Method for extracting platinum and palladium from copper smelting waste liquid

Abstract

The invention belongs to the technical field of resource recycling, and particularly relates to a method for extracting platinum and palladium from copper smelting waste liquid. The biomass is sulfonated and then modified and neutralized together with N235, the modified biomass-based adsorbent with excellent selectivity and adsorbability on trace platinum and palladium is obtained, when the modified biomass-based adsorbent is used for extracting platinum and palladium from copper smelting waste liquid, the modified biomass-based adsorbent has the characteristics of high selectivity, large saturated adsorption capacity and high adsorption rate, the adsorption capacity can reach 500mg / g, and the adsorption rate is high. According to the method, Pd with the concentration of 50 mg / L and Pt with the concentration of 10 mg / L in the solution can be adsorbed to 0.1 mg / L or below, the adsorption rate can reach 99% or above, then the platinum and palladium extraction process is simple in technology and short in flow, and the final platinum and palladium recovery rate reaches 95% or above.

Description

Technical Field

[0001] The invention belongs to the technical field of resource recycling, and more specifically relates to a method for extracting platinum and palladium from copper smelting waste liquid. Background Art

[0002] Platinum and palladium are widely used in daily life, high-tech, medicine and health and other fields. There is a certain gap between the demand and output of platinum and palladium metals. In the actual production of refined copper, most companies will dispose of smelting dust, copper anode mud and flue gas. This process produces a large amount of acidic waste liquid, which contains trace amounts of platinum and palladium, generally 5-50 mg / L. The recovery of platinum and palladium from this type of acidic waste liquid has great economic value.

[0003] At present, the main problems with trace platinum and palladium (≤100 mg / L) in solutions are low adsorption efficiency, complex process flow, high acid concentration that easily corrodes equipment, easy generation of ammonia nitrogen wastewater leading to eutrophication, and failure to achieve industrial application. For example, in some methods, the LIX84-I+TOA+HCl system is used to extract platinum and palladium, and the extraction rate is high. However, the use of 10M high acid stripping causes serious corrosion to the equipment, and the extraction-stripping process is complicated. In some methods, the ionic liquid CyphosIL101 is used to selectively extract Pt and Pd, and the recovery rate is greater than 99%. However, when stripping the ionic liquid, the steps are cumbersome, and it is easy to cause ammonia nitrogen wastewater. The requirements for the liquid system are high and it is still in the laboratory research stage. In some methods, sugarcane bagasse biochar chitosan is used as a raw material to prepare an adsorbent, which can make the adsorption efficiency of Pt (IV) in water reach 81%, and the static saturated adsorption capacity is 217 mg / g, but the adsorption efficiency is not high, and the selective adsorption capacity for Pt is poor. In some methods, benzimidazole polymer resin (PS-MBI) is used to selectively recover Pd (II) in chlorinated media, but it is easy to cause a large amount of acid and alkali consumption when eluting with HCl and thiourea, and ammonia nitrogen wastewater is easy to be generated during the desorption process.

[0004] However, the above method has the problems of low adsorption efficiency, complex process flow, high acid concentration that easily corrodes equipment, easy generation of ammonia nitrogen wastewater leading to eutrophication, etc., which restrict its application in extracting platinum and palladium from copper smelting waste liquid. Therefore, how to provide a method for extracting platinum and palladium from copper smelting waste liquid to solve the problems of difficulty in recovering extremely low content platinum and palladium in acidic waste liquid generated in the copper smelting process and low recovery rate has become a difficult problem that technical personnel in this field need to solve urgently. Summary of the invention

[0005] The purpose of the present invention is to provide a method for extracting platinum and palladium from copper smelting waste liquid, by preparing a modified biomass-based adsorbent for enriching trace amounts of platinum and palladium in copper smelting waste liquid, so as to solve the problems existing in the above-mentioned prior art.

[0006] To achieve the above object, the present invention provides the following solutions:

[0007] One of the technical solutions of the present invention is to provide a method for preparing a modified biomass-based adsorbent, the steps comprising:

[0008] After the biomass is subjected to sulfonation treatment, trioctyldecyl tertiary amine (N235) is added to carry out a modification reaction to obtain the modified biomass-based adsorbent.

[0009] Furthermore, the biomass is biomass containing cellulose.

[0010] Optionally, the biomass includes at least one of wheat straw, rice straw, corn straw and sugarcane bagasse.

