A silver ion scavenger, its preparation method and application

Abstract

This invention belongs to the field of precious metal enrichment technology, specifically relating to a silver ion scavenger, its preparation method, and its application. The silver ion scavenger of this invention, based on the traditional mercapto-functionalized silica adsorbent system, partially replaces the traditionally used nano-silica with activated thermally desorbed solids. A screened 3-(1-imidazolyl)propyltriethoxysilane halide is used as a coupling agent to achieve coupling treatment of the activated thermally desorbed solids, enabling it to partially replace nano-silica, effectively saving production costs, and achieving efficient utilization of the thermally desorbed solids.

Description

Technical Field

[0001] This invention belongs to the field of precious metal enrichment technology, specifically relating to a silver ion scavenger, its preparation method, and its application. Background Technology

[0002] Silver is one of the earliest discovered and utilized precious metal elements by humankind. It has the widest distribution, with a content 20 times that of gold and almost equal to the total content of the platinum group metals. Silver is chemically stable, has low reactivity, is expensive, has excellent thermal and electrical conductivity, is not easily corroded by chemicals, and is soft and malleable. These properties mean that silver can be widely used in many fields. In environments with high concentrations of chloride ions, silver ions readily coordinate with chloride ions to form silver complexes. Directly discharging silver-containing wastewater into the environment not only causes serious environmental pollution but also wastes resources. Therefore, recovering silver from "secondary resources" such as precious metal-containing waste materials, wastewater, and waste liquids has significant economic and social importance.

[0003] Furthermore, industries such as non-ferrous metal smelting, electroplating, photocopying, and conductive paste production generate silver-containing solutions or tailings containing trace amounts of silver. Achieving deep separation and recovery of this silver directly impacts the economic benefits of these enterprises. Common recovery methods include precipitation, extraction, and adsorption. However, for silver-containing solutions with concentrations of only a few mg / L, their separation and recovery efficiency is significantly reduced. Adsorption, on the other hand, is highly suitable for recovering silver from such extremely dilute, large-volume silver-containing solutions. Its adsorption properties, such as selectivity and capacity, are crucial to the practicality and economic viability of this technology. Therefore, developing better capture materials is essential. Summary of the Invention

[0004] The first objective of this invention is to provide a silver ion capture agent that partially replaces nano-silica raw materials with low-cost thermal desorption solid slag, which can be used for the efficient capture of silver ions and has the advantages of high application efficiency and low production cost. The second objective of this invention is to provide a method for preparing a silver ion scavenger, wherein the method effectively ensures the scavenging performance of the product by selecting an optimized coupling agent to couple the thermally desorbed solid slag and nano-silica raw material. A third objective of this invention is to provide a method for silver ion enrichment based on the aforementioned silver ion scavenger.

[0005] To address the aforementioned technical problems, this invention provides a method for preparing a silver ion scavenger, comprising the following steps: (1) Nano-silica was activated by adding concentrated hydrochloric acid to obtain activated silica; (2) The hot desorbed solid residue is calcined and activated at high temperature, and then screened to obtain activated hot desorbed solid residue; (3) Under nitrogen protection, the activated silica, activated thermal desorption solid residue, silane functionalized ionic liquid and anhydrous ethanol are mixed and coupled to obtain the coupling product. (4) The coupling product is added to aminothiourea solution and mixed, and glutaraldehyde solution is added to carry out cross-linking reaction to obtain the desired silver ion scavenger.

[0006] Specifically, in the preparation method of the silver ion scavenger, in step (1), the temperature of the activation treatment step is 60-80℃ and the reaction time is 4-5h.

[0007] Specifically, in the preparation method of the silver ion scavenger, in step (2): The thermally desorbed solids include waste lubricating oil thermally desorbed solids; and / or; The temperature of the high-temperature calcination activation step is 800-1000℃; and / or; The calcination time for the high-temperature calcination activation step is 2-3 hours; and / or; The particle size of the activated thermal desorption solid residue is 10-200 μm.

[0008] Specifically, in the preparation method of the silver ion scavenger, in step (3): The mass ratio of activated silica to activated thermal desorption solid residue is 2-3:1; and / or; The amount of the silane-functionalized ionic liquid used accounts for 30-50 wt% of the total amount of the activated silica and the activated thermal desorption solid residue; and / or, The coupling reaction is performed at a temperature of 20-30°C; and / or; The coupling reaction takes 4-6 hours.

