A liposomal carbon-based aerogel composite material for recycling gold, a preparation method and application thereof

Abstract

The present application relates to gold recovery technical field, specifically to a kind of for recycling gold polythionic acid carbon-based aerogel composite material, preparation method and application, the polythionic acid carbon-based aerogel composite material is obtained by loading polythionic acid on carbon aerogel template;The mass ratio of polythionic acid and carbon aerogel template is 1~4:1~2;The carbon aerogel template is obtained by pyrolysis carbonization after delignification of Basham, and the pyrolysis temperature is 400℃~1000℃.The composite material obtained in the application has the selective coordination reduction capacity of polythionic acid and the high specific surface area, excellent mechanical properties and photothermal effect of carbon skeleton, can efficiently and selectively adsorb and reduce gold ions to gold element from complex gold-containing waste liquid, solve the problems such as poor selectivity and difficult recovery of traditional adsorbent, and has broad prospects in the field of electronic waste recycling.

Description

Technical Field

[0001] This invention relates to the field of gold recovery technology, specifically to a polythioctic acid@carbon-based aerogel composite material for gold recovery, its preparation method, and its application. Background Technology

[0002] Gold (Au), with its exceptional electrical conductivity, catalytic activity, chemical stability, and biocompatibility, plays an indispensable role in high-tech fields such as electronics, catalysis, aerospace, electroplating, nanotechnology, and biomedicine. However, as a non-renewable and rare resource, primary gold ore reserves are dwindling, and mining difficulties are constantly increasing. While traditional cyanide gold extraction processes are widely used, their high toxicity causes severe environmental pollution. Furthermore, the complex extraction process is time-consuming and labor-intensive, making it difficult to effectively meet the growing global demand for gold. Meanwhile, the tens of millions of tons of electronic waste generated globally each year contain gold content far exceeding that of primary ore, earning it the reputation of a highly promising "urban mine." Therefore, developing efficient and environmentally friendly gold recycling technologies, especially for secondary resources such as electronic waste leachate, is not only a strategic measure for achieving sustainable resource utilization but also a core element in promoting the development of a circular economy.

[0003] In response to the aforementioned demand for gold recovery technologies, current strategies for recovering gold from waste liquids mainly encompass chemical precipitation, solvent extraction, electrolysis, and adsorption. Among these, adsorption methods have gained increasing attention from the academic community due to their significant advantages such as ease of operation, low energy consumption, and environmental friendliness. However, traditional adsorption materials, including activated carbon, despite their widespread application, suffer from limited adsorption capacity for gold, poor selectivity, and insufficient mechanical strength. These limitations result in low efficiency and high operating costs in practical applications of large-scale, continuous flow treatment of electronic waste liquids.

[0004] Therefore, there is an urgent need to develop a self-supporting adsorption material with ultra-high adsorption capacity, excellent selectivity and good mechanical properties to promote the upgrading of precious metal recycling technology and ultimately realize its industrial application. Summary of the Invention

[0005] To address the above problems, this invention provides a polythioctic acid@carbon-based aerogel composite material for gold recovery, its preparation method, and its application.

[0006] This invention is achieved through the following technical solution: A polythioctic acid@carbon-based aerogel composite material for gold recovery, wherein the polythioctic acid@carbon-based aerogel composite material is obtained by loading polythioctic acid onto a carbon aerogel template; the mass ratio of polythioctic acid to carbon aerogel template is 1~4:1~2.

[0007] The carbon aerogel template is obtained by pyrolysis and carbonization of balsa wood after lignin removal, with the pyrolysis temperature being 400℃~1000℃.

[0008] The preparation method of the polythioctic acid@carbon-based aerogel composite material specifically includes the following steps: 1) Sodium chlorite, acetic acid and balsa wood blocks are reacted in water to obtain delignified wood; the ratio of sodium chlorite, acetic acid and balsa wood blocks is 1g~3g:1mL~3mL:1g~5g.

