Highly Active Liquid Waste Research Articles

Effect of ligand initial conformation and counteranion on complexation behaviors of R-BTBP toward Pd(II) contained in highly active liquid waste

Soft N-donor bis-triazin bipyridines derives (R-BTBP) are a type of very promising extratant for extraction and complexation with long-lived trivalent minor actinides over lanthanides from highly active liquid waste (HLW). In addition to minor actinides, R-BTBP also holds very strong complexation ability toward fission palladium. However, few studies have been focused on the separation and complexation with the fission product Pd(II) by R-BTBP. Herein, the complexation behaviors of Pd(II) with four typical R-BTBP ligands were systematically studied by single crystal X-ray diffraction, 1H NMR titration and theoretical calculation. The effects of R-BTBP initial conformation and nitrate anions on the complexation behaviors of R-BTBP with Pd(II) were thoughtfully analyzed. Both the 1:1 and 2:1 binuclear complexes could be formed between Pd(II) and R-BTBP with initial II conformation in the presence of nitrate anions, while only one 1:1 type Pd(II) complex could be formed for those with initial OO conformation. Without nitrate anion, only one 1:1 type complex was formed in solution. The structure of the 1:1 Pd(II)/R-BTBP complex was firstly characterized by single crystal crystallography. DFT calculation results showed that a significant large rotational energy barrier (21.8∼22.6 kcal/mol) must be overcome to form the II type 2:1 Pd(II) complex for those OO type R-BTBP ligands, however which would not prevent them from forming the 1:1 type complex.

Development of Two novel silica based symmetric triazine-ring opening N-donor ligands functional adsorbents for highly efficient separation of palladium from HNO3 solution.

The synthesis and characterization of two novel symmetric triazine-ring opening ligands CA-MP (pyridine derivative)/CA-BOPhen (1,10-phenanthroline derivative) functionalized SiO2-P (P = Polymer) adsorbents for separation of Pd(II) from HNO3 solutions are presented. SEM, N2 adsorption/desorption isotherms, TGA and EDS spectroscopy characterization results showed that CA-MP and CA-BOPhen were successfully introduced into the pores of SiO2-P carrier via physical intermolecular interactions. CA-MP@SiO2-P and CA-BOPhen@SiO2-P show high efficiency, high selectivity, extremely fast adsorption rates towards Pd(II) over 19 typical fission or corrosion products in HNO3 solution. The distribution coefficient Kd values of CA-MP@SiO2-P and CA-BOPhen@SiO2-P are up to 206.5 and 205.7 cm3/g, respectively, within 10-15 min of contact time in 0.4 M HNO3. The adsorption capacities of them to Pd(II) were determined to be 0.36 mmol/g and 0.23 mmol/g, respectively. The fast adsorption rates and high selectivity of two adsorbents towards Pd(II) were related to the formation of the highly preorganized complex [Pd(NO3)(L)]+ (L = CA-MP or CA-BOPhen). These results demonstrate that CA-MP@SiO2-P and CA-BOPhen@SiO2-P possess great potential for highly efficient removal of Pd(II) from highly active liquid waste (HLW).

Quantitative determination of total cesium in highly active liquid waste by using liquid electrode plasma optical emission spectrometry

A sensitive analytical method for determination of total cesium (Cs) in highly active liquid waste (HALW) by using modified liquid electrode plasma optical emission spectrometry (LEP-OES) is developed in this study. The instrument is modified to measure radioactive samples in a glove box. The effects of important factors, including pulsed voltage sequence and nitric acid concentration, on the emission of Cs are investigated. The limit of detection (LOD) and limit of quantification (LOQ) are 0.005 mg/L and 0.02 mg/L, respectively. The achieved LOD is one order lower than that of recently developed spectroscopic methods using liquid discharge plasma. The developed method is validated by subjecting a simulated HALW sample to inductively coupled plasma mass spectrometry (ICP-MS). The recoveries obtained from a spike-and-recovery test are 96–102%, implying good accuracy. The method is successfully applied to the quantification of Cs in a real HALW sample at the Tokai reprocessing plant in Japan. Apart from dilution and filtration of the HALW sample, no other pre-treatment process is required. The results agree well with the values obtained using gamma spectrometry. The developed method offers a reliable technique for rapid analysis of total Cs in HALW samples.