[0009] Specifically, in the preparation method of the silver ion scavenger, in step (3), the silane-functionalized ionic liquid includes 3-(1-imidazolyl)propyltriethoxysilane halide.

[0010] Specifically, in the preparation method of the silver ion scavenger, in step (4): The ratio of the amount of aminothiourea used to the total amount of activated silica and activated thermal desorption solids is 3-5:1; and / or, The ratio of the amount of glutaraldehyde used to the total amount of activated silica and activated thermal desorption solid residue is 2-3:1; and / or, The crosslinking reaction is performed at a temperature of 60-80°C; and / or, The cross-linking reaction takes 2-5 hours.

[0011] Specifically, in the preparation method of the silver ion scavenger, step (4) further includes the steps of collecting the crosslinking product and filtering, washing and drying.

[0012] The present invention also discloses a silver ion scavenger prepared by the method described above.

[0013] The present invention also discloses the application of the silver ion scavenger in the field of silver ion enrichment.

[0014] The present invention also discloses a method for silver ion enrichment, including the step of using the silver ion scavenger to capture silver ions.

[0015] The silver ion scavenger of this invention, based on the traditional mercapto-functionalized silica adsorbent system, partially replaces the traditionally used nano-silica with activated thermally desorbed solids. 3-(1-imidazolyl)propyltriethoxysilane halide, selected through screening, serves as a coupling agent, enabling the coupling treatment of the activated thermally desorbed solids. This allows it to partially replace nano-silica, effectively saving production costs and achieving efficient utilization of the thermally desorbed solids.

[0016] The silver ion scavenger described in this invention, by means of a thiol-functionalized scavenger, can achieve efficient and advantageous scavenging of silver ions, and can also achieve efficient scavenging of silver ions in mixed liquids, thus having high application value. Detailed Implementation

[0017] In the following embodiments of the present invention, in order to effectively reduce the cost of traditional nano-silica-based silver ion scavengers and realize the waste utilization of thermally desorbed solids, the present invention provides a method for preparing a silver ion scavenger, comprising the following steps: (1) Nano-silica was activated by adding concentrated hydrochloric acid to obtain activated silica; (2) The hot desorbed solid residue is calcined and activated at high temperature, and then screened to obtain activated hot desorbed solid residue; (3) Under nitrogen protection, the activated silica, activated thermal desorption solid residue, silane functionalized ionic liquid and anhydrous ethanol are mixed and coupled to obtain the coupling product. (4) The coupling product is added to aminothiourea solution and mixed, and glutaraldehyde solution is added to carry out cross-linking reaction to obtain the desired silver ion scavenger.

[0018] In some specific embodiments, in step (1), the temperature of the activation treatment step is 60-80℃ and the reaction time is 4-5h.

[0019] Specifically, in the preparation method of the silver ion scavenger, in step (2): The thermally desorbed solids include waste lubricating oil thermally desorbed solids; and / or; The temperature of the high-temperature calcination activation step is 800-1000℃; and / or; The calcination time for the high-temperature calcination activation step is 2-3 hours; and / or; The particle size of the activated thermal desorption solid residue is 10-200 μm.

[0020] In some specific embodiments, in step (3): The mass ratio of activated silica to activated thermal desorption solid residue is 2-3:1; and / or; The amount of the silane-functionalized ionic liquid used accounts for 30-50 wt% of the total amount of the activated silica and the activated thermal desorption solid residue; and / or, The coupling reaction is performed at a temperature of 20-30°C; and / or; The coupling reaction takes 4-6 hours.

[0021] In some specific embodiments, in step (3), the silane-functionalized ionic liquid includes 3-(1-imidazolyl)propyltriethoxysilane halide.

[0022] In some specific embodiments, in step (4): The ratio of the amount of aminothiourea used to the total amount of activated silica and activated thermal desorption solids is 3-5:1; and / or, The ratio of the amount of glutaraldehyde used to the total amount of activated silica and activated thermal desorption solid residue is 5-10:1; and / or, The crosslinking reaction is performed at a temperature of 60-80°C; and / or, The cross-linking reaction takes 2-5 hours.

[0023] In some specific embodiments, step (4) further includes collecting the crosslinking product and filtering, washing and drying it.

[0024] In the following embodiments of the present invention, all materials used are common materials in the art, and commercially available conventional products are acceptable. There are no significant differences between products from different manufacturers and models.

