Authors:Jin-xin Guo, Xuan Sun, Dong-li Du, Xu Wu, Ming-xia Li, Hua Pang, Si-xiu Sun, and Ai-hua Wang
The recovery of uranium(VI) from chloride solution using a liquid emulsion membrane (LEM) technique was studied. The emulsion
is constituted by the quaternary salt of benzyloctadecyldimethyl ammonium chloride (BODMAC, R4NCl) as a carrier, kerosene as organic diluent, Span 80 as emulsifying agent and 0.5 mol/l Na2CO3 as stripping phase. The important variables affecting the LEM permeation process such as the concentrations of extractant,
internal strip phase, types of organic diluent, and the presence of magnesium chloride or magnesium sulfate were investigated.
It was found that, at a given condition, the maximum extraction rate of uranium(VI) reached 80%. The emulsion was stable at
low pH in the presence of certain amounts of electrolytes such as NaCl and MgCl2.
Uranium is extracted by a water-in-oil emulsion consisted from 0.01M 8-hydroxyquinoline /HOx/ in cyclohexane and aqueous solution or Arsenazo III and glycine. Analyzed solution is adjusted to 0.02M 1,2-diaminocyclohexane-N,N,N,N-tetraacetic acid /DCTA/ and pH 7.5±0.1. Preconcentration factor of about 400 can be achieved and when the uranium concentration in the outer solution is above 5 g.dm–3 /5 ppb/ its spectrophotometric determination in the inner solution of the double emulsion system is possible. Thorium practically does not interfere at the ratio Th:U=20:1.
Studies on functional propertiesof a protein concentrate produced from the seeds of bakul (Mimusops elengiL.; Sapotaceae) have been carried out. Solubility of the protein was minimum at pH 4.0. Water and oil holding capacities of the seed protein concentrate were 1.70 g g-1and 3.23 g g-1, respectively. Minimum foaming capacity, minimum emulsifying activity, minimum emulsion stability and maximum foam stability were found at pH 4.0. Moreover, emulsion stability of the protein concentrate was high (above 88.3%) over the pH range of 2-10.
By using low energy beta emitter to microautoradiography, it is expected that high resolution microautoradiogram can be made. In this report, the authors pay attention to the use of monochromatic and low energy electron on the metallic samples, and used51Cr that emits Auger electrons with the energy of 4.5keV and65Zn that emits Auger electrons with energy of 7keV in the study of the resolution of Auger electron microautoradiograph. From the results of the study, it was clearly confirmed that the resolution of the microautoradiograph using51Cr was better than 0.5 m and the resolution using65Zn was better than 1 m.In order to make high resolution microautoradiograph, it is essentially important to know the sensitivity of the nuclear emulsion to the low energy electrons in advance, for securing the reasonable exposure to the nuclear emulsion. In this regard, the investigation on the sensitivities of those emulsions to the Auger electrons with the energy of 5.4keV from55Fe and 7keV from65Zn was made using Ilford and Fuji nuclear emulsions.
Authors:N. Gupta, R. Srivastava, V. Choudhary, I. Varma, and S. Patnaik
Copolymers of vinyl acetate and ethylene were prepared by emulsion polymerization using ammonium persulphate and sodium metabisulphite as initiators in presence of cyclohexane. Several copolymer samples were prepared by changing initial pressure of ethylene from 100 to 250 psi. The copolymer composition was determined by 1H-NMR and thermogravimetric analysis in nitrogen atmosphere.
Authors:Gy. Marosi, P. Anna, Gy. Bertalan, A. Tohl, R. Lágner, I. Balogh, and I. Papp
Different levels of fibre technologies and application, from synthesis to degradation has been studied using the methods of thermal analysis. Recent results of these studies on synthetic and natural fibres are summarized. The effect of chemical and physical modification of polyolefin fibres as well as the synthesis of polymer emulsion used as additive in fibre technologies could be followed by DSC, DMA, TG methods.
A survey of liquid membranes and related transport mechanisms is presented. Possibilities and advantages of application of pertraction as a separation and concentration operation are discussed. Pertraction into emulsions is analyzed from the process point of view in more detail. A further development of this operation will be connected with a better understanding of interphase phenomena.
The objectives of this study were to produce microencapsulated liquorice root extract (LRE) and determine storage stability of the product obtained. Maltodextrin (MD) and gum arabic (GA) as wall material were used to produce microencapsulated LRE by spray drying technology. Ratio of MD to GA was determined by response surface methodology. Three parameters: microencapsulation yield (MY), microencapsulation efficiency (ME), and Carr index as response were evaluated for optimization. MD emulsion was best for microencapsulation of LRE. Control emulsion was prepared without using any wall material. MD and control emulsions were stored for 6 months. Both preserved their bioactive and physical properties during storage. Total phenolic content (TPC) and antioxidant activity (AA) of MD and control emulsions ranged from 8.09–9.09 and 34.59–39.02 mg GAE/g (TPC); 44.78–51.27 and 136.13–171.08 mg TEAC/g (AA), respectively, during storage. Furthermore, moisture content, water activity, solubility, wettability, Carr index, and Hausner ratio of samples were found to vary between 1.54–3.12%, 0.16–0.32, 93.54–99.22%, 180–240 sec, 22.5–35.63, and 1.29–1.56, respectively, during storage. This study provides direct comparative data on properties of LRE powders produced without using wall material and microencapsulated using wall material by spray drying.
A pot experimental was conducted to the effect of foliar application of chemical insecticide (malathion) and biological insecticide (yeast emulsion) on growth vigor, pigments content, of bean plants and the quality of vielded seeds as well as its chemical composition. In the majority of cases, the two insecticides appeared to cause pronounced effect on growth parameters during growth of bean plants. Malathion application induced slight increase or marked decrease in pigments content and photosynthetic activity of 50 and 85 days old plant, respectively. On the other hand, yeast emulsion appeared to cause nonsignificant effect on the above-mentioned parameters, all over the growth period of bean plants. Foliar application of malathion caused significant decrease in growth promotery substances (i.e. IAA, GA3and cytokinin) with simultaneous increase in IAA-oxidase as well as abscisic acid content of bean plant. The application of yeast emulsion appeared without significant effect on growth regulators content of bean plants. Moreover, yield and yield attributes as well as the biochemical aspects of yielded seeds showed variable changes in response to malathion and yeast emulsion application.
Membrane extraction, i.e. separation in double-emulsion systems, is analyzed theoretically as a three-phase distribution process. Its efficiency is evaluated from the point of view of chemical equilibria and diffusion transport kinetics. Optimization criteria of the process as a preconcentration technique are discussed. The main advantages of membrane extraction as compared with solvent extraction are in higher yields (for preconcentration) and higher capacity for recovery of solutes. No advantage is seen in applications for a mutual separation of solutes if the same, inexpensive reagent can be used in a conventional extraction process. All phenomena caused by thermodynamic instability of double emulsions and mutual contamination of the feed and receiving phases diminish its maximal efficiency, which should be characterized by the introduced parameters, pertraction factor (p) and multiplication factor (N). These factors are suitable for expression of efficient distribution, system capacity, process economics, and separation kinetics. The kinetics were approximated by means of a non-linear extraction isotherm.