Thiourea-based aromatic porous organic polymer as well as preparation method and application thereof

Abstract

The invention relates to a thiourea-based aromatic porous organic polymer as well as a preparation method and application thereof, and belongs to the technical field of functional polymer adsorption materials. The preparation method comprises the following steps: respectively dissolving a plurality of ternary aromatic amine monomers with different electron pushing (electron donating) effects and cheap binary isothiocyanate monomers, mixing, uniformly shaking, and reacting to obtain a porous organic polymer network which is shown as organogel; and grinding the organogel into powder, then carrying out solvent exchange in dichloromethane, treating in methanol by using a Soxhlet extractor, and finally drying to obtain the product. The thiourea-based aromatic porous organic polymer provided by the invention has good adsorptive selectivity to Au, high adsorption capacity, wide pH adaptation range, good cyclic adsorption performance, simple preparation method and relatively high practical application value.

Description

Technical Field

[0001] The invention relates to the technical field of functional polymer adsorbent preparation and precious metal efficient recovery, and in particular to a thiourea-based aromatic porous organic polymer and a preparation method and application thereof. Background Art

[0002] With the rapid development of the electronic information industry, the replacement speed of electronic products is getting faster and faster. Due to the short service life of electronic equipment, the large amount of electronic waste generated will cause great harm to the environment if it is not properly handled. The amount of electronic waste in the world will increase at an average annual rate of 4%, reaching 74 million tons by 2030. Electronic waste contains many precious metal elements, and its content is generally higher than that of ordinary ores, so it is called an urban mine. It is estimated that each ton of mobile phone contains 130 kg of copper, 3.5 kg of silver, 0.34 kg of gold, and 0.14 kg of palladium. Most of the precious metals in electronic waste have not been properly recycled, but have caused great pollution to the environment. Therefore, by recovering precious metal elements from electronic waste, we can not only reduce the demand for natural resources and the adverse impact on the environment, but also extend the service life of limited precious metal resources.

[0003] Among electronic waste, gold is the most valuable. Recovery of gold from electronic waste begins with pretreatment, usually one or more physical separation processes, followed by metal recovery operations such as pyrometallurgy, hydrometallurgy and microbial leaching. Hydrometallurgy is considered to have great potential in existing industrial solutions for electronic waste treatment. Traditional hydrometallurgical methods include solvent extraction, ion exchange, electrochemical reduction, chemical / physical adsorption, etc., among which chemical / physical adsorption is the most energy-saving and environmentally friendly. However, hydrometallurgical systems are usually complex. This is because the source of the leachate - electronic waste is a complex mixture of metals, glass, plastics, ceramics, etc. It is estimated that up to 69 different chemical elements may be found in electronic waste. Therefore, it is necessary to design and develop efficient adsorbents and achieve the recovery of precious metals from complex systems by selective adsorption.

[0004] In recent years, porous organic polymers (POPs) have received extensive attention as an emerging chemical / physical adsorbent for precious metals. Porous organic polymers are porous materials composed of light elements such as C, H, N, and O. They have the advantages of large specific surface area, good physicochemical stability, clear chemical composition, wide range of monomer selection, and strong designability. They are one of the hot spots in material research. Chinese patent CN 119039545 A reported a guanidine-based ionic porous organic polymer material that can be used as an adsorbent for Au in water. Its saturated adsorption capacity is 1270.76 mg / g, but its adsorption capacity is still far from practical application. Chinese patent CN 110078888A reported a porous organic polymer connected by a thiourea structure, which is used as a catalyst for Michael reaction, but its preparation conditions are relatively harsh.

[0005] At present, there is no report on the use of thiourea-based aromatic porous polymers for recycling Au from electronic waste. Summary of the invention

[0006] In view of the problems in the prior art such as the complicated preparation process of the adsorbent, low gold adsorption capacity, poor adsorption selectivity, and poor cycle stability of the adsorbent, the present invention proposes a thiourea-based aromatic porous organic polymer and its preparation method and application. The aromatic porous polymer is constructed based on building blocks with different electron-donating (donating) effects, and thiourea groups are introduced to improve its adsorption capacity for Au.

[0007] The technical solution of the present invention is as follows:

[0008] A method for preparing thiourea-based aromatic porous organic polymers (POPs) comprises the following steps: dissolving a ternary aromatic amine monomer and a diisothiocyanate monomer respectively, mixing and shaking, and reacting to obtain an organic gel; grinding the organic gel into powder, then solvent exchanging in dichloromethane, washing, and finally drying to obtain the obtained product.

