Adsorbent for hydrophobic surface induced in-situ adsorption and reduction of noble metal ions, preparation method of adsorbent, method for adsorbing, reducing and inducing recovery of noble metal ions and application of adsorbent

Abstract

The invention discloses an adsorbent for hydrophobic surface induced in-situ adsorption and reduction of precious metal ions, a preparation method of the adsorbent, a method for adsorbing, reducing and inducing recovery of the precious metal ions and application, and belongs to the technical field of precious metal recovery. The adsorbent comprises an adsorbent matrix and a hydrophobic layer covering the surface of the matrix; the hydrophobic layer is obtained by carbonizing a prepolymer. The noble metal ions are converted into a metal layer to cover the surface of the adsorbent due to an adsorption reduction phenomenon on the surface hydrophobic layer of the adsorbent; and the metal and the adsorbent can be separated through ultrasound, and the adsorbent can be used as the adsorbent again after being subjected to ultrasound separation. The adsorbent can quickly and efficiently adsorb and reduce precious metal ions in solutions mixed with different metals, the precious metal ion recovery method is simple, efficient, green and environmentally friendly, the adsorbent can be repeatedly used, the precious metal recovery procedure is simplified, meanwhile, the use of an eluent is remarkably reduced, and the adsorbent has application prospects in the field of precious metal recovery.

Description

Technical Field

[0001] The present application relates to an adsorbent for inducing in-situ adsorption and reduction of noble metal ions on a hydrophobic surface, a preparation method thereof, a method for adsorbing, reducing and inducing the recovery of noble metal ions, and an application thereof, belonging to the technical field of noble metal recovery. Background Art

[0002] With the increasing global resource tension and the improvement of environmental protection requirements, the recycling of noble metals has become increasingly important. Noble metal resources are limited and widely used. Therefore, recycling noble metals not only reduces the dependence on primary resources but also can reduce environmental pollution and production costs. In current metal recycling technologies, the extraction methods of noble metals mainly include oxidation-reduction methods, ion exchange methods, adsorption methods, and biological enrichment methods, etc. Among them, the adsorption method is particularly suitable for the recovery of noble metals due to its low cost, high selectivity, and easy operation.

[0003] In the prior art, the traditional adsorption method uses the strong interaction between metal ions and the adsorbent to enrich metal ions, and then the target metal is obtained by elution or calcination, or the metal ions are promoted to be transformed into metals by adding reducing aids. For example, as disclosed in CN106041116A, silver nanoparticles dispersed in the solution are obtained by mixing activated sludge and alkaline silver ammonia solution and in-situ adsorbing and reducing them by activated sludge microorganisms. CN 113058571B also discloses a bifunctional polymer adsorbent, in which dopamine and tetrafluoroterephthalonitrile are polymerized to prepare a polymer adsorbent rich in a large number of indole structures and amide functional groups on the surface, thereby improving the specific adsorption of gold ions. In the process of adsorbing noble metals by the above adsorbents, the noble metals exist in the form of metal nanoparticles, resulting in easy loss during the separation process. CN 102407340B discloses a method for adsorbing anions by using ultrafine carbon powder as a template and then in-situ reducing silver ions to form a silver shell layer attached to the surface of the ultrafine carbon powder by using a reducing agent. This method relies on the reduction of sodium borohydride, increasing the cost and operation complexity. Therefore, it is necessary to develop a noble metal recycling technology that does not require an external reducing agent, is green and environmentally friendly, so as to improve economic efficiency and reduce environmental pollution. Summary of the Invention

[0004] In order to solve the foregoing technical problems, the present application provides a technical solution of an adsorbent for inducing in-situ adsorption and reduction of noble metal ions on a hydrophobic surface. By using the strong selective adsorption of the adsorbent for noble metal ions, the noble metal ions are in-situ reduced on the surface of the adsorbent to form an adsorbent layer coated with noble metals. The remarkable feature of this method is that no reducing agent is required during the adsorption and reduction process. After the reaction is completed, the noble metal shell layer is separated from the adsorbent particles by ultrasonic technology, and the adsorbent can be reused. This method is also applicable to complex systems containing multiple metal ions, can effectively and selectively recover noble metal ions, improve the recovery efficiency, reduce the recovery cost, and reduce the use of eluents.

[0005] The present application adopts the following technical solutions: According to the first aspect of the present application, there is provided an adsorbent for hydrophobic surface-induced in-situ adsorption and reduction of precious metal ions, characterized in that the adsorbent comprises an adsorbent matrix and a hydrophobic layer covering the surface of the matrix; The hydrophobic layer is obtained by carbonizing a prepolymer.

[0006] The adsorbent matrix is at least one of activated carbon, titanium oxide, and alumina.

[0007] The particle size of the adsorbent is 50 μm to 5 mm.