Preparation and characterization of a novel macroporous silica-bipyridine asymmetric multidentate functional adsorbent and its application for heavy metal palladium removal

The effective removal of heavy metal 107Pd(II) from highly active liquid waste (HLW) is very valuable for reducing its hazardous and risk to public health and environment. For this purpose, a novel silica-bipyridine multidentate functional adsorbent was synthesized by vacuum infusing a new asymmetric N-donor ligand CA-MTBP (bipyridine derivative) into the macroporous SiO2-P support. SEM, N2 adsorption–desorption isotherms, TGA, XRD, FT-IR, 29Si solid-state NMR and XPS spectroscopy were utilized to systematically characterize the physicochemical properties of the adsorbent. The characterization results indicated that CA-MTBP was successfully immobilized onto the pores of SiO2-P by intermolecular interaction. Strong hydrogen-bonding interactions identified by single crystal structure of the ligand and 29Si NMR may play a key role in achieving this immobilization. TGA and TOC studies showed that CA-MTBP/SiO2-P had excellent thermal stability and highly HNO3 resistance. EDS and XPS investigations provided directly evidences for Pd(II) being selectively adsorbed onto the adsorbent. The adsorbent had excellent adsorption capability, fast adsorption kinetics and high selectivity for Pd(II) over other typical tested metals in HNO3 media.

Extraction behavior of cesium and some typical fission and non-fission products with a new 1,3-di(1-decyloxy)-2,4-crown-6-calix[4]arene

Abstract A new macrocyclic supramolecular recognition agent, 1,3-di(1-decyloxy)-2,4-crown-6-calix[4]arene (DecylCalix[4]C6), was synthesized by a multistep reaction through separation and purification by column chromatography packed with silica gel. The extraction behavior of some representative fission and non-fission products such as La(III), Y(III), Cs(I), Rb(I), Pd(II), Mo(VI), Zr(IV), Sr(II), Ba(II), Ru(III), Na(I), and K(I), which were contained in highly active liquid waste (HLW), with DecylCalix[4]C6/1-octanol in HNO3 medium was investigated, in particular by examining the impact of contact time, the HNO3 concentration in the range of 0.4 to 5.0 M, and the temperature. DecylCalix[4]C6 showed excellent extraction ability and high selectivity for Cs(I) over the tested metals except for Rb(I). It was attributed to the effective recognition and complxation of DecylCalix[4]C6 for Cs(I). The optimum HNO3 concentration for the Cs(I) extraction was 3.0 M. The composition of the extracted species of Cs(I) with DecylCalix[4]C6 was determined to be (CsDecylCalix [4]C6)NO3. It is valuable for the effective partitioning of Cs(I) from highly active liquid waste with DecylCalix[4]C6 by liquid-liquid solvent extraction.

Preparation of a Macroporous Silica-Based Multidentate Soft-Ligand Material and its Application in the Adsorption of Palladium and the Others

To separate Pd(II), a macroporous silica-based soft-ligand 2,6-bis(5,6-di(iso-butyl)-1,2,4-triazine-3-yl)pyridine (BDIBTP) material, BDIBTP/SiO2-P, was synthesized by vacuum treatment. It was a multidentate chelating composite prepared by impregnation and immobilization of BDIBTP and 1-octanol molecules into the pores of the macroporous SiO2-P particles with a mean diameter of 50 µm. 1-Octanol was used to modify BDIBTP through intermolecular interaction force. The adsorption of some typical fission products Zr(IV), Pd(II), La(III), Y(III), Ru(III), Rh(III), and Mo(VI) contained in highly active liquid waste (HLW) onto the BDIBTP/ SiO2-P materials was investigated. It was carried out by examining the effects of contact time and the concentration of HNO3 in the range of 0.3 M−7.0 M. BDIBTP/SiO2-P showed excellent adsorption ability and high selectivity for Pd(II) over all of the tested metals. It was ascribed to the effective complexation of Pd(II) with BDIBTP/SiO2-P. Consideration of the complexation of BDIBTP for minor actinides MAs(III), the possibility and feasibility of effective partitioning of Pd(II) and MAs(III) simultaneously from a simulated HLW were discussed. A new concept process entitled MPS for the MA(III) and Pd(II) Separation has been proposed.