[0025] In the following embodiments of the present invention, the thermally desorbed solid residue used is waste lubricating oil thermally desorbed solid residue. This solid residue is generated during the refining process of waste lubricating oil using thermal desorption technology. Its composition is complex, containing many inorganic components such as SiO2, Al2O3, and Fe2O3. The following embodiments of the present invention address the treatment and application of thermally desorbed solid residue waste generated by general processes.

[0026] Example 1 The preparation method of the silver ion scavenger described in this embodiment includes the following steps: (1) Take nano-silica (about 500 nm) and add it to concentrated hydrochloric acid. Activate it at 70°C for 5 h. After filtration, washing (with deionized water) and drying (at 60°C), activated silica is obtained. (2) Take the hot desorption solid residue and place it in a muffle furnace. Activate it by high-temperature calcination at 900℃ for 3 hours. After cooling, sieve it to obtain activated hot desorption solid residue with a particle size of 20-30μm. (3) Under nitrogen protection, the above activated silica and activated thermal desorption solid residue were mixed at a mass ratio of 2:1 to obtain a matrix material; 3-(1-imidazolyl)propyltriethoxysilane halide, accounting for 40 wt% of the matrix material, and sufficient anhydrous ethanol were added and mixed, and the coupling reaction was carried out at room temperature for 5 hours. The reaction product was collected, filtered, ethanol was removed under reduced pressure, washed (with deionized water), and dried (at 60°C) to obtain the coupling product. (4) Add the coupling product to 4 times the amount of aminothiourea (prepared in solution, sufficient amount is sufficient) and mix it with 3 times the amount of glutaraldehyde (prepared in 50wt% aqueous solution). Heat to 70°C for crosslinking reaction for 4 hours. Collect the crosslinking product, filter, wash (with deionized water), and dry (at 60°C) to obtain the desired silver ion scavenger.

[0027] Example 2 The preparation method of the silver ion scavenger described in this embodiment includes the following steps: (1) Take nano-silica (about 400 nm) and add it to concentrated hydrochloric acid. Activate it at 60 °C for 5 h. After filtration, washing (with deionized water) and drying (at 60 °C), activated silica is obtained. (2) Take the hot desorption solid residue and place it in a muffle furnace. Activate it by high-temperature calcination at 800℃ for 2 hours. After cooling, sieve it to obtain activated hot desorption solid residue with a particle size of 50-80μm. (3) Under nitrogen protection, the above activated silica and activated thermal desorption solid residue are mixed at a mass ratio of 3:1 to obtain a matrix material; 30 wt% of the matrix material is added to 3-(1-imidazolyl)propyltriethoxysilane halide and sufficient anhydrous ethanol are mixed and the mixture is carried out at room temperature for 4 hours. The reaction product is collected, filtered, ethanol is removed under reduced pressure, washed (with deionized water), and dried (at 60°C) to obtain the coupling product. (4) Add the coupling product to 3 times the amount of aminothiourea (prepared in solution, sufficient amount is sufficient) and mix it with 2 times the amount of glutaraldehyde (prepared in 50wt% aqueous solution). Heat to 60°C for crosslinking reaction for 2 hours. Collect the crosslinking product, filter, wash (with deionized water), and dry (at 60°C) to obtain the desired silver ion scavenger.

[0028] Example 3 The preparation method of the silver ion scavenger described in this embodiment includes the following steps: (1) Take nano-silica (about 600 nm) and add it to concentrated hydrochloric acid. Activate it at 80 °C for 4 h. After filtration, washing (with deionized water) and drying (at 60 °C), activated silica is obtained. (2) Take the hot desorption solid residue and place it in a muffle furnace. Activate it by high-temperature calcination at 1000℃ for 2 hours. After cooling, sieve it to obtain activated hot desorption solid residue with a particle size of about 100μm. (3) Under nitrogen protection, the activated silica and activated thermal desorption solid residue were mixed at a mass ratio of 2:1 to obtain a matrix material; 3-(1-imidazolyl)propyltriethoxysilane halide, accounting for 50 wt% of the matrix material, and sufficient anhydrous ethanol were added and mixed, and the coupling reaction was carried out at room temperature for 6 hours. The reaction product was collected, filtered, ethanol was removed under reduced pressure, washed (with deionized water), and dried (at 60°C) to obtain the coupling product. (4) Add the coupling product to 5 times the amount of aminothiourea (prepared in solution, sufficient amount is sufficient) and mix it with 2 times the amount of glutaraldehyde (prepared in 50wt% aqueous solution). Heat to 80°C for crosslinking reaction for 3 hours. Collect the crosslinking product, filter, wash (with deionized water), and dry (at 60°C) to obtain the desired silver ion scavenger.

