为从高放射废液(HLLW)中回收钯和银,采用循环伏安法和恒电位沉积法研究钯和银在模拟硝酸溶液中的电化学行为。利用扫描电子显微镜(SEM)和X射线衍射仪(XRD)观察沉积产物的形貌并分析其组成。结果表明,在单独电沉积银时亚硝酸根的生成促...为从高放射废液(HLLW)中回收钯和银,采用循环伏安法和恒电位沉积法研究钯和银在模拟硝酸溶液中的电化学行为。利用扫描电子显微镜(SEM)和X射线衍射仪(XRD)观察沉积产物的形貌并分析其组成。结果表明,在单独电沉积银时亚硝酸根的生成促进银的溶解。当同时电沉积钯和银时,相同时间内更多金属被沉积,且沉积的银没有再出现溶解。在-0.4~-0.6 V (vs MSE)的电位下,溶液中的金属被完全电沉积回收,沉积物组成为银和氢化钯。钯的电沉积可以促进析氢,随后加速亚硝酸根和氢气之间的反应,使溶液中的亚硝酸浓度降低,从而抑制银的再溶解。展开更多
The demand for Li-ion batteries (LIBs) for vehicles is increasing. However, LIBs use valuable rare metals, such as Co and Li, aswell as environmentally toxic reagents. LIBs are also necessary to utilize for a long per...The demand for Li-ion batteries (LIBs) for vehicles is increasing. However, LIBs use valuable rare metals, such as Co and Li, aswell as environmentally toxic reagents. LIBs are also necessary to utilize for a long period and to recycle useful materials. The reduction, reuse,and recycle (3R) of spent LIBs is an important consideration in constructing a circular economy. In this paper, a flowsheet of the 3R of LIBs isproposed and methods to reduce the utilization of valuable rare metals and the amount of spent LIBs by remanufacturing used parts and designingnew batteries considering the concept of 3R are described. Next, several technological processes for the reuse and recycling of LIBs are introduced.These technologies include discharge, sorting, crushing, binder removal, physical separation, and pyrometallurgical and hydrometallurgicalprocessing. Each process, as well as the related physical, chemical, and biological treatments, are discussed. Finally, the problem of developedtechnologies and future subjects for 3R of LIBs are described.展开更多
The extraction chromatography–electrodeposition(EC–ED) process was proposed for the quantitative recovery of palladium from high-level liquid waste(HLLW) in this study. The process coupled the extraction chromatogra...The extraction chromatography–electrodeposition(EC–ED) process was proposed for the quantitative recovery of palladium from high-level liquid waste(HLLW) in this study. The process coupled the extraction chromatography method to obtain the decontamination of Pd(II) from HLLW with the electrochemical method to recover metallic palladium from the concentrated solution.Separation of Pd(II) from a nitric acid medium by extraction chromatography using iso Bu-BTP/SiO_2-P adsorbent and the electrochemical behavior of Pd(II) in nitric acid solution in the presence of thiourea(TU) were investigated.iso Bu-BTP/SiO_2-P exhibited a high selectivity for Pd(II)over other fission products(FPs), and Pd(II) could be desorbed by TU from loaded BTP/SiO_2-P. The adsorbent performed good stability against HNO_3 because the adsorption performance kept Pd(II) after extended contact with HNO_3 solution. The column experiment achieved the separation of Pd(II) from simulated HLLW successfully.The electrochemical behavior of Pd(II) in palladium desorption solution containing TU and nitric acid was investigated at a platinum electrode by cyclic voltammetry. A weak reduction wave at-0.4 V was due to the reduction in Pd(II) to Pd(0), and the deposition process wasirreversible. In electrowinning experiments, a maximum of92% palladium could be obtained.展开更多