[0011] Furthermore, the sulfonation treatment step includes: mixing biomass, water and concentrated sulfuric acid (98%), stirring evenly, and after the biomass is completely carbon black, standing for 3 hours under vacuum conditions to obtain sulfonated biomass.

[0012] Optionally, the usage ratio of the biomass, water and concentrated sulfuric acid is 20g:50mL:50mL.

[0013] Optionally, the vacuum degree of the vacuum condition is 1×10 -1 MPa.

[0014] Furthermore, the usage ratio of the biomass to trioctyldecyl tertiary amine is 20g:10-40mL.

[0015] Furthermore, the modification reaction time is 3 hours.

[0016] Furthermore, the method further includes the steps of neutralizing and drying the reaction product after the modification reaction.

[0017] Optionally, the neutralization step includes: adding deionized water to the reaction product, adjusting the pH to 7 using sodium hydroxide, filtering, and then washing with an ethanol solution (40% by volume) and deionized water in sequence.

[0018] Optionally, the sodium hydroxide is added in the form of an aqueous solution with a concentration of 4M.

[0019] Optionally, the drying temperature is 120° C. and the drying time is 12 hours.

[0020] In some specific embodiments, the drying step includes: drying the neutralized product at 120°C for 12 hours, wherein the vacuum drying temperature rise rate is 7°C / min, during which argon gas is introduced for protection, and the flow rate of argon gas is 0.5 L / min.

[0021] The second technical solution of the present invention is to provide a modified biomass-based adsorbent, which is prepared by the above-mentioned preparation method.

[0022] The third technical solution of the present invention is to provide an application of the modified biomass-based adsorbent in adsorbing trace amounts of platinum and palladium in copper smelting waste liquid.

[0023] Technical solution 4 of the present invention: Provided is a method for extracting platinum and palladium from copper smelting waste liquid, the steps comprising:

[0024] The modified biomass-based adsorbent is mixed with copper smelting waste liquid and stirred, followed by solid-liquid separation, and the obtained solid product is calcined to obtain platinum-palladium powder.

[0025] Furthermore, the modified biomass-based adsorbent is ground and then passed through a 40-mesh sieve.

[0026] Furthermore, the solid-liquid ratio of the modified biomass-based adsorbent and the copper smelting waste liquid is 1 g / L.

[0027] Furthermore, the mixing and stirring time is 48 hours, and the rotation speed is 250-300 rpm.

[0028] Furthermore, the solid-liquid separation is performed by vacuum filtration.

[0029] Furthermore, the calcination is carried out in an air atmosphere at a temperature of 750-800° C., a heating rate of 7° C. / min, and a holding time of 240 min.

[0030] The present invention discloses the following technical effects:

[0031] After the cellulose in the biomass is modified by graft copolymerization, the present invention can quickly and effectively adsorb platinum-palladium compounds through electrostatic interaction and hydrogen bonding, and then obtain a powder containing platinum-palladium by calcination. The raw material source of the modified biomass-based adsorbent of the present invention is green and environmentally friendly. The modified biomass-based adsorbent has high selectivity for platinum-palladium, large saturated adsorption capacity, and fast adsorption rate. The adsorption capacity can reach 500 mg / g, and the adsorption rate of other Pb, As, Bi, Cu and Te in the solution is less than 10%. After 30 minutes of reaction, Pd and Pt can reach adsorption saturation, and 50 mg / L of Pd and 10 mg / L of Pt in the solution can be adsorbed to less than 0.1 mg / L, and the adsorption rate can reach more than 99%. The platinum-palladium extraction process of the present invention is simple in process and short in flow. The final platinum-palladium recovery rate reaches more than 95%, and the trace-level platinum-palladium enrichment and extraction in copper smelting waste liquid can be realized, turning waste into treasure. The present invention provides a new method for green and efficient extraction from waste liquid containing extremely low platinum-palladium, which is conducive to the sustainable development of the rare and precious metal industry.

[0032] The present invention rationally utilizes biomass and turns waste into treasure. The prepared adsorbent has good adsorption performance, low cost, and simple production process. The process for recovering platinum and palladium is simple and efficient. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The drawings constituting a part of the present application are used to provide a further understanding of the present application. The illustrative embodiments and descriptions of the present application are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0034] Figure 1 Flow chart for preparing adsorbent and adsorption extraction of copper smelting waste liquid.

