[en] The design and preparation of the hydrophobic catalyst used for the hydrogen-water phase catalytic exchange reaction are discussed. Two kinds of the processes for the detritiation from the heavy water, liquid phase catalytic exchange (LPCE) and combined electrolysis catalytic exchange (CECE) are reviewed briefly

[en] Boronic acids are important for effective separation of biological active cis-diols. For the purpose of constructing a new type of saccharide-sensitive material which can not only provide convenient separation but also improve the access of boronic acid to guest molecules, the fluorogenic boronic acid terminated, thermo-sensitive polymers (BA-polyNIPAm) were grafted to an alkyne modified silica gel through the exploitation of click chemistry. The BA-polyNIPAm grafted silica gel (BA-polyNIPAm-SG) was characterized by FT-IR, fluorescence spectra, fluorescence microscopy, elemental analysis (EA), thermal gravimetric analysis (TGA), scanning electron microscope (SEM) and so on. BA-polyNIPAm-SG displayed affinity binding ability for saccharides under physiological pH value and allowed saccharides to be conveniently separated from solution. The maximum binding capacities for fructose and glucose are 83.2 μmol/g and 70.4 μmol/g polymer, respectively. The intensity of fluorescence emission of BA-polyNIPAm-SG increased with the increasing of fructose concentration. The present study provides a new kind of composite material which contains moveable and flexible grippers for recognizing and binding guest molecules. - Highlights: • Fluorogenic boronic acid terminated polymers were conjugated to silica particle. • The prepared material can conveniently separate saccharides from solution. • The prepared material displays increased fluorescence emission upon binding fructose

No abstract available

[en] Highlights: • Highly oriented nanoporous fibers have been fabricated by airflow bubble-spinning. • The airflow bubble-spinning gets rid of the potential safety hazards. • Effect of processing variables on porous structures on fiber surface was studied. - Abstract: Highly oriented Poly(lactic acid) (PLA) nanofibers with nanoporous structures has been successfully fabricated via airflow bubble-spinning without electrostatic hazard. In this work, the volatile solvent was necessary for preparing the nanoporous fiber, which was attributed to the competition between phase separation and solvent evaporation. The interconnected porous structures were affected by the processing variables of solution concentration, airflow temperature, collecting distance and relative humidity (RH). Besides, the rheological properties of solutions were studied and the highly oriented PLA nanofibers with nanoporous structure were also completely characterized using scanning electron microscope (SEM). This study provided a novel technique that successfully gets rid of the potential safety hazards caused by unexpected static to prepare highly oriented nanoporous fibers, which would demonstrate an impressive prospect for the fields of adsorption and filtration.

[en] Highlights: • The CeO₂-SH catalyst showed >97% conversion of NO_x at 230–450 °C. • The resistance to Na and K of the CeO₂ catalyst was enhanced significantly. • Surface sulfate species bind to Ce⁴⁺ improve the N₂ selectivity in NH₃-SCO. -- Abstract: A series of CeO₂ catalysts prepared with sulfate (S) and nitrate (N) precursors by hydrothermal (H) and precipitation (P) methods were investigated in selective catalytic reduction of NO_x by NH₃ (NH₃-SCR). The catalytic activity of CeO₂ was significantly affected by the preparation methods and the precursor type. CeO₂-SH, which was prepared by hydrothermal method with cerium (IV) sulfate as a precursor, showed excellent SCR activity and high N₂ selectivity in the temperature range of 230–450 °C. Based on the results obtained by temperature-programmed reduction (H₂-TPR), transmission infrared spectra (IR) and thermal gravimetric analysis (TGA), the excellent performance of CeO₂-SH was correlated with the surface sulfate species formed in the hydrothermal reaction. These results indicated that sulfate species bind with Ce⁴⁺ on the CeO₂-SH catalyst, and the specific sulfate species, such as Ce(SO₄)₂ or CeOSO₄, were formed. The adsorption of NH₃ was promoted by these sulfate species, and the probability of immediate oxidation of NH₃ to N₂O on Ce⁴⁺ was reduced. Accordingly, the selective oxidation of NH₃ was enhanced, which contributed to the high N₂ selectivity in the SCR reaction. However, the location of sulfate on the CeO₂-SP catalyst was different. Plenty of sulfate species were likely deposited on CeO₂-SP surface, covering the active sites for NO oxidation, which resulted in poor SCR activity in the test temperature range. Moreover, the resistance to alkali metals, such as Na and K, was improved over the CeO₂-SH catalyst

