Authors:Mária Szűcs, Patrizia Vaghi, Giuseppina Sandri, M. Bonferoni, Carla Caramella, Piroska Szabó-Révész, and I. Erős
Polymeric emulsifiers provide exceptional stability to oil-in-water, water-in-oil or multiple emulsions by their steric stabilization.
Pemulens as polymeric emulsifiers are able to stabilize o/w type emulsions because their short lipophilic part integrates into the oil droplets while their long hydrophilic part forms
a micro gel around the droplet. In our present study the microstructure and integration of the polymeric emulsifier at the
water-oil interface was investigated with thermogravimetric and microscopical methods. It was established that depending on
the amount of both of the polymeric emulsifier and added coemulsifier the microstructure of the system changes.
Model studies on TBP—diluent—aqueous HNO3 extraction systems were performed to establish the mechanism of emulsyfying during the reprocessing of spent reactor fuel
with mixtures of TBP solutions. The systems of interest were emulsified under fixed conditions. The rate of separation of
the primary emulsion as well as the turbidity of each phase were determined. The experiments were performed on mixtures of
pure components of the extraction systems. Emulsion stability was investigated in terms of the influence of such factors as
main products of TBP decay, the type of diluents, HNO3 concentration and concentration of TBP in different diluents.
Emulsion liquid membranes (ELM) with di-2-ethylhexylphosphoric acid in n-alkane, and dipicrylamine and cobalt(III) dicarbollide in nitrobenzene stabilized in double emulsions by SPAN 80/85 surfactant were used for preconcentration of radioactive fission products (137Cs,90Sr,139Ce, and152Eu) from slightly acidic nitrate solutions. The efficiency of sulfuric, phosphotungstic and silicotungstic acids as stripping agents, and picric acid as the bulky anion additive was investigated. A group separation of the fission products is possible by the ELM technique and can be considered for their removal from waste water solutions.
Authors:Viktor Misuk, Andreas Mai, Konstantinos Giannopoulos, Dominik Karl, Julian Heinrich, Daniel Rauber, and Holger Löwe
The method of combining the concept of fluorous biphasic catalysis (FCB) with micro multiple emulsions benefits from the advantages of homogeneous as well as from heterogeneous catalysis in continuous micro flow. In this particular case, three immiscible fluid phases in continuous micro segmented flow were used to perform palladium-catalyzed Heck cross-coupling reactions of styrene with aryl halides. A capillary tube-in-tube coaxial flow setup in combination with a glass micro reactor was used to produce monodisperse aqueous phase/organic phase/perfluorinated phase double emulsions. The resulting emulsions had a core–shell droplet structure composed of a perfluorcarbon fluid in which a palladium catalyst with fluorinated phosphine ligands was dissolved, an organic phase consisting of a solvent and two reagents, and an alkaline aqueous solution. The fluorous and organic phases of the double emulsion form a thermomorphous system which can be converted into one phase by an increase of temperature above 150 °C, and the catalytic reaction is performed temporarily. By decreasing the temperature, a phase separation takes place; after that, the organic phase contains the product and the catalyst is located in the fluorous phase. The separated catalyst solution was reused several times without a noticeable loss of activity. The main advantage of this method is to use temporarily very high catalyst concentrations in each droplet, while employing only small amounts of the catalyst for the overall reaction volume.
The selective separation ability of the cyclic crowns, known for liquid-liquid extraction, e.g. alkali metals, is found to be effective for emulsion membrane extraction. 18-C-6, DB-18-C-6, DC-18-C-6 crowns were used as carriers. The co-transport of the ionic pair SrL2+. 2A through the membrane has been studied. Calcium was considered as a main competing ion. Even in the case of 20-fold preconcentration, there have been found conditions under which the pertraction process can reach Sr/Ca separation factors of about 500 and the yield of strontium is high (95–98%). The presence of calcium up to 1000-fold excess has no influence on the yield of strontium (1.10–5M). The calcium content in the isolated emulsion was caused by second emulsification of the outer solution. The influence of potassium on strontium pertraction has been studied and some transport data of Cs and Y have been obtained.
Dissolution of -irradiated alkali halides in the emulsions of aromatic hydrocarbon and water results in the formation of halogen charge transfer complexes and hydrogen. These have been identified by spectrophotometry. Further, their formation has been verified by studying the absorption of a chemical model involving hydrogen incorporated in halogen complex. These products are correlated to the F and hole centers of the irradiated salts.
Authors:X. Wang, X. Li, H. Yan, Y. Qu, G. Sun, X. Xie, and Y. Zhang
The kinetic characteristic of thermal decomposition of the Emulsion Explosive Base Containing Fe and Mn elements (EEBCFM)
which was used to prepare nano-MnFe2O4 particles via detonation method was investigated by means of non-isothermal DSC and TG methods at various heating rates of
2.5, 5 and 7.5°C min−1respectively under the atmosphere of dynamic air from room temperature to 400°C.
The results indicated that the EEBCFM was sensitive to temperature, especially to heating rate and could decompose at the
temperature up to 60°C. The maximum speed of decomposition (dα/dT)m at the heating rate of 5 and 7.5°C min−1 was more than 10 times of that at 2.5°C min−1 and nearly 10 times of that of the second-category coal mine permitted commercial emulsion explosive (SCPCEE). The plenty
of metal ions could seriously reduce the thermal stability of emulsion explosive, and the decomposition reaction in the conversion
degree range of 0.0∼0.6 was most probably controlled by nucleation and growth mechanism and the mechanism function could be
described with Avrami-Erofeev equation with n=2. When the fractional extent of reaction α>0.6, the combustion of oil phase primarily controlled the decomposition reaction.
Halogenated hydrocarbon emulsion liquid membranes (e.g. trichlorobenzene) which were stabilized with polyamine tenside, using 18-crown-6 and picric acid as carriers, were applied to separation of strontium and calcium. Application in the separation of Sr/Ca enable us to enhance preconcentration factor for strontium due to decreasing occlusion of freed solution and better hydrodynamic parameters of the emulsion.
Authors:B. Ormsby, G. Foster, T. Learner, S. Ritchie, and M. Schilling
After improvements were made to a modified Polymer Labs MkIII DMTA instrument to facilitate repeatable controlled humidity
(RH) experiments using isothermal and thermal scanning conditions, the viscoelastic properties of titanium white pigmented
artists’ acrylic emulsion films were measured in tensile mode. The effects of temperature, relative humidity and accelerated
ageing regimes on two brands of titanium white paints were explored. These paints are highly responsive to changes in temperature
and relative humidity, formulation differences affect properties slightly, and while light ageing had a negligible effect,
thermal ageing resulted in decreased storage modulus and increased film density.
Authors:V. Mikulaj, P. Rajec, A. Švec, N. Cuong, and V. Ahn
A continuous extraction device for preconcentration of metals with light phase internal recycle has been developed. This system was used for preconcentration of cobalt and uranium from 20–30 dm3 samples with 10.8 dm3/hours feed rate. The emulsion membranes were created of surfactants and LIX 64 N (for cobalt) or di-2ethylhexyl-phosphoric acid (for uranium) as a carrier to control stability and permeability for long time periods. The results from continuous extraction of cobalt and uranium using the device constructed have shown the possibility to reach 100–200-fold preconcentration of metals with high yield (min. 92%).