The research and developments of a new type of inorganic ion exchanger, crystalline silicotitanate (CST) are reviewed. This material is stable against radiation, and the CST has high selectivity for Cs over Na, K and ...The research and developments of a new type of inorganic ion exchanger, crystalline silicotitanate (CST) are reviewed. This material is stable against radiation, and the CST has high selectivity for Cs over Na, K and Rb. It performs well in acidic, neutral, and basic solutions. The results of ion exchange tests show that CST is an excellent candidate for Cs removal from high-level liquid waste.展开更多
Basic properties of a silica-based octyl(phenyl)-N,N-diisobutylcarbamoyl-methylphosphine oxide (CMPO) extraction resin (CMPO/SiO2-P) was investigated.Adsorption behavior for some rare earth elements (RE) which are con...Basic properties of a silica-based octyl(phenyl)-N,N-diisobutylcarbamoyl-methylphosphine oxide (CMPO) extraction resin (CMPO/SiO2-P) was investigated.Adsorption behavior for some rare earth elements (RE) which are constituents of high level liquid waste (HLLW) and the long-term stability of the extraction resin in nitric acid solution were examined.The CMPO extraction resin was significantly stable in 3 mol·L?1 HNO3 solution at 50oC.Furthermore,the RE(III) were efficiently separated from non-adsorptive fission product (FP) elements such as Sr(II) in a column experiment using a highly nitric acid solution.The separation behaviors of the elements are considered to result from the difference in their adsorption and elution selectivity based on the complex formation with CMPO.There was no strong dependency of RE(III) separation efficiency on feed solution flow rate.Only from the perspectives of the acid-resistant behavior of CMPO extraction resin and the elution kinetics for the metal ions with the extraction resin,the CMPO extraction resin can be used in the modified MAREC process for HLLW partitioning.展开更多
Bentonite has been considered as the buffer material for embedding canisters with high-level radioactive waste(HLW)in the deep geology repositories. GMZ bentonite deposit which is located in Xinghe County,Inner Mongol...Bentonite has been considered as the buffer material for embedding canisters with high-level radioactive waste(HLW)in the deep geology repositories. GMZ bentonite deposit which is located in Xinghe County,Inner Mongolia has been proposed as buffer/backfill material for HLW repository in China. Liquid limit of natural Na-bentonite GMZ01 and commercial Na-bentonite MX80 which were previously put in the oven at 80℃and 95℃,and exposed to water for different times were measured.The liquid limit of GMZ01 increased slightly at the beginning, and then decreased as the heating time increased.展开更多
A process for actinide(Ⅲ)and lanthanum(Ⅲ)extraction separation from high-level liquid waste(HLLW)was proposed,with N,N,N’,N’-tetraoctyl diglycolamide(TODGA)as the extractant,tri-n–butyl phosphate(TBP)as the phase...A process for actinide(Ⅲ)and lanthanum(Ⅲ)extraction separation from high-level liquid waste(HLLW)was proposed,with N,N,N’,N’-tetraoctyl diglycolamide(TODGA)as the extractant,tri-n–butyl phosphate(TBP)as the phase modifier and 2,6-bis[1-(propan-1-ol)-1,2,3-triazol-4-yl]pyridine(PyTri-Diol or PTD)as hydrophilic stripping agent.This‘hot test’was successfully carried out,achieving 99.92%removal of americium-241(^(241)Am)with a separation factor SF(Eu/Am)of 3.8×10^(3)in the actinide(Ⅲ)product solution.The results show that bisamide podand extractants can effectively realize the extraction and separation of actinide(Ⅲ)and lanthanum(Ⅲ)from Chinese commercial HLLW and thus have a bright practical application potential for the treatment of commercial HLLW.展开更多
