Fluid mobilities

D. E. Martire and R. E. Boehm, Unified molecular theory of clrromatography and its application to supercritical fluid mobile phases. 1. Eluid-liquid (absorption) clrromatography , J. Phys. Chem. 91 2433-2446 (1987). 

D. E. Martue, Unified theory of absorption clrromatography gas, liquid and supercritical fluid mobile phases , ]. Liq. Chmmatogr. 10 1569-1588 (1987). 

The coupling of supercritical fluid extraction (SEE) with gas chromatography (SEE-GC) provides an excellent example of the application of multidimensional chromatography principles to a sample preparation method. In SEE, the analytical matrix is packed into an extraction vessel and a supercritical fluid, usually carbon dioxide, is passed through it. The analyte matrix may be viewed as the stationary phase, while the supercritical fluid can be viewed as the mobile phase. In order to obtain an effective extraction, the solubility of the analyte in the supercritical fluid mobile phase must be considered, along with its affinity to the matrix stationary phase. The effluent from the extraction is then collected and transferred to a gas chromatograph. In his comprehensive text, Taylor provides an excellent description of the principles and applications of SEE (44), while Pawliszyn presents a description of the supercritical fluid as the mobile phase in his development of a kinetic model for the extraction process (45). 

Oil recovery can also be affected by extreme variations in rock permeability, such as when high-permeability thief zones between injectors and producers allow most of the injected drive fluid to channel quickly to producers, leaving oil in other zones relatively unrecovered. A need exists for a low-cost fluid that can be injected into such thief zones (from either injectors or producers) to reduce fluid mobility, thus diverting pressure energy into displacing oil from adjacent lower-permeability zones. 

First we compare the results for clinopyroxene which was the only phase common to both of these studies. The results from the pure H2O experiments are somewhat inconsistent. Keppler (1996) found that Th was more mobile than U, contrary to all observations, whereas Brenan et al. (1995) found the reverse. However, subduction zone fluids are almost certain to contain solutes like Na and Cl derived from seawater and Keppler and Wyllie (1990) showed that the solubility of U, but not Th, is enhanced by the presence of Cl, although the salinities used by Keppler (1996) were very high. Both Brenan et al. (1995) and Keppler (1996) found that U was an order of magnitude more fluid mobile than Th when NaCl was present, although, in the Brenan et al. (1995) experiments, the absolute D "opyroxene/flu.d lower in the presence of NaCl than... 

Therefore, since both Ba and Sr are fluid mobile, the large Ra-excesses at high Ba/Th and Sr/Th ratios are inferred to result from fluid addition to the mantle wedge. At the other end of the arrays in Figure 10 it is notable that the intercept for any arc is with the Ba/Th, not ( Ra/ °Th) axis. This contrasts strikingly with MORB, for example. 

A second possibility is that the inclined U-Th arrays reflect addition of fluids containing some Th (Fig. 8c) and Pa from a source with higher U/Th than the mantle wedge (e.g., Yokoyama et al. 2002). As discussed earlier, U is significantly more fluid-mobile than Pa or Th, but the absolute magnitude remains to be confirmed. Bourdon et al. (2003) used a plot of ( Pa/ U) versus Nb/U ratios for the Tonga lavas to show that a... 

Alteration is always a cause for concern in geochemical investigations and the best approach will always be to avoid samples with visual or chemical evidence for alteration. The differential fluid mobility of U, Th, Pa and Ra undoubtedly provides the potential for weathering or hydrothermal circulation to disturb the U-series signatures of arc lavas. In a study of lavas from Mt. Pelee on Martinique, Villemant et al. (1996) found that domeforming lavas were in U-Th equilibrium whereas plinian deposits from the same eruptions had small U-excesses which they interpreted to reflect hydrothermal alteration. However, whilst the addition of U could be due to hydrothermal alteration, the plinian deposits were also displaced to lower °Th/ Th ratios which cannot. Instead, the two rock types may just be from separate magma batches. 

Both nonionic and anionic surfactants have been evaluated in this application (488,489) including internal olefin sulfonates (487, 490), linear alkylxylene sulfonates (490), petroleum sulfonates (491), alcohol ethoxysulfates (487,489,492). Ethoxylated alcohols have been added to some anionic surfactant formulations to improve interfacial properties (486). The use of water thickening polymers, either xanthan or polyacrylamide to reduce injected fluid mobility mobility has been proposed for both alkaline flooding (493) and surfactant enhanced alkaline flooding (492). Crosslinked polymers have been used to increase volumetric sweep efficiency of surfactant - polymer - alkaline agent formulations (493). 

Early applications of polymers to extraction processes were based on the ability of polymers to alter solution rheology. Pye(3l) and Sandiford(32) showed that fluid mobility could be effectively reduced by the addition of small amounts of polymer to the solvent. 

The nature of a supercritical fluid enables both gas and liquid chromatographic detectors to be used in SFC. Flame ionization (FID), nitrogen phosphorus (NPD), flame photometric (FPD) GC detectors (p. 100 etseq.) and UV and fluorescence HPLC monitors are all compatible with a supercritical fluid mobile phase and can be adapted to operate at the required pressures (up to several hundred bar). A very wide range of solute types can therefore be detected in SFC. In addition the coupled or hyphenated techniques of SFC-MS and SFC-FT-IR are attractive possibilities (cf. GC-MS and GC-IR, p. 114 el seq.). 

The first studies of Li isotopes in subduction zones concentrated on young convergent margin lavas. Moriguti and Nakamura (1998b) reported correlated Li isotope and fluid-mobile element (notably boron) concentration variations in the Izu arc, southeastern Japan (8 Li = +1.1 to +7.6), consistent with significant incorporation of Li from altered oceanic crust into arc lava sources (Fig. 6). A similar trend has been reported in samples of basalts and basaltic andesites from Mt. Shasta, California (5 Li = +2.5 to +6.5 Magna et al. 2003). 

Because Li isotopes may be used as a tracer to identify the existence of recycled material in the mantle, systematic studies of arc lavas have been undertaken (Morignti and Nakamura 1998 Tomascak et al. 2000 Leeman et al. 2004 and others). However, most arc lavas have 5 Li values that are indistinguishable from those of MORB. Thus Li seems to be decoupled from other fluid mobile elements, becanse Li can partition into Mg-silicates (pyroxene, olivine) in the mantle (Tomascak et al. 2002). 

The porosity of sedimentary rocks and the migration of water between pore spaces (permeability) influence in another way silicate mineral equilibria. Fluid mobility in a rock leads to the realization of a mechanical equilibrium where fluid pressure (hydrostatic pressure) is... 

Weight loss is a good indicator of fluid loss and excretion. The first wave of fluid mobilized is from the periphery. The excretion of chloride and water is considered passive, and the excretion of potassium and magnesium is increased. In long-term use. the excretion of calcium is decreased. 

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