[0029] Example 4 The preparation method of the silver ion scavenger described in this embodiment includes the following steps: (1) Take nano-silica (about 500 nm) and add it to concentrated hydrochloric acid. Activate it at 70 °C for 4 h. After filtration, washing (with deionized water) and drying (at 60 °C), activated silica is obtained. (2) The hot desorption solid residue was placed in a muffle furnace and calcined at 900°C for 3 hours. After cooling, it was sieved to obtain activated hot desorption solid residue with a particle size of 200 μm. (3) Under nitrogen protection, the above activated silica and activated thermal desorption solid residue are mixed at a mass ratio of 3:1 to obtain a matrix material; 3-(1-imidazolyl)propyltriethoxysilane halide, accounting for 50wt% of the matrix material, and sufficient anhydrous ethanol are added and mixed, and the coupling reaction is carried out at room temperature for 5 hours. The reaction product is collected, filtered, ethanol is removed under reduced pressure, washed (with deionized water), and dried (at 60°C) to obtain the coupling product. (4) Add the coupling product to aminothiourea (prepared in solution, sufficient amount is sufficient) in a quantity of 4 times the amount of the matrix material and mix it with glutaraldehyde (prepared in 30wt% aqueous solution) in a quantity of 2 times the amount of the matrix material and mix it with the mixture. Heat to 60°C for crosslinking reaction for 2 hours. Collect the crosslinking product and filter, wash (with deionized water) and dry (at 60°C) to obtain the desired silver ion scavenger.

[0030] Example 5 The preparation method of the silver ion scavenger described in this embodiment includes the following steps: (1) Take nano-silica (about 500 nm) and add it to concentrated hydrochloric acid. Activate it at 60°C for 4-5 h. After filtration, washing (with deionized water) and drying (at 60°C), activated silica is obtained. (2) Take the hot desorption solid residue and place it in a muffle furnace. Activate it by high-temperature calcination at 900℃ for 3 hours. After cooling, sieve it to obtain activated hot desorption solid residue with a particle size of 100-120μm. (3) Under nitrogen protection, the activated silica and activated thermal desorption solid residue were mixed at a mass ratio of 2.5:1 to obtain a matrix material; 3-(1-imidazolyl)propyltriethoxysilane halide, accounting for 40 wt% of the matrix material, and sufficient anhydrous ethanol were added and mixed, and the coupling reaction was carried out at room temperature for 4 hours. The reaction product was collected, filtered, ethanol was removed under reduced pressure, washed (with deionized water), and dried (at 60°C) to obtain the coupling product. (4) Add the coupling product to 4 times the amount of the matrix material, aminothiourea (prepared in solution, sufficient amount is fine), and add 2.5 times the amount of the matrix material, glutaraldehyde (prepared in 40wt% aqueous solution), and heat to 70°C for crosslinking reaction for 3 hours. Collect the crosslinking product, filter, wash (with deionized water), and dry (at 60°C) to obtain the desired silver ion scavenger.

[0031] Comparative Example 1 The preparation method of the silver ion scavenger described in this comparative example is the same as that in Example 1, except that in step (3), APTES is used instead of the 3-(1-imidazolyl)propyltriethoxysilane halide.

[0032] Comparative Example 2 The preparation method of the silver ion scavenger described in this comparative example is the same as that in Example 1, except that the activated thermal desorption solid slag is not added, and only activated silica is used as the matrix material.

[0033] Comparative Example 3 The preparation method of the silver ion scavenger described in this comparative example is the same as that in Example 1, except that the activated thermal desorption solid slag is not added, activated silica is used as the matrix material, and APTES is used instead of the 3-(1-imidazolyl)propyltriethoxysilane halide.

[0034] Comparative Example 4 The preparation method of the silver ion scavenger described in this comparative example is the same as that in Example 1, except that the step of activating the thermal desorption solid residue in step (2) is omitted, and the thermal desorption solid residue is directly screened and mixed with activated silica.

[0035] Experimental Example 1. Adsorption of silver ions in pure solution Prepare a 50 mg / L silver ion aqueous solution. Take 5 mL of the silver ion solution and add 10 mg of the silver ion scavenging agent prepared in Example 1 and Comparative Examples 1-4 respectively. Perform adsorption by shaking at room temperature for 24 h.

