CdS-MoS2 (at) AS composite material as well as preparation method and application thereof

Abstract

The invention provides a CdS-MoS2 (at) AS composite material and a preparation method and application thereof, and belongs to the technical field of precious metal recovery, the CdS-MoS2 (at) AS composite material comprises activated alumina balls, and CdS nanoparticles and MoS2 nanoparticles loaded on the activated alumina balls. According to the preparation method, CdS and MoS2 nanoparticles are synchronously loaded on the surfaces of the three-dimensional porous activated aluminum oxide balls, the CdS-MoS2 (at) AS composite material is constructed, the Au < 3 + > selective capturing capacity is enhanced through cooperation of sulfur vacancies and MoS2 edge active sites, and efficient selective recovery of low-concentration gold is achieved. By utilizing surface chemical regulation and control of CdS-MoS2 and a synergistic effect of a three-dimensional material aluminum oxide ball, chemical adsorption is taken as a leading part, dynamic limitation under low concentration is broken through, the selective adsorption effect on gold ions is good, high temperature and high pressure are not needed in a desorption-regeneration process, and the method has the advantages of high recovery efficiency, simple and non-toxic process, low energy consumption, no pollution and the like; and the low-concentration gold recovery process is quicker, and the cost benefit is higher.

Description

Technical Field

[0001] The present invention relates to the technical field of precious metal recovery, and particularly relates to a CdS-MoS2@AS composite material, a preparation method thereof, and an application thereof. Background Art

[0002] In the recovery scenario of low-concentration gold solutions, the traditional thiosulfate method faces multiple technical bottlenecks. The adsorption kinetics of the gold complex ion (Au(S2O3)2 3- ) is sluggish, and the diffusion rate of Au(S2O3)2 3- at the solid-liquid interface is low, resulting in a long adsorption equilibrium time; coexisting metals such as copper (Cu 2+ ) and lead (Pb 2+ ) are prone to form stable complexes with thiosulfate (such as Cu(S2O3)2 3- ), occupying the active sites, and it is difficult to improve the gold purity; ammonium thiosulfate is easily decomposed into sulfides (such as H2S) and sulfates at low concentrations, resulting in poisoning of the adsorption sites; traditional processes need to load precious metals such as Pt and Pd to improve the adsorption activity, but the cost is high and it is easily affected by sulfur poisoning. Although researchers have tried to optimize the performance through material modification (such as mesoporous structure design and surface functionalization), there are still the following unresolved contradictions: non-selective adsorption makes it difficult to break through 90% in gold purity; the material is difficult to recycle and is not easy to recover. Summary of the Invention

[0003] In view of the technical problems existing in the background art, the present application provides a CdS-MoS2@AS composite material, a preparation method thereof, and an application thereof, aiming to solve the technical problems of weak selectivity of the adsorption material for Au and high cost in low-concentration thiosulfate leaching gold solutions.

[0004] In a first aspect, an embodiment of the present application provides a CdS-MoS2@AS composite material, including activated alumina spheres and CdS nanoparticles and MoS2 nanoparticles loaded on the activated alumina spheres.

[0005] In some embodiments, the mass ratio of the activated alumina spheres, CdS nanoparticles, and MoS2 nanoparticles is (5~20):(0.34~0.69):(0.32~0.64).

[0006] In the technical solution of the embodiment of the present application, the present invention develops a novel CdS / MoS2@AS composite material, constructs an efficient recovery system for low-concentration gold solutions based on the synergistic mechanism of chemisorption-ion exchange, and through the dual-functional sites on the material surface (S 2- defects provided by CdS and Lewis acid sites provided by MoS2) for the gold complex ion (Au(S2O3)2 3-) for directional capture and interface charge regulation to achieve selective adsorption and controllable desorption of gold, and the mesoporous confinement effect in the activated alumina spheres and the synergistic effect of the surface hydroxyl groups are used to quickly intercept gold ligand ions.