[0035] Figure 2 This is the adsorption isotherm of platinum and palladium.

[0036] Figure 3 This is a physical picture of the calcined product obtained in Example 1.

[0037] Figure 4 These are the SEM images and energy spectrum images of the calcined metal palladium particles obtained in Example 1, where a is the SEM image and b is the energy spectrum image.

[0038] Figure 5 These are the SEM images and energy spectrum images of the calcined metal platinum particles obtained in Example 1, where a is the SEM image and b is the energy spectrum image. DETAILED DESCRIPTION

[0039] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0040] It should be understood that the terms described in the present invention are only for describing a particular embodiment and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. The intermediate value in any stated value or stated range, and each smaller range between any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0041] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0042] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to those skilled in the art. The present invention description and examples are exemplary only.

[0043] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0044] The copper smelting waste liquid used in the specific implementation scheme of the present invention is an acidic polybasic waste liquid generated in the copper smelting process. "Polybasic" means that in addition to Pt and Pd, the solution also contains other metal ions such as Pb, As, Bi, Cu and Te.

[0045] "Trace platinum and palladium" means that the platinum and palladium content in the solution is 50 mg / L or less.

[0046] The raw materials and reagents used in the specific embodiments of the present invention are all commercially available products.

[0047] The "normal pressure" referred to in the specific implementation scheme of the present invention is 1 atmosphere (101.325 kPa), and the "normal temperature" and "room temperature" refer to 25±2°C.

[0048] The acidic waste liquid produced during copper smelting contains extremely low levels of Pt and Pd, with PtCl6 2- 、PdCl4 2- Complex ions exist, such as Formula 1 and Formula 2. The present invention sulfonates biomass, which contains a large amount of cellulose. The surface of cellulose is sulfonated by sulfonic acid groups. The CO bonds in cellulose copolymerize with the NH bonds of the sulfonated groups, which can quickly and effectively adsorb compounds through electrostatic interactions and hydrogen bonds, which is beneficial to the negatively charged PtCl6 2- 、PdCl4 2- Electrostatic adsorption of ions. Sulfonic acid groups react with strong acids to generate [R-SO3H2] + , (R represents biomass) as shown in formula 3, the generated [R-SO3H2] + Can be used with PtCl6 2- 、PdCl4 2- Ion exchange occurs, as shown in Formula 4 and Formula 5. Using N235 modified sulfonated adsorbent, the tertiary amine groups on the surface of the sulfonated-modified adsorbent react with strong acid to form R3NH + , as shown in Formula 6, and then with PtCl6 2- 、PdCl4 2-An anion exchange reaction occurs, as shown in Formula 7 and Formula 8, and the adsorbent loaded with Pd and Pt is calcined at high temperature in a muffle furnace under air atmosphere to finally obtain a platinum-palladium powder, as shown in Formula 9 and Formula 10. After calcination, the adsorbent that has not been modified with N235 also finally obtains a platinum-palladium powder, but the adsorption efficiency is low, as shown in Formula 11 and Formula 12.

[0049]

[0050] R-SO3H+HCl=R-SO3H2Cl Formula 3

[0051]

[0052] R3N+HCl=R3NHCl Formula 6

[0053]

[0054] (R3NH)2PtCl6+O2→Pt+6HCl+CO2+H2O+2NH3 Formula 9

[0055] (R3NH)2PdCl4+O2→Pd+4HCl+CO2+H2O+2NH3 Formula 10

[0056] [(R-SO3)2H2]2PtCl6+O2→Pt+6HCl+CO2+H2O+2SO2 Equation 11

[0057] [(R-SO3)2H2]2PdCl4+O2→Pt+4HCl+CO2+H2O+2SO2 Equation 12

[0058] The modified biomass-based adsorbent prepared by the present invention can effectively adsorb extremely low platinum and palladium in copper smelting waste liquid, wherein the cellulose and hemicellulose contained in the biomass provide oxygen-containing groups that can combine with platinum and palladium metal ions, and are well complexed with platinum and palladium metal ions, and finally enrich the platinum and palladium metal ions. Subsequently, after the process of adsorption-calcination, it is prepared into platinum and palladium powder. For example, wheat straw is mainly composed of cellulose and lignin and a small amount of hemicellulose, and these components contain various functional groups such as carboxyl, hydroxyl, carbon phthalide, polysaccharide and amino, and these functional groups have a strong affinity for metal ions.

