Adsorption and separation behavior of palladium(II) from simulated high-level liquid waste using a novel silica-based adsorbents

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Hao Wu ◽  
Naoki Osawa ◽  
Masahiko Kubota ◽  
Seong-Yun Kim
Keyword(s):  
Nitric Acid ◽  
Selective Adsorption ◽  
Packed Column ◽  
Liquid Waste ◽  
Freundlich Isotherm ◽  
Effect Of Temperature ◽  
Adsorption Model ◽  
High Level Liquid Waste ◽  
Adsorption Selectivity ◽  
Successful Recovery

Abstract Aiming at selective adsorption and separation of Pd(II) in nitric acid solution, a hybrid soft N and hard O donor adsorbent (TAMIA-EH+TOA)/SiO2–P (P = Polymer) was successfully synthesized. The adsorption performances of (TAMIA-EH+TOA)/SiO2–P adsorbent towards Pd(II) were systematically investigated as a function of contact time, effect of concentration of nitric acid, effect of temperature etc. Adsorption speed of Pd(II) was fairly fast and can reach equilibrium state within only 0.5 h. The distribution coefficient of Pd(II) was more than 103 when [HNO3] = 0.1. Though it decreased gradually with an increase in the concentration of HNO3, the adsorption selectivity of (TAMIA-EH+TOA)/SiO2–P adsorbent towards Pd(II) was still significant than other co-existing metal ions in the whole HNO3 range from 0.1 to 5 M. The adsorption isotherm of Pd(II) onto (TAMIA-EH+TOA)/SiO2–P adsorbent fitted well with Langmuir adsorption model but Freundlich isotherm model. The calculated results of adsorption thermodynamic parameters indicated that the adsorption process of Pd(II) was exothermic and happened in a natural way. Furthermore, the separation chromatography experiment by utilizing (TAMIA-EH+TOA)/SiO2–P adsorbent packed column was carried out. Based on the results of plotted elution curves, it was found that the successful recovery of Pd(II) (96.27%) was achieved by eluting with thiourea solution.

Adsorption Materials Development for the Separation of Actinides and Specific Fission Products from High Level Waste

2014 ◽  
Vol 94 ◽  
pp. 103-110 ◽  
Author(s):  
Yue Zhou Wei ◽  
Shun Yan Ning ◽  
Qi Long Wang ◽  
Zi Chen ◽  
Yan Wu ◽  
...  
Keyword(s):  
Spent Nuclear Fuel ◽  
Selective Adsorption ◽  
Packed Column ◽  
Liquid Waste ◽  
Separation Method ◽  
High Level Waste ◽  
Small Scale ◽  
Fast Diffusion ◽  
High Level Liquid Waste ◽  
High Level

The long-term radiotoxicity of high level liquid waste (HLLW) generated in spent nuclear fuel reprocessing is governed by the content of several long-lived minor actinides (MA) and some specific fission product nuclides. To efficiently separate MA (Am, Cm) and some FPs such as Cs and Sr from the HLLW, we have been studying an advanced aqueous partitioning process, which uses selective adsorption as separation method. In this work, we prepared different types of porous silica-based organic/inorganic adsorbents with fast diffusion kinetics, improved chemical stability and low pressure drop in a packed column. So they are advantageously applicable to efficient separation of the MA and specific FP elements from HLLW. Adsorption and separation behaviors of the MA and some FP elements such as Cs and Sr were studied. Small scale separation tests using simulated and genuine nuclear waste solutions were carried out and the obtained results indicate that the proposed separation method based on selective adsorption is essentially feasible.