[0009] Preferably, the diisocyanate monomer includes any one of p-phenylene diisocyanate (PDI), 4,4′-diisothiocyanate-1,1′-biphenyl, bis(4-isothiocyanatophenyl)diazine, 4,4′-diisothiocyanate-1,1′-p-terphenyl, 4,4′-diisothiocyanate-3,3′,5,5′-tetramethyl-1,1′-biphenyl, and 1,4-diisothiocyanate-2,5-dimethylbenzene.

[0010] The diisocyanate monomer includes p-phenylene diisocyanate (PDI).

[0011] Preferably, the trivalent aromatic amine monomer includes any one of tris(4-aminophenyl)amine (TAPA) and 1,3,5-tris(4-aminophenoxy)benzene (TAPOB).

[0012] Preferably, the dissolving further comprises ultrasound or microwave treatment.

[0013] Preferably, the dissolving solvent is N,N-dimethylacetamide (DMAc), N,N-dimethylformamide (DMF) or dimethyl sulfoxide (DMSO).

[0014] Preferably, the solvent exchange time is 6 to 12 hours, and the number of exchanges is 2 to 4 times.

[0015] Preferably, the household mill has a rotation speed of 12000 to 22000 rpm.

[0016] Preferably, the washing is performed with an organic solvent, the organic solvent is any one or more of methanol, ethanol, propanol, and acetone, the treatment temperature is 50 to 65° C., and the number of washing times is 6 to 12 times.

[0017] Preferably, the drying is specifically: drying under vacuum at 60° C. to 80° C. for 12 to 24 hours.

[0018] The present invention also provides a thiourea-based aromatic porous organic polymer prepared by the above-mentioned preparation method of the thiourea-based aromatic porous organic polymer.

[0019] The present invention also provides the use of the thiourea-based aromatic porous organic polymer as an adsorbent to adsorb Au in water.

[0020] The principle of using thiourea-based aromatic porous polymer to adsorb Au is: 1. The main form of gold in the acid leaching solution of waste is [AuCl4] - , and according to Pearson's hard-soft acid-base theory, there is a strong soft-soft interaction between the thiourea structure and [AuCl4]-. 2. As a hydrogen-rich structure, thiourea interacts with hydrogen bonds. 3. The amino group in thiourea can be further protonated or positively charged through the Menshutkin reaction, and reacts with [AuCl4] - There is a charge interaction between them. 4. At the same time, [AuCl4] - It has a higher redox potential and is more susceptible to reduction reactions. The thiourea structure containing N and S can reduce Au(III) to Au(I) and Au(0) while chelating Au(III).

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] (1) The present invention is based on the nucleophilic addition reaction of isothiocyanate and aromatic amine, selects a ternary aromatic amine monomer and a diisothiocyanate monomer to react, and cross-links to generate a porous organic polymer network with a thiourea structure. This material has the advantages of simple preparation method, low reaction condition requirements, low cost, etc., and is easy to industrialize.

[0023] (2) The thiourea-based POPs selected by the present invention have great selectivity for gold due to the strong interaction between the thiourea sites they contain and gold. The maximum adsorption capacity of the adsorbent can reach 4745.87 mg / g. In addition, since the adsorbent has a certain reduction effect, the room temperature reaction can avoid the oxidation of the material, and the cyclic adsorption performance is good. It is at the leading level among current adsorbents and realizes environmentally friendly room temperature gold refining.

[0024] (3) The thiourea-based POPs prepared in the present invention are applicable to a wide pH range and maintain a relatively high adsorption capacity under the condition of pH 1-7. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is the infrared spectrum of the adsorbent synthesized in Example 1.

[0026] Figure 2 is the XRD pattern of the adsorbent synthesized in Example 1.

[0027] Figure 3 is the adsorbent synthesized in Example 1 13 C NMR spectrum.

[0028] Figure 4 The infrared spectra of stability of the compound synthesized in Example 1 under six conditions are shown in FIG.

[0029] Figure 5 It is the N2 adsorption-desorption curve and pore size distribution diagram of the adsorbent synthesized in Example 1 at 77.4K.

[0030] Figure 6 This is the experimental result display of the adsorption capacity at different pH values ​​of Experimental Example 1.