[0009] 2) The delignified wood was pyrolyzed and carbonized twice using Joule heating under argon protection to obtain a carbon aerogel template; the temperature of the first pyrolysis and carbonization was 400℃~600℃; the temperature of the second pyrolysis and carbonization was 600℃~1000℃; the time of the first pyrolysis and carbonization and the second pyrolysis and carbonization did not exceed 5s, and the time of the first pyrolysis and carbonization was longer than the time of the second pyrolysis and carbonization.

[0010] 3) Polythioctic acid and carbon aerogel template are reacted in anhydrous ethanol to obtain polythioctic acid@carbon-based aerogel composite material; the mass ratio of polythioctic acid to carbon aerogel template is 1~4:1~2.

[0011] Preferably, the water in step 1) is deionized water.

[0012] Preferably, the reaction temperature in step 1) is 80℃~110℃, and the reaction time is 12h~24h.

[0013] Preferably, the reaction temperature in step 3) is 60℃~100℃, and the reaction time is 12h~24h.

[0014] Preferably, the size of the balsa wood block is 1cm × 1cm × 0.5cm.

[0015] Preferably, the polythioctic acid has a molecular weight of 206.33 Da.

[0016] The application of the carbon-based aerogel in gold recovery.

[0017] Compared with the prior art, the present invention has the following beneficial effects: This invention provides a polythioctic acid (PPA)@carbon-based aerogel composite material for gold recovery. The PPA@carbon-based aerogel composite material is obtained by loading PPA onto a carbon aerogel template; the mass ratio of PPA to the carbon aerogel template is 1-4:1-2; the carbon aerogel template is obtained by pyrolysis and carbonization of balsa wood after delignification, with a pyrolysis temperature of 400℃-1000℃. PPA is rich in functional groups such as thiol groups and possesses unique reactivity. This invention loads it onto a three-dimensional, interconnected, structurally tunable carbon aerogel framework to construct a macroscopic monolithic composite material. Compared with traditional powder materials, this composite material exhibits higher structural stability, ease of recovery, and continuous flow processing potential. The reaction interface of this composite material can create active centers, which not only possess strong coordination adsorption capabilities but also promote efficient reduction reactions. To further shorten reaction time and reduce energy consumption, this invention innovatively utilizes a Joule heating device for in-situ rapid heating of the material, thereby achieving efficient selective adsorption and in-situ reduction of Au(III) in water to Au(O). This technology offers a green and low-carbon solution for recovering gold from complex water systems such as electronic waste leachates, integrating rapid and selective adsorption with the elementalization of precious metals. This technology is of great significance in ensuring water environment safety and promoting a sustainable circular economy for gold resources. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a graph showing the contact angle test results of the polythiooctanoic acid@carbon-based composite aerogel material of the present invention.

[0020] Figure 2 The images show the XRD patterns and polarized light microscope images of the polythioctic acid@carbon-based composite aerogel material of the present invention before and after adsorption of Au(III) solutions of different concentrations; where a is an XRD pattern image and b is a polarized light microscope image.

[0021] Figure 3 The compression performance test of the polythioctic acid / carbon-based composite aerogel of the present invention is shown in the illustration (the illustration is a photograph of the compression process).

[0022] Figure 4 This is an adsorption diagram of Au(III) on the adsorbent materials synthesized from carbon aerogel templates at different temperatures according to the present invention.

[0023] Figure 5The image shows the isothermal adsorption of Au(III) on polythiooctanoic acid@carbon-based composite aerogel materials synthesized using different pyrolytic carbon aerogels as templates in this invention.

[0024] Figure 6 The figure shows the effect of pH on the adsorption of polythiooctanoic acid@carbon-based composite aerogel according to the present invention; where a represents 50 ppm Au(III) and b represents 1000 ppm Au(III).

[0025] Figure 7 The present invention relates to the selective capture of gold in seawater and river water by polythiooctanoic acid@carbon-based composite aerogel; wherein a is seawater and b is river water.