[0008] According to the second aspect of the present application, there is provided a preparation method of the above-mentioned adsorbent for hydrophobic surface-induced in-situ adsorption and reduction of precious metal ions, characterized in that it comprises the following steps: S1. Heating and reacting a mixture containing an emulsifier, a polymer monomer, an initiator, and water to obtain a prepolymer; S2. Mixing the prepolymer with the adsorbent matrix and then performing high-temperature carbonization to obtain the adsorbent for hydrophobic surface-induced in-situ adsorption and reduction of precious metal ions.

[0009] Optionally, the emulsifier is selected from at least one of polyvinyl alcohol, OP-10, Tween, Span, sodium gluconate, and sodium alginate.

[0010] Optionally, the polymer monomer is selected from at least one of styrene and divinylbenzene.

[0011] Optionally, the initiator is selected from at least one of benzoyl peroxide, azobisisobutyronitrile, and lauryl peroxide.

[0012] The adsorbent matrix is at least one of activated carbon, titanium oxide, and alumina.

[0013] Optionally, the weight ratio of the initiator to the polymer monomer is 0.01 to 0.1:1.

[0014] Optionally, the weight ratio of water to the polymer monomer is 3 to 15:1.

[0015] Optionally, the concentration of the emulsifier in the mixture is 0.1 to 3 wt.%.

[0016] Optionally, the weight ratio of the prepolymer to the adsorbent matrix is 0.3 to 1:1.

[0017] Optionally, the mixture further comprises a pore-forming agent.

[0018] Optionally, the pore-forming agent is selected from at least one of alkanes having 6 to 15 carbon atoms.

[0019] Optionally, the weight ratio of the pore former to the polymer monomer is 0 to 2.57:1, and the lower limit of this weight ratio is not 0.

[0020] Optionally, the conditions for the heating reaction include: the reaction temperature is 70 to 85 °C, and the reaction time is 0.5 to 6 h.

[0021] Optionally, the weight ratio of the prepolymer to the adsorbent matrix is 0.3 to 1:1.

[0022] Optionally, the conditions for the high-temperature carbonization include: the carbonization temperature is 700 to 1000 °C, and the heat preservation time is 0.5 to 4 h.

[0023] According to the third aspect of the present application, a method for recovering noble metal ions by adsorption reduction induction is provided, which is characterized by including the following steps: Adsorption reduction: contacting a liquid containing noble metal ions with an adsorbent, and the heavy metal ions are directly adsorbed and reduced to noble metal particles and covered on the surface of the adsorbent; Recovery: subjecting the adsorbent after the adsorption reduction to ultrasonic treatment to separate and recover the adsorbent and the noble metal particles; The adsorbent is selected from at least one of the adsorbents for inducing in-situ adsorption and reduction of noble metal ions on a hydrophobic surface described in claim 1 and the adsorbents for inducing in-situ adsorption and reduction of noble metal ions on a hydrophobic surface obtained by the preparation method according to any one of claims 2 to 7.

[0024] In the method for recovering noble metal ions by adsorption reduction induction of the present application, no additional reducing agent is added. When a solution containing noble metal ions is contacted with the adsorbent, the noble metal ions undergo an adsorption reduction phenomenon on the hydrophobic layer of the adsorbent surface and are transformed into a metal layer covering the surface of the adsorbent; then the metal and the adsorbent can be separated by ultrasonic treatment. After the adsorbent is separated by ultrasonic treatment, it can be reused as an adsorbent.

[0025] Optionally, the noble metal is selected from at least one of gold, silver, platinum, and palladium; The concentration of noble metal ions in the liquid containing noble metal ions is 1 to 10000 ppm, and the pH value of the liquid is 2 to 7.

[0026] Optionally, the temperature during the adsorption reduction process is 10 to 80 °C.

[0027] The adsorbent prepared in this application for in-situ adsorption and reduction of noble metal ions on a hydrophobic surface is a hydrophobic adsorbent. After contacting the adsorbent with a solution containing noble metals, without the addition of an external reducing agent, due to the strong adsorption of the adsorbent to the noble metals, it induces the rapid aggregation of noble metal ions in the liquid phase on the surface of the adsorbent, generating a high-concentration surface region. At the same time, the hydrophobic surface hinders the entry of water into the bulk of the adsorbent, thereby inducing an in-situ reduction phenomenon on the surface to obtain an adsorbent wrapped with noble metals. After the adsorption and reduction are completed, the noble metal layer and the adsorbent can be separated by ultrasound, and the adsorbent can be reused. The present invention can rapidly and efficiently adsorb and reduce noble metal ions in a solution mixed with different metals. This method for recovering noble metal ions is simple, efficient, environmentally friendly, and the adsorbent can be reused. While simplifying the noble metal recovery process, it significantly reduces the use of eluents and has application prospects in the field of noble metal recovery.