[0031] Figure 7 This is the experimental result display of the adsorption kinetics of the adsorbent in Experimental Example 2.

[0032] Figure 8 This is the experimental result display of the adsorption isotherm of the adsorbent in Experimental Example 3.

[0033] Fig. 9 This is the result of comparing the maximum adsorption capacity of the adsorbent in Experimental Example 3.

[0034] Fig.10 This is the experimental result showing the adsorption selectivity of the adsorbent in Experimental Example 4.

[0035] Fig.11 This is the experimental result display of the cyclic stability of the adsorbent in Experimental Example 5. DETAILED DESCRIPTION

[0036] In order to make the above-mentioned purpose, features and advantages of the present invention more obvious and easy to understand, the specific implementation of the present invention is described in detail below. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention, so the present invention is not limited by the specific implementation disclosed below.

[0037] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art of the present invention. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention. In the embodiments, if specific conditions are not specified, they are carried out according to normal conditions or conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0038] Example 1

[0039] (1) Preparation of thiourea-based POPs organogel based on p-phenylene diisothiocyanate p-phenylene diisothiocyanate (0.30 mmol) and tris(4-aminophenyl)amine (0.20 mmol) were weighed and placed in two 1 mL centrifuge tubes, respectively. 0.2 ml of N,N-dimethylacetamide (DMAc) was added to each of the two centrifuge tubes, and ultrasonic treatment was performed for 15 minutes. The solutions in the two centrifuge tubes were then mixed in one of the centrifuge tubes and shaken for 10 seconds to make them uniformly dispersed. After reacting at room temperature for 15 minutes, a dark brown gel was formed. The gel was left to stand for 6 hours to fully react, and a thiourea-based POPs organogel was obtained.

[0040] (2) Preparation of thiourea-based POPs adsorbent powder based on p-phenylene diisothiocyanate

[0041] Add the organic gel in step (1) into a grinder and grind it at a speed of 5000 / min for 10 minutes to obtain a small particle gel. Add the obtained small particle gel into a 100 ml beaker, add 50 ml of dichloromethane, and mechanically stir at 200 rpm for 6 hours to replace the solvent. Then filter and separate the small particle gel. Then continue the above solvent replacement operation twice. Put the obtained product into a Soxhlet extractor and treat it with methanol at 65 degrees for 12 hours. Then use a vacuum oven at 80 degrees for 12 hours to obtain the target product, named Thiourea-POP-1, which appears as a dark brown powder. It can be used for gold adsorption, and the maximum adsorption capacity is 4745.86 mg / g at 50 degrees Celsius.

[0042] The infrared spectra of the adsorbent Thiourea-POP-1 and the raw material monomer obtained in this example are as follows: Figure 1 In the spectrum of Thiourea-POP-1, p-phenylene diisothiocyanate (PDT) is at 2000 cm- 1 The peaks around 3300 cm- 1 , 3400cm- 1 The double peaks on the left and right disappeared, indicating that the monomers had reacted completely.

[0043] XRD spectrum Figure 2 As shown, it shows that Thiourea-POP-1 is a typical amorphous polymer.

[0044] Solid State 13 C NMR spectrum Figure 3 As shown, the peak at 175 ppm is assigned to the thiourea carbon atom, further confirming the formation of the thiourea bond in the reaction. The other peaks in the range of 150 to 110 ppm correspond to aromatic carbon atoms.

[0045] The stability of the adsorbent obtained in this example under six conditions is as follows: Figure 4 As shown, according to the infrared spectrum, it can be seen that Thiourea-POP-1 has no obvious changes under the six conditions, indicating that it has good stability.

[0046] The N2 adsorption-desorption curve and pore size distribution diagram of the adsorbent obtained in this example at 77.4K are shown in FIG. Figure 5 As shown in the curve, it can be observed that the specific surface area of ​​the material is 40.61m 2 / g, which is consistent with the specific surface area of ​​typical organic gels and the pore structure is mainly mesopores.