[0059] The raw material of the adsorbent of the present invention is biomass, which is green and environmentally friendly. The adsorbent has high selectivity for platinum and palladium, large saturated adsorption capacity and fast adsorption rate. The process for extracting platinum and palladium is simple and the process is short, and the final platinum and palladium recovery rate reaches more than 95%.

[0060] In a specific embodiment of the present invention, wheat straw is selected as biomass, but this should not be considered as a limitation of the present invention. The flow chart of preparing the adsorbent and adsorbing and extracting the copper smelting waste liquid is as follows: Figure 1 shown.

[0061] Example 1

[0062] Preparation of modified biomass-based adsorbents:

[0063] Weigh 20g of wheat straw and put it into a beaker. Then add 50mL of deionized water and slowly add 50mL of concentrated sulfuric acid into the beaker. Stir with a glass rod to make sure that the wheat straw is fully in contact. After the wheat straw is completely carbon black, put it into a vacuum dryer with a vacuum degree of 1×10 -1 MPa, sealed and allowed to stand for three hours to obtain sulfonated wheat straw; then 10mL N235 was added for stirring, and the mixture was poured into a hydrothermal synthesis reactor, placed in a homogeneous reactor and rotated at room temperature and pressure for 3 hours to obtain a synthetic product; then solid-liquid separation was performed, and 150mL deionized water was added to the solid product, and the pH was adjusted to 7.00 using a 4M NaOH solution; after solid-liquid separation, 10mL 40% (volume ratio) ethanol solution and 10mL deionized water were used to wash the solid product, respectively, and the washing was repeated three times, and then centrifuged at a speed of 3000rpm for 10min to perform solid-liquid separation to obtain a neutralized product; finally, the neutralized product was moved into a vacuum tube furnace, the vacuum tube furnace was set at a temperature of 120°C, the heating rate was 7°C / min, argon was introduced for drying for 12h, and the argon flow rate was 0.5L / min to obtain 16.5320g of a modified biomass-based adsorbent.

[0064] The steps for extracting platinum and palladium from copper smelting wastewater are as follows:

[0065] The modified biomass-based adsorbent was ground and passed through a 40-mesh sieve. 10 g of the sieved modified biomass-based adsorbent was mixed with 10 L of copper smelting waste liquid (the composition content is shown in Table 1), and adsorbed with stirring at a stirring rate of 250 rpm at room temperature for 48 h. After the adsorption was completed, the solid-liquid separation was performed, wherein the composition content of the liquid part was as shown in Table 1. The solid part was moved into a muffle furnace, the temperature was set to 750°C, the heating rate was 7°C / min, and calcined for 240 min in an air atmosphere to finally obtain 0.6022 g of a calcined product.

[0066] Table 1

[0067]

[0068]

[0069] Table 1 shows that the adsorption rates of platinum and palladium are 99% and 99.8% respectively, and the adsorption rates of impurities such as Pb, As, Bi, Cu, and Te are 5.0%, 0.7%, 2.9%, 6.3%, and 4.1% respectively.

[0070] The calcined product was tested and analyzed, and the mass percentages of palladium and platinum in the calcined product were 81.1% and 15.9% respectively. It was calculated that the recovery rates of platinum were 95.7% and the recovery rates of palladium were 97.7%.

[0071] The detection and analysis methods are: ICP-OES and EDS for component analysis, and SEM for surface characteristics.

[0072] Example 2

[0073] Preparation of modified biomass-based adsorbents:

[0074] Weigh 20g of wheat straw and add it to a beaker. Then add 50mL of deionized water and slowly add 50mL of concentrated sulfuric acid to the beaker. Stir with a glass rod to make sure that the wheat straw is fully in contact. After the wheat straw is completely carbonized, place it in a vacuum dryer with a vacuum degree of 1×10 -1 MPa, sealed and allowed to stand for three hours to obtain sulfonated wheat straw; then 20mL N235 was added for stirring, and the mixture was poured into a hydrothermal synthesis reactor, placed in a homogeneous reactor and rotated at room temperature and pressure for 3 hours to obtain a synthetic product; then solid-liquid separation was performed, and 150mL deionized water was added to the solid product, and the pH was adjusted to 7.00 using a 4M NaOH solution; after solid-liquid separation, 10mL 40% (volume ratio) ethanol solution and 10mL deionized water were used to wash the mixture, respectively, and the mixture was repeated three times, and then centrifuged in a centrifuge at a speed of 3000rpm for 10min to perform solid-liquid separation to obtain a neutralized product; finally, the neutralized product was moved into a vacuum tube furnace, the vacuum tube furnace was set at a temperature of 120°C, the heating rate was 7°C / min, argon was introduced for drying for 12h, and the argon flow rate was 0.5L / min to obtain 16.5650g of a modified biomass-based adsorbent.