[0028] According to the fourth aspect of this application, there is provided an application of the above-mentioned adsorbent for in-situ adsorption and reduction of noble metal ions on a hydrophobic surface, the adsorbent for in-situ adsorption and reduction of noble metal ions obtained according to the above preparation method, and the above-mentioned method for recovering noble metal ions induced by adsorption and reduction in noble metal recovery.

[0029] The beneficial effects of this application include: The adsorbent for in-situ adsorption and reduction of noble metal ions on a hydrophobic surface provided by this application, through a simple and easily synthesized hydrophobic coating applied to the surface of the adsorbent, enables the adsorbent to utilize the high-selectivity adsorption of noble metal ions during application to promote their in-situ reduction on the surface of the adsorbent, forming an adsorbent layer coated with noble metals. The significant advantage of this method is that no reducing agent needs to be added during the adsorption and reduction process, and after the reaction is completed, the noble metal shell layer and the adsorbent particles can be separated by ultrasonic technology to achieve the reuse of the adsorbent. Based on this adsorbent, a green, efficient, and external-reducing-agent-free method for recovering noble metal ions can be realized. Description of the Drawings

[0030] Figure 1 SEM electron microscope photographs and elemental energy spectrum photographs of the carbon spheres after adsorption in Example 1; Figure 2 Optical microscope photographs of the carbon spheres after adsorption of palladium ions in Example 1 and intensity diagrams of each element corresponding to the red frame; Figure 3 XRD patterns of the adsorbent and the adsorbent after adsorption and reduction of palladium, gold, and silver ions in Examples 1 to 3; Figure 4 Adsorbent and palladium recovery rate under repeated use in Example 14; Detailed Description of the Invention

[0031] The present application will be described in detail below in conjunction with embodiments, but the present application is not limited to these embodiments.

[0032] Unless otherwise specified, the raw materials in the embodiments of the present application are all purchased through commercial channels.

[0033] Unless otherwise specified, the test methods are all conventional methods, and the instrument settings are all the settings recommended by the manufacturer.

[0034] The method for determining the content of residual precious metal ions in the solution in the examples and test examples is determined by ICP-OES of the PerkinElmer Avio550 Max model. The residual amount of metal ions in the solution is calculated according to the formula: Residual amount of metal ions in solution (%) = × 100%; The metal recovery rate is determined by the Mettler electronic balance XPR226DR / AC and calculated according to the formula: Metal recovery rate (%) = × 100%; The contact angle is measured using the Krüss DSA100 from Germany; SEM & EDS test analysis is performed using the JSM-7800F.

[0035] Example 1 Step 1: Preparation of prepolymer In 70 g of 0.3% aqueous solution of polyvinyl alcohol, 7 g of divinylbenzene and 0.07 g of benzoyl peroxide mixed solution were added with stirring, and the temperature was raised to 70 °C and reacted for 2 h to obtain a prepolymer.

[0036] Step 2: Preparation of adsorbent Take 2 g of the prepolymer obtained above, mix it with 2 g of 350 μm carbon spheres, and heat it to 900 °C at a rate of 5 °C / min under nitrogen atmosphere and keep it for 2 h to obtain an adsorbent.

[0037] Step 3: Noble metal adsorption and reduction Put 0.1 g of the adsorbent obtained above into 100 mL of 500 ppm chloropalladic acid solution with a pH value of 2 at a temperature of 25 °C. The mixture was placed in an oscillator and adsorbed and reduced at 150 rpm for 2 hours.

[0038] The SEM electron micrograph and elemental energy spectrum of the adsorbent after adsorption and reduction are as Figure 1 shown. The optical micrograph of the adsorbent after adsorption and reduction and the intensity diagrams of each element corresponding to the red-framed area in the optical micrograph are as Figure 2 shown. The XRD patterns of the adsorbent and the adsorbent after palladium ion adsorption and reduction are as Figure 3 shown.

[0039] Step 4: Recover precious metals After the adsorption and reduction of the precious metal are completed, the solution containing the adsorbent is placed in an ultrasonic instrument, the ultrasonic power is set to 50 W, the ultrasonic time is set to 10 min, the adsorbent and the precious metal are separated by ultrasonic treatment, and the adsorbent solid and the solution containing the precious metal particles are separated by sieving to obtain metallic palladium.

[0040] Embodiment 2: Step 1: Preparing the prepolymer In 70 g of 0.3% polyvinyl alcohol aqueous solution, add 7 g of styrene, 17.99 g of tridecane and 0.7 g of benzoyl peroxide mixed solution with stirring, heat to 85° C. and react for 0.5 h to obtain a prepolymer.

[0041] Step 2: Preparation of adsorbent 2 g of the prepolymer obtained above was taken and mixed with 2 g of 350 μm carbon balls, and the temperature was raised to 900° C. at 5° C. / min under nitrogen conditions and kept at this temperature for 2 h to obtain an adsorbent.