[0047] Example 2

[0048] Weigh phenylene diisocyanate (0.30mmol) and 1,3,5-tris(4-aminophenoxy)benzene (TAPOB) (0.20mmol) and place them in two 1mL centrifuge tubes respectively. Add 0.2ml of N,N-dimethylacetamide (DMAc) to each of the two centrifuge tubes and use ultrasonic treatment for 15 minutes. Then mix the solutions in the two centrifuge tubes in any of the centrifuge tubes and shake for 10s to make it evenly dispersed. After reacting at room temperature for 15 minutes, a light brown gel is formed. The gel is left to stand for 6h to fully react to obtain a thiourea-based POPs organogel. Add the organogel to a grinder and grind it at a speed of 5000 / min for 10min to obtain a small particle gel. Add the obtained small particle gel to a 100ml beaker, add 50ml of dichloromethane, and mechanically stir at 200rpm for 6h to replace the solvent. Then filter and separate the small particle gel. Then continue to load the above solvent replacement operation twice. The obtained product was placed in a Soxhlet extractor and treated with methanol at 65 degrees for 12 hours. It was then dried in a vacuum oven at 80 degrees for 12 hours to obtain the target product, named Thiourea-POP-2, which appeared as a gray powder and could be used for gold adsorption. The maximum adsorption capacity was 4366.62 mg / g at 50 degrees Celsius.

[0049] Example 3

[0050] Weigh 4,4′-diisothiocyanato-1,1′-biphenyl (0.30 mmol) and tris(4-aminophenyl)amine (0.20 mmol) and place them in two 1 mL centrifuge tubes, add 0.2 ml of N,N-dimethylacetamide (DMAc) to each of the two centrifuge tubes, and use microwave dissolution for 15 minutes. Then mix the solutions in the two centrifuge tubes in one of the centrifuge tubes and shake for 15 seconds to make it evenly dispersed. After reacting at room temperature for 15 minutes, a brown gel is formed. The gel is left to stand for 6 hours to fully react to obtain a thiourea-based POPs organogel. Add it to a grinder and grind it at a speed of 5000 / min for 10 minutes to obtain a small particle gel. Add the obtained small particle gel to a 100 ml beaker, add 50 ml of dichloromethane, and mechanically stir at 200 rpm for 6 hours to replace the solvent. Then filter and separate the small particle gel. Then repeat the above solvent replacement operation twice. The obtained product is washed with hot acetone at 65 degrees for 12 hours. Then, it was dried in a vacuum oven at 80 degrees for 12 hours to obtain the target product, which appeared as brown powder. It can be used for gold adsorption, and the maximum adsorption capacity at 50 degrees Celsius is 3124.58 mg / g.

[0051] Example 4

[0052] Weigh 1,4-diisothiocyanato-2,5-dimethylbenzene (0.30mmol) and 1,3,5-tris(4-aminophenoxy)benzene (TAPOB) (0.20mmol) and place them in two 1mL centrifuge tubes, add 0.2ml of N,N-dimethylacetamide (DMAc) to each of the two centrifuge tubes, and use ultrasonic treatment for 15 minutes. Then mix the solutions in the two centrifuge tubes in one of the centrifuge tubes and shake for 10s to make it evenly dispersed. After reacting at room temperature for 15 minutes, a light brown gel is formed. The gel is left to stand for 6h to fully react to obtain an organic gel. Add it to a grinder and grind it at a speed of 5000 / min for 10min to obtain a small particle gel. Add the obtained small particle gel to a 100ml beaker, add 50ml of dichloromethane, and mechanically stir at 200rpm for 6h to replace the solvent. Then filter and separate the small particle gel. Then continue to load the above solvent replacement operation twice. The obtained product was washed with hot acetone at 65 degrees for 12 hours. It was then dried in a vacuum oven at 80 degrees for 12 hours to obtain the target product, which appeared as a gray powder and could be used for gold adsorption. The maximum adsorption capacity was 3785.12 mg / g at 50 degrees Celsius.

[0053] Comparative Example 1

[0054] Weigh phenylene diisocyanate (0.30mmol) and 1,3,5-tris(4-aminophenyl)benzene (0.20mmol) and place them in two 1mL centrifuge tubes respectively. Add 0.2ml of N,N-dimethylacetamide (DMAc) to each of the two centrifuge tubes and treat them with microwaves for 15 minutes. Then mix the solutions in the two centrifuge tubes in one of the centrifuge tubes and shake for 10s to make it evenly dispersed. After reacting at room temperature for 15 minutes, a brown gel is formed. The gel is left to stand for 6h to fully react to obtain a thiourea-based POPs organogel. Add the organogel to a grinder and grind it at a speed of 5000 / min for 10min to obtain a small particle gel. Add the obtained small particle gel to a 100ml beaker, add 50ml of dichloromethane, and mechanically stir at 200rpm for 6h to replace the solvent. Then filter and separate the small particle gel. Then continue to reload the above solvent replacement operation twice. The obtained product is placed in a Soxhlet extractor and treated with methanol at 65 degrees for 12h. It was then dried in a vacuum oven at 80 degrees for 12 hours to obtain the target product, named Thiourea-POP-3, which appeared as a brown powder and could be used for gold adsorption. The maximum adsorption capacity was 1104.52 mg / g at 50 degrees Celsius.