[0026] Figure 8 The diagrams show the kinetic adsorption of the polythioctic acid@carbon-based composite aerogel of the present invention under light and dark conditions; where a is the kinetic adsorption diagram under light and b is the kinetic adsorption diagram under light. Detailed Implementation

[0027] To facilitate understanding of the present invention, a more comprehensive description is provided below, along with preferred embodiments. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the present invention.

[0028] Unless otherwise defined, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this invention and in its specification is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0029] The inventive concept of this invention is as follows: In response to the aforementioned demand for gold recovery technology, current strategies for recovering gold from waste liquids mainly encompass chemical precipitation, solvent extraction, electrolysis, and adsorption. Among these, adsorption methods have gained increasing attention from the academic community due to their significant advantages such as ease of operation, low energy consumption, and environmental friendliness. However, traditional adsorption materials, including activated carbon, despite their widespread application, suffer from limited adsorption capacity for gold, poor selectivity, and insufficient mechanical strength. These limitations result in low efficiency and high operating costs in practical applications of large-scale, continuous flow treatment of electronic waste liquids. Therefore, there is an urgent need to develop a self-supporting adsorption material with ultra-high adsorption capacity, excellent selectivity, and good mechanical properties to promote the upgrading of precious metal recovery technology and ultimately achieve its industrial application.

[0030] Based on this, the present invention proposes a polythioctic acid@carbon-based aerogel composite material for gold recovery.

[0031] Lipoic acid, with its edge-unsaturated sulfur atoms, exhibits strong coordination and reduction capabilities for Au(III) ions, enabling it to efficiently adsorb and reduce them in situ to Au(0), thus significantly improving adsorption capacity and selectivity. This demonstrates great potential for efficient Au(III) recovery in solution. However, pure polylipoic acid faces several limitations in application: the high surface tension of water within the material makes it prone to clogging, leading to aggregation and poor accessibility of adsorption sites, resulting in poor selectivity for gold; the material has low mechanical strength, making it difficult to effectively separate and recover from the treatment system; furthermore, its synthesis process is typically time-consuming and energy-intensive.

[0032] Balsa wood, due to its unique natural tubular structure, was chosen as the ideal matrix for synthesizing high-performance carbon aerogels in this invention. Using a Joule heating device, rapid carbonization of balsa wood can be achieved within seconds, producing carbon aerogels with a specific structure. The Joule heating device, through its temperature pulse function, can efficiently transfer energy to the interior of the wood within seconds, ensuring that while it is fully carbonized, it retains a certain degree of rigidity and mechanical ductility. Using this unique three-dimensional porous carbon aerogel framework with high specific surface area and good mechanical elasticity as a template and carrier, a polythioctic acid / carbon aerogel porous adsorbent material was successfully constructed through in-situ polymerization of thioctic acid monomers. This composite material integrates both selective enrichment and efficient reduction and fixation functions.

[0033] Specifically: 1) Selective enrichment function: The thiol and other functional groups in polythioctic acid can efficiently coordinate with Au(III), giving the material excellent selective adsorption capacity, suitable for complex waste liquid systems containing multiple coexisting ions; 2) The reducing sites of polythioctic acid can reduce the adsorbed Au(III) to Au(0) in situ and fix it inside the material, effectively preventing the secondary release of gold and ensuring recovery efficiency; 3) Synergistic effect: The three-dimensional porous framework of carbon aerogel not only provides abundant adsorption sites and stable mechanical support, but also promotes mass transfer efficiency; its photothermal effect can further enhance adsorption kinetics under light conditions; the synergistic effect of the framework and functional sites significantly improves the overall adsorption performance of the material.

[0034] Ultimately, this composite material enables high-capacity and highly selective recovery of gold resources from complex waste leachate systems, overcoming the inherent limitations of traditional powder adsorbents in terms of structural strength, adsorption selectivity, separation and recovery, and recyclability. Furthermore, its overall synthesis time is short, its efficiency is high, and its cost is low, demonstrating significant advantages in low-carbon and environmentally friendly practices.