Adsorption of Some Typical Fission Products onto a Novel Macroporous Silica-based Dialkyl Derivative of Pyridine Impregnated Material

A macroporous silica-based multidentate soft-ligand 2,6-bis(5,6-di(iso-hexyl)-1,2,4-triazine-3-yl)pyridine (BDIHTP) material, BDIHTP/SiO2-P, was synthesized by impregnating and immobilizating BDIHTP into the pores of the SiO2-P particles. The adsorption behavior of some typical fission products Mo(VI), Zr(IV), Ru(III), Pd(II), Rh(III), and a part of rare earths La(III), Ce(III), Nd(III), Eu(III), Gd(III), Dy(III), Er(III), Yb(III), and Y(III) contained in highly active liquid waste (HLW) onto BDIHTP/SiO2-P was investigated. The effects of contact time and the concentration of HNO3 in the range of 0.3 M to 5.0 M were examined. The BDIHTP/SiO2-P materials showed excellent adsorption ability and high selectivity for Pd(II) greater than all of the tested metals. It was contributed to the effective complexation of Pd(II), a soft-Lewis acid and an electron-pair acceptor, with BDIHTP, a soft-Lewis base and an electron-pair donor. The chromatographic partitioning of the tested metals from 1.0 M HNO3 by BDIHTP/SiO2-P packed column was performed. Pd(II) was effectively eluted with 0.2 M thiourea-0.1 M HNO3 and then separated from the others. The results are beneficial to partitioning of the long-lived minor actinides and Pd(II) together from HLW by the BDIHTP/SiO2-P materials.

Preparation of a macroporous silica–pyridine multidentate material and its adsorption behavior for some typical elements

AbstractA new macroporous silica‐based‐polymer (SiO2‐P) soft ligand composite material, 2,6‐bis(5,6‐di(iso‐butyl)‐1,2,4‐triazine‐3‐yl)pyridine (BDIBTP/SiO2‐P), was synthesized by impregnation and immobilization of BDIBTP and 1‐octanol molecules into the pores of the SiO2‐P particles. The impact of some typical alkali metal and alkaline earths Cs(I), Na(I), K(I), Rb(I), Sr(II), and Ba(II) containing in highly active liquid waste (HLW) on the adsorption of Pd(II) onto BDIBTP/SiO2‐P was studied. It was performed by examining the effects of contact time and the HNO3 concentration in the range of 0.3–7.0 M. BDIBTP/SiO2‐P showed strong adsorption ability and high selectivity for Pd(II) over all the tested metals. The chromatographic partitioning of Pd(II) from a simulated HLW solution was conducted by BDIBTP/SiO2‐P packed column. Pd(II) was effectively eluted with 0.2 M thiourea–0.1 M HNO3. The others showed no adverse impact on separation of Pd(II). The results are beneficial to partitioning of minor actinides and Pd(II) together from HLW by BDIBTP/SiO2‐P in the MPS process developed. © 2012 American Institute of Chemical Engineers AIChE J, 2012

Synthesis and Characterization of a New Polymer-Based Supramolecular Recognition Material and its Adsorption for Cesium

A novel macroporous polymer-based 25,27-bis(iso-propyloxy)calix[4]arene-26,28-crown-6 (BiPCalix[4]C6) supramolecular recognition material, BiPCalix[4]C6/XAD-7, was synthesized. It was performed by vacuum impregnation and immobilization of BiPCalix[4]C6 into the pores of the macroporous XAD-7 particles. The composition and structure were characterized using SEM, BET, TG-DSC, FT-IR, and XRD, respectively. The adsorption of some typical metals contained in highly active liquid waste (HLW) such as Ru(III), Mo(VI), K(I), Rb(I), Cs(I), Sr(II), Ba(II), La(III), and Y(III) onto the BiPCalix[4]C6/XAD-7 materials was investigated. The effects of the HNO3 concentration and contact time on the adsorption of the tested metals were evaluated. It was found that at the optimum concentration of 4.0 M HNO3, BiPCalix[4]C6/XAD-7 exhibited excellent adsorption ability and high selectivity for Cs(I) over all the other tested metals, which showed weak or almost no adsorption except Rb(I). It demonstrated that application of the polymer-based supramolecular recognition material, BiPCalix[4]C6/XAD-7, in partitioning of Cs(I) from HLW is promising.