[0055] Comparative Example 2

[0056] Weigh phenylene diisocyanate (0.30 mmol) and 2,4,6-tris(4-aminophenyl)-1,3,5-triazine (TAPT) (0.15 mmol) and place them in two 1 mL centrifuge tubes, add 0.2 ml of N,N-dimethylacetamide (DMAc) to each of the two centrifuge tubes, and use ultrasonic treatment for 15 minutes. Then mix the solutions in the two centrifuge tubes in one of the centrifuge tubes and shake for 10 seconds to make it evenly dispersed. After reacting at room temperature for 15 minutes, a golden yellow gel is formed. The gel is left to stand for 6 hours to fully react to obtain a thiourea-based POPs organogel. Add the organogel to a grinder and grind it at a speed of 5000 / min for 10 minutes to obtain a small particle gel. Add the obtained small particle gel to a 100 ml beaker, add 50 ml of dichloromethane, and mechanically stir at 200 rpm for 6 hours to replace the solvent. Then filter and separate the small particle gel. Then continue to load the above solvent replacement operation twice. The obtained product was placed in a Soxhlet extractor and treated with methanol at 65 degrees for 12 hours. It was then dried in a vacuum oven at 80 degrees for 12 hours to obtain the target product, named Thiourea-POP-4, which appeared as a yellow powder and could be used for gold adsorption. The maximum adsorption capacity was 474.62 mg / g at 50 degrees Celsius.

[0057] Comparative Example 3

[0058] Weigh p-phenylene diisothiocyanate (0.30mmol) and tris(4-aminophenyl)amine (58.1mg, 0.20mmol) and place them in two 1mL reaction bottles respectively. The raw materials are dissolved in an Ar atmosphere, mixed together and ultrasonically dispersed for 3 minutes, and frozen and deoxygenated 3 times; heated to 60°C, reacted for 72 hours, cooled to room temperature, and then 10mL of acetone was added, stirred for 1 hour, filtered, washed with dichloromethane, acetone, methanol, and water in turn, repeated 3 times, and unreacted monomers were removed. The solid product was vacuum dried at 80°C for 24 hours to obtain Thiourea-POP-1S, which was dark brown powder and could be used for gold adsorption. The maximum adsorption capacity at 50 degrees Celsius was 1864.21mg / g, which was not only complicated in process, but also relatively poor in performance compared to the material prepared by the method of Example 1.

[0059] Performance Testing

[0060] Experimental Example 1

[0061] Effect of Solution pH on Gold Adsorption Capacity

[0062] Accurately weigh 7 portions of 3 mg of Thiourea-POP-1 prepared in Example 1 and add them to 5 ml sample bottles respectively. Adjust the pH of the Au aqueous solution with an initial concentration of 3253.77 ppm (measured by ICP) to 1, 2, 3, 4, 5, 6, and 7 respectively. Measure 5 ml of each of the seven pH gold solutions and add them to seven sample bottles respectively. Set the temperature of the constant temperature oscillation device to 40 degrees and the speed to 150 r / min, and place the sample bottle in it and oscillate for 24 hours to reach adsorption equilibrium. Collect the supernatant in the sample bottle and filter it, and then detect the concentration of gold ions by inductively coupled plasma optical emission spectrometry (ICP-OES). Calculate the gold adsorption amount Qe (mg / g) at equilibrium using the following equation (1):

[0063] Qe=((Co-Ce)×V) / m(1);

[0064] Where Co is the initial concentration of gold in the solution (mg / L), Ce is the concentration of Au in the solution at adsorption equilibrium (mg / L), V is the volume of the solution (L), and m is the mass of the adsorbent (g).