Bentonite has been considered as a buffer material for embedding canisters with high-level radioactive waste（HLW） in deep geological repositories.GMZ bentonite deposit,located in Xinghe County,Inner Mongolia Autonom...Bentonite has been considered as a buffer material for embedding canisters with high-level radioactive waste（HLW） in deep geological repositories.GMZ bentonite deposit,located in Xinghe County,Inner Mongolia Autonomous Region,China was proposed as a buffer/backfill material for HLW repository in China.The liquid limits of natural Na-bentonite GMZ01 and commercial Na-bentonite MX80,which are previously heated at 80 ℃ and 95 ℃,respectively,and exposed to water for different times are measured.It is observed that the liquid limit of GMZ01 increases slightly at the beginning,and then decreases as the heating time increases,while the liquid limit of MX80 decreases with the heating time.The liquid limits of both GMZ01 and MX80 decrease with increasing water-exposure time.After the samples are heated at 80℃and 95 ℃ for several months,the mineralogical composition of GMZ01 does not exhibit evident change,whereas MX80 experiences some changes.In addition,the chemical composition,cation exchange capacity（CEC） and exchangeable cation of all the samples do not change significantly.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
The exchange performances and the distribution coefficient of Cesium Ion-Sieve (Cs-IS) for cesium and for some rare earth elements were compared. In particula r, the effects of neodymium on the cesium ion exchange an...The exchange performances and the distribution coefficient of Cesium Ion-Sieve (Cs-IS) for cesium and for some rare earth elements were compared. In particula r, the effects of neodymium on the cesium ion exchange and the Cs+ selectivity v ariation on Cs-IS owing to introduction of rare earth elements into HLLW were s tudied. Though rare earth elements exhibit a small influence on the distributio n coefficient for Cs+, they impair Cs-exchange capacity of Cs-IS to some ext ent. This interruption on the selectivity to Cs+ can be significantly eliminat ed provided an appropriate ratio of liquid to solid V:m is used.展开更多
The adsorption behavior of241Am(Ⅲ) and Eu(Ⅲ) by silica/polymer-based iso Hex-BTP adsorbent(iso HexBTP/Si O2-P) was investigated by a batch experiment method. iso Hex-BTP/Si O2-P exhibited high affinity and selectivi...The adsorption behavior of241Am(Ⅲ) and Eu(Ⅲ) by silica/polymer-based iso Hex-BTP adsorbent(iso HexBTP/Si O2-P) was investigated by a batch experiment method. iso Hex-BTP/Si O2-P exhibited high affinity and selectivity for241Am(Ⅲ) over152Eu(Ⅲ) in 2–4 mol/dm3 nitric acid solutions. Within the experimental contact time range of 0.5–24 h, iso Hex-BTP/Si O2-P showed high selectivity for241Am(Ⅲ) compared to152Eu(Ⅲ) in3 mol/dm3 nitric acid solution. However, the adsorption kinetics of241Am(Ⅲ) and152Eu(Ⅲ) was slow. Eu(Ⅲ)adsorption followed the pseudo-second-order kinetic model, indicating chemical adsorption as the rate-limiting step of the adsorption process. And the adsorption agreed well with the Langmuir adsorption model at various temperatures. The adsorption kinetics and isotherm data indicated that the equilibrium adsorption capacity, the adsorption rate, the maximum adsorption capacity and the adsorption affinity, increased with temperature. The thermodynamic parameters, negative change in Gibbs free energy, and positive change in enthalpy and entropy,suggested that the adsorption of Eu(Ⅲ) was spontaneous and endothermic process with an increase of entropy.展开更多