[0007] In a second aspect, the present invention provides a method for preparing a CdS-MoS2@AS composite material, comprising the following steps: Dispersing cadmium nitrate tetrahydrate, ammonium molybdate tetrahydrate and thiourea in deionized water to obtain a mixed solution; Activated alumina balls were added to the mixed solution, and a CdS-MoS2@AS composite material was obtained after a hydrothermal reaction.

[0008] In some embodiments, the molar ratio of cadmium nitrate tetrahydrate, ammonium molybdate tetrahydrate, and thiourea is (3-9):(2-6):(89-267).

[0009] In some embodiments, the amount of activated alumina balls added is 50-200 g / L.

[0010] In some embodiments, the hydrothermal reaction conditions are: temperature of 160-220° C., and reaction time of 18-24 h.

[0011] In some embodiments, the activated alumina spheres have a diameter of 3 to 6 mm.

[0012] In the third aspect, the embodiment of the present application provides an application of a CdS-MoS2@AS composite material, comprising the following steps: adding the CdS-MoS2@AS composite material to a thiosulfate gold leaching solution, adjusting the pH of the thiosulfate gold leaching solution to 8-12, mixing and stirring, and adsorbing Au(S2O3)2 on the CdS-MoS2@AS composite material. 3- .

[0013] In the technical solution of the embodiment of the present application, CdS-MoS2@AS composite material is used to recover gold at low concentration. The principle is to use CdS to capture Au(S2O3)2 3- Au 3+ The edge sulfur vacancies of MoS2 provide Lewis acid sites, which selectively bind Au. 3+ (Compared to Cu 2+ , Pb 2+ has a stronger affinity) and Au 3+ Reduced to Au, Au is adsorbed on the CdS-MoS2@AS composite material to achieve Au 3+ The mesoporous structure of the alumina ball carrier and the surface hydroxyl group (-OH) form a dual effect of "physical confinement-chemical adsorption". The mesoporous channel selectively intercepts the size of the gold ion, and the hydroxyl group and Au 3+The electrostatic adsorption enhances the material affinity. The reaction equation is as follows: Leaching: Au + 5S2O3 2- + Cu(NH3)4 2+ = Au(S2O3)2 3− + 4NH3+ Cu(S2O3)3 5- ; Recycling: Au(S2O3)2 3− + e - = Au + 2S2O3 2- .

[0014] In some embodiments, Au(S2O3)2 in thiosulfate gold leaching solution 3- The concentration is 0.625~25 mg / L, and the addition amount of CdS-MoS2@AS composite material is 262.8~1033.2 mg / L.

[0015] In some embodiments, CdS-MoS2@AS composites adsorb Au(S2O3)2 3- The treatment time is 10~60min.

[0016] Different from the existing technical solutions, the beneficial effects of this application include: 1. The present invention simultaneously loads CdS and MoS2 nanoparticles on the surface of three-dimensional porous activated alumina balls (AS) to construct CdS-MoS2@AS composite materials, and utilizes sulfur vacancies and MoS2 edge active sites to synergistically enhance Au 3+ The selective capture capability enables efficient and selective recovery of low-concentration gold. Leveraging the surface chemical regulation of CdS-MoS2 and the synergistic effect of the three-dimensional material alumina spheres, chemical adsorption is dominant, breaking through the kinetic limitations at low concentrations. The selective adsorption of gold ions is effective, and the desorption-regeneration process does not require high temperature or high pressure. This process offers advantages such as high recovery efficiency, simple and non-toxic process, low energy consumption, and no pollution, making the low-concentration gold recovery process faster and more cost-effective.

[0017] 2. The present invention uses three-dimensional porous activated alumina spheres as a carrier, providing a high specific surface area, which facilitates the loading of cadmium sulfide and molybdenum disulfide materials and achieves efficient gold recovery. The three-dimensional structure enables material recycling.

[0018] 3. The present invention can realize the adsorption of trace gold and Au(S2O3)2 in a low concentration thiosulfate system. 3- The recovery rate can reach 100%, and it can be completely recovered within 10 minutes, providing an efficient solution for trace gold recovery.