Interference of Zr(IV) during the extraction of trivalent Nd(III) from the aqueous waste generated from metallic fuel reprocessing

2020 ◽  
Vol 108 (7) ◽  
pp. 543-554
Author(s):  
T. Prathibha ◽  
K. Rama Swami ◽  
S. Sriram ◽  
K. A. Venkatesan
Keyword(s):  
Nitric Acid ◽  
Mechanical Stability ◽  
Nitric Acid Concentration ◽  
Liquid Waste ◽  
Aggregate Size ◽  
Metallic Fuel ◽  
High Level Liquid Waste ◽  
Spectral Techniques ◽  
Extraction Behavior ◽  
Fuel Reprocessing

AbstractA metallic alloy of uranium–zirconium and uranium–plutonium–zirconium has been proposed as a fuel for fast reactors, owing to the possibility of achieving high breeding ratio in a short span of time. About 6–10 wt.% of zirconium has been added to these actinide fuels to increase the melting temperature and thermal-mechanical stability. Aqueous reprocessing of the spent metallic fuel generates the high-level liquid waste (HLLW) that contains about 60 % of the total zirconium from the fuel. In view of this, the extraction behavior of a trivalent representative ion, Nd(III) in the presence of Zr(IV) was studied from nitric acid medium using the candidate ligands proposed for trivalent actinide separation from HLLW, such as N,N,N′N′-tetraoctyldiglycolamide (TODGA), and N,N-di-octyl-2-hydroxyacetamide (DOHyA). The extraction was studied as a function of nitric acid concentration, zirconium and neodymium concentration and Nd(III) to Zr(IV) ratio. The findings of dynamic light scattering (DLS) and ATR-FTIR spectral techniques were used for understanding the complex chemistry of Zr(IV) extraction under different conditions. Poor extraction of nitric acid, smaller aggregate size, no third phase formation during the extraction of Zr(IV) and Nd(III) and other unique solvent properties favor the DOHyA molecule in n-dodecane as a solvent for partitioning of trivalent actinides from HLLW generated from metallic fuel reprocessing.

The Application Research of Concentration & Denitration Technology in Advanced Reprocessing Process

2012 ◽  
Vol 560-561 ◽  
pp. 637-643
Author(s):  
Yong Li ◽  
Xue Gang Liu ◽  
Jin Chen
Keyword(s):  
Nitric Acid ◽  
Nuclear Power ◽  
Liquid Waste ◽  
Fission Products ◽  
Extraction Process ◽  
Purex Process ◽  
Current Status ◽  
Spent Fuel ◽  
High Level Liquid Waste ◽  
High Level

The proper management of spent fuel arising from nuclear power production is a key issue for the sustainable development of nuclear energy. While conventional reprocessing process, PUREX process, was successful to recover uranium and plutonium, in recent years some countries have turned to focus on advanced reprocessing process, which features of partitioning of minor actinides (MA) and long-lived fission products(LLFP). Most advanced reprocessing processes under development involve new extractants and additional extraction cycles. In China, TRPO extraction process has been developed to partition MA/LLFP from high-level liquid waste(HLLW) since early 1980’s. In parallel to R&D work on separation technologies, studies on concentration & denitration process have been evolved to prepare feed solutions to suit qualifications of extraction. Industrially, concentration & denitration is the internationally recognized standard to treat HLLW released from PUREX before vitrification. It enables to minimize the volume of interim storage, to restrain the corrosion of storage tank, to recover nitric acid in HLLW and to reduce the required evaporation duty of the vitrification process. Generally, the constitution of concentrated HLLW has little impact on the following vitrification process. But when concentration & denitration acts as pretreatment process of partitioning, the composition of actinides, fission products, and nitric acid in concentrated HLLW solution plays significant role in extraction process. A series of technical issues relevant to the connection between concentration ﹠denitration and extractions should be solved. This paper describes current status of concentration & denitration technology utilized in industry and under reprocessing plants. The specific separation requirements in advanced reprocessing process and challenges to apply concentration & denitration process are addressed. Besides, concentration & denitration process was tested in laboratory to adjust feed solutions for TRPO and Cyanex301 partitioning. Results demonstrate its promising prospect in advanced reprocessing process.