Technetium(^(99)Tc), a major fission product in nuclear reactors, of high yield, long-half-life and high mobility in the environment must be removed in nuclear fuel reprocessing. Considering rhenium(Re) and Tc are bot...Technetium(^(99)Tc), a major fission product in nuclear reactors, of high yield, long-half-life and high mobility in the environment must be removed in nuclear fuel reprocessing. Considering rhenium(Re) and Tc are both VIIB elements, Re is a good chemical analogue to ^(99)Tc. Herein, we use Re as a substitution of ^(99)Tc to study adsorption and desorption behavior. Porous 4-vinylpyridine–divinylbenzene-based(4VP–DVB) adsorbent containing tertiary amine groups is synthesized by suspension polymerization and characterized by BET, TGA, SEM and laser particle size analyzer. The adsorbent has high adsorption efficiency toward Re(VII) in 0.1 mol/L nitric acid solution, and the adsorption equilibrium can be achieved in 30 min. The adsorption kinetics of Re(VII)follows pseudo-second-order rate equation, the adsorption isotherm matches well with the Langmuir isotherm, and the adsorption capacity of Re(VII) on 4VP–DVB adsorbent is 352.1 mg/g at 298 K. Thermodynamic study reveals that the adsorption process is exothermic. This adsorbent is of separation convenience when a fixed-bed column is used,compared to the batch adsorption treatment.展开更多
A porous silica-polymer-based adsorbent,isoBuBTP/Si O2-P,was prepared by a vacuum impregnation method and used for the recovery of ruthenium,rhodium,and palladium from nitric acid solution.The experimental results rev...A porous silica-polymer-based adsorbent,isoBuBTP/Si O2-P,was prepared by a vacuum impregnation method and used for the recovery of ruthenium,rhodium,and palladium from nitric acid solution.The experimental results revealed that iso Bu-BTP/SiO2-P exhibited unique adsorption properties such as high saturation adsorption capacity(Ru:0.35 mmol g^-1,Rh:0.32 mmol g^-1,Pd:1.05 mmol g^-1)and excellent selectivity over other metal ions,such as lanthanides(SF(PGM/M)>40)in 1 M HNO3 solution.The adsorption process conformed to the pseudosecond-order model and Langmuir model.From the UV,FTIR,and XPS analyses,it can be concluded that the strong affinity between functional groups(C–N=C)and metal ions as well as NO3-played a role in coordination during the adsorption process.Furthermore,the desorption behavior was studied,and it was found that the adsorbed Pd,Rh,and Ru could be eluted with a 0.01 M nitric acid–0.1M thiocarbamide solution,5M hydrochloric acid,and sodium hypochlorite(CP)solution,respectively.Finally,based on those findings,a simple process for the separation and recovery of Pd,Rh,and Ru from high-level liquid waste using iso Bu-BTP/SiO2-P was designed and proposed.展开更多
基金the financial supports from the National Natural Science Foundation of China (No. 11975082)。
文摘为从高放射废液(HLLW)中回收钯和银,采用循环伏安法和恒电位沉积法研究钯和银在模拟硝酸溶液中的电化学行为。利用扫描电子显微镜(SEM)和X射线衍射仪(XRD)观察沉积产物的形貌并分析其组成。结果表明,在单独电沉积银时亚硝酸根的生成促进银的溶解。当同时电沉积钯和银时,相同时间内更多金属被沉积,且沉积的银没有再出现溶解。在-0.4~-0.6 V (vs MSE)的电位下,溶液中的金属被完全电沉积回收,沉积物组成为银和氢化钯。钯的电沉积可以促进析氢,随后加速亚硝酸根和氢气之间的反应,使溶液中的亚硝酸浓度降低,从而抑制银的再溶解。
文摘The demand for Li-ion batteries (LIBs) for vehicles is increasing. However, LIBs use valuable rare metals, such as Co and Li, aswell as environmentally toxic reagents. LIBs are also necessary to utilize for a long period and to recycle useful materials. The reduction, reuse,and recycle (3R) of spent LIBs is an important consideration in constructing a circular economy. In this paper, a flowsheet of the 3R of LIBs isproposed and methods to reduce the utilization of valuable rare metals and the amount of spent LIBs by remanufacturing used parts and designingnew batteries considering the concept of 3R are described. Next, several technological processes for the reuse and recycling of LIBs are introduced.These technologies include discharge, sorting, crushing, binder removal, physical separation, and pyrometallurgical and hydrometallurgicalprocessing. Each process, as well as the related physical, chemical, and biological treatments, are discussed. Finally, the problem of developedtechnologies and future subjects for 3R of LIBs are described.