[0042] Step 3: Noble metal adsorption and reduction 0.1 g of the adsorbent was put into 100 mL of 5000 ppm chloroauric acid solution with a pH value of 3 at 25 °C, and the mixture was placed in an oscillator for adsorption reduction at 150 rpm for 2 h.

[0043] The XRD pattern of the adsorbent is similar to that in Example 1. The XRD pattern of the adsorbent after adsorption of reduced gold ions is as follows: Figure 3 shown.

[0044] Step 4: Recover precious metals After the adsorption and reduction of the precious metal are completed, the adsorbent is separated from the solution and placed in an ultrasonic instrument. The ultrasonic power is set to 50 W and the ultrasonic time is set to 10 min. The adsorbent and the precious metal are separated by ultrasonic treatment. The adsorbent solid and the solution containing the precious metal particles are separated by sieving to obtain metallic palladium.

[0045] Embodiment 3: Step 1: Preparing the prepolymer In 70g of 0.3% polyvinyl alcohol aqueous solution, add a mixed solution of 0.67g of divinylbenzene, 4g of styrene, 5g of tridecane and 0.3g of benzoyl peroxide with stirring, heat to 75°C and react for 6h to obtain a prepolymer.

[0046] Step 2: Preparation of adsorbent 2 g of the prepolymer obtained above was taken and mixed with 2 g of 350 μm carbon balls, and the temperature was raised to 900° C. at 5° C. / min under nitrogen conditions and kept at this temperature for 2 h to obtain an adsorbent.

[0047] Step 3: Noble metal adsorption and reduction 0.1 g of the adsorbent was put into 100 mL of 50 ppm silver nitrate solution with a pH value of 3 at a temperature of 25° C. The mixed solution was placed in an oscillator and adsorbed and reduced at 150 rpm for 2 hours. The XRD pattern of the adsorbent was similar to that in Example 1. The XRD pattern of the adsorbent after adsorption and reduction of silver ions was as follows: Figure 3 shown.

[0048] Step 4: Recover precious metals After the adsorption and reduction of the precious metal are completed, the solution containing the adsorbent is placed in an ultrasonic instrument, the ultrasonic power is set to 50 W, the ultrasonic time is set to 10 min, the adsorbent and the precious metal are separated by ultrasonic treatment, and the adsorbent solid and the solution containing the precious metal particles are separated by sieving to obtain metallic palladium.

[0049] Embodiment 4: Step 1: Preparing the prepolymer In 70g of 3% polyvinyl alcohol aqueous solution, add a mixed solution of 13.33g of divinylbenzene, 20g of styrene, 0.7g of tridecane and 0.07g of benzoyl peroxide with stirring, heat to 70°C and react for 2h to obtain a prepolymer.

[0050] Step 2: Preparation of adsorbent 2 g of the prepolymer obtained above was taken and mixed with 2 g of 350 μm carbon balls, and the temperature was raised to 900° C. at 5° C. / min under nitrogen conditions and kept at this temperature for 2 h to obtain an adsorbent.

[0051] Step 3: Noble metal adsorption and reduction 0.1 g of the adsorbent was put into 100 mL of 5000 ppm chloroplatinic acid solution with a pH value of 3 at 25 ° C, and the mixture was placed in an oscillator for adsorption reduction at 150 rpm for 2 hours. After the adsorption and reduction of the noble metals were completed, the adsorbent was separated from the solution and placed in an ultrasonic instrument with an ultrasonic power of 50 W and an ultrasonic time of 10 min.

[0052] Step 4: Recover precious metals After the adsorption and reduction of the precious metal are completed, the solution containing the adsorbent is placed in an ultrasonic instrument, the ultrasonic power is set to 50 W, the ultrasonic time is set to 10 min, the adsorbent and the precious metal are separated by ultrasonic treatment, and the adsorbent solid and the solution containing the precious metal particles are separated by sieving to obtain metallic palladium.

[0053] Embodiment 5: Step 1: Preparing the prepolymer In 70 g of 0.5% OP-10 aqueous solution, a mixed solution of 0.8 g of divinylbenzene, 6 g of styrene, 0.8 g of dodecane and 0.08 g of benzoyl peroxide was added, and the temperature was raised to 75° C. and reacted for 1.5 hours to obtain a prepolymer.

[0054] Step 2: Preparation of adsorbent 2 g of the prepolymer was mixed with 3 g of 200 μm alumina particles, and the temperature was increased to 850° C. at 10° C. / min under nitrogen conditions for carbonization, and kept at this temperature for 2 h to obtain an adsorbent.

[0055] Step 3: Noble Metal Adsorption and Reduction 0.2 g of the adsorbent was put into 200 mL of 1000 ppm chloroauric acid solution with a pH value of 4 and reacted at 30 °C and 150 rpm for 2.5 hours.