Preparation of a Macroporous Silica-Based Pyridine Impregnated Material and Its Adsorption for Palladium

A macroporous silica-based 2,6-bis(5,6-di(iso-hexyl)-1,2,4-triazine-3-yl)pyridine (BDIHTP) multinitrogen molecular recognition material, BDIHTP/SiO2-P, was prepared. It was performed through impregnation and immobilization of BDIHTP into the pores of the macroporous SiO2-P particle support with a mean diameter of 50 μm. The adsorption of some typical alkali metal and alkaline earths Cs(I), Na(I), K(I), Rb(I), Sr(II), and Ba(II), as well as Pd(II), a representative of precious metals, contained in highly active liquid waste (HLW), onto the BDIHTP/SiO2-P material was investigated at 298 K. It was carried out by examining the effects of contact time and the HNO3 concentration in the range 0.3–5.0 M. BDIHTP/SiO2-P showed excellent adsorption ability and high selectivity for Pd(II) over all the tested metals, which had weak or almost no adsorption. It was attributed to the strong chemical complexation of Pd(II), a soft Lewis acid and an electron-pair acceptor, with nitrogen inside BDIHTP, a soft Lewis base and...

Synthesis of a macroporous silica‐based derivative of pyridine material and its application in separation of palladium

AbstractA novel macroporous silica‐based 2,6‐bis(5,6‐dibutyl‐1,2,4‐triazine‐3‐yl)pyridine (BDBTP) material, BDBTP/SiO2‐P, was prepared through impregnation and immobilization of BDBTP and octanol into the pores of the SiO2‐P particles. The adsorption of 10 typical fission and nonfission elements contained in highly active liquid waste (HLW) onto BDBTP/SiO2‐P was investigated by examining the effect of contact time and the HNO3 concentration in the range of 0.1–5.0 M. Pd(II), a weak Lewis acid and an electron‐pair acceptor, was strongly complexed with nitrogen, a weak Lewis base and an electron‐pair donor. BDBTP/SiO2‐P showed excellent adsorption ability and high selectivity for Pd(II) over all the tested metals. The separation of Pd(II) from a simulated HLW was performed by BDBTP/SiO2‐P packed column. Pd(II) was effectively eluted with 0.2 M thiourea and separated from the others. It demonstrated that in HNO3, application of the macroporous silica‐based BDBTP/SiO2‐P material in partitioning and recovery of Pd(II) from HLW is promising. © 2010 American Institute of Chemical Engineers AIChE J, 2010

Chromatographic partitioning of cesium by a macroporous silica‐calix[4]arene‐crown supramolecular recognition composite

AbstractA macroporous silica‐based 1,3‐[(2,4‐diethyl‐heptylethoxy)oxy]‐2,4‐crown‐6‐calix[4]arene (Calix[4]arene‐R14) supramolecular recognition polymeric composite, (Calix[4]+Oct)/SiO2‐P, was synthesized. It was performed by impregnating and immobilizing Calix[4]arene‐R14 and n‐octanol into the pores of the macroporous SiO2‐P particles support. n‐Octanol was used to modify Calix[4]arene‐R14 through hydrogen bonding. The effect of eight typical fission products contained in highly active liquid waste (HLW) on the adsorption of Cs(I), one of the heat generators, was investigated at 298 K by examining the effect of contact time and the HNO3 concentration in a range of 0.3–7.0 M. (Calix[4]+Oct)/SiO2‐P showed excellent adsorption ability and high selectivity for Cs(I) at 4.0 M HNO3 over the tested elements. The partitioning of Cs(I) from a simulated HLW was operated by (Calix[4]+Oct)/SiO2‐P packed column. Cs(I) was able to be effectively eluted by water and separated from the tested metals. It is demonstrated that (Calix[4]+Oct)/SiO2‐P is promising to apply in chromatographic separation of Cs(I) from HLW. © 2010 American Institute of Chemical Engineers AIChE J, 2010