基金supported by the National Natural Science Foundation of China(Nos.11305102,91126006,and 21261140335)
文摘The extraction chromatography–electrodeposition(EC–ED) process was proposed for the quantitative recovery of palladium from high-level liquid waste(HLLW) in this study. The process coupled the extraction chromatography method to obtain the decontamination of Pd(II) from HLLW with the electrochemical method to recover metallic palladium from the concentrated solution.Separation of Pd(II) from a nitric acid medium by extraction chromatography using iso Bu-BTP/SiO_2-P adsorbent and the electrochemical behavior of Pd(II) in nitric acid solution in the presence of thiourea(TU) were investigated.iso Bu-BTP/SiO_2-P exhibited a high selectivity for Pd(II)over other fission products(FPs), and Pd(II) could be desorbed by TU from loaded BTP/SiO_2-P. The adsorbent performed good stability against HNO_3 because the adsorption performance kept Pd(II) after extended contact with HNO_3 solution. The column experiment achieved the separation of Pd(II) from simulated HLLW successfully.The electrochemical behavior of Pd(II) in palladium desorption solution containing TU and nitric acid was investigated at a platinum electrode by cyclic voltammetry. A weak reduction wave at-0.4 V was due to the reduction in Pd(II) to Pd(0), and the deposition process wasirreversible. In electrowinning experiments, a maximum of92% palladium could be obtained.
基金supported by the National Natural Science Foundation of China(Nos.91226111 and 11675103)
文摘Technetium(^(99)Tc), a major fission product in nuclear reactors, of high yield, long-half-life and high mobility in the environment must be removed in nuclear fuel reprocessing. Considering rhenium(Re) and Tc are both VIIB elements, Re is a good chemical analogue to ^(99)Tc. Herein, we use Re as a substitution of ^(99)Tc to study adsorption and desorption behavior. Porous 4-vinylpyridine–divinylbenzene-based(4VP–DVB) adsorbent containing tertiary amine groups is synthesized by suspension polymerization and characterized by BET, TGA, SEM and laser particle size analyzer. The adsorbent has high adsorption efficiency toward Re(VII) in 0.1 mol/L nitric acid solution, and the adsorption equilibrium can be achieved in 30 min. The adsorption kinetics of Re(VII)follows pseudo-second-order rate equation, the adsorption isotherm matches well with the Langmuir isotherm, and the adsorption capacity of Re(VII) on 4VP–DVB adsorbent is 352.1 mg/g at 298 K. Thermodynamic study reveals that the adsorption process is exothermic. This adsorbent is of separation convenience when a fixed-bed column is used,compared to the batch adsorption treatment.
基金This work was supported by the National Natural Science Foundation of China(Nos.11705032,11675102,and 11975082)the Natural Science Foundation of Guangxi Province(No.2017GXNSFBA198175)the Science and Technology Major Project of Guangxi Province(No.AA17204100).
文摘A porous silica-polymer-based adsorbent,isoBuBTP/Si O2-P,was prepared by a vacuum impregnation method and used for the recovery of ruthenium,rhodium,and palladium from nitric acid solution.The experimental results revealed that iso Bu-BTP/SiO2-P exhibited unique adsorption properties such as high saturation adsorption capacity(Ru:0.35 mmol g^-1,Rh:0.32 mmol g^-1,Pd:1.05 mmol g^-1)and excellent selectivity over other metal ions,such as lanthanides(SF(PGM/M)>40)in 1 M HNO3 solution.The adsorption process conformed to the pseudosecond-order model and Langmuir model.From the UV,FTIR,and XPS analyses,it can be concluded that the strong affinity between functional groups(C–N=C)and metal ions as well as NO3-played a role in coordination during the adsorption process.Furthermore,the desorption behavior was studied,and it was found that the adsorbed Pd,Rh,and Ru could be eluted with a 0.01 M nitric acid–0.1M thiocarbamide solution,5M hydrochloric acid,and sodium hypochlorite(CP)solution,respectively.Finally,based on those findings,a simple process for the separation and recovery of Pd,Rh,and Ru from high-level liquid waste using iso Bu-BTP/SiO2-P was designed and proposed.