[0056] Step 4: Recover precious metals After the adsorption and reduction of the precious metals are completed, the solution containing the adsorbent is placed in an ultrasonic instrument, the ultrasonic power is set to 60 W, the ultrasonic time is set to 20 min, the adsorbent and the precious metal are separated by ultrasonic treatment, and the adsorbent solid and the solution containing the precious metal particles are separated by sieving.

[0057] Embodiment 6: Step 1: Preparing the prepolymer 0.6 g of divinylbenzene, 8 g of styrene, 0.6 g of tetradecane and 0.06 g of azobisisobutyronitrile were added to 100 g of 0.1% sodium gluconate aqueous solution, and the temperature was raised to 80° C. to react for 2 hours to obtain a prepolymer.

[0058] Step 2: Preparation of adsorbent 3 g of the prepolymer was mixed with 10 g of 50 μm activated carbon, the temperature was raised to 950°C at 3°C / min under nitrogen for carbonization, and the temperature was kept for 2 h to obtain an adsorbent.

[0059] Step 3: Noble Metal Adsorption and Reduction 0.3 g of the adsorbent was added to 150 mL of 750 ppm chloroplatinic acid solution at pH 5 and reacted at 180 rpm at 30 °C for 3 h.

[0060] Step 4: Recover precious metals After the adsorption and reduction of the precious metal are completed, the solution containing the adsorbent is placed in an ultrasonic instrument, the ultrasonic power is set to 70W, the ultrasonic time is set to 15 minutes, the adsorbent and the precious metal are separated by ultrasonic treatment, and the adsorbent solid and the solution containing the precious metal particles are separated by sieving to obtain metallic platinum.

[0061] Embodiment 7: Step 1: Preparing the prepolymer 1 g of divinylbenzene, 7 g of styrene, 1 g of pentadecane and 0.1 g of lauryl peroxide were added to 80 g of 0.4% sodium alginate aqueous solution, and the temperature was raised to 85° C. for reaction for 1 hour to obtain a prepolymer.

[0062] Step 2: Preparation of adsorbent 3 g of the prepolymer was mixed with 10 g of 5 mm titanium oxide, and the temperature was raised to 700 °C at 8 °C / min under nitrogen for carbonization and kept at this temperature for 2 h to obtain an adsorbent.

[0063] Step 3: Noble metal adsorption and reduction 0.2 g of the adsorbent was placed in 100 mL of 500 ppm silver nitrate solution at pH 3 and reacted at 25°C for 1.5 hours.

[0064] Step 4: Recover precious metals After the adsorption and reduction of the precious metal are completed, the solution containing the adsorbent is placed in an ultrasonic instrument, the ultrasonic power is set to 45W, the ultrasonic time is set to 5 minutes, the adsorbent and the precious metal are separated by ultrasonic treatment, and the adsorbent solid and the solution containing the precious metal particles are separated by sieving to obtain metallic silver.

[0065] Embodiment 8: Step 1: Preparing the prepolymer 0.9 g of divinylbenzene, 9 g of styrene, 0.9 g of n-hexane and 0.09 g of azobisisobutyronitrile were added to 90 g of 1% Tween aqueous solution, and the temperature was raised to 70° C. to react for 3 hours to obtain a prepolymer.

[0066] Step 2: Preparation of adsorbent 2 g of the prepolymer was mixed with 2 g of 800 μm activated carbon, and the temperature was increased to 1000°C at 5°C / min under nitrogen for carbonization, and kept at this temperature for 2 h to obtain an adsorbent.

[0067] Step 3: Noble metal adsorption and reduction 0.15 g of the adsorbent was added to 100 mL of 200 ppm chloropalladic acid solution at pH 6 and reacted at 20 °C for 2 h.

[0068] Step 4: Recover precious metals After the adsorption and reduction of the precious metal are completed, the solution containing the adsorbent is placed in an ultrasonic instrument, the ultrasonic power is set to 50W, the ultrasonic time is set to 15 minutes, the adsorbent and the precious metal are separated by ultrasonic treatment, and the adsorbent solid and the solution containing the precious metal particles are separated by sieving to obtain metallic palladium.

[0069] Embodiment 9: Step 1: Preparing the prepolymer 0.5 g of divinylbenzene, 8 g of styrene, 0.5 g of n-hexane and 0.05 g of benzoyl peroxide were added to 60 g of 0.5% Span aqueous solution, and the temperature was raised to 75° C. to react for 2 hours to obtain a prepolymer.

[0070] Step 2: Preparation of adsorbent 3 g of the prepolymer was mixed with 10 g of 1 mm alumina, and the temperature was raised to 950 °C at 10 °C / min under nitrogen for carbonization and kept at this temperature for 2 h to obtain an adsorbent.

[0071] Step 3: Noble metal adsorption and reduction 0.25 g of the adsorbent was added to 100 mL of 300 ppm chloroauric acid solution at pH 2 and reacted at 25 °C for 3 h.