Adsorption of cesium and some typical coexistent elements onto a modified macroporous silica-based supramolecular recognition material

To find an effective method in separation of Cs(I), an advanced macroporous silica-based supramolecular recognition composite, (Calix[4] + MODB)/SiO 2-P, was synthesized. It was done by impregnation and immobilization of 1,3-[(2,4-diethylheptylethoxy)oxy]-2,4-crown-6-calix[4]arene (Calix[4]arene-R14) and methyloctyl-2-di-methy-lbutanemide (MODB) into the pores of the SiO 2-P particles. MODB was used to modify Calix[4]arene-R14. The adsorption of some typical fission products such as Mo(VI), Pd(II), La(III), Y(III), Ru(III), Rh(III), Cs(I), and Zr(IV) contained in highly active liquid waste (HLW) onto (Calix[4] + MODB)/SiO 2-P was investigated. It was performed by examining the effects of contact time, the concentration of HNO 3 in the range of 0.3–7.0 M, and operation temperature on the adsorption of the tested metals. (Calix[4] + MODB)/SiO 2-P showed strong adsorption ability and excellent selectivity for Cs(I) over all the tested metals. The separation of Cs(I) from a simulated HLW containing 5.0 mM of the tested elements was performed by (Calix[4] + MODB)/SiO 2-P packed column at 298 K. Mo(VI), Pd(II), La(III), Y(III), Ru(III), Rh(III), and Zr(IV) showed no adsorption and were eluted into effluent along with 3.0 M HNO 3. Cs(I) adsorbed by (Calix[4] + MODB)/SiO 2-P was effectively eluted with water and then separated from the others. The results demonstrated that in 3.0 M HNO 3, (Calix[4] + MODB)/SiO 2-P is promising to apply in separation of Cs(I), one of the heat generators, from HLW in the SPEC ( Strontium/Cesium Partitioning from HLW by Extraction Chromatography) process developed recently.

SPEC: A New Process for Strontium and Cesium Partitioning Utilizing Two Macroporous Silica-Based Supramolecular Recognition Agents Impregnated Polymeric Composites

To effectively separate two heat generators Cs(I) and Sr(II) from a highly active liquid waste (HLW), two macroporous silica-based polymeric composites (Calix[4]arene-R14 + M)/SiO2-P and (DtBuCH18C6 + M)/SiO2-P were synthesized. It was done by impregnating and immobilizing the supramolecular recognition agent, 1,3-[(2,4-diethylheptyl ethoxy)oxy]-2,4-crown-6-calix[4]arene (Calix[4]arene-R14) or 4,4′,(5′)-di-(tert-butylcyclo hexano)-18-crown-6 (DtBuCH18C6), into the pores of the macroporous SiO2-P particles with a mean diameter of 50 µm. It was found that in the first column packed with (Calix[4]arene-R14 + M)/SiO2-P, all of the tested elements were effectively eluted and separated into two groups: (1) Na(I), K(I), Sr(II), Ba(II), Rh(III), Ru(III), Pd(II), Zr(IV), RE(III) (La-Lu and Y), and Mo(VI) (Sr-containing group), and (2) Cs(I)-Rb(I) (Cs-group) by eluting with 4.0 M HNO3 and water, respectively, at 298 K. The heat emitting element Cs(I) flowed into the second group along with Rb(I), while Sr(II) showed no sorption and flowed into the Sr-containing group. In the second column packed with (DtBuCH18C6 + M)/SiO2-P, the Sr-containing group was separated into (1) Na(I), K(I), Rh(III), Ru(III), RE(III) (La-Lu and Y), Pd(II), Zr(IV), and Mo(VI) (non-sorption group), and (2) Sr(II)-Ba(II) (Sr-group), by eluting with 2.0 M HNO3 and water, respectively. The heat emitting element Sr(II) adsorbed by (DtBuCH18C6 + M)/SiO2-P flowed into the second group along with Ba(II). Based on the results, a new process entitled SPEC (Strontium/Cesium Partitioning from HLW by Extraction Chromatography) for heat generator partitioning from a simulated highly active liquid waste utilizing two macroporous silica-based supramolecular recognition composites has been developed.