[0035] The beneficial effects of the present invention will be illustrated below through specific embodiments.

[0036] Balsa wood blocks (balsa wood is a fast-growing, renewable natural wood. The raw materials are environmentally friendly, inexpensive, and widely available. Its inherent three-dimensional porous structure can serve as an ideal carbon skeleton template.) The balsa wood blocks used in this invention were purchased from Guangzhou Qiqing Wood Trading Co., Ltd., and their dimensions are 1cm × 1cm × 0.5cm (length × width × thickness).

[0037] Polythioctic acid (DL-lipoic acid) was purchased from Aladdin and has a molecular weight of 206.33 Da.

[0038] Example 1 A method for preparing a polythioctic acid@carbon-based aerogel composite material for gold recovery.

[0039] 1) Synthesis of delignified wood In a 250 mL double-necked flask containing 50 mL of deionized water, 1 g of sodium chlorite (NaClO2) was dissolved and stirred. Then, 1 mL of acetic acid (CH3COOH) was added and mixed thoroughly to obtain a mixed solution. 1 g of pre-treated balsa wood blocks (washed and dried) was added to this mixed solution. The pre-treatment temperature was 60 °C for 12 h. Subsequently, the double-necked flask containing the balsa wood block mixed solution was placed in an 80 °C constant temperature oil bath and heated for 12 h. After the reaction was complete, the wood blocks were filtered and recovered, and repeatedly washed with deionized water. The resulting white wood blocks were frozen for 3 h and then freeze-dried to obtain delignified wood.

[0040] 2) Joule thermal rapid pyrolysis of carbon aerogels Delignified wood was placed in a Joule heating apparatus and then protected with argon gas. The Joule heating apparatus was activated, and the wood was heated at 400°C for 3 seconds for pre-carbonization, followed by a second heating at 600°C for 1 second. After cooling to room temperature, a carbon aerogel template was obtained. The carbon aerogel template was repeatedly washed with deionized water. Finally, it was dried in a vacuum drying oven at 60°C for later use.

[0041] 3) Synthesis of polythioctic acid@carbon-based aerogel composites 1 g of DL-lipoic acid was dissolved in 50 mL of anhydrous ethanol, and then 1 g of the carbon aerogel template from step two was added to obtain a mixture. The mixture was then heated to 60 °C in a constant-temperature oil bath for 12 h. After the reaction was complete, the reactor was cooled to room temperature. The polylipoic acid@carbon-based aerogel composite material was recovered by filtration and repeatedly washed with deionized water. It was then dried in a vacuum drying oven at 60 °C.

[0042] Example 2 A method for preparing a polythioctic acid@carbon-based aerogel composite material for gold recovery.

[0043] 1) Synthesis of delignified wood In a 250 mL double-necked flask containing 200 mL of deionized water, 3 g of sodium chlorite (NaClO2) was dissolved and stirred. Then, 3 mL of acetic acid (CH3COOH) was added and mixed thoroughly to obtain a mixed solution. 5 g of balsa wood blocks that had undergone water washing and drying pretreatment were added to this mixed solution. The drying pretreatment was carried out at 60 °C for 12 h. Subsequently, the double-necked flask containing the balsa wood block mixed solution was placed in a constant temperature oil bath at 110 °C and heated for 24 h. After the reaction was completed, the wood blocks were filtered and recovered, and repeatedly washed with deionized water. The resulting white wood blocks were frozen for 3 h and then freeze-dried to obtain delignified wood.

[0044] 2) Joule thermal rapid pyrolysis of carbon aerogels Delignified wood was placed in a Joule heating apparatus and then protected with argon gas. The Joule heating apparatus was activated, and the wood was heated at 600°C for 3 seconds for pre-carbonization, followed by a second heating at 1000°C for 1 second. After cooling to room temperature, a carbon aerogel template was obtained. The carbon aerogel template was repeatedly washed with deionized water. Finally, it was dried in a vacuum drying oven at 60°C for later use.