[0075] The steps for extracting platinum and palladium from copper smelting wastewater are as follows:

[0076] The modified biomass-based adsorbent was ground and passed through a 40-mesh sieve. 10 g of the sieved modified biomass-based adsorbent was mixed with 10 L of copper smelting waste liquid (the composition content is shown in Table 2), and adsorbed with stirring at a stirring rate of 300 rpm at room temperature for 48 h. After the adsorption was completed, the solid and liquid were separated. The composition content of the liquid part was as shown in Table 2. The solid part was moved into a muffle furnace, the temperature was set to 800 ° C, the heating rate was 7 ° C / min, and calcined for 240 min in an air atmosphere to finally obtain 0.6014 g of a calcined product.

[0077] Table 2

[0078]

[0079] Table 2 shows that the adsorption rates of platinum and palladium are 99.2% and 99.8% respectively, and the adsorption rates of impurities such as Pb, As, Bi, Cu, and Te are 4.9%, 1.0%, 2.6%, 6.0%, and 4.7% respectively.

[0080] The calcined product was tested and analyzed, and the mass percentages of palladium and platinum in the calcined product were 81.4% and 15.8% respectively. It was calculated that the recovery rate of platinum was 95.0% and the recovery rate of palladium was 97.9%.

[0081] The detection and analysis method is the same as in Example 1.

[0082] Example 3

[0083] Preparation of modified biomass-based adsorbents:

[0084] Weigh 20g of wheat straw and put it into a beaker. Then add 50mL of deionized water and slowly add 50mL of concentrated sulfuric acid into the beaker. Stir with a glass rod to make sure that the wheat straw is fully in contact. After the wheat straw is completely carbon black, put it into a vacuum dryer with a vacuum degree of 1×10 -1 MPa, sealed and allowed to stand for three hours to obtain sulfonated wheat straw; then 30mL N235 was added for stirring, and the mixture was poured into a hydrothermal synthesis reactor, placed in a homogeneous reactor and rotated at room temperature and pressure for 3 hours to obtain a synthetic product; then solid-liquid separation was performed, and 150mL deionized water was added to the solid product, and the pH was adjusted to 7.00 using a 4M NaOH solution; after solid-liquid separation, 10mL 40% (volume ratio) ethanol solution and 10mL deionized water were used for washing, respectively, and the washing was repeated three times, and then centrifuged at a speed of 3000rpm for 10min to perform solid-liquid separation to obtain a neutralized product; finally, the neutralized product was moved into a vacuum tube furnace, the vacuum tube furnace was set at a temperature of 120°C, the heating rate was 7°C / min, argon was introduced for drying for 12h, and the argon flow rate was 0.5L / min to obtain 16.6752g of modified biomass-based adsorbent.

[0085] The steps for extracting platinum and palladium from copper smelting wastewater are as follows:

[0086] The modified biomass-based adsorbent was ground and passed through a 40-mesh sieve. 10 g of the sieved modified biomass-based adsorbent was mixed with 10 L of copper smelting waste liquid (the composition content is shown in Table 3). The mixture was stirred and adsorbed at a stirring rate of 250 rpm at room temperature for 48 h. After the adsorption was completed, the solid-liquid separation was performed. The composition content of the liquid part was as shown in Table 3. The solid part was moved into a muffle furnace, the temperature was set to 800 ° C, the heating rate was 7 ° C / min, and calcined for 240 min in an air atmosphere to finally obtain 0.6010 g of a calcined product.

[0087] Table 3

[0088]

[0089] Table 3 shows that the adsorption rates of platinum and palladium are 99.0% and 99.8% respectively, and the adsorption rates of impurities such as Pb, As, Bi, Cu, and Te are 4.9%, 1.1%, 3.1%, 6.5%, and 4.1% respectively.