SPEC Process II. Adsorption of strontium and some typical co-existent elements contained in high level liquid waste onto a macroporous silica-based crown ether impregnated functional composite

To separate Sr(II), one of the heat emitting nuclides, from high level liquid waste (HLLW), a macroporous silica-based DtBuCH18C6 polymeric composite, DtOct/SiO(2)-P, was synthesized by means of molecular modification of 4,4',(5')-di(tert-butylcyclohexano)-18-crown-6 (DtBuC H18C6) with a long-chain 1-octanol. It was performed by impregnating and immobilizing DtBuCH18C6 and 1-octanol molecules into the pores of the SiO(2)-P particles, the macroporous silica-based support. The adsorption of Sr(II) and some co-existent typical elements Na(I), K(I), Cs(I), Ru(III), Mo(VI), Pd(II), Ba(II), La(III), and Y(III) contained in highly active liquid waste (HLW) towards DtOct/SiO(2)-P was investigated at 323 K. The effects of contact time and the concentration of HNO(3) in a range of 0.1-5.0M on the adsorption of the tested metals were examined. The macroporous silica-based DtOct/SiO(2)-P polymeric composite showed strong adsorption ability and high selectivity for Sr(II) over all of the tested metals except Ba(II). The optimum acidity of Sr(II) adsorption onto DtOct/SiO(2)-P was determined to be 2.0M HNO(3). The bleeding behavior of DtOct/SiO(2)-P in aqueous phase was evaluated using total organic carbon (TOC) analysis. The content of TOC increased with increasing the HNO(3) concentration and contact time. It resulted from the decrease in the stability of the associated species, C(8)H(17)-OHaEuro cent DtBuCH18C6 formed through hydrogen binding, because of high temperature.

SPEC Process III. Synthesis of a Macroporous Silica-Based Crown Ether-Impregnated Polymeric Composite Modified with 1-Octanol and its Adsorption Capacity for Sr(II) Ions and Some Typical Co-Existent Metal Ions

A macroporous silica-based 4,4′,(5′)-di(t-butylcyclohexano)-18-crown-6 (DtBuCH18C6)-impregnated polymeric composite, (DtBuCH18C6 + Oct)/SiO2-P, was synthesized by molecular modification of DtBuCH18C6 with 1-octanol through hydrogen bonding. This was achieved by impregnating and immobilizing DtBuCH18C6 and 1-octanol molecules in the pores of macroporous SiO2-P particles possessing a mean pore diameter of 50 μm. The adsorption of some fission and non-fission products contained in highly active liquid waste (HLW) such as Ru(III), Mo(VI), Pd(II), Na(I), K(I), Cs(I), Sr(II), Ba(II), La(III) and Y(III) onto (DtBuCH18C6 + Oct)/SiO2-P was investigated at 298 K. The effects of contact time and HNO3 concentration within the range 0.1–5.0 M were examined. Increasing the HNO3 concentration from 0.1 M to 2.0 M led to a significant increase in the adsorption of Sr(II), followed by a decrease when the HNO3 concentration was increased further to 5.0 M. The optimum concentration of HNO3 in the adsorption of Sr(II) onto (DtBuCH18C6 + Oct)/SiO2-P was determined as 2.0 M. For the other ions examined with the exception of Ba(II), very weak or almost non-existent adsorption capacities were observed at all HNO3concentrations. The leaching of total organic carbon (TOC) from (DtBuCH18C6 + Oct)/SiO2-P into the aqueous phase was evaluated. Over the HNO3 concentration range 0.1–3.0 M, the quantity of TOC leached was ca. 40 ppm compared with 355.8–373.3 ppm at HNO3 concentrations above 4.0 M. Significant reduction of TOC leaching from the macroporous silica-based DtBuCH18C6-impregnated polymeric composite was achieved in 2.0 M HNO3. Such behaviour could be of great benefit in using (DtBuCH18C6 + Oct)/SiO2-P for the partitioning of Sr(II) from HLW by extraction chromatography.