[0065] Figure 6 This is a display of the adsorption capacity at different pH values ​​of Experimental Example 1. It can be seen that Thiourea-POP-1 does not have significant changes under the conditions of pH = 1-7, and exhibits a removal rate of more than 99% for high-concentration gold solutions.

[0066] Experimental Example 2

[0067] Adsorption kinetics of adsorbents

[0068] Accurately weigh 6 portions of 5 mg of Thiourea-POP-1 prepared in Example 1, add them to 6 50 ml centrifuge tubes respectively, and add 25 ml of 679.50 ppm (determined by ICP) gold solution (pH = 2) to the above 6 centrifuge tubes respectively, set the temperature of the constant temperature oscillation device to 25 degrees, set the speed to 150 r / min, put the sample bottle in it and oscillate for 1, 2, 4, 8, 14, 24.67 hours respectively, collect the supernatant in the sample bottle and filter, and then detect the concentration of gold ions by inductively coupled plasma optical emission spectrometer (ICP-OES). The gold adsorption amount Qt (mg / g) at different times is calculated using the following equation (2):

[0069] Qt=((Co-Ct)×V) / m(2)

[0070] Where Co is the initial concentration of gold in the solution (mg / L), Ct is the concentration of Au in the solution at a certain time (mg / L), V is the volume of the solution (L), and m is the mass of the adsorbent (g).

[0071] Figure 7 This is the adsorption kinetics result of the adsorbent in Experiment 2. It can be seen that Thiourea-POP-1 can reach the maximum adsorption capacity in about 25 hours. It is worth mentioning that the longer time is due to the higher initial concentration selected. At the same time, since the adsorption model and the pseudo-second-order kinetic model have a higher degree of fit, the adsorption of gold by the adsorbent is chemical adsorption.

[0072] Experimental Example 3

[0073] Adsorption isotherms of adsorbents

[0074] Accurately weigh 5 portions of 3 mg of Thiourea-POP-1 prepared in Example 1, add them to 5 20 ml sample bottles respectively, and add 10 ml of 100.59, 192.08, 933.62, 1360.65, 1989.85 ppm (determined by ICP-OES) gold solution (pH = 2) to the above 5 sample bottles respectively, set the temperature of the constant temperature oscillation device to 50 degrees, set the speed to 150r / min, put the sample bottles in it and oscillate for 48 hours to reach equilibrium, collect the supernatant in the sample bottle and filter it, and then detect the concentration of gold ions by inductively coupled plasma emission spectrometer (ICP-OES). The maximum adsorption capacity Qe (mg / g) of gold at different concentrations is calculated using the above-mentioned equation (1). Based on the same operation as above, the maximum adsorption capacity Qe (mg / g) of the four Thiourea-POP obtained in Examples 2 to 5 is calculated respectively.

[0075] Figure 8 The adsorption isotherm experimental results of the adsorbent of Experimental Example 3 are shown. It can be seen that with the increase of the initial concentration of gold ions, the adsorption capacity of Thiourea-POP-1 gradually increases, reaching a maximum of 4745.86 mg / g. The fitting results of the adsorption model are more consistent with the Langmuir model (0.9965). Fig. 9 The results of the comparison of the maximum adsorption capacity of the adsorbents in Experimental Example 3 show that Thiourea-POP-1, which has the strongest electron-pushing structure, exhibits the largest adsorption capacity, and Thiourea-POP-4, which has the strongest electron-pulling structure, exhibits the smallest adsorption capacity. At the same time, the performance of Thiourea-POP-1S obtained by the preparation method reported in Chinese patent CN110078888A is much worse than that of Thiourea-POP-1. This may be due to the incomplete polymerization reaction during the preparation of Thiourea-POP-1S, or the oxidative decomposition of the skeleton during its high-temperature preparation, which deteriorates the performance of the product.

[0076] Experimental Example 4

[0077] Adsorption selectivity of adsorbent

[0078] Accurately weigh 5 mg of Thiourea-POP-1 prepared in Example 1 and add it to a 20 ml sample bottle, and add 10 ml of a mixed ion solution (pH = 2) containing 100 ppm of Ca (II), Co (II), Cu (II), Fe (III), K (I), Mg (II), Mn (II), Na (I), Ni (II), Zn (II), Au (iii) to the sample bottle, set the temperature of the constant temperature oscillator to 25 degrees and the speed to 150 r / min, put the sample bottle in it and oscillate for 48 hours to reach equilibrium, collect the supernatant in the sample bottle and filter it, and then detect the concentration of the mixed example by inductively coupled plasma optical emission spectrometry (ICP-OES). The adsorption capacity Qe (mg / g) of the mixed ions at different concentrations is calculated using the above-mentioned equation (1).