[0090] The calcined product was tested and analyzed, and the mass percentages of palladium and platinum in the calcined product were 81.4% and 15.9% respectively. It was calculated that the recovery rate of platinum was 95.6%, and the recovery rate of palladium was 97.8%.

[0091] The detection and analysis method is the same as in Example 1.

[0092] Example 4

[0093] Preparation of modified biomass-based adsorbents:

[0094] Weigh 20g of wheat straw and put it into a beaker. Then add 50mL of deionized water and slowly add 50mL of concentrated sulfuric acid into the beaker. Stir with a glass rod to make sure that the wheat straw is fully in contact. After the wheat straw is completely carbon black, put it into a vacuum dryer with a vacuum degree of 1×10 -1 MPa, sealed and allowed to stand for three hours to obtain sulfonated wheat straw; then 40mL N235 was added for stirring, and the mixture was poured into a hydrothermal synthesis reactor, placed in a homogeneous reactor and rotated at room temperature and pressure for 3 hours to obtain a synthetic product; then solid-liquid separation was performed, and 150mL deionized water was added to the solid product, and the pH was adjusted to 7.00 using a 4M NaOH solution; after solid-liquid separation, 10mL 40% (volume ratio) ethanol solution and 10mL deionized water were used to wash the mixture, respectively, and the mixture was repeated three times, and then centrifuged at a speed of 3000rpm for 10min to perform solid-liquid separation to obtain a neutralized product; finally, the neutralized product was moved into a vacuum tube furnace, the vacuum tube furnace was set at a temperature of 120°C, the heating rate was 7°C / min, argon was introduced for drying for 12h, and the argon flow rate was 0.5L / min to obtain 16.6950g of a modified biomass-based adsorbent.

[0095] The steps for extracting platinum and palladium from copper smelting wastewater are as follows:

[0096] The modified biomass-based adsorbent was ground and passed through a 40-mesh sieve. 10 g of the sieved modified biomass-based adsorbent was mixed with 10 L of copper smelting waste liquid (the composition content is shown in Table 4), and adsorbed with stirring at a stirring rate of 300 rpm at room temperature for 48 hours. After the adsorption was completed, the solid-liquid separation was performed, wherein the composition content of the liquid part was as shown in Table 4. The solid part was moved into a muffle furnace, the temperature was set to 750°C, the heating rate was 7°C / min, and calcined for 240 min in an air atmosphere to finally obtain 0.6023 g of a calcined product.

[0097] Table 4

[0098]

[0099] Table 4 shows that the adsorption rates of platinum and palladium are 99.2% and 99.8% respectively, and the adsorption rates of impurities such as Pb, As, Bi, Cu, and Te are 5.1%, 0.9%, 3.1%, 7.2%, and 4.9% respectively.

[0100] The calcined product was tested and analyzed, and the mass percentages of palladium and platinum in the calcined product were 81.3% and 16.0% respectively. It was calculated that the recovery rate of platinum was 96.4% and the recovery rate of palladium was 97.9%.

[0101] The detection and analysis method is the same as in Example 1.

[0102] Comparative Example 1

[0103] Preparation of modified biomass-based adsorbents:

[0104] Weigh 20g of wheat straw and put it into a beaker. Then add 50mL of deionized water and slowly add 50mL of concentrated sulfuric acid into the beaker. Stir with a glass rod to make sure that the wheat straw is fully in contact. After the wheat straw is completely carbon black, put it into a vacuum dryer with a vacuum degree of 1×10 -1 MPa, sealed and allowed to stand for three hours to obtain sulfonated wheat straw; then 10mL N235 was added for stirring, and the mixture was poured into a hydrothermal synthesis kettle, placed in a homogeneous reactor and rotated at room temperature and pressure for 3 hours to obtain a synthetic product; then solid-liquid separation was performed, and 150mL deionized water was added to the solid product, and the pH was adjusted to 7.00 using a 4M NaOH solution; after solid-liquid separation, 10mL 40% (volume ratio) ethanol solution and 10mL deionized water were used to wash the mixture, respectively, and the mixture was repeated three times, and then centrifuged in a centrifuge at a speed of 3000rpm for 10min to perform solid-liquid separation to obtain a neutralized product; finally, the neutralized product was moved into a 70°C electric heated forced air drying oven and dried for 12 hours to obtain 15.6950g of a modified biomass-based adsorbent.