[0045] 3) Synthesis of polythioctic acid@carbon-based aerogel composites 4g of DL-lipoic acid was dissolved in 100mL of anhydrous ethanol, and then 2g of the carbon aerogel template from step two was added to obtain a mixture. The mixture was then heated to 100℃ in a constant-temperature oil bath for 24h. After the reaction was complete, the reactor was cooled to room temperature. The polylipoic acid@carbon-based aerogel composite material was recovered by filtration and repeatedly washed with deionized water. It was then dried in a vacuum drying oven at 60℃.

[0046] Experimental Example 1 The following experiments were conducted using the polythioctic acid@carbon-based composite aerogel material prepared in Example 1.

[0047] 1. Hydrophilicity test of materials: The surface hydrophilicity of the polythiooctanoic acid@carbon-based composite aerogel material prepared in Example 1 was characterized using the seated drop method. Before testing, the sample was placed flat on the test platform of the contact angle measuring instrument. Deionized water droplets were vertically added to the sample surface using a micro-injection system. The spreading and penetration process of the droplets on the sample surface was dynamically recorded using a high-speed camera system, and images were acquired at three key time points: when the droplets just contacted the material surface (initial state), when the droplets began to penetrate (morphological change), and when the droplets were completely wetted (contact angle approaching 0°). The static contact angle at each time point was calculated using the instrument's built-in analysis software, and the corresponding absorption time was recorded. By comparing the contact angle changes at different time points and the time required for complete wetting, the dynamic hydrophilicity and water absorption rate of the composite aerogel material were comprehensively evaluated.

[0048] The results are as follows Figure 1 As shown, the polythioctic acid@carbon-based composite aerogel material achieved rapid and complete wetting within 0.68 seconds of contact with water, with the contact angle quickly dropping to 0°. This indicates that the composite material possesses excellent superhydrophilic properties, effectively promoting full contact with aqueous solutions. In gold adsorption, this rapid wetting capability can significantly improve the mass transfer efficiency of gold ions, thereby enhancing the overall adsorption rate and adsorption capacity.

[0049] 2. XRD and polarizing microscope images of the material: The results are as follows Figure 2 As shown, Figure 2 The XRD pattern of α (bottom black curve) shows a diffraction peak at 2θ 34.6° in the lipoic acid@carbon-based composite aerogel, corresponding to the crystalline structure of lignocellulose. This indicates that the composite aerogel successfully retains the original wood-based framework structure, which is crucial for maintaining the material's mechanical stability and porosity, thus providing favorable conditions for subsequent adsorption and reduction reactions. The XRD patterns of the composite aerogel after adsorbing different initial concentrations of Au(III) solution (red curve: 50 ppm, blue curve: 200 ppm, green curve: 1000 ppm) are shown. The results indicate that the abundant active groups in the lipoic acid@carbon-based composite aerogel can effectively adsorb and reduce Au(III) ions. Specifically, sharp characteristic diffraction peaks were observed at 2θ at 38.1°, 44.4°, 64.5°, and 77.5°. These peak positions perfectly match the standard PDF card (JCPDS 04-0784) for elemental gold Au(0), strongly demonstrating that the adsorbed Au(III) was successfully reduced to elemental gold nanoparticles by the active groups in the material. Notably, the characteristic peak intensity of Au(0) significantly increased as the initial Au(III) concentration increased from 50 ppm to 1000 ppm, directly indicating that the content of elemental gold generated increased with increasing initial concentration. Furthermore, Figure 2 The polarized light microscope in b shows that a large number of reduced gold particles fill the pores of the material, thus strongly demonstrating the excellent gold reduction activity of the lipoic acid@carbon-based composite aerogel material.