[0079] Fig.10 The adsorption selectivity experimental results of the adsorbent of Experimental Example 4 are shown. It can be seen that the adsorbent exhibits high selectivity, with a gold removal rate close to 100%, while other metals exhibit lower removal rates.

[0080] Experimental Example 5

[0081] Cyclic stability of adsorbents

[0082] Accurately weigh 1 portion of 3 mg of Thiourea-POP-1 prepared in Example 1, add it to a 20 ml sample bottle, and add 10 ml of 200 ppm gold solution (pH = 2) to the sample bottle, set the temperature of the constant temperature oscillation device to 25 degrees, set the speed to 150 r / min, put the sample bottle in it and shake it for 24 hours to reach equilibrium, collect the supernatant in the sample bottle and filter it, and then detect the gold concentration by inductively coupled plasma emission spectrometry (ICP-OES). After the adsorption is completed, filter to obtain the adsorbent, rinse it repeatedly with deionized water, and dry it at 80 ° C for 12 hours. Then put the adsorbent into 10 mL of 1M hydrochloric acid thiourea solution (hydrochloric acid and thiourea concentrations are both 1M) and stir it at room temperature for 10 hours to desorb. Then continue to rinse the desorbed adsorbent repeatedly with deionized water and dry it at 80 ° C for 12 hours to obtain a new adsorbent and repeat the above operation. The adsorption capacity Qe (mg / g) of mixed ions at different concentrations was calculated using the above mentioned equation (1).

[0083] Fig.11This is the result of the cyclic stability test of the adsorbent of Experimental Example 5. It can be seen that the adsorbent can maintain a gold removal rate of more than 85% in the first five cycles, indicating that the adsorbent of the present application has good cyclic performance.

[0084] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which the present invention belongs. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The various technical features of the above-described embodiments can be combined arbitrarily. In order to make the description concise, all possible combinations of the various technical features in the above-described embodiments are not described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

Claims

1. A method for preparing a thiourea-based aromatic porous organic polymer, characterized in that: The method comprises the following steps: dissolving a ternary aromatic amine monomer and a diisothiocyanate monomer respectively, mixing and shaking, and reacting to obtain an organic gel; grinding the organic gel into powder, and then solvent exchanging in dichloromethane, washing, and finally drying to obtain the powder.

2. The preparation method according to claim 1, characterized in that: The diisocyanate monomer is selected from any one or more of p-phenylene diisocyanate, 4,4′-diisothiocyanate-1,1′-biphenyl, bis(4-isothiocyanatophenyl)diazobenzene, 4,4′-diisothiocyanate-1,1′-p-terphenyl, 4,4′-diisothiocyanate-3,3′,5,5′-tetramethyl-1,1′-biphenyl, and 1,4-diisothiocyanate-2,5-dimethylbenzene.

3. The preparation method according to claim 1, characterized in that: The ternary aromatic amine monomer includes any one of tris(4-aminophenyl)amine and 1,3,5-tris(4-aminophenoxy)benzene.

4. The preparation method according to claim 1, characterized in that: The dissolution also includes ultrasound and microwave treatment.

5. The preparation method according to claim 1, characterized in that: The solvent exchange time is 6 to 12 hours, and the number of exchanges is 2 to 4 times.

6. The preparation method according to claim 1, characterized in that: The powdering step is: using a household grinding machine at a rotation speed of 12000 to 22000 rpm.

7. The preparation method according to claim 1, characterized in that: The washing is performed with an organic solvent, wherein the organic solvent is any one or more of methanol, ethanol, propanol, and acetone, the treatment temperature is 50 to 65° C., and the washing times are 6 to 12 times.

8. The preparation method according to claim 1, characterized in that: The drying is specifically: drying at 60°C to 80°C under vacuum for 12 to 24 hours.

9. The thiourea-based aromatic porous organic polymer prepared by the method for preparing the thiourea-based aromatic porous organic polymer according to any one of claims 1 to 8.

10. Use of the thiourea-based aromatic porous organic polymer according to claim 9 as an adsorbent for adsorbing Au in water.

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