[0019] The above description is only an overview of the technical solution of this application. In order to understand the technical means of this application more clearly, it can be implemented according to the content of the specification. And in order to make the above and other purposes, features and advantages of this application more obvious and understandable, the specific implementation manners of this application are given below. Brief Description of the Drawings

[0020] In order to more clearly illustrate the technical solution of this application, the drawings used in this application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0021] Figure 1 For the recovery rate of Au in the Au(S2O3)2 solution with different materials in Example 3 and Comparative Examples 1-3 of this application 3- of this application.

[0022] Figure 2 For the recovery rate of Au in the Au(S2O3)2 solution in Example 3 of this application 3- changing with time.

[0023] Figure 3 For the recovery rate of Au in the Au(S2O3)2 solution under different pH conditions in Examples 3-7 of this application 3- of this application.

[0024] Figure 4 For the recovery rate of Au at different Au(S2O3)2 concentrations in Example 3 and Examples 8-13 of this application 3- of this application.

[0025] Figure 5 For the recovery rate of Au at different Au(S2O3)2 concentrations changing with time in Example 3 and Examples 8-13 of this application 3- of this application.

[0026] Figure 6 For the recovery rate of Au under different metal cation conditions in Comparative Examples 4-8

[0027] Figure 7 For the recovery rate of Au under different anion conditions in Comparative Examples 9-13 Detailed Description of the Preferred Embodiments

[0028] The embodiments of the technical solution of this application will be described in detail below with reference to the drawings. The following embodiments are only used to illustrate the technical solution of this application more clearly, so they are only examples and cannot be used to limit the protection scope of this application.

[0029] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field to which this application belongs; the terms used herein are for the purpose of describing specific embodiments only and are not intended to limit this application; the terms "comprising" and "having" and any variations thereof in the specification and claims of this application and the above drawings are intended to cover non-exclusive inclusion.

[0030] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in connection with the embodiments can be included in at least one embodiment of this application. The phrase appears in various places in the specification and does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art will explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments.

[0031] Some specific embodiments are listed below. It should be noted that the embodiments described below are exemplary and are only used to explain this application and should not be construed as a limitation of this application. For those embodiments where specific technologies or conditions are not indicated, they shall be carried out according to the technologies or conditions described in the literature in this field or according to the product specifications. For reagents or instruments whose manufacturers are not indicated, they are all conventional products that can be obtained through commercial purchase.

[0032] I. Preparation Method Example 1 A preparation method of CdS-MoS2@AS composite material, comprising the following steps: Dissolve 3 mmol of cadmium nitrate tetrahydrate (Cd(NO3)2·4H2O) and 9 mmol of thiourea in a certain amount of deionized water, stir for 30 min, and then add 2 mmol of ammonium molybdate tetrahydrate ((NH4)6Mo7O 24 ·4H2O), 80 mmol of thiourea (CH4N2S), stir for 30 min to dissolve to form a homogeneous solution, then add 10 g of activated alumina balls, and let stand for 3 h; then transfer to a stainless steel autoclave with a polytetrafluoroethylene inner liner, react at a constant temperature of 180 °C for 24 h, after the reaction is completed, naturally cool to room temperature; wash the obtained product with deionized water, and put the washed product into a vacuum drying oven and dry at -60 °C for 24 h to obtain the CdS-MoS2@AS composite material.

[0033] Example 2 A preparation method of CdS-MoS2@AS composite material, comprising the following steps: Dissolve 9 mmol of cadmium nitrate tetrahydrate (Cd(NO3)2·4H2O) and 27 mmol of thiourea in a certain amount of deionized water, stir for 30 min, and then add 6 mmol of ammonium molybdate tetrahydrate ((NH4)6Mo7O 24·4H2O), 240 mmol of thiourea (CH4N2S). After stirring for 30 min to dissolve and make it a homogeneous solution, 10 g of activated alumina balls were added and left standing for 3 h. Then it was transferred to a stainless-steel autoclave with a PTFE liner and reacted at a constant temperature of 180 °C for 24 h. After the reaction, it was naturally cooled to room temperature. The obtained product was washed clean with deionized water, and the washed product was placed in a vacuum drying oven and dried at -60 °C for 24 h to obtain the CdS-MoS2@AS composite material.