A functional microcapsule was prepared by encapsulating the fine crystalline ammonium tungstophosphate （AWP） in calcium alginate polymer （CaALG）. The characterization of AWP-CaALG microcapsule was examined by SEM ...A functional microcapsule was prepared by encapsulating the fine crystalline ammonium tungstophosphate （AWP） in calcium alginate polymer （CaALG）. The characterization of AWP-CaALG microcapsule was examined by SEM and EPMA. The ad- sorption behavior of Cs（Ⅰ）, Rb（Ⅰ）, Sr（Ⅱ）, Pd（II）, Ru（Ⅲ）, Rh（Ⅲ）, La（Ⅲ）, Ce（Ⅲ）, Dy（Ⅲ） and Zr（IV） was investigated by the batch method. The batch experiments were carried out by varying the shaking times, HNO3 concentration, and initial concen- tration of metal ions. Relatively large K＋ values above 105 cm3/g for Cs（I） were obtained in the range of 0.1-5 M HNO3, re- sulting in a separation factor of Cs/Rb exceeding 102. In contrast, the K＋ values of Sr（II）, Pd（II）, Ru（Ⅲ）, La（Ⅲ）, Dy（Ⅲ）, Ce（Ⅲ） and Zr（IV） were considerably lower than 50 cm3/g. The K＋ value of Cs（1） decreased in the order of the coexisting ions, H＋ 〉 Na＋ 〉〉 NH4＋, and a linear relationship with a slop of about -1 was obtained between log Kd and log [NH4＋] （[NH4＋] 〉 0.01 M） The adsorption of Cs（I） was found to be controlled by chemisorption mechanism, and followed a Langmuir-type adsorption equation. A high uptake percentage of 99.4% for Cs（I） was obtained by using the dissolved solutions of spent fuel from FBR-JOYO （JAEA）.展开更多
In this study,the electrochemical behavior of Pd(II)in nitric acid media was investigated using various electrochemical techniques.By analyzing the cyclic voltammogram of Pd(II)recorded at Pt electrode,a series of ele...In this study,the electrochemical behavior of Pd(II)in nitric acid media was investigated using various electrochemical techniques.By analyzing the cyclic voltammogram of Pd(II)recorded at Pt electrode,a series of electrochemical reactions associated with palladium were recognized,indicating that Pd(II)undergoes a single step two-electrons irreversible process.Electroreduction reaction of Pd(II)and auto-catalytic reactions of nitrous acid are supposed to play a leading role in low and high concentrations of nitric acid,respectively.Stirring could facilitate the reduction of Pd(II)in relatively low nitric acid concentration(3 mol/L).The value of charge transfer coefficient was determined to be 0.18 for the measurements at 298 K.The diffusion coefficient of Pd(II)increased from 1.89×10 8cm2/s at 288 K to 4.23×10 8cm2/s at 318 K,and the activation energy was calculated to be 21.5 kJ/mol.In electrowinning experiments,SEM images of palladium obtained by electrolysis reveal the dendrite growth in all cases,which is uniform all over the entire surface of Pt electrode.The recovery ratios of Pd at different nitric acid concentrations are high,and the faradic efficiency of electrolysis decreases with increasing the nitric acid concentration.When stirring was introduced during electrolysis,the electrodeposition rate of Pd increased substantially.展开更多
文摘The research and developments of a new type of inorganic ion exchanger, crystalline silicotitanate (CST) are reviewed. This material is stable against radiation, and the CST has high selectivity for Cs over Na, K and Rb. It performs well in acidic, neutral, and basic solutions. The results of ion exchange tests show that CST is an excellent candidate for Cs removal from high-level liquid waste.
文摘Basic properties of a silica-based octyl(phenyl)-N,N-diisobutylcarbamoyl-methylphosphine oxide (CMPO) extraction resin (CMPO/SiO2-P) was investigated.Adsorption behavior for some rare earth elements (RE) which are constituents of high level liquid waste (HLLW) and the long-term stability of the extraction resin in nitric acid solution were examined.The CMPO extraction resin was significantly stable in 3 mol·L?1 HNO3 solution at 50oC.Furthermore,the RE(III) were efficiently separated from non-adsorptive fission product (FP) elements such as Sr(II) in a column experiment using a highly nitric acid solution.The separation behaviors of the elements are considered to result from the difference in their adsorption and elution selectivity based on the complex formation with CMPO.There was no strong dependency of RE(III) separation efficiency on feed solution flow rate.Only from the perspectives of the acid-resistant behavior of CMPO extraction resin and the elution kinetics for the metal ions with the extraction resin,the CMPO extraction resin can be used in the modified MAREC process for HLLW partitioning.
