Several diamide derivates were synthesized in our laboratory. The extraction of actinides and some fission products by these
compounds were studied. N,N,N’,N’-tetra-(2-ethylhexyl)-3-oxa pentanediamide [TEHOPDA) was proven to be a suitable extractant
for the removal of actinides from nitric acid solution. The actinides can be stripped from the loaded solvent by the dilute
nitric acid. TEHOPDA showed a high loading capacity to actinides and lanthanides with a mixture of n-octanol and kerosene
as the diluent. Considering the effective-extraction and easy-stripping of actinides, 0.25 mol/l TEHOPDA — 30% n-octanol +
70% kerosene was selected as the solvent. A cascade extraction experiment was carried out with the simulated dissolver solution
of spend fuel as feed. 99.99% U and 99.999% Am, Pu, and Np were extracted in a 4-stage test. Based on the experimental results,
a conceptual reprocessing process was proposed.
Valency control of neptunium is an important issue in the partitioning of high level liquid waste (HLLW) from power-reactor
spent fuel treatment. The redox behavior of neptunium in HLLW is quite different from that in nitric acid because of the effect
of the large amount of ions in HLLW. In order to remove neptunium from HLLW, we studied the reduction of neptunium in synthetic
HLLW (SHLLW) to maintain its valency at IV so that it can be extracted by TRPO extractant in the well developed Chinese TRPO
process. Five different reductants were tested and the reduction behavior was investigated. The influence of some active elements
in SHLLW was studied. The mechanism that the reductants react with neptunium through Fe element was supposed and proved by
experiments. The reduction rate of Np(V) was highly enhanced by Fe element. Finally, a hybrid reductant was suggested and
good reduction efficiency was obtained.
A new distributor which can be used more perfectly for half-way development is described in this paper. The distributor is made from two microscope slides which are specially treated and glued together like a funnel. The mobile phase can be delivered to the new distributor by means of a syringe; the solution fills the capillary crack immediately and then leaks on to the thin layer plate. Development can then begin at the same starting line. Compared with the old device the distance traveled by the mobile-phase front before it becomes even (which we denote the ‘even distance’) is much lower, so the new device is more suitable for re-chromatography of two close spots. Mixtures of dyes have been used to verify this supposition, with satisfactory results.
An improved method of two-dimensional development in thin-layer chromatography is described. The innovative feature is that before the second development the thin layer on the glass plate is divided into several zones and these zones are developed with different mobile phases, instead of with the same mobile phase, as in traditional two-dimensional TLC. The operating procedure and the device are described in detail, as are means of avoiding interference. A mixture of ten dyes was used to evaluate the technique and the results obtained were satisfactory.
Authors:Jie Wang, Dongyuan Wang, Gaohong She, Zuo Wang, Jing Wang, Hongxia Zhang, Ledao Li, and Ge Wang
In this paper a semi-automatic sample applicator made in an ordinary laboratory without help from others is described in detail. All the components of the applicator are available commercially at low cost and the process of assembly of the applicator is very simple and practical, especially the spraying head and the applicator mechanism. Factors that could affect the function of the applicator, for example the type and position of the spraying head, the gas pressure, and the application speed were tested. The type and position of the spraying head have a discernible effect whereas gas pressure does not. The relative standard deviation of band length and band width are <1% and <2.5%, respectively. The errors mainly arise from the clearance of the screw used for transmission of the shaft. The mechanism of the processes affecting band uniformity were researched and are described in detail. The application speed is an important factor, the faster the application speed, the better.