[0034] Example 3 Prepare 100 mL of 25 mg / L Au(S2O3)2 3- : Dissolve 0.0213 g of (NH4)2S2O3 in 80 mL of deionized water, gradually add 20 ml of HAuCl4, and then adjust the pH to 8 with 6 mol / L NaOH.

[0035] In the prepared Au(S2O3)2 3- solution, add 6 CdS-MoS2@AS small balls (about 46 mg). After adding, magnetic stirring was carried out at a speed of 250 rpm for 60 min to carry out the adsorption of Au(S2O3)2 3- test.

[0036] Example 4 The difference between Example 4 and Example 3 is that the pH was adjusted to 9 with 6 mol / L NaOH, and other steps were the same as those in Example 3.

[0037] Example 5 The difference between Example 5 and Example 3 is that the pH was adjusted to 10 with 6 mol / L NaOH, and other steps were the same as those in Example 3.

[0038] Example 6 The difference between Example 6 and Example 3 is that the pH was adjusted to 11 with 6 mol / L NaOH, and other steps were the same as those in Example 3.

[0039] Example 7 The difference between Example 7 and Example 3 is that the pH was adjusted to 12 with 6 mol / L NaOH, and other steps were the same as those in Example 3.

[0040] Example 8 The difference between Example 8 and Example 3 is that the concentration of the prepared Au(S2O3)2 3- solution was 0.625 mg / L, and other steps were the same as those in Example 3.

[0041] Example 9 Example 9 is different from Example 3 in that the concentration of the Au(S2O3)2 solution configured is 1.25 mg / L, and the other steps are the same as those in Example 3. 3- The concentration of the solution is 1.25 mg / L, and the other steps are the same as those in Example 3.

[0042] Example 10 Example 10 is different from Example 3 in that the concentration of the Au(S2O3)2 solution configured is 3.75 mg / L, and the other steps are the same as those in Example 3. 3- The concentration of the solution is 3.75 mg / L, and the other steps are the same as those in Example 3.

[0043] Example 11 Example 11 is different from Example 3 in that the concentration of the Au(S2O3)2 solution configured is 6.25 mg / L, and the other steps are the same as those in Example 3. 3- The concentration of the solution is 6.25 mg / L, and the other steps are the same as those in Example 3.

[0044] Example 12 Example 12 is different from Example 3 in that the concentration of the Au(S2O3)2 solution configured is 8.75 mg / L, and the other steps are the same as those in Example 3. 3- The concentration of the solution is 8.75 mg / L, and the other steps are the same as those in Example 3.

[0045] Example 13 Example 13 is different from Example 3 in that the concentration of the Au(S2O3)2 solution configured is 12.5 mg / L, and the other steps are the same as those in Example 3. 3- The concentration of the solution is 12.5 mg / L, and the other steps are the same as those in Example 3.

[0046] Comparative Example 1 Comparative Example 1 is different from Example 1 in that the CdS-MoS2@AS microspheres are replaced with AS microspheres, and the other steps are the same as those in Example 3.

[0047] Comparative Example 2 Comparative Example 2 is different from Example 1 in that the CdS-MoS2@AS microspheres are replaced with CdS@AS microspheres, and the other steps are the same as those in Example 3.

[0048] Comparative Example 3 Comparative Example 3 is different from Example 1 in that the CdS-MoS2@AS microspheres are replaced with MoS2@AS microspheres, and the other steps are the same as those in Example 3.

[0049] Comparative Example 4 Comparative Example 4 is different from Example 1 in that 0.05 mmol of Pb is added to the Au(S2O3)2 solution, and the other steps are the same as those in Example 3. 3- The concentration of the solution is 1.25 mg / L, and the other steps are the same as those in Example 3. 2+ The concentration of the solution is 1.25 mg / L, and the other steps are the same as those in Example 3.