文摘Bentonite has been considered as the buffer material for embedding canisters with high-level radioactive waste(HLW)in the deep geology repositories. GMZ bentonite deposit which is located in Xinghe County,Inner Mongolia has been proposed as buffer/backfill material for HLW repository in China. Liquid limit of natural Na-bentonite GMZ01 and commercial Na-bentonite MX80 which were previously put in the oven at 80℃and 95℃,and exposed to water for different times were measured.The liquid limit of GMZ01 increased slightly at the beginning, and then decreased as the heating time increased.
文摘A process for actinide(Ⅲ)and lanthanum(Ⅲ)extraction separation from high-level liquid waste(HLLW)was proposed,with N,N,N’,N’-tetraoctyl diglycolamide(TODGA)as the extractant,tri-n–butyl phosphate(TBP)as the phase modifier and 2,6-bis[1-(propan-1-ol)-1,2,3-triazol-4-yl]pyridine(PyTri-Diol or PTD)as hydrophilic stripping agent.This‘hot test’was successfully carried out,achieving 99.92%removal of americium-241(^(241)Am)with a separation factor SF(Eu/Am)of 3.8×10^(3)in the actinide(Ⅲ)product solution.The results show that bisamide podand extractants can effectively realize the extraction and separation of actinide(Ⅲ)and lanthanum(Ⅲ)from Chinese commercial HLLW and thus have a bright practical application potential for the treatment of commercial HLLW.
基金Supported by the International Atomic Energy Agency’s Technical Cooperation Project(IAEA-TC/CPR/4/024)
文摘Bentonite has been considered as a buffer material for embedding canisters with high-level radioactive waste（HLW） in deep geological repositories.GMZ bentonite deposit,located in Xinghe County,Inner Mongolia Autonomous Region,China was proposed as a buffer/backfill material for HLW repository in China.The liquid limits of natural Na-bentonite GMZ01 and commercial Na-bentonite MX80,which are previously heated at 80 ℃ and 95 ℃,respectively,and exposed to water for different times are measured.It is observed that the liquid limit of GMZ01 increases slightly at the beginning,and then decreases as the heating time increases,while the liquid limit of MX80 decreases with the heating time.The liquid limits of both GMZ01 and MX80 decrease with increasing water-exposure time.After the samples are heated at 80℃and 95 ℃ for several months,the mineralogical composition of GMZ01 does not exhibit evident change,whereas MX80 experiences some changes.In addition,the chemical composition,cation exchange capacity（CEC） and exchangeable cation of all the samples do not change significantly.
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.
文摘The exchange performances and the distribution coefficient of Cesium Ion-Sieve (Cs-IS) for cesium and for some rare earth elements were compared. In particula r, the effects of neodymium on the cesium ion exchange and the Cs+ selectivity v ariation on Cs-IS owing to introduction of rare earth elements into HLLW were s tudied. Though rare earth elements exhibit a small influence on the distributio n coefficient for Cs+, they impair Cs-exchange capacity of Cs-IS to some ext ent. This interruption on the selectivity to Cs+ can be significantly eliminat ed provided an appropriate ratio of liquid to solid V:m is used.