[0050] 3. Material elasticity property testing: Mechanical properties of polythioctic acid (Polythioctic Acid)@carbon-based composite aerogel and unloaded carbon-wood composite were compared using an electronic universal testing machine to evaluate the enhancing effect of Polythioctic Acid loading on the mechanical ductility of the materials. For compression testing, both materials were prepared as smooth-sided specimens, placed in the center of a compression fixture, and loaded at a constant rate until structural failure or load reduction to its peak value. Load-displacement curves were recorded, and the maximum compressive stress and corresponding compressive displacement were calculated. For tensile testing, a constant tensile load was applied until the specimen fractured, and the maximum tensile force and corresponding tensile displacement were obtained. The compressive displacement, elongation at break, and other indicators of the two materials were compared.

[0051] The results are as follows Figure 3 As shown, the compression test of the polythioctic acid@carbon-based composite aerogel material was conducted using an electronic universal testing machine. The results showed that the compressive strength of the composite material reached 6.567 MPa, and the compressive modulus was 0.628 MPa. Compared with the carbon aerogel template in step 2) (compressive strength of 0.288 MPa and compressive modulus of 0.811 MPa), the compressive strength of the polythioctic acid@carbon-based composite aerogel material was significantly improved, while the compressive modulus was relatively reduced. The results indicate that the composite material not only possesses excellent compressibility but also exhibits significant elasticity. This is because the introduction of polythioctic acid forms a denser cross-linked network within the carbon-based aerogel or effectively fills its pores, thereby significantly enhancing the structural integrity, rigidity, and load-bearing capacity of the material, enabling it to effectively resist deformation and maintain structural stability under compression. Furthermore, the introduction of polythioctic acid also helps to construct a high-density functional interface, laying the foundation for the application of this material in engineering fields such as dynamic filtration or packed beds.

[0052] Experimental Example 2 1. This experiment is used to demonstrate the effect of pyrolysis of carbon aerogel templates at different temperatures on their adsorption performance. To investigate the effect of pyrolysis temperature on adsorption performance, delignified wood obtained in step 1) of Example 1 was first pre-carbonized at 600℃, and then completely carbonized at 650℃, 700℃, and 800℃ to prepare a series of adsorbent materials. The differences in equilibrium adsorption capacity of adsorbent materials synthesized from carbon aerogel templates at different pyrolysis temperatures in an Au(III) solution with an initial concentration of 1000 ppm were examined.

[0053] Depend on Figure 4It was found that after carbonization at 500℃, 600℃, 700℃, and 800℃, the equilibrium adsorption capacities of the resulting adsorbents for an initial concentration of 1000 ppm Au(III) solution were 599 mg / g, 746.5 mg / g, 765.5 mg / g, and 736.75 mg / g, respectively. The material carbonized at 700℃ exhibited the highest adsorption capacity, while the adsorption capacity of the material carbonized at 500℃ decreased significantly. Considering factors such as equilibrium adsorption capacity, material rigidity, and energy consumption, 700℃ was ultimately determined as the optimal pyrolysis carbonization temperature.

[0054] 2. This experiment is used to illustrate and compare the isothermal adsorption performance of Au(III) on polythiooctanoic acid@carbon-based composite aerogel materials synthesized using different pyrolytic carbon aerogels as templates.

[0055] The specific implementation steps are as follows: Different polythioctic acid@carbon-based aerogel composites were synthesized using the carbon aerogel templates obtained at different temperatures through the synthesis method described in step 3) of Example 1. 50 mg of each polythioctic acid@carbon-based aerogel composite synthesized using different pyrolytic carbon aerogel templates was added to 50 mL of Au(III) solutions of different concentrations. The mixture was placed in a constant-temperature shaking chamber and shaken at 160 rpm for 24 h at a constant temperature of 30°C to reach adsorption equilibrium. The initial concentration gradient of the Au(III) solution was set to 100 mg / L, 200 mg / L, 400 mg / L, 600 mg / L, 800 mg / L, 1000 mg / L, 1600 mg / L, and 2000 mg / L. After adsorption equilibrium, the solution was filtered, and the supernatant was collected. The concentration of Au(III) before and after adsorption was determined by flame atomic absorption spectrometry.