Effect of pKa on the extraction behavior of Am(III) in organo phosphorus acid and diglycolamide solvent system

2018 ◽  
Vol 106 (2) ◽  
pp. 107-118 ◽  
Author(s):  
K. Rama Swami ◽  
R. Kumaresan ◽  
P. K. Nayak ◽  
K. A. Venkatesan ◽  
M. P. Antony
Keyword(s):  
Nitric Acid ◽  
Metal Ions ◽  
Phosphinic Acid ◽  
Liquid Waste ◽  
High Level Liquid Waste ◽  
Single Cycle ◽  
Cyanex 272 ◽  
Extraction Behavior ◽  
Trivalent Actinides ◽  
High Level

AbstractA combination of neutral and acidic extractant has been proposed for the single-cycle separation of trivalent actinides from high-level liquid waste (HLLW). The nature of acidic extractant in the combined solvent formulation plays a profound role in deciding the extraction and stripping of trivalent actinides. Therefore, the extraction behavior of Am(III) in a solution of tetra-bis(2-ethylhexyl)-diglycolamide (TEHDGA) and acidic extractant (HA) was studied from nitric acid medium. The acidic extractants chosen were bis(2-ethylhexyl)phosphoric acid (HDEHP), bis(2-ethylhexyl)phosphonic acid (PC88A) and bis(2,4,4-trimethylpentyl)phosphinic acid (CYANEX-272) whose pKavalues were 3.24, 4.51 and 6.37, respectively. The distribution ratio of Am(III) was measured as a function of various parameters such as concentration of nitric acid, TEHDGA, HA etc. The data were compared with those obtained in individual solvent systems namely 0.1 M TEHDGA/n-DD and HA/n-DD. Slope analysis of the extraction data indicated the synergic participation of both TEHDGA and HDEHP in the extraction of Am(III) at all acidities. However, antagonistic effect was observed at lower acidity when TEHDGA was mixed to PC88A or CYANEX-272 present inn-DD. Accordingly, a suitable mechanism has been proposed for the extraction of Am(III) at all acidities using these combined solvent formulation. Studies with fast reactor simulated high level liquid waste indicated that extraction of Am(III) was accompanied by co-extraction of lanthanides and unwanted metal ions such as Zr(IV), Mo(VI), Y(III) and Pd(II). However, addition of trans-1,2-diaminocyclohexane-N,N,N,N′-tetraaceticacid (CyDTA) reduced the extraction of unwanted metal ions. Batch extraction and stripping studies indicated the possibility of using 0.1 M TEHDGA+0.25 M HDEHP inn-dodecane for the single cycle separation of Am(III) from FR-SHLLW.

scholarly journals Micro-PIXE analysis on adsorbent of extraction chromatography for MA(III) recovery

2016 ◽  
Vol 26 (03n04) ◽  
pp. 73-83
Author(s):  
Y. Takahatake ◽  
S. Watanabe ◽  
H. Kofuji ◽  
M. Takeuchi ◽  
K. Nomura ◽  
...  
Keyword(s):  
Extraction Chromatography ◽  
Packed Column ◽  
Liquid Waste ◽  
Flow Sheet ◽  
Simple Experiment ◽  
High Level Liquid Waste ◽  
Energy Agency ◽  
Pixe Analysis ◽  
Conducting Research ◽  
High Level

Japan Atomic Energy Agency (JAEA) has been conducting research and development of MA(III) recovery from high level liquid waste (HLLW) by extraction chromatography technology for reduction in amount and environmental impact of radioactive waste. The behavior of adsorbed cations inside the adsorbent packed in a column is necessary to be evaluated for improvement of the adsorbent or flow-sheet to achieve targeted MA(III) recovery performance. In this paper, micro-PIXE analysis was carried out on the particles sampled from various positions of the column to reveal the behavior of cations inside the packed column with CMPO/SiO2-P adsorbent using RE(III) as simulated elements of MA(III). Simple experiment and data analysis were shown to be effective to reveal inside of the column, and formation and transportation of the adsorption bands were observed for some cations which are extractable by the CMPO extractant. Some part of Zr(IV) and Mo(VI) were found to remain inside the column without distinct transportation even after the elution operation. Those results will contribute to design more practical MA(III) recovery flow-sheet.

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