[0072] Step 4: Recover precious metals After the adsorption and reduction of the precious metal are completed, the solution containing the adsorbent is placed in an ultrasonic instrument, the ultrasonic power is set to 60W, the ultrasonic time is set to 10 minutes, the adsorbent and the precious metal are separated by ultrasonic treatment, and the adsorbent solid and the solution containing the precious metal particles are separated by sieving to obtain metallic gold.

[0073] Embodiment 10: Step 1: Preparing the prepolymer 0.6 g of divinylbenzene, 7 g of styrene, 0.6 g of dodecane and 0.06 g of azobisisobutyronitrile were added to 70 g of 0.6% OP-10 aqueous solution, and the temperature was raised to 80° C. and reacted for 1.5 hours to obtain a prepolymer.

[0074] Step 2: Preparation of adsorbent 2.5 g of the prepolymer was mixed with 2.5 g of 2 mm activated carbon, and the temperature was raised to 850 °C at 6 °C / min under nitrogen for carbonization, and kept at this temperature for 2 h to obtain an adsorbent.

[0075] Step 3: Noble metal adsorption and reduction 0.2 g of the adsorbent was added to 200 mL of 400 ppm chloroplatinic acid solution at pH 3 and reacted at 30 °C for 2 h.

[0076] Step 4: Recover precious metals After the adsorption and reduction of the precious metal are completed, the solution containing the adsorbent is placed in an ultrasonic instrument, the ultrasonic power is set to 55W, the ultrasonic time is set to 15 minutes, the adsorbent and the precious metal are separated by ultrasonic treatment, and the adsorbent solid and the solution containing the precious metal particles are separated by sieving to obtain metallic platinum.

[0077] Embodiment 11: Step 1: Preparing the prepolymer 0.7 g of divinylbenzene, 6 g of styrene, 0.7 g of tetradecane and 0.07 g of lauryl peroxide were added to 80 g of 0.7% Tween aqueous solution, and the temperature was raised to 85° C. for reaction for 1 hour to obtain a prepolymer.

[0078] Step 2: Preparation of adsorbent 3 g of the prepolymer was mixed with 5 g of 300 μm titanium oxide, and the temperature was increased to 900 °C at 8 °C / min under nitrogen for carbonization and kept at this temperature for 2 h to obtain an adsorbent.

[0079] Step 3: Noble Metal Adsorption and Reduction 0.15 g of the adsorbent was added to 150 mL of 600 ppm silver nitrate solution at pH 4 and reacted at 25 °C for 1 hour.

[0080] Step 4: Recover precious metals After the adsorption and reduction of the precious metal are completed, the solution containing the adsorbent is placed in an ultrasonic instrument, the ultrasonic power is set to 45W, the ultrasonic time is set to 10 minutes, the adsorbent and the precious metal are separated by ultrasonic treatment, and the adsorbent solid and the solution containing the precious metal particles are separated by sieving to obtain metallic silver.

[0081] Embodiment 12: Step 1: Preparing the prepolymer 0.8 g of divinylbenzene, 8 g of styrene, 0.8 g of pentadecane and 0.08 g of azobisisobutyronitrile were added to 100 g of 0.3% sodium alginate aqueous solution, and the temperature was raised to 70° C. for reaction for 2 hours to obtain a prepolymer.

[0082] Step 2: Preparation of adsorbent 2 g of the prepolymer was mixed with 6 g of 200 μm alumina, and the mixture was heated to 700°C at 5°C / min under nitrogen for carbonization and kept at this temperature for 2 h to obtain an adsorbent.

[0083] Step 3: Noble Metal Adsorption and Reduction 0.2 g of the adsorbent was added to 1000 mL of 1 ppm chloropalladic acid solution at pH 2 and reacted at 20 °C for 3 h.

[0084] Step 4: Recover precious metals After the adsorption and reduction of the precious metal are completed, the solution containing the adsorbent is placed in an ultrasonic instrument, the ultrasonic power is set to 40W, the ultrasonic time is set to 15 minutes, the adsorbent and the precious metal are separated by ultrasonic treatment, and the adsorbent solid and the solution containing the precious metal particles are separated by sieving to obtain metallic palladium.

[0085] Embodiment 13: Step 1: Preparing the prepolymer 0.9 g of divinylbenzene, 9 g of styrene, 0.9 g of pentadecane and 0.09 g of benzoyl peroxide were added to 90 g of 0.4% polyvinyl alcohol aqueous solution, and the temperature was raised to 75° C. to react for 3 hours to obtain a prepolymer.

[0086] Step 2: Preparation of adsorbent 2.5 g of the prepolymer was mixed with 5 g of 50 μm activated carbon, and the temperature was increased to 1000° C. at 7° C. / min under nitrogen for carbonization, and kept at this temperature for 2 h to obtain an adsorbent.

[0087] Step 3: Noble Metal Adsorption and Reduction 1.0 g of the adsorbent was added to 10 mL of 10000 ppm chloroauric acid solution at pH 5 and reacted at 25 °C for 2.5 h.