[0056] Depend on Figure 5 It can be seen that within a certain initial Au(III) concentration range, the adsorption capacity increases with increasing concentration. Among them, the polythioctic acid@carbon-based composite aerogel material synthesized using a carbon aerogel template with a pyrolysis carbonization temperature of 700℃ showed the best removal effect for Au(III), with a maximum equilibrium adsorption capacity of 987 mg / g, demonstrating its excellent adsorption performance. The adsorption data were fitted using Langmuir and Freundlich isotherm adsorption models, and the correlation coefficients were compared. R 2 It can be seen that the adsorption of Au(III) by the adsorbent material conforms to the Langmuir isotherm adsorption model and belongs to monolayer adsorption. This indicates that the adsorption occurs on a uniform adsorption site on the surface of the adsorbent and there is no interaction between adsorbate molecules.

[0057] Experimental Example 3 Effect of pH on Adsorption: First, 50 mg of the polythioctic acid@carbon-based composite aerogel material prepared in Example 1 was added to 50 mL of Au(III) solution. To systematically study the comprehensive effect of solution pH on the material's Au(III) adsorption performance, the initial concentration of Au(III) solution in the first group of experiments was set to 50 ppm, and the pH of the adsorption solution was precisely controlled at 1, 2, 3, 4, 5, 6, and 7 by adding hydrochloric acid or sodium hydroxide solution dropwise. Subsequently, to further explore the effect of pH at higher initial metal ion concentrations, a second group of experiments was conducted, with the initial concentration of Au(III) adjusted to 1000 ppm and the pH values ​​set to 1, 3, and 5, respectively. After all adsorption systems reached equilibrium, each sample was filtered to obtain a clear supernatant. Finally, flame atomic absorption spectrometry was used to accurately determine the change in Au(III) concentration in the supernatant before and after adsorption.

[0058] Depend on Figure 6 As shown in 'a', when the Au(III) adsorbent solution is at a low concentration of 50 ppm, changes in the solution pH have no significant effect on the equilibrium adsorption capacity of the composite material. However, when the concentration of the adsorbent solution is higher, such as... Figure 6 As shown in b, when the Au(III) adsorbent concentration was increased to 1000 ppm, the equilibrium adsorption capacity showed a slight decrease; even so, under the extremely harsh condition of pH 1, the adsorption capacity of the adsorbent material could still reach 727.5 mg / g. This indicates that the polythioctic acid@carbon-based composite aerogel has a wide pH operating range, strong acid resistance under complex acidic conditions, and can still maintain excellent adsorption performance.

[0059] Test Example 4 1. Selectivity of Adsorption Materials: River water and seawater were selected as complex background matrix aqueous solutions. A mixed solution containing Au(III) and other coexisting ions (Cu, Ni, Zn, Cd, Pb, and K) was prepared, with an initial concentration of 100 ppm for all ions. 50 mg of the polythioctic acid@carbon-based composite aerogel material prepared in Example 1 was added to 50 mL of the above Au(III) solution. After adsorption reached equilibrium, the solution was filtered to obtain the supernatant. The concentration of Au(III) before and after adsorption was determined by flame atomic absorption spectrometry.

[0060] Figure 7This study demonstrates the adsorption performance of the composite material for Au(III) after the introduction of typical coexisting heavy metal ions from seawater and river water. The results show that even under competitive interference from multiple coexisting ions, the composite material maintains excellent selective adsorption capacity for the target ion Au(III), and its adsorption efficiency does not show significant attenuation. This fully demonstrates that the composite material has good anti-interference ability in complex aquatic environments and can achieve effective selective enrichment of Au(III) ions, indicating its broad prospects for practical applications.