[0050] Comparative Example 5 The difference between Comparative Example 5 and Example 1 is that 0.05 mmol of Ca is added to the Au(S2O3)2 3- solution, and the other steps are the same as those in Example 3. 2+

[0051] Comparative Example 6 The difference between Comparative Example 6 and Example 1 is that 0.05 mmol of K is added to the Au(S2O3)2 3- solution, and the other steps are the same as those in Example 3. 2+

[0052] Comparative Example 7 The difference between Comparative Example 7 and Example 1 is that 0.05 mmol of Zn is added to the Au(S2O3)2 3- solution, and the other steps are the same as those in Example 3. 2+

[0053] Comparative Example 8 The difference between Comparative Example 8 and Example 1 is that 0.05 mmol of Cu is added to the Au(S2O3)2 3- solution, and the other steps are the same as those in Example 3. 2+

[0054] Comparative Example 9 The difference between Comparative Example 9 and Example 1 is that 0.05 mmol of Cl is added to the Au(S2O3)2 3- solution, and the other steps are the same as those in Example 3. -

[0055] Comparative Example 10 The difference between Comparative Example 10 and Example 1 is that 0.05 mmol of F is added to the Au(S2O3)2 3- solution, and the other steps are the same as those in Example 3. -

[0056] Comparative Example 11 The difference between Comparative Example 11 and Example 1 is that 0.05 mmol of CO3 is added to the Au(S2O3)2 3- solution, and the other steps are the same as those in Example 3. 2-

[0057] Comparative Example 12 The difference between Comparative Example 12 and Example 1 is that 0.05 mmol of SO4 is added to the Au(S2O3)2 3- solution, and the other steps are the same as those in Example 3. 2-

[0058] ​​​​​​​​Comparative Example 13 The difference between Comparative Example 13 and Example 1 is that 0.05 mmol of PO4 3- was added to the Au(S2O3)2 2- solution, and the other steps were the same as those in Example 3.

[0059] II. Testing Method 1. Au recovery rate detection method: Take 2 mL of the reaction suspension in the adsorption experiment of Au(S2O3)2 3- as a sample, filter it with a 0.22 μm filter membrane, and calculate the recovery rate by measuring the residual concentration of Au through an atomic absorption spectrophotometer; Recovery rate = [(gold content in the solution before the reaction - gold content in the solution after the reaction) / gold content in the solution before the reaction]×100%.

[0060] III. Analysis of Test Results of Each Example and Comparative Example (1) The Au recovery rate of the reaction suspension after the completion of the Au(S2O3)2 3- adsorption test in Example 3 and Comparative Examples 1 - 3 was detected, and the test results are shown in Figure 1 . As Figure 1 shown, different materials have different recovery rates for Au. Among them, the CdS - MoS2@AS composite material has the best recovery effect, which is 96.47%.

[0061] (2) During the Au(S2O3)2 3- adsorption test in Example 3, samples were taken every 10 minutes for Au recovery rate detection, and the test results are shown in Figure 2 . As Figure 2 shown, for the 25 mg / L Au(S2O3)2 3- solution, the recovery effect is the best after 60 minutes of adsorption reaction, approaching 100%.

[0062] (3) The Au recovery rate of the reaction suspension after the completion of the Au(S2O3)2 3- adsorption test in Examples 3 - 7 was detected, and the test results are shown in Figure 3 . As Figure 3 shown, under alkaline conditions, the CdS - MoS2@AS composite material has universality for Au recovery, all above 93%.

[0063] (4) The Au recovery rate of the reaction suspension after the completion of the Au(S2O3)2 3- adsorption test in Example 3 and Examples 8 - 13 was detected, and the test results are shown in Figure 4 . As Figure 4 shown, for different Au(S2O3)2 3-The concentration has a certain influence on the recovery rate of Au. Except for the poor recovery efficiency at 0.625 mg / L due to too low concentration, the recovery rates are all 100% at 3.75 mg / L, 6.25 mg / L, and 8.75 mg / L, 98.21% at 12.5 mg / L, and 96.47% at 25 mg / L.

