molar ratio of 1:3 into a 3L three-necked round-bottom flask, add 0.005g of catalyst tetrabutyl titanate, use an overhead mechanical stirring device, and equip it with an air inlet and an air outlet. Pass nitrogen three times at room temperature to replace the air in the container to prevent side reactions under high temperature conditions. At 150°C, when the raw material is in a slurry state, turn on the stirring paddle and perform slurrying. This process is maintained for 30 minutes to ensure that the catalyst and the raw material are evenly mixed. After the slurrying stage, the esterification stage begins. Under a nitrogen atmosphere, the reaction system is heated to 280°C and stirred for 4 hours, and the esterification is completed. Product A is collected with a yield of 92%. The 1H-NMR nuclear magnetic spectrum of product A is shown as follows Figure 2 As shown, the molecular weight range of substance A measured by gel permeation chromatography (GPC) is 1400-1950 Da.

[0098] S2. Put 0.5 mol of substance A into a 3L three-necked round-bottom flask, add 1L of dichloromethane to dissolve, and transfer to an ice-water bath. Transfer 100 ml of a 0.01 mol / L Dess-Martin periodic acid mixed solution to a constant pressure dropping funnel, slowly drip it under the protection of a nitrogen atmosphere, and stir to react for 4 to 6 hours. After the reaction is completed, quench the unreacted Dess-Martin periodic acid with deionized water-dichloromethane (volume ratio of 1:5), filter, collect the liquid, vacuum evaporate the solvent, dissolve the residue in chloroform solution, vacuum evaporate again to remove the chloroform solvent, and quickly freeze with liquid nitrogen to remove the residual solvent. Collect the oily brown solid B with a yield of 45%.

[0099] S3. Transfer 0.2 mol of compound B, 0.3-0.6 mol of hydroxylamine hydrochloride and 1 L of anhydrous ethanol to a 3 L three-necked flask. Transfer pyridine to a constant pressure dropping funnel, drip into the three-necked flask under nitrogen protection, add 60 ml of saturated sodium ethoxide, stir for 30 min, heat to reflux, react for 8 h, and end the reaction. Slowly pour the reaction solution into a beaker of 2 L of water, extract with ether 5 times, dry the organic phase with anhydrous magnesium sulfate, filter, and concentrate under reduced pressure to obtain a low molecular weight polymer extractant with a yield of 74%.

[0100] In summary, the present application provides a low molecular weight polymeric extractant and a method for treating copper and nickel-containing acidic wastewater. The polymeric molecular skeleton of the extractant is low molecular weight polymerized isosorbide terephthalate. Through the synergistic effect of the spatially specific molecular skeleton and the functionalized functional groups of the chelating extraction, the selective chelation of copper and nickel ions is achieved, and the targeted capture of the target metal is realized. In addition, the extraction cycle test shows that the low molecular weight polymeric extractant has a good circulation effect in a strong acid environment. At the same time, the extractant uses a low molecular weight polymer as a molecular skeleton, which can avoid the secondary pollution caused by the traditional extractant dissolving in the water phase.

[0101] It should be noted that the present application is not limited to the above-mentioned embodiments. The above-mentioned embodiments are only examples, and the embodiments having the same structure as the technical idea and exerting the same effect within the scope of the technical solution of the present application are all included in the technical scope of the present application. In addition, without departing from the scope of the main purpose of the present application, various modifications that can be thought of by those skilled in the art to the embodiments and other methods of combining some of the constituent elements in the embodiments are also included in the scope of the present application.

Claims

1. A low molecular weight polymeric extractant, characterized in that: The polymeric molecular skeleton of the low molecular weight polymeric extractant is low molecular weight polymerized isosorbide terephthalate, and its structural formula is: Among them, 2≤n≤10.

2. A method for treating copper- and nickel-containing acidic wastewater using a low molecular weight polymeric extractant, wherein the low molecular weight polymeric extractant according to claim 1 is used for extraction, characterized in that: The following steps are involved: The low molecular weight polymer extractant is mixed with a diluent, and ultrasonically dissolved to obtain a diluted solution; the diluent is a mixture of chloroform and sulfonated kerosene; A pH regulator is added to the acidic wastewater containing copper and nickel to adjust the pH value of the solution to 1-5, and then the diluted solution is added and the solution is oscillated in a water bath for a predetermined time to achieve selective extraction of copper and nickel in the solution.

3. The method for treating copper- and nickel-containing acidic wastewater using a low molecular weight polymeric extractant according to claim 2, characterized in that: The copper- and nickel-containing acidic wastewater contains one or more of sulfate anions, chloride ions, fluoride ions, nitrate anions, and methanesulfonate ions.

4. The method for treating copper- and nickel-containing acidic wastewater using a low molecular weight polymeric extractant according to claim 2, characterized in that: The mass ratio of the low molecular weight polymer extractant to the chloroform and the sulfonated kerosene is 1:(5-10):(10-100).

5. The method for treating copper- and nickel-containing acidic wastewater using a low molecular weight polymeric extractant according to claim 2, characterized in that: The pH regulator is one or more of hydrochloric acid, sulfuric acid, nitric acid, and a hydrochloric acid / ammonium fluoride mixture.

6. The method for treating copper- and nickel-containing acidic wastewater using a low molecular weight polymeric extractant according to claim 2, characterized in that: The volume ratio of the copper- and nickel-containing acidic wastewater to the diluted dissolving solution is 5:(1-2).

7. The method for treating copper- and nickel-containing acidic wastewater using a low molecular weight polymeric extractant according to claim 2, characterized in that: The temperature of the water bath oscillation is 25-28° C., and the time is 5-10 min.

8. The method for treating copper- and nickel-containing acidic wastewater using a low molecular weight polymeric extractant according to claim 2, characterized in that: The copper- and nickel-containing acidic wastewater is one or more of acidic catalyst waste liquid, acidic metallurgical waste liquid, acidic electronic waste leaching solution, acidic photovoltaic module etching solution, and acidic waste circuit board electroplating solution.

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