[0036] After adsorption was completed, the residual concentration of silver ions in the silver ion aqueous solution was measured, and the collection rate of the silver ion scavenger under each scheme was calculated and recorded in Table 1 below.

[0037] The formula for calculating the capture rate is: (initial concentration of silver ions - residual concentration of silver ions) / initial concentration of silver ions × 100%.

[0038] Table 1. Capture Rate Results As can be seen, the silver ion capture agent of the present invention partially replaces the traditionally used nano-silica with activated thermal desorption solid slag. The selected 3-(1-imidazolyl)propyltriethoxysilane halide is used as a coupling agent to achieve coupling treatment of activated thermal desorption solid slag, so that it can partially replace nano-silica, effectively saving production costs and achieving efficient utilization of thermal desorption solid slag.

[0039] 2. Adsorption of silver ions in the mixed solution Preparation of the test mixture: The silver ion concentration was 50 mg / L, and Cu(II) was adjusted to 10000 ppm and Ni(II) to 10000 ppm. Take 5 mL of the mixture solution and add 10 mg of the silver ion scavenging agent prepared in Example 1 and Comparative Examples 1-4 respectively. Shake and adsorb at room temperature for 24 h.

[0040] After adsorption was completed, the residual concentration of silver ions in the mixed solution was measured, and the capture rate of the silver ion scavenger under each scheme was calculated and recorded in Table 2 below.

[0041] The formula for calculating the capture rate is: (initial concentration of silver ions - residual concentration of silver ions) / initial concentration of silver ions × 100%.

[0042] Table 2. Capture Rate Results It is evident that the silver ion scavenger described in this invention not only has a high silver ion capture efficiency, but also retains preferential silver ion capture performance in the mixed liquid.

[0043] The embodiments of the present invention have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A method for preparing a silver ion scavenger, characterized in that, Includes the following steps: (1) Nano-silica was activated by adding concentrated hydrochloric acid to obtain activated silica; (2) The hot desorbed solid residue is calcined and activated at high temperature, and then screened to obtain activated hot desorbed solid residue; (3) Under nitrogen protection, the activated silica, activated thermal desorption solid residue, silane functionalized ionic liquid and anhydrous ethanol are mixed and coupled to obtain the coupling product. (4) The coupling product is added to aminothiourea solution and mixed, and glutaraldehyde solution is added to carry out cross-linking reaction to obtain the desired silver ion scavenger.

2. The method for preparing the silver ion scavenger according to claim 1, characterized in that, In step (1), the temperature of the activation treatment step is 60-80℃ and the reaction time is 4-5h.

3. The method for preparing the silver ion scavenger according to claim 1 or 2, characterized in that, In step (2): The thermally desorbed solids include waste lubricating oil thermally desorbed solids; and / or; The temperature of the high-temperature calcination activation step is 800-1000℃; and / or; The calcination time for the high-temperature calcination activation step is 2-3 hours; and / or; The particle size of the activated thermal desorption solid residue is 10-200 μm.

4. The method for preparing the silver ion scavenger according to any one of claims 1-3, characterized in that, In step (3): The mass ratio of activated silica to activated thermal desorption solid residue is 2-3:1; and / or; The amount of the silane-functionalized ionic liquid used accounts for 30-50 wt% of the total amount of the activated silica and the activated thermal desorption solid residue; and / or, The coupling reaction is performed at a temperature of 20-30°C; and / or; The coupling reaction takes 4-6 hours.

5. The method for preparing the silver ion scavenger according to claim 4, characterized in that, In step (3), the silane-functionalized ionic liquid includes 3-(1-imidazolyl)propyltriethoxysilane halide.

6. The method for preparing the silver ion scavenger according to any one of claims 1-5, characterized in that, In step (4): The ratio of the amount of aminothiourea used to the total amount of activated silica and activated thermal desorption solids is 3-5:1; and / or, The ratio of the amount of glutaraldehyde used to the total amount of activated silica and activated thermal desorption solid residue is 2-3:1; and / or, The crosslinking reaction is performed at a temperature of 60-80°C; and / or, The cross-linking reaction takes 2-5 hours.

7. The method for preparing the silver ion scavenger according to claim 6, characterized in that, Step (4) also includes collecting the cross-linked products and filtering, washing and drying them.

8. A silver ion scavenger prepared by the method according to any one of claims 1-7.

9. The application of the silver ion scavenger according to claim 8 in the field of silver ion enrichment.

10. A method for enriching silver ions, characterized in that, The step includes using the silver ion trapping agent as described in claim 7 to capture silver ions.

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