[0088] Step 4: Recover precious metals After the adsorption and reduction of the precious metal are completed, the solution containing the adsorbent is placed in an ultrasonic instrument, the ultrasonic power is set to 60W, the ultrasonic time is set to 10 minutes, the adsorbent and the precious metal are separated by ultrasonic treatment, and the adsorbent solid and the solution containing the precious metal particles are separated by sieving to obtain metallic gold.

[0089] Embodiment 14: Step 1: Preparing the prepolymer In 70g of 0.3% polyvinyl alcohol aqueous solution, add a mixed solution of 0.7g of divinylbenzene, 7g of styrene, 0.7g of tridecane and 0.07g of benzoyl peroxide with stirring, heat to 70°C and react for 2h to obtain a prepolymer.

[0090] Step 2: Preparation of adsorbent 2 g of the above obtained prepolymer was mixed with 2 g of 350 μm carbon balls, and the temperature was raised to 900° C. at 5° C. / min under nitrogen conditions and kept at this temperature for 2 h to obtain an adsorbent.

[0091] Step 3: Noble Metal Adsorption and Reduction 0.1 g of the above obtained adsorbent was put into 100 mL of 500 ppm chloropalladic acid solution with a pH value of 3 at a temperature of 25°C, and the mixed solution was placed in an oscillator for adsorption reduction at 150 rpm for 2 hours. After the adsorption and reduction of the noble metal was completed, the adsorbent was separated from the solution and placed in an ultrasonic instrument with an ultrasonic power set to 50 W and an ultrasonic time set to 10 min.

[0092] Step 4: Recover precious metals After the adsorption and reduction of the precious metals are completed, the solution containing the adsorbent is placed in an ultrasonic instrument, the ultrasonic power is set to 50 W, the ultrasonic time is set to 10 min, the adsorbent and the precious metal are separated by ultrasonic treatment, the adsorbent solid and the solution containing the precious metal particles are separated by sieving to obtain metallic palladium, and the adsorbent is recovered by drying. The above steps are repeated 5 times, and the palladium recovery rate of the adsorbent is as follows: Figure 4 shown.

[0093] Comparative Example 1: Step 1: Preparing the prepolymer In 70g of 0.3% polyvinyl alcohol aqueous solution, add a mixed solution of 0.7g of divinylbenzene, 7g of styrene, 0.7g of tridecane and 0.07g of benzoyl peroxide with stirring, heat to 70°C and react for 2h to obtain a prepolymer.

[0094] Step 2: Preparation of adsorbent 2 g of the prepolymer obtained above was taken and mixed with 2 g of 10 μm carbon balls, and the temperature was raised to 900° C. at 5° C. / min under nitrogen conditions and kept at this temperature for 2 h to obtain an adsorbent.

[0095] Step 3: Noble Metal Adsorption and Reduction 0.1 g of the above obtained adsorbent was put into 100 mL of 500 ppm chloropalladic acid solution with a pH value of 3 at a temperature of 25°C, and the mixed solution was placed in an oscillator for adsorption reduction at 150 rpm for 2 hours. After the adsorption and reduction of the noble metal was completed, the adsorbent was separated from the solution and placed in an ultrasonic instrument with an ultrasonic power set to 50 W and an ultrasonic time set to 10 min.

[0096] Step 4: Recover precious metals After the adsorption and reduction of the precious metal are completed, the solution containing the adsorbent is placed in an ultrasonic instrument, the ultrasonic power is set to 50 W, the ultrasonic time is set to 10 min, the adsorbent and the precious metal are separated by ultrasonic treatment, and the adsorbent solid and the solution containing the precious metal particles are separated by sieving to obtain metallic palladium.

[0097] Comparative Example 2: 0.1 g of carbon balls were placed in 100 mL of 500 ppm chloropalladic acid solution with a pH of 3 at 25 °C, and the mixture was placed in an oscillator at 150 rpm for 2 hours for adsorption reduction. After the noble metal adsorption and reduction were completed, the adsorbent was separated from the solution.

[0098] Comparative Example 3: Step 1: Preparing the prepolymer In 70g of 0.3% polyvinyl alcohol aqueous solution, add a mixed solution of 0.7g of divinylbenzene, 7g of styrene, 0.7g of tridecane and 0.07g of benzoyl peroxide with stirring, heat to 70°C and react for 2h to obtain a prepolymer.

[0099] Step 2: Preparation of adsorbent 2 g of the above obtained prepolymer was mixed with 20 g of 1 mm alumina balls, and the temperature was raised to 1200° C. at 5° C. / min under nitrogen conditions and kept at this temperature for 2 h to obtain an adsorbent.