[en] The hydrophobic catalyst used in the hydrogen-water isotope exchange is prepared with Pt as the active metal, PTFE as the hydrophobic material, active carbon or silicon dioxide as the support. The isotope catalytic exchange reaction between hydrogen and water is carried out in the trickle bed and the effects of different carriers, mass fraction of Pt and PTFE on the catalytic activity are discussed. The experimental results show that the activity of Pt-C-PTFE hydrophobic catalyst with the ratio between PTFE and Pt-C from 1 to 2 is higher than other kinds of catalysts and the overall volume transfer coefficient is increased with the increasing of the hydrogen flow rate and reaction temperature

[en] The preparation of Pt-SDB hydrophobic catalyst is studied, in which platinum as active metal and polystyrene divinylbenzene (SDB) as the carrier. Hydrogen isotope exchange reaction is carried out with Pt-SDB catalyst in counter-current in the trickle bed. The effect of preparing condition on the activity of catalyst is discussed. The results show that the excellent catalyst is obtained by reduced at the temperature of 200 degree C over 8 hours. Hydrophobic catalyst is high activity and stability as the amount of platinum content is 3%, the platinum can reach the economic use with the content of (1-2)%

[en] The authors study the Pt-SDB hydrophobic catalyst used in the hydrogen-water exchange reaction. Platinum is as active metal and the polystyrene divinylbenzene (SDB) is as hydrophobic carrier in the Pt-SDB hydrophobic catalyst. The experimental results show that the efficiency of catalytic exchange reaction is higher in random bed with a packing ratio of 1:1 mixture of catalyst and hydrophilic or 1:4 in order bed. The volume transfer coefficient increases with increasing temperature, but the trend is slow down when the temperature is above 60 degree C

[en] Cementation is one of the most popular solidification technology for the low-and-intermediate level liquid radioactive waste. It has been applied in all of domestic PWR NPPs. The process characteristics and operation of the cementations in the different NPPs are introduced,and the advantage and disadvantage of the cementation are analyzed in this paper. A drum and a cask are compared as a package of the solidified waste, the drum can decrease over 50% final volume of the waste, furthermore the cost for manufacture and transportation for this drum is more cheaper than the cask, but an additional shielding may be necessary for the waste with higher level radioactivity that is packed in drum. More waste can be contained if an appropriate in-drum mixer is used while secondary waste will be unavoidable if the out-drum mixing is adopted. A carriage can make it easier to decontaminate on the surface of equipment and on the floor, furthermore the carriage is more economical than a roller conveyor in manufacture and maintenance. The cementation recipe for the waste should be optimized and additive material should be as less as possible to increase the containing rate of the waste. (authors)

[en] Catalytic performance of Sn/Al₂O₃ catalysts prepared by impregnation (IM) and sol-gel (SG) method for selective catalytic reduction of NO_x by propene under lean burn condition were investigated. The physical properties of catalyst were characterized by BET, XRD, XPS and TPD. The results showed that NO₂ had higher reactivity than NO to nitrogen, the maximum NO conversion was 82% on the 5% Sn/Al₂O₃ (SG) catalyst, and the maximum NO₂ conversion reached nearly 100% around 425C. Such a temperature of maximum NO conversion was in accordance with those of NO_x desorption accompanied with O₂ around 450C. The activity of NO reduction was enhanced remarkably by the presence of H₂O and SO₂ at low temperature, and the temperature window was also broadened in the presence of H₂O and SO₂, however the NO_x desorption and NO conversion decreased sharply on the 300ppm SO₂ treated catalyst, the catalytic activity was inhibited by the presence of SO₂ due to formation of sulfate species (SO₄^2-) on the catalysts. The presence of oxygen played an essential role in NO reduction, and the activity of the 5% Sn/Al₂O₃ (SG) was not decreased in the presence of large oxygen