• KSBB Journal
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• v.16 no.1
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• pp.48-53
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• 2001

Bovine serum albumin(BSA) was solubilized into the reverse micellar phase consisting of sodium bis(2-ethylhexyl) sulfosuccinate(AOT) and isooctane using the phase transfer method. Of particular interest in this study were the effects of pH and the added salt type and concentration on the solubilization efficiency. When univalent or divalent salts such as KCl, NaCl, $MgCl_2$, or $CaCl_2$ were added to the aqueous phase at a concentration of 0.1 M, maximum solubilization efficiency was attained at a pH ranging from 5 to 7, depending on the added salt type. Increased salt concentration up to 1 M resulted in an increased solubilization efficiency for $CaCl_2$ and NaCl, while the addition of $MgCl_2$ beyond 0.1 M showed an anomalous trend. Further, it was noteworthy that too a large extent the protein precipitated in the interface between the organic and aqueous phases at lower pHs and lower salt concentrations. The size of the reverse micelle water pool was estimated by measuring the molar ratio of the surfactant to the water, $W_0$. Irrespective of pH in the aqueous phase, the resulting value of $W_0$ was almost constant, eg., 20 for $MgCl_2$ . However, the value of $W_0$ decreased with increased salt concentration in the cases of KCl and $CaCl_2$.

• Journal of the Korean Ceramic Society
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• v.39 no.2
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• pp.204-209
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• 2002

In this study, $UO_4{\cdot}2NH_4F$, the precipitates which has low solubility, was obtained by chemical precipitation method to recover and reuse the trace uranium from the liquid waste producing in AUC process and for this compound it was characterized by means of chemical analysis, TG-DTA, XRD and FT-IR analyses. This compound was analyzed as $UO_4{\cdot}2NH_4F$ and shape of this precipitate was hexagonal type, having the size of 2∼3 ${\mu}m$. Also, the intermediates were obtained as $UO_4F,\;UO_4,\;UO_3,\;and\;U_3O_8$ by the thermal decomposition over the temperature of 220, 310, 515 and 640$^{\circ}C$, respectively. It is concluded that under the condition of a constant heating rate of 5$^{\circ}C$/min in air atmosphere range of between room temperature and 800$^{\circ}C$, thermal decomposition reaction mechanism of $UO_4{\cdot}2NH_4F$ is as follow; $UO_4{\cdot}2NH_4F{\rightarrow}UO_4F{\rightarrow}UO_4{\rightarrow}UO_3{\rightarrow}U_3O_8$.