[0064] For Au(S2O3)2 in Example 3 and Examples 8 - 13 3- During the adsorption test, samples were taken every 10 minutes for the detection of Au recovery rate. The detection results are shown in Figure 5 . As Figure 5 shown, except for the poor recovery efficiency at 0.5 mg / L due to too low concentration, most of the Au in the Au(S2O3)2 3- solution at 3.75 mg / L, 6.25 mg / L, and 8.75 mg / L was recovered after 10 minutes of reaction, and the Au in the Au(S2O3)2 3- solution at 12.5 mg / L and 25 mg / L was recovered after 60 minutes of reaction.

[0065] (5) For Au(S2O3)2 in Comparative Examples 4 - 8 3- The reaction suspension after the adsorption test was detected for Au recovery rate. The detection results are shown in Figure 6 . As Figure 6 shown, except for the certain influence of Pb 2+ on the recovery rate, the other metal cations have no influence on the recovery rate, and the recovery rates are all 100%.

[0066] (6) For Au(S2O3)2 in Comparative Examples 9 - 13 3- The reaction suspension after the adsorption test was detected for Au recovery rate. The detection results are shown in Figure 7 . As Figure 7 shown, the anions have no influence on the Au recovery rate, and the recovery rates are all 100%.

[0067] It should be noted that this application is not limited to the above embodiments. The above embodiments are only examples, and the embodiments with the same structure in essence as the technical idea and the same function and effect within the technical solution scope of this application are all included in the technical scope of this application. In addition, within the scope not departing from the main idea of this application, various deformations that can be thought of by those skilled in the art are applied to the embodiments, and other ways constructed by combining some constituent elements of the embodiments are also included in the scope of this application.

Claims

1. A CdS-MoS2@AS composite material, characterized in that, It includes activated alumina balls and CdS nanoparticles and MoS2 nanoparticles supported on the activated alumina balls.

2. The CdS-MoS2@AS composite material according to claim 1, wherein The mass ratio of the activated alumina balls, CdS nanoparticles and MoS2 nanoparticles is (5~20):(0.34~0.69):(0.32~0.64).

3. A method for preparing the CdS-MoS2@AS composite material as described in claim 1 or 2, characterized in that, It includes the following steps: Disperse cadmium nitrate tetrahydrate, ammonium molybdate tetrahydrate and thiourea in deionized water to obtain a mixed solution; Add activated alumina balls to the mixed solution, and obtain a CdS-MoS2@AS composite material after hydrothermal reaction.

4. The preparation method of the CdS-MoS2@AS composite material according to claim 3, characterized in that, The molar ratio of cadmium nitrate tetrahydrate, ammonium molybdate tetrahydrate and thiourea is (3~9):(2~6):(89~267).

5. The preparation method of the CdS-MoS2@AS composite material according to claim 3, wherein, The addition amount of the activated alumina balls is 50~200 g / L.

6. The preparation method of the CdS-MoS2@AS composite material according to claim 3, characterized in that, The hydrothermal reaction conditions are: the temperature is 160~220°C, and the reaction time is 18~24 h.

7. The preparation method of the CdS-MoS2@AS composite material according to claim 3, characterized in that, The diameter of the activated alumina balls is 3~6 mm.

8. Use of the CdS-MoS2@AS composite material as described in claim 1 or 2, characterized in that, It includes the following steps: adding the CdS-MoS2@AS composite material into a thiosulfate gold leaching solution, adjusting the pH of the thiosulfate gold leaching solution to 8-12, mixing and stirring, and performing the adsorption of Au(S2O3)2 by the CdS-MoS2@AS composite material 3- .

9. Use of the CdS-MoS2@AS composite material according to claim 8, characterized in that, Au(S2O3)2 in the thiosulfate gold leaching solution 3- The concentration is 0.625 - 25 mg / L, and the addition amount of the CdS-MoS2@AS composite material is 262.8 - 1033.2 mg / L.

10. Use of the CdS-MoS2@AS composite material according to claim 8, characterized in that, The adsorption time of the CdS-MoS2@AS composite material for Au(S2O3)2 3- is 10 to 60 minutes.

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