基金Supported by National Natural Science Foundation of China(Nos.11305102,91126006,21261140335 and 91226111)Doctoral Fund of Ministry of Education of China(No.20130073110046)
文摘The adsorption behavior of241Am(Ⅲ) and Eu(Ⅲ) by silica/polymer-based iso Hex-BTP adsorbent(iso HexBTP/Si O2-P) was investigated by a batch experiment method. iso Hex-BTP/Si O2-P exhibited high affinity and selectivity for241Am(Ⅲ) over152Eu(Ⅲ) in 2–4 mol/dm3 nitric acid solutions. Within the experimental contact time range of 0.5–24 h, iso Hex-BTP/Si O2-P showed high selectivity for241Am(Ⅲ) compared to152Eu(Ⅲ) in3 mol/dm3 nitric acid solution. However, the adsorption kinetics of241Am(Ⅲ) and152Eu(Ⅲ) was slow. Eu(Ⅲ)adsorption followed the pseudo-second-order kinetic model, indicating chemical adsorption as the rate-limiting step of the adsorption process. And the adsorption agreed well with the Langmuir adsorption model at various temperatures. The adsorption kinetics and isotherm data indicated that the equilibrium adsorption capacity, the adsorption rate, the maximum adsorption capacity and the adsorption affinity, increased with temperature. The thermodynamic parameters, negative change in Gibbs free energy, and positive change in enthalpy and entropy,suggested that the adsorption of Eu(Ⅲ) was spontaneous and endothermic process with an increase of entropy.
文摘A functional microcapsule was prepared by encapsulating the fine crystalline ammonium tungstophosphate （AWP） in calcium alginate polymer （CaALG）. The characterization of AWP-CaALG microcapsule was examined by SEM and EPMA. The ad- sorption behavior of Cs（Ⅰ）, Rb（Ⅰ）, Sr（Ⅱ）, Pd（II）, Ru（Ⅲ）, Rh（Ⅲ）, La（Ⅲ）, Ce（Ⅲ）, Dy（Ⅲ） and Zr（IV） was investigated by the batch method. The batch experiments were carried out by varying the shaking times, HNO3 concentration, and initial concen- tration of metal ions. Relatively large K＋ values above 105 cm3/g for Cs（I） were obtained in the range of 0.1-5 M HNO3, re- sulting in a separation factor of Cs/Rb exceeding 102. In contrast, the K＋ values of Sr（II）, Pd（II）, Ru（Ⅲ）, La（Ⅲ）, Dy（Ⅲ）, Ce（Ⅲ） and Zr（IV） were considerably lower than 50 cm3/g. The K＋ value of Cs（1） decreased in the order of the coexisting ions, H＋ 〉 Na＋ 〉〉 NH4＋, and a linear relationship with a slop of about -1 was obtained between log Kd and log [NH4＋] （[NH4＋] 〉 0.01 M） The adsorption of Cs（I） was found to be controlled by chemisorption mechanism, and followed a Langmuir-type adsorption equation. A high uptake percentage of 99.4% for Cs（I） was obtained by using the dissolved solutions of spent fuel from FBR-JOYO （JAEA）.
基金supported by the National Natural Science Foundation of China(91026019,91126006)
文摘In this study,the electrochemical behavior of Pd(II)in nitric acid media was investigated using various electrochemical techniques.By analyzing the cyclic voltammogram of Pd(II)recorded at Pt electrode,a series of electrochemical reactions associated with palladium were recognized,indicating that Pd(II)undergoes a single step two-electrons irreversible process.Electroreduction reaction of Pd(II)and auto-catalytic reactions of nitrous acid are supposed to play a leading role in low and high concentrations of nitric acid,respectively.Stirring could facilitate the reduction of Pd(II)in relatively low nitric acid concentration(3 mol/L).The value of charge transfer coefficient was determined to be 0.18 for the measurements at 298 K.The diffusion coefficient of Pd(II)increased from 1.89×10 8cm2/s at 288 K to 4.23×10 8cm2/s at 318 K,and the activation energy was calculated to be 21.5 kJ/mol.In electrowinning experiments,SEM images of palladium obtained by electrolysis reveal the dendrite growth in all cases,which is uniform all over the entire surface of Pt electrode.The recovery ratios of Pd at different nitric acid concentrations are high,and the faradic efficiency of electrolysis decreases with increasing the nitric acid concentration.When stirring was introduced during electrolysis,the electrodeposition rate of Pd increased substantially.