Authors:Ping Zhang, Hairong Wang, Jianchen Wang, and Jing Chen
To simplify TRPO process, a novel ligand, N,N’-dimethyl-3-oxa-glutaramic acid (DMOGA), was synthesized and used for stripping
of An(III, IV) from 30% TRPO-kerosene. The distribution ratios for transuranium elements, including Np(IV), Pu(IV), Am(III),
and some fission products, including Eu(III), Fe and Zr between 30% TRPO-kerosene and various HNO3-DMOGA solutions were measured. An(III, IV) and Ln(III) extracted to TRPO from simulated high level liquid waste could be
recovered with an efficiency of 99.9% above in one stream with a 3-stage crosscurrent strip experiment with 0.2M DMOGA in
HNO3 solution. Using this new agent, the back extraction of TRU elements from loaded TRPO phase becomes more simple and practical.
Therefore, the original TRPO process could be simplified.
Authors:Jing Huang, Yanfei Kang, Taili Yang, Yao Wang, and Shurong Wang
Ternary nanostructured CuO/Ti0.8Ce0.2O2 catalysts were prepared by a one-step surfactant-assisted method of nanoparticle assembly. The textural and structural properties of the CuO/Ti0.8Ce0.2O2 catalysts were characterized by XRD, TGA, BET, XPS and H2-TPR. Their catalytic performance for low-temperature CO oxidation was studied by using a catlab system. CuO supported on binary Ti0.8Ce0.2O2 support showed higher catalytic activity than CuO supported on single CeO2 or TiO2 support. The calcination temperature had a remarkable influence on the catalytic activity of the CuO/Ti0.8Ce0.2O2 catalysts. The CuO/Ti0.8Ce0.2O2 catalyst calcined at 500 °C exhibited the highest catalytic activity with T50% and T100% at 82 and 123 °C, respectively. According to the XRD, BET and H2-TPR analyses, the higher surface areas and more highly dispersed small particle size CuO should be responsible for the high catalytic activity of catalysts.
The TRPO process has been developed in China for removing transuranium (TRU) elements from the high-level liquid waste (HLLW)
since 1980s. In order to meet the requirements of the TRPO process tests, a series of annular centrifugal contactors have
also been developed at the Institute of Nuclear and New Energy Technology (INET), Tsinghua University, China. In particular,
the Ø10 mm annular centrifugal contactor has been applied successfully in laboratory scale tests of the TRPO process. The
Ø70 mm annular centrifugal contactor for semi-industry scale tests of the TRPO process has good performance and two design
characteristics, namely a modular design and an overflow structure.
This work reports the synthesis, radiolabeling and preliminary biodistribution results in tumor-bearing mice of the 99mTc(CO)3–AOPA colchicine conjugate. The novel ligand was successfully synthesized by conjugation of N-(acetyloxy)-2-picolylamino (AOPA) to deacetylcolchicine via a short carbonyl-methylene linker. Radiolabeling was performed
in high yield with [99mTc(CO)3]+ core. 99mTc(CO)3–AOPA colchicine conjugate was hydrophilic and was stable at room temperature. Biodistribution studies in tumor-bearing mice
showed that 99mTc(CO)3–AOPA colchicine conjugate accumulated in the tumor with good uptake and retention. However, its clearance from normal organs
was not so fast, resulting in poor T/NT ratios. Further modification on the linker or/and 99mTc-chelate to improve the tumor targeting efficacy and in vivo kinetic profiles is currently in progress.
Authors:Lixia Wang, Wanchun Zhu, Dafang Zheng, Xue Yu, Jing Cui, Mingjun Jia, Wenxiang Zhang, and Zhenlu Wang
The reaction of direct transformation of ethanol to ethyl acetate was investigated on reduced Cu/ZrO2 catalysts prepared by a co-precipitation procedure. The catalytic performances of these Cu–Zr mixed oxides were considerably
influenced by changing the molar ratio of Cu to Zr. The highest selectivity to ethyl acetate was found over Cu/ZrO2(1) catalyst (molar ratio of Cu to Zr was 1). A variety of characterization techniques, such as N2 adsorption, XRD, XPS, TPR and NH3-TPD were carried out on the catalysts. The results revealed that the presence of a certain amount of Cu+ species may play very important role in improving the selectivity to ethyl acetate of the Cu/ZrO2 catalysts.