Fluorocarbon absorption

Over a dozen prospective adsorbents for krypton were studied and evaluated with respect to adsorption capacity and cost for DOG streams from nuclear reprocessing plants (Monson, 1981). Results showed that, at subambient temperature (-40 to -80 °C), the commercially available hydrogen mordenite had sufficient adsorptive capacity to be the most cost-effective material studied. Silver mordenite has a higher capacity for krypton retention, but is 50 times more expensive than hydrogen mordenite. The results indicated that a solid adsorbent system was feasible and competitive with other developing systems which utilize fluorocarbon absorption and cryogenic distillation. Further work by Ruthven et al. (1981) confirmed that a dealuminated (i.e., aluminum depleted) hydrogen mordenite had... 

Optical Properties and Radiation Effects. Within the range of wavelengths measured (uv, visible, and near-ir radiation), Teflon PFA fluorocarbon film transmits slightly less energy than FEP film (29) (Table 6). In thin sections, the resin is colorless and transparent in thicker sections, it becomes translucent. It is highly transparent to it radiation uv absorption is low in thin sections. Weather-O-Meter tests indicate unlimited outdoor life. 

Reactants and reagents can be conveniently loaded into the dry zeolite by adsorption. This can be accomplished by intimately mixing the solid or liquid reactant and the powdered zeolite, by absorption from the gas phase, or by diffusion in a solvent slurry containing the zeolite and dissolved reactant. The choice of solvent for the slurry method is critical. It must be volatile enough to be removable at a pressure and temperature that does not result in evacuation of the reactant or its decomposition. In addition, the reactant must have a greater affinity for the interior of the zeolite than for the slurry solvent itself. The lack of affinity for the interior of the zeolite is an acute problem for non-polar hydrocarbons that lack binding sites for the intrazeolitic cations. The use of fluorocarbons such as perfluorohexane as slurry solvents takes advantage of the fluorophobicity of many hydrocarbons and has alleviated this problem to some extent.29... 

Although absorption of fluorocarbons via inhalation is rapid, and maximal blood concentrations are reached in about 15 min, pulmonary uptake is low (Azar et al. 1973 Trochimowicz et al. 1974 Mullin et al. 1979). Negligible metabolism and tissue retention take place. Blood concentrations fall rapidly following cessation of exposure as the parent compound is exhaled unchanged. Rapid elimination is typical of poorly soluble materials with high vapor pressures and demonstrates a lack of potential to bioaccumulate (Emmen et al. 2000). 

Lee and Meisel incorporated Py, at levels of 10 M or more, into 1200 EW acid form samples that were swollen with water and with ferf-butyl alcohol. It was concluded based on the /3//1 value for water swollen samples that the Py molecules were located in the water clusters and were most likely near fluorocarbon—water interfaces. It was also concluded, based on both absorption and emission spectra, that the probes had strong interactions with the SO3 groups that were exchanged with Ag+ and Pb + cations in the case of water containing samples. Likewise, the pyrene molecules were rationalized as being surrounded by terf-butanol molecules in that case. However, excimer formation (due to the presence of adjacent pyrene molecules) in the ferf-butyl alcohol system suggested the loss of cluster morphology-... 

AddnlRefs not used above A) R.A. Ebel et al, Recovery of Uranium Hexafluoride from a Process Gas Stream by Absorption-Distillation Techniques Employing a Liquid Fluorocarbon Medium , K-1366, Union Carbide Nuclear Co, Oak Ridge, Contract W7405-eng-26 (1959)... 

Here is an extremely sensitive method for measuring nitrite (NOj) down to 1 nM in natural waters. The water sample is treated with sulfanilamide and N-( 1 -naphthylethylenediamine) in acid solution to produce a colored product with a molar absorptivity of 4.5 X ItHM" 1 cm- 1 at 540 nm. The colored solution is pumped into a 4.5-meter-long, coiled Teflon tube whose fluorocarbon wall has a refractive index of 1.29. The aqueous solution inside the tube has a refractive index near 1.33. The colored solution is pumped through the coiled tube. An optical fiber delivers white light into one end of the tube, and an optical fiber at the other end leads to a polychromator and detector. 

Thrush and Zwolenik163 passed a dc pulse discharge through fluorocarbon vapors and, from the observation of predissociation in the absorption spectra, deduced upper limits of 132 and 120 kcal/mole, respectively, for D C—F and D CF—F. This upper limit for D C—F is 18 kcal/mole greater than deduced by Andrew and Barrow54 from a Birge-Sponer extrapolation. 

Infrared Spectroscopy. The GO RE-TEX substrate was chosen for its complete fluorocarbon composition. As it contains no hydrocarbon, we are able to investigate the IR spectra of the polymerized lipid coating, free from substrate band interference. The GORE-TEX is opaque near 1200 cm l due to absorptions of the CF2 and CF3 groups. 