Separation of strontium ions from a simulated highly active liquid waste using a composite of silica‐crown ether in a polymer

To partition Sr(II) from highly active liquid waste (HLW), a macroporous silica-based 4,4',(5')-di(t-butylcyclohexano)-18-crown-6 (DtBuCH18C6)-tri-n-butyl phosphate (TBP) polymeric composite, (DtBuCH18C6+TBP)/SiO(2)-P, was synthesized. It was done by impregnation and immobilization of DtBuCH18C6 and TBP into the pores of the SiO(2)-P particles, where DtBuCH18C6 was modified with TBP. The sorption of Sr(II) and some co-existent elements contained in a simulated HLW onto (DtBuCH18C6+TBP)/SiO(2)-P was investigated at 323 K. It was found that in 2.0 M HNO(3), Sr(II) exhibited strong sorption ability and high selectivity over all the tested metals except Ba(II). Chromatographic partitioning of Sr(II) from 2.0 M HNO(3) containing 5 mM of the tested elements was performed by (DtBuCH18C6+TBP)/SiO(2)-P packed column. La(III), Y(III), Na(I), K(I), Cs(I), Ru(III), Mo(VI), and Pd(II) had almost no sorption and flowed into effluent along with 2.0 M HNO(3). Sr(II) adsorbed strongly by (DtBuCH18C6+TBP)/SiO(2)-P was then eluted effectively by water, while Ba(II) flowed into effluent along with Sr(II) due to the similar chemical properties. In addition, the bleeding of total organic carbon in aqueous phase was evaluated. The results demonstrated that in 2.0 M HNO(3), application of the macroporous silica-based DtBuCH18C6 polymeric composite in chromatographic partitioning of Sr(II) from the simulated HLW is feasible.

Development of the chromatographic partitioning of cesium and strontium utilizing two macroporous silica-based calix[4]arene-crown and amide impregnated polymeric composites: PREC partitioning process

To partition effectively Cs(I) and Sr(II), two harmful heat emitting nuclides, from a highly active liquid waste by extraction chromatography, two kinds of macroporous silica-based polymeric materials, Calix[4]arene-R14/SiO 2-P and TODGA/SiO 2-P, were synthesized. Two chelating agents, 1,3-[(2,4-diethyl-heptylethoxy)oxy]-2,4-crown-6-calix[4]arene (Calix[4]arene-R14), an excellent supramolecular compound having molecular recognition ability for Cs(I), and N, N, N′, N′-tetraoctyl-3-oxapentane-1,5-diamide (TODGA) were impregnated and immobilized into the pores of SiO 2-P particles support by a vacuum sucking technique. The loading and elution of 11 typical simulated fission and non-fission products from 4.0 M or 2.0 M HNO 3 were performed at 298 K. It was found that in the first column packed with the Calix[4]arene-R14/SiO 2-P, all of the simulated elements were separated effectively into two groups: (1) Na(I), K(I), Sr(II), Fe(III), Ba(II), Ru(III), Pd(II), Zr(IV), and Mo(VI) (noted as Sr-group); (2) Cs(I)–Rb(I) (Cs-group) by eluting with 4.0 M HNO 3 and distilled water, respectively. The harmful element Cs(I) flowed into the second group along with Rb(I) because of their close sorption and elution properties towards Calix[4]arene-R14/SiO 2-P, while Sr(II) showed no sorption and flowed into Sr-containing group. In the second column packed with TODGA/SiO 2-P, the Sr-group was separated into (1) Ba(II), Ru(III), Na(I), K(I), Fe(III), and Mo(VI) (non-sorption group); (2) Sr(II); (3) Pd(II); and (4) Zr(IV) by eluting with 2.0 M HNO 3, 0.01 M HNO 3, 0.05 M DTPA–pH 2.5, and 0.5 M H 2C 2O 4, respectively. Sr(II) adsorbed towards TODGA/SiO 2-P flowed into the second group and showed the excellent separation efficiency from others. Based on the elution behavior of the tested elements, an advanced PREC (Partitioning and Recovery of two heat generators from an acidic HLW (high activity liquid waste) by Extraction Chromatography) process was proposed.