[0105] The steps for extracting platinum and palladium from copper smelting wastewater are as follows:

[0106] The modified biomass-based adsorbent was ground and passed through a 40-mesh sieve. 10 g of the sieved modified biomass-based adsorbent was mixed with 10 L of copper smelting waste liquid (the composition content is shown in Table 5), and the mixture was stirred and adsorbed at a stirring rate of 250 rpm at room temperature for 48 h. After the adsorption was completed, the solid-liquid separation was performed, wherein the composition content of the liquid part was as shown in Table 5. The solid part was moved into a muffle furnace, the temperature was set to 750 ° C, the heating rate was 7 ° C / min, and calcined for 240 min in an air atmosphere to finally obtain 0.5739 g of a calcined product.

[0107] Table 5

[0108]

[0109] Table 5 shows that the adsorption rates of platinum and palladium are 85.0% and 98.2% respectively, and the adsorption rates of impurities such as Pb, As, Bi, Cu, and Te are 6.8%, 3.1%, 5.9%, 5.3%, and 7.7% respectively.

[0110] The calcined product was tested and analyzed, and the mass percentages of palladium and platinum in the calcined product were 82.0% and 13.4% respectively. It was calculated that the recovery rate of platinum was 94.2% and the recovery rate of palladium was 76.9%.

[0111] The detection and analysis method is the same as in Example 1.

[0112] Comparative Example 2

[0113] Preparation of modified biomass-based adsorbent (sulfonated wheat straw adsorbent):

[0114] Weigh 20g of wheat straw and put it into a beaker. Then add 50mL of deionized water and slowly add 50mL of concentrated sulfuric acid into the beaker. Stir with a glass rod to make sure that the wheat straw is fully in contact. After the wheat straw is completely carbon black, put it into a vacuum dryer with a vacuum degree of 1×10 -1 MPa, sealed and allowed to stand for three hours to obtain sulfonated wheat straw; 150 mL of deionized water was added to the sulfonated wheat straw, and the pH was adjusted to 7.00 using a 4 M NaOH solution; after solid-liquid separation, it was washed with 10 mL of deionized water, repeated three times, and then centrifuged in a centrifuge at a speed of 3000 rpm for 10 min to perform solid-liquid separation to obtain a neutralized product; finally, the neutralized product was transferred into a vacuum tube furnace, the vacuum tube furnace was set to a temperature of 120 ° C, the heating rate was 7 ° C / min, argon was introduced for drying for 12 hours, and the argon flow rate was 0.5 L / min to obtain 11.6371 g of modified biomass-based adsorbent.

[0115] The steps for extracting platinum and palladium from copper smelting wastewater are as follows:

[0116] The modified biomass-based adsorbent was ground and passed through a 40-mesh sieve. 10 g of the sieved modified biomass-based adsorbent was mixed with 10 L of copper smelting waste liquid (the composition content is shown in Table 6), and the mixture was stirred and adsorbed at a stirring rate of 250 rpm at room temperature for 48 h. After the adsorption was completed, the solid-liquid separation was performed, wherein the composition content of the liquid part was as shown in Table 6. The solid part was moved into a muffle furnace, the temperature was set to 750 ° C, the heating rate was 7 ° C / min, and calcined for 240 min in an air atmosphere to finally obtain 0.2461 g of a calcined product.

[0117] Table 6

[0118]

[0119] Table 6 shows that the adsorption rates of platinum and palladium are 41.0% and 42.2%, respectively, and the adsorption rates of impurities such as Pb, As, Bi, Cu, and Te are 4.8%, 0.7%, 2.9%, 5.8%, and 5.2%, respectively.

[0120] The calcined product was tested and analyzed, and the mass percentages of palladium and platinum in the calcined product were 79.4% and 15.8% respectively. It was calculated that the recovery rate of platinum was 38.9% and the recovery rate of palladium was 39.1%.

[0121] The detection and analysis method is the same as in Example 1.

[0122] Comparative Example 3

[0123] Preparation of modified biomass-based adsorbents:

[0124] Same as Comparative Example 2.

