Nitric oxide, sorption

Justino CIL, Rocha-Santos TA, Duarte AC, Rocha-Santos TA (2010) Review of analytical figures of merit of sensors and biosensors in clinical applications. Trends Anal Chem 29(10) 172-1183 Keefe MK, Benkstein KD, Hup JT (2000) Luminescent sensor molecules based on coordinated metals a review of recent developments. Coord Chem Rev 205(l) 201-228 Kharitonov SA, Barnes PJ (2000) CUnical aspects of exhaled nitric oxide. Eur Respir J 16 781-792 King WH Jr (1964) Piezoelectric sorption detector. Anal Chem 36 1735-1739... 

The XPS results presented in Table 16 confirm the adsorption/desorption data (silver ions on carbon) as well as the electrochemical deposition/dissolution (silver on the electrodes) proposal. The smallest amount of adsorbed metallic silver (in lattice form) and the highest quantity of ionic silver on the oxidized carbon surface confirms the partial ion-exchange nature of the adsorption process for this material. Moreover, the highest number of i.solated silver atoms on this carbon (r.p.a. = 20%) shows that the reduction of metal ions took place after sorption on surface functional groups. The ionic and isolated atomic forms of adsorbed silver exhibit electrochemical activity (see Figs. 48 and 51) and can be eluted with dilute nitric acid (.see Table 14). The relatively high participation of metallic... 

FIGURE 4-39 The acid deposition process. Acid precursors, notably oxides of nitrogen and sulfur, are emitted to the atmosphere, primarily by fuel-burning equipment. Acid precursors are oxidized in the atmosphere to nitric and sulfuric acids by a variety of homogeneous and heterogeneous reactions. The acids are deposited by precipitation-related processes such as washout and rainout, by sorption of nitric acid vapor, and by dry deposition of acidic particulate material such as ammonium sulfate aerosol. (Stern et ah, 1984.)... 

Accurately estimating the total amount of acid deposited on a receptor, such as a lake, or a forest, is problematic because acids are deposited by difficult-to-quantify dry processes as well as wet processes. The wet deposition of both sulfuric and nitric acids is believed to account for only about half of the total deposition of these acids on surface waters, soils, and vegetation. Data from whole watershed mass balance studies (e.g., Table 4-13) support the hypothesis that total deposition of sulfate considerably exceeds what is measured in the form of wet deposition alone. A significant amount of H2S04 is deposited as sulfate aerosols, such as ammonium sulfate ](NH4)2S04]. The direct absorption of S03, followed by oxidation of S03 to H2S04 at the absorbing surface, is another deposition mechanism. Dry deposition of nitric acid includes sorption of nitric acid vapor onto surfaces, as well as deposition... 

Several hydrous oxides, such as those of aluminum, siTicon and, iron have been used to extract traces ions. Nevertheless, the sorption mechanism is not definitively established. Those oxides probably exhibit some ion exchange capacity among their properties and they can act as anionic or cationic exchangers and sometimes both. The separation of plutonium traces in the presence of HF by sorption onto an alumina column is based on its chemical similarities with thorium and lantanide elements reported by Abrao (2) In this case only thorium and rare earths are sorbed onto alumina from nitric acid-fluoride solutions while