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  • Author or Editor: Tao Zhao x
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Abstract  

The factors affecting the sorption of radiocobalt by bentonite and kaolinite were studied with the aim to assess important factors which should be included in modelling radiocobalt migration in soils and waters. The distribution coefficients of radiocobalt sorption on bentonite and kaolinite from aqueous solutions were determined by using the batch method, and it was found that they were insensitive to the loading, the initial pH, the ionic strength, the humic substance and the sorption direction. Thus, the sorption characteristics of radiocobalt on bentonite and kaolinite facilitated the mathematical modelling of radiocobalt migration. In addition, the sorption kinetics and the sorption mechanism of radiocobalt on bentonite and kaolinite were also examined.

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Barley yellow dwarf virus-GAV (BYDV-GAV) is one of the most serious viruses on wheat in China. In this study, five BYDV-GAV isolates collected from five regions in Northwestern China were sequenced. The complete genome sequences generated in this study along with nine genome sequences of BYDV-GAV isolates available in GeneBank were compared and analyzed. The comparative analysis indicated that the complete genomes of BYDV-GAV showed a low level of genetic diversity with nucleotide sequence identities ranging between 97.0% and 99.7%, and the RNA-dependent RNA polymerase gene (ORF1 + ORF2) was the most variable within the complete genome. Phylogenetic analysis indicated that the BYDV-GAV isolates in Northwestern China could be divided into two groups. In addition, two potential recombination events were detected among the 14 BYDV-GAV isolates. This study provided a detailed description of molecular characterization of BYDV-GAV in Northwestern China based on the complete genome sequences, which increased the understanding of genetic diversity of barley yellow dwarf viruses.

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Studies on ion exchange equilibria and kinetics

I. Na+−H+ cation exchange equilibrium and kinetics

Journal of Radioanalytical and Nuclear Chemistry
Authors: Tao Zuyi, Zhao Aimin, Tong Wengong, Xiao Rong, and Chen Xingqu

Abstract  

The kinetics and equilibria of cation exchange HR+Na+=NaR+H+ with 001×7 strong acidic resin have been studied. The isotherm for this reaction has been determined, and the rational equilibrium constant, Ka, calculated. It is found experimentally that at low concentration, the reverse exchange RNa/H+ is faster than the forward exchange; on the contrary, at high concentration, the forward exchange is faster than the reverse exchange. The integral particle interdiffusion coefficients have been calculated and the film interdiffusion coefficients estimated.

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Studies on ion exchange equilibria and kinetics

II. UO 2 2+ −H+ cation exchange kinetics

Journal of Radioanalytical and Nuclear Chemistry
Authors: Zhao Aimin, Tao Zuyi, Tong Wengong, and Chen Xingqu

Abstract  

The kinetics of cation exchange 2RH+UO 2 2+ =R2UO2+2H+ for the forward and reverse reaction with strongly acidic 001×7 resin has been studied. It was found experimentally that at low concentration, the forward exchange rate is controlled by film diffusion and at high concentration by particle diffusion. On the contrary, the reverse exchange rate is controlled by particle diffusion at any concentration. The integral particle inter-diffusion coefficients for forward and reverse exchange have been calculated.

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Abstract  

The kinetics of particle-diffusion controlled ion exchange in the ternary system of cations UO 2 2+ –Na+–H+–001×7 strong acidic resin has been studied. In the [R–H+]/(Na++UO 2 2+ ) system, the change of the amount of Na+ in the resin phase with time showed a high peak. In the [R–Na+]/(H++UO 2 2+ ) system, the change of the amount of H+ in the resin phase with time also showed a high peak. In the [R2–UO 2 2+ ]/(H++Na+) system, the change of amount of H+ in the resin phase with time showed merely a small peak. This kinetic character of the ternary ion exchange system in the finite solution volume has been analyzed according to the Nerst-Planck equation, and on the whole, the trend of the experimental results is consistent with the resulting numerical solution of the set of Nerst-Planck equations.

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Abstract  

The i-butyldodecylsulfoxide (BDSO) was synthesized. The extraction of uranium(VI) has been carried out with BDSO in toluene from various HNO3 concentrations. It was found that the distribution ratio increases with increasing nitric acid concentration up to 3.0 mol/l and then decreases. The distribution ratios also increase with increasing extractant concentration. The extracted species appears to be UO2(NO3)2·2BDSO and the equilibrium constant value is 15.2. The influence of temperature, sodium nitrate and oxalate concentrations on the extraction was also investigated, and the thermodynamic functions of the extraction reaction were obtained.

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Abstract

A thermal dynamic model of nanoformulations entrapped in artesunate liposomes was established and biological thermodynamics was applied for investigation of the drug formulations. Effects of artesunate liposomes on the growth metabolism of Escherichia coli were studied by microcalorimetry. The results showed that (1) Comparison of artesunate and artesunate liposomes, the thermogenesis curves of E. coli were significant different in the metabolic process: lag phase (AB), log phase (BC), stationary phase (CD), and decline phase (DE); (2) Linear fit of the data of total metabolic heat of E. coli effected by different concentration artesunate (1–300 μg), the equation can be obtained as follows: Y = 364720.61−1075.25x, R = 0.9985; Linear fit of the data of total metabolic heat of E. coli effected by different concentration artesunate liposomes (30–120 μg), the linear equation can be obtained as follows: Y = 54251.5765−35.71122x, R = 0.98345; (3) The half inhibitory concentration I C50 was 50.05 μg/mL, the relative sensitivity was obviously different; (4) Artesunate liposomes having better sustained release properties as compare to artesunate.

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Summary  

The parameters affecting the formation of the microemulsion were investigated and the microemulsion region was determined. The extraction of uranium(VI) from HNO3 solution into a water in oil microemulsion was studied. The effects of the concentration of extractant (TRPO), the volume ratio of oil to water and the acidity of outer water phase on the extraction equilibrium of uranium(VI) are discussed and the appropriate conditions are obtained. The result showed the microemulsion has great efficiency for uranium(VI) extraction.

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Summary  

The synergistic extraction of uranium(VI) from aqueous nitric acid solution with a mixture of tri-n-butyl phosphate (TBP) and i-butyldodecylsulfoxide (BDSO) in toluene was investigated. The effects of the concentrations of extractant, nitric acid, sodium nitrate and sodium oxalate on the distribution ratios of uranium(VI) have been studied. The values of enthalpy change for the extraction reactions with BDSO, TBP and a mixture of TBP and BDSO in toluene were -23.2±0.8 kJ/mol, -29.2±1.4 kJ/mol and -30.6±0.6 kJ/mol, respectively. It has been found that the maximum synergistic extraction effect occurs when the molar ratio of TBP to BDSO is close to 1. The composition of the complex of the synergistic extraction is UO2(NO3)2 . BDSO . TBP.

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