[0061] 2. Investigating the effect of light absorption on the kinetic adsorption of the adsorbent material: Two sets of comparative experiments with and without light were designed and conducted. First, 50 mg of the polythiooctanoic acid@carbon-based composite aerogel material prepared in Example 1 was introduced into 50 mL of Au(III) solution to construct the adsorption system. The initial concentration of Au(III) in the adsorbent solution was set at 200 ppm. To investigate the adsorption kinetics, samples were taken at several preset time points (1 h, 3 h, 6 h, 9 h, 12 h, 24 h). After sampling, the solution was filtered to obtain the supernatant. Finally, flame atomic absorption spectrometry was used to determine the change in Au(III) concentration before and after adsorption.

[0062] Figure 8 Figure 'a' shows the adsorption kinetics curve of the composite adsorbent under no-light conditions, reaching adsorption equilibrium after 20 hours of adsorption. In contrast, Figure 8 As shown in b, under illumination, the adsorption kinetics of this material are significantly accelerated, reaching adsorption equilibrium in approximately 6 hours. Combined with... Figure 8 a and Figure 8 The comparison results in b show that the photoresponse characteristics of this composite adsorbent material not only significantly improve the photothermal conversion efficiency, but also accelerate the mass transfer process of gold ions in the liquid phase system. This results in the adsorption kinetics time of Au(III) at a concentration of 200 ppm being reduced by approximately 1.5 times under illumination compared to the unilluminated condition. This further demonstrates that the composite adsorbent material possesses significant photoresponse characteristics, which contribute to improving photothermal conversion efficiency and accelerating mass transfer kinetics.

[0063] It should be noted that the polythioctic acid@carbon-based aerogel composite material prepared in Example 2 was used in the tests of Examples 1 to 4, and the test results were the same as those of the polythioctic acid@carbon-based aerogel composite material prepared in Example 1. Therefore, no further details will be provided.

[0064] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are 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.

[0065] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention. Those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the scope of protection of the present invention. Therefore, the scope of protection of this invention should be determined by the appended claims.

Claims

1. A polythioctic acid@carbon-based aerogel composite material for gold recovery, characterized in that, The polythioctic acid@carbon-based aerogel composite material is obtained by loading polythioctic acid onto a carbon aerogel template; the mass ratio of polythioctic acid to carbon aerogel template is 1~4:1~2. The carbon aerogel template is obtained by pyrolysis and carbonization of balsa wood after lignin removal, with the pyrolysis temperature being 400℃~1000℃.

2. The method for preparing the polythioctic acid@carbon-based aerogel composite material according to claim 1, characterized in that, Specifically, the following steps are included: 1) Sodium chlorite, acetic acid and balsa wood blocks are reacted in water to obtain delignified wood; the ratio of sodium chlorite, acetic acid and balsa wood blocks is 1g~3g:1mL~3mL:1g~5g; 2) The delignified wood was pyrolyzed and carbonized twice using Joule heating under argon protection to obtain a carbon aerogel template; the temperature of the first pyrolysis and carbonization was 400℃~600℃; the temperature of the second pyrolysis and carbonization was 600℃~1000℃; the time of the first pyrolysis and carbonization and the second pyrolysis and carbonization did not exceed 5s, and the time of the first pyrolysis and carbonization was longer than the time of the second pyrolysis and carbonization. 3) Polythioctic acid and carbon aerogel template are reacted in anhydrous ethanol to obtain polythioctic acid@carbon-based aerogel composite material; the mass ratio of polythioctic acid to carbon aerogel template is 1~4:1~2.

3. The preparation method according to claim 2, characterized in that, The water in step 1) is deionized water.

4. The preparation method according to claim 2, characterized in that, The reaction temperature in step 1) is 80℃~110℃, and the reaction time is 12h~24h.

5. The preparation method according to claim 2, characterized in that, The reaction temperature in step 3) is 60℃~100℃, and the reaction time is 12h~24h.

6. The preparation method according to claim 2, characterized in that, The dimensions of the balsa wood block are 1cm × 1cm × 0.5cm.

7. The preparation method according to claim 2, characterized in that, The molecular weight of the polythioctic acid is 206.33 Da.

8. The application of the carbon-based aerogel according to claim 1 in gold recovery.

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