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[en] A fiber-optic sensor system is described for the on-line determination of bromide in spent brine. In this method, the bromide is selectively oxidized to bromine in a flow reactor containing a packed bed of chloramine-T; the optical absorption of the resulting bromine is then used for quantification. The technique exhibits a dynamic range from 20 to 5000 mg l-1 bromide, provides continuous readout, is not affected by the presence of high concentrations of chloride and has a response time of about 2 min. (author). 13 refs.; 8 figs.; 1 tab
[en] Sandia laboratories has initiated some experiments to assess the mechanisms which influence the migration of fluids in rock salt. Two series of laboratory studies have been concluded recently, and plans for an initial in-situ experiment have been formulated. In addition, theoretical modeling studies are underway to provide formulations for predictions for both experiments and actual waste emplacements
[en] The purpose of this paper is to examine the effect of the design variables of multistage flash (MSF) process on the performance and/or the cost of the desalting plant, and to establish certain design trends
[en] Iron and Pu Reduction: (1) Very different appearances in iron reaction products were noted depending on pH, brine and initial iron phase; (2) Plutonium was associated with the Fe phases; (3) Green rust was often noted at the higher pH; (4) XANES established the green rust to be an Fe2/3 phase with a bromide center; and (5) This green rust phase was linked to Pu as Pu(IV).
[en] Use of unconventional water resources such as desalination is becoming inevitable sources to alleviate water scarcity in the world. Desalination of brackish water is one of the non conventional water resources that the Tunisian government developed in order to enhance the quality of water distributed in the south. Despite the many benefits desalination technology has to offer a list of potential environmental like the emissions of air pollutant, the energy demand, land use but the main impact of desalination plant is caused by the discharge of an effluent of very high salinity. The constant discharge of reject streams with high salinity and temperature can be fatal for marine life. The purpose of this study is to evaluate the chemical composition of reject brine from Gabes desalination plant and Jerba desalination plant. Both desalination plants are planted to securing the fresh water supply for consumer consumption to the respectively government Gabes and Jerba when the level of salinity is exceeded 3g /l. The average capacity of these plants varied between 25000m3/d and 30 000m3/d. Water samples were collected from several locations at reject site of both desalination plant Jerba and Gabes. All samples have been analysed for major, nutritive and minor constituents The analyses reveal a difference between the compositions of brine of the both stations, The comparison between quality of the effluent discharged and Tunisian norms of reject in hydraulic areas (NT 106 002) showed that the concentration of calcium, chlorides sodium sulphates are higher than the allowable limits the norms.
[en] Gamma radiolysis of a complex salt brine generates hydrogen and oxygen in a 3 to 1 ratio at an equilibrium pressure of about 100 atmospheres. However, it must be emphasized that the equilibrium pressure can only be realized if the space is limited. Synergistic effects between the different ions present in the brine are required to explain the high gas pressure
[en] Essential to the use of stable isotopes as natural tracers and geothermometers is the knowledge of equilibrium isotope partitioning between different phases and species, which is usually a function of temperature only. The one exception known to date is oxygen and hydrogen isotope fractionation between liquid water and other phases (steam, gases, minerals), which changes upon the addition of salts to water, i.e., the isotope salt salt effect. Our knowledge of this effect, the difference between activity and composition (a-X) of isotopic water molecules in salt solutions, is very limited and controversial, especially at elevated temperatures. For the last several years, we have been conducting a detailed, systematic experimental study at Oak Ridge National Laboratory to determine the isotope salt effects from room temperature to elevated temperatures (currently to 500 degree C). From this effort, a simple, coherent picture of the isotope salt effect is emerging, that differs markedly from the complex results reported in the literature. In this communication, we present an overview on the isotope salt effect, obtained chiefly from our study. Observed isotope salt effects in salt solutions are significant even at elevated temperatures. The importance and implications of the isotope salt effect for isotopic studies of brine-dominated systems are also discussed in general terms
[en] Several solvent extraction techniques for determining oxidation states of actinides in solution are available, but these techniques are accurate only if oxidation states remain constant during extraction. The reliability of these techniques for determining Pu oxidation states was tested with solutions that contained Pu concentrations sufficient for spectrophotometric analysis. Oxidation states were accurately determined in solutions that contained Pu(IV) or Pu(V), or in Pu(VI) solutions with 10-3 M KMnO4 added as a holding oxidant. However, during solvent extraction of Pu(VI) solutions that did not contain a holding oxidant, significant conversion of Pu(V) to Pu(VI) occurred. Therefore, these techniques cannot be used to reliably differentiate between Pu(V) and Pu(VI) in solution. Another solvent-extraction procedure designed to determine reduced (Pu(III)+Pu(IV)) and oxidized (Pu(V)+Pu(VI)) Pu concentrations in dilute solutions in brines (< 6 M ionic strength Na and Mg brines ) was tested and found to be reasonably reliable