[0100] Step 3: Noble Metal Adsorption and Reduction 0.1 g of the above obtained adsorbent was put into 100 mL of 50000 ppm chloropalladic acid solution with a pH value of 3 at a temperature of 25°C, and the mixed solution was placed in an oscillator for adsorption reduction at 150 rpm for 2 hours. After the adsorption and reduction of the noble metal was completed, the adsorbent was separated from the solution and placed in an ultrasonic instrument with an ultrasonic power set to 50 W and an ultrasonic time set to 10 min.

[0101] Step 4: Recover precious metals After the adsorption and reduction of the precious metal are completed, the solution containing the adsorbent is placed in an ultrasonic instrument, the ultrasonic power is set to 50 W, the ultrasonic time is set to 10 min, the adsorbent and the precious metal are separated by ultrasonic treatment, and the adsorbent solid and the solution containing the precious metal particles are separated by sieving to obtain metallic palladium.

[0102] The contact angles of the adsorbents prepared in step 2 of Examples 1 to 13 and Comparative Examples 1 to 3 were tested, and the residual precious metal ion content in the adsorbent solution after the adsorbent completed the precious metal adsorption and reduction in step 3 was tested, and the weight of the adsorbent before and after the adsorption and reduction was weighed to calculate the metal recovery rate. The results are shown in Table 1.

[0103] Table 1

[0104] The above are only a few embodiments of the present application and do not constitute any form of limitation to the present application. Although the present application is disclosed as above with preferred embodiments, it is not intended to limit the present application. Any technician familiar with the profession, without departing from the scope of the technical solution of the present application, using the technical content disclosed above to make slight changes or modifications are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. An adsorbent for in-situ adsorption and reduction of precious metal ions induced by hydrophobic surfaces, characterized in that: The adsorbent comprises an adsorbent matrix and a hydrophobic layer covering the surface of the matrix; The hydrophobic layer is obtained by carbonizing a prepolymer.

2. The method for preparing the adsorbent for in-situ adsorption and reduction of precious metal ions induced by hydrophobic surface according to claim 1, characterized in that: The steps include: S1, heating a mixture containing an emulsifier, a polymer monomer, an initiator, and water to react to obtain a prepolymer; S2. The prepolymer is mixed with an adsorbent matrix and then carbonized at high temperature to obtain the adsorbent for in-situ adsorption and reduction of precious metal ions induced by hydrophobic surface.

3. The preparation method according to claim 2, characterized in that: The emulsifier is selected from at least one of polyvinyl alcohol, OP-10, Tween, Span, sodium gluconate, and sodium alginate; The polymer monomer is selected from at least one of styrene and divinylbenzene; The initiator is selected from at least one of benzoyl peroxide, azobisisobutyronitrile and lauryl peroxide; The adsorbent matrix is ​​at least one of activated carbon, titanium oxide and aluminum oxide.

4. The preparation method according to claim 2, characterized in that: The weight ratio of initiator to polymer monomer is 0.01~0.1:1; The weight ratio of water to polymer monomer is 3 to 15:1; The emulsifier concentration in the mixture is 0.1~3wt.%; The weight ratio of the prepolymer to the adsorbent matrix is ​​0.3~1:

1.

5. The preparation method according to claim 2, characterized in that: A porogen is also included in the mixture; The porogen is selected from at least one of C6 to C15 alkanes; The weight ratio of the porogen to the polymer monomer is 0~2.57:

1.

6. The preparation method according to claim 2, characterized in that: The conditions for the heating reaction include: a reaction temperature of 70 to 85° C. and a reaction time of 0.5 to 6 h.

7. The preparation method according to claim 2, characterized in that: The conditions for high temperature carbonization include: carbonization temperature of 700~1000°C and insulation time of 0.5~4h.

8. A method for recovering precious metal ions by adsorption reduction induction, characterized in that: The steps include: Adsorption reduction: The liquid containing precious metal ions is brought into contact with the adsorbent, and the heavy metal ions are directly adsorbed and reduced to precious metal particles that cover the surface of the adsorbent; Recovery: subjecting the adsorbent after adsorption reduction to ultrasonic treatment to separate the adsorbent and precious metal particles and recover them; The adsorbent is selected from at least one of the adsorbent for hydrophobic surface induced in situ adsorption and reduction of precious metal ions according to claim 1 and the adsorbent for hydrophobic surface induced in situ adsorption and reduction of precious metal ions obtained by the preparation method according to any one of claims 2 to 7.

9. The method according to claim 8, characterized in that The precious metal is selected from at least one of gold, silver, platinum and palladium; The concentration of the noble metal ions in the liquid containing the noble metal ions is 1-10000 ppm, and the pH value of the liquid is 2-7.

10. Use of the adsorbent for hydrophobic surface induced in situ adsorption and reduction of precious metal ions according to claim 1, the adsorbent for hydrophobic surface induced in situ adsorption and reduction of precious metal ions obtained by the preparation method according to any one of claims 2 to 7, and the method for recovering precious metal ions induced by adsorption and reduction according to claim 8 or 9 in precious metal recovery.

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