[0125] The steps for extracting platinum and palladium from copper smelting wastewater are as follows:

[0126] The modified biomass-based adsorbent was ground and passed through a 40-mesh sieve. 10 g of the sieved modified biomass-based adsorbent was mixed with 10 L of copper smelting waste liquid (the composition content is shown in Table 7), and adsorbed with stirring at a stirring rate of 300 rpm at room temperature for 48 h. After the adsorption was completed, the solid-liquid separation was carried out, wherein the composition content of the liquid part was as shown in Table 7. The solid part was moved into a muffle furnace, the temperature was set to 800 ° C, the heating rate was 7 ° C / min, and calcined for 240 min in an air atmosphere to finally obtain 0.2481 g of a calcined product.

[0127] Table 7

[0128]

[0129] Table 7 shows that the adsorption rates of platinum and palladium are 42.0% and 41.4%, respectively, and the adsorption rates of impurities such as Pb, As, Bi, Cu, and Te are 4.7%, 0.7%, 3.2%, 6.9%, and 6.6%, respectively.

[0130] The calcined product was tested and analyzed, and the mass percentages of palladium and platinum in the calcined product were 80.2% and 15.4% respectively. It was calculated that the recovery rate of platinum was 38.2% and the recovery rate of palladium was 39.8%.

[0131] The detection and analysis method is the same as in Example 1.

[0132] Figure 2 This is the adsorption isotherm of platinum and palladium.

[0133] Figure 3 This is a physical picture of the calcined product obtained in Example 1.

[0134] Figure 4 These are the SEM images and energy spectrum images of the calcined metal palladium particles obtained in Example 1, where a is the SEM image and b is the energy spectrum image.

[0135] Figure 5 These are the SEM images and energy spectrum images of the calcined metal platinum particles obtained in Example 1, where a is the SEM image and b is the energy spectrum image.

[0136] Depend on Figures 4-5 It can be known that Figure 4 Points 1 and 2 in a represent metal palladium particles. Figure 5 Points 4 and 5 in a represent metal platinum particles.

[0137] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0138] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing a modified biomass-based adsorbent, characterized in that: The steps include: After the biomass is subjected to sulfonation treatment, trioctyldecyl tertiary amine is added to carry out a modification reaction to obtain the modified biomass-based adsorbent.

2. The preparation method according to claim 1, characterized in that The biomass is biomass containing cellulose; and / or, The ratio of the biomass to trioctyldecyl tertiary amine is 20 g:10-40 mL; and / or, The modification reaction time is 3h.

3. The preparation method according to claim 1, characterized in that: The sulfonation treatment step comprises: mixing biomass, water and concentrated sulfuric acid, stirring evenly, and after the biomass is completely carbon black, standing for 3 hours under vacuum conditions to obtain the sulfonated biomass.

4. The preparation method according to claim 3, characterized in that: The ratio of the biomass, water and concentrated sulfuric acid is 20 g:50 mL:50 mL; and / or, The vacuum degree of the vacuum condition is 1×10 -1 MPa.

5. The preparation method according to claim 1, characterized in that: The method also includes the steps of neutralizing and drying the reaction product after the modification reaction.

6. The preparation method according to claim 5, characterized in that: The neutralization step comprises: adjusting the pH of the reaction product to 7 using sodium hydroxide, and then washing with ethanol solution and water in sequence; and / or, The sodium hydroxide is added in the form of an aqueous solution with a concentration of 4M; and / or, The drying temperature is 120° C. and the drying time is 12 hours.

7. A modified biomass-based adsorbent, characterized in that: The modified biomass-based adsorbent is prepared by the preparation method according to any one of claims 1 to 6.

8. Use of the modified biomass-based adsorbent according to claim 7 in adsorbing trace amounts of platinum and palladium in copper smelting wastewater.

9. A method for extracting platinum and palladium from copper smelting waste liquid, characterized in that the steps include: The modified biomass-based adsorbent according to claim 7 is mixed and stirred with copper smelting waste liquid, followed by solid-liquid separation, and the obtained solid product is calcined to obtain platinum-palladium powder.

10. The method according to claim 9, characterized in that The modified biomass-based adsorbent is ground and then passed through a 40-mesh sieve; and / or, The solid-to-liquid ratio of the modified biomass-based adsorbent to the copper smelting waste liquid is 1 g / L; and / or, The mixing time is 48 hours and the rotation speed is 250-300 rpm; and / or, The calcination is carried out in an air atmosphere at a temperature of 750-800° C., a heating rate of 7° C. / min, and a heat preservation time of 240 min.

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