In the process (Fig. 1), anhydrous hydrogen fluoride and carbon tetrachloride (or chloroform) are bubbled through molten antimony pentachloride catalyst in a steam-jacketed atmospheric pressure reactor at 65 to 95°C. The gaseous mixture of fluorocarbon and unreacted chlorocarbon is distilled to separate and recycle the chlorocarbon to the reaction. Waste hydrogen chloride is recycled by use of water absorption and the last traces of hydrogen chloride and chlorine are removed in a caustic scrubbing tower. 

The optical absorption of the unirradiated and irradiated samples was measured. The spectrum of unirradiated sample has two peaks at 200 and 275 mn. The intensity absorption of ultraviolet region increased with increasing the dose and new absorption band was observed at 215 nm after gamma-ray irradiation. The optical densities normalized by that of unirradiated sample as shown in Fig. 4. Several absorption peaks at 200, 215 and 275 nm were associated with fluorocarbon and peroxy radicals and C=0 groups respectively 131. The cross-linkage and chemical bond breaking of the polymer chain were caused by gamma-ray irradiation. 

Absorption of fluorocarbons and bromofluorocarbons via inhalation in experimental animals is rapid the maximal blood concentrations of the substances develop within 5 min and equilibrium is achieved within the next 15 rain of exposure (Azar et al. 1973 Trochimowicz et al. 1974 Mullin et al. 1979). Blood concentrations do not increase further with increasing durations of exposure for a given concentration of these substances. In a fertility study (Alexander et al. 1996), blood samples were taken from P (parental generation) male rats after 15 wk exposure, and from P females after 3 wk premating, 3 wk... 

Absorption spectroscopy and laser induced fluorescence (LIF), give access to the concentration of molecules, atoms, and ions in the ground state. LIF is enable to achieve highly spatial and time resolved analyses. This technique is thus particularly suitable to investigate composition changes in the plasma, and obtain spatial or time concentration profiles. Published results in fluorine plasmas using absorption [25-27] and LIF [28-32] mainly concern temperature measurements [25] or the quantification of CFV radicals [26-31] in fluorocarbon-based plasmas and SOx in SF6—02 discharges [32], Recently LIF has been used to measure plasma-surface interaction products [33]. 

It was also revealed by means of ultraviolet, visible and infrared optical absorption and hydrogen ion-exchange capacity measurements that the radiation induced defects such as fluorocarbon and peroxy radicals, and C=0 including in carbonyl groups were related to the new proton conduction processes. The modification of the hydrogen absorption characteristics due to the radiation induced defects in the near sttrface regions induces the enhancement of the proton conductivity. 

The reactions observed for the dimer complex adsorbed in a Nafion film coated on an ITO electrode at different pH by in situ absorption spectral measurements are summarized as shown in Fig. 11. At higher positive potentials and at potentiostatic conditions, a band at around 450 nm was observed indicating the formation of H20-Ru "-Ru -OH2 at acidic conditions and formation of H20-Ru" "-Ru -OH at basic conditions in addition to the absorbance at 655 nm. This shows that during the catalytic water oxidation process, the diaquo dimer complex exists as an intermediate. In a Nafion polymer membrane, the metal complex is isolated and experiences a micro-heterogeneous environment imposed by hydrophobic fluorocarbon moiety and... 

Absorption Spectrum of 7RbF 6PaF4. Tetravalent protactinium should have a 5f electron and show discrete optical absorption. This is demonstrated in Table II which shows the absorption spectrum characteristic of tetravalent protactinium. The spectrum was obtained from a mull in a Fluorocarbon oil, held between CaF2 flats. A Cary 14 MR spectrophotometer was used. 

Fluorocarbon compounds are lipid soluble and, thus, generally well absorbed through the lung. Absorption after ingestion is much lower than after inhalation. Most of the fluorinated hydrocarbons are immediately absorbed. 

Naturally, leather absorbs some liquid water but mainly is water resistant. The leather industries do not claim that it is waterproof. So-called waterproof leathers are finished with water repellent agents such as organo-silicon, fluorocarbon and so on. Water absorption of leather can be tested by a static absorption method (ASTM D1815, 2000a). Cut the conditioned specimen with a circular cutter. Measure the diameter and thickness of the specimen. Calculate its volume in cubic centimetres. Weigh the specimen to the nearest 0.01 g. Immerse the specimen in distilled water at 23 1 °C in ahorizontal position with the grain side up. Leave the specimen immersed for a period of 30 min. At the end of immersion, take out the specimen and blot the surface of the specimen with filter paper to remove excess water. Weigh the specimen immediately to the nearest 0.01 g. Calculate the amount of water absorbed by the specimen ... 

In addition to their long atmospheric lifetime, fluorocarbons also have strong infrared absorption bands between 1000 and 1400 cm , where the atmosphere is relatively transparent. This IR absorption is used for analytical determination of the... 

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