Group partitioning of minor actinides and rare earths from highly active liquid waste by extraction chromatography utilizing two macroporous silica-based impregnated polymeric composites

Through an advanced vacuum sucking technique, two macroporous silica-based N, N, N′, N′-tetraoctyl-3-oxapentane-1,5-diamide (TODGA) and octyl(phenyl)- N, N-diisobutylcarbamoyl-methylphoshine oxide (CMPO) polymeric composites, TODGA/SiO 2-P and CMPO/SiO 2-P, were synthesized by impregnating and immobilizing the chelating agents into the pores of the SiO 2-P particles. To partition long-lived minor actinides (MA(III)), such as Am(III) and Cm(III) from highly active liquid waste (HLW), the loading and elution of 15 typically simulated fission and non-fission products from a 3.0 M HNO 3 were performed. In the first column packed with TODGA/SiO 2-P, the simulated elements were effectively separated into following groups: (1) non-adsorption group, (2) MA– lRE–FPs group, (3) hRE group, and (4) micro quantity of Zr(IV). MA(III) was predicted to flow into the second group along with Nd(III) due to their close adsorption and elution onto TODGA/SiO 2-P. In the second column packed with CMPO/SiO 2-P, after conditioning the acidity in MA– lRE–FPs containing 0.05 M DTPA to 3.0 M HNO 3, it was separated into (1) Sr(II) and Pd(II), (2) MA– mRE, (3) lRE, and (4) Zr(IV). MA(III) was believed to flow into MA– mRE effluent along with Gd(III) because of the similar adsorption towards CMPO/SiO 2-P. In terms of the position of MA(III) appeared, an improved MAREC process for long-lived MA(III) partitioning from HLW was proposed.

Synthesis and application of a macroporous silica-based polymeric octyl(phenyl)-N,N-diisobutylcarbamoylmethylphoshine oxide composite for the chromatographic separation of high level liquid waste

The Minor Actinides Recovery from HLW by Extraction Chromatography (MAREC) process was used mainly for the separation of minor actinides (MAs) and some specific fission products (FPs) from highly active liquid waste (HLW) by the composite CMPO/SiO2-P of the macroporous silica based polymeric octyl(phenyl)-N,N-diisobutylcarbamoylmethylphoshine oxide (CMPO) and others. In this study a cascade of chromatographic separation was performed on a 3.0M HNO3 solution containing 5.0 . 10-3M of 13 elements, at 323 K. The cascade consisted of three columns the first and second ones were packed with CMPO/SiO2-P and the third with SiO2-P particles. The first column was employed to prepare various eluents containing saturated CMPO. The second column was used for separation into groups. The CMPO of CMPO/SiO2-P was recovered from the effluent by the third column and a CMPO-free effluent containing minor actinides was obtained. The elements contained in the simulated HLW of 3.0M HNO3 were separated into (1) a non-adsorption group (Sr, Cs, and Ru etc.), (2) a MA-hRE (heavy rare earth)-Mo-Zr group, and (3) a lRE (light rare earth) group by eluting with 3.0M HNO3, 0.05M DTPA (diethylenetriaminepentaacetic acid) (pH 2.0) and HNO3 (pH 3.5), respectively. The resultant MA-hRE-Mo-Zr mixture containing minor actinides was then separated into the groups (1) Pd-Ru, (2) MA-hRE, and (3) Mo-Zr by utilizing 3.0M HNO3, distilled water, and 0.05M DTPA (pH 2.0) as eluents. More than 92% of CMPO in the MA-hRE containing effluent was adsorbed by SiO2-P particles. The effectivity and technical feasibility of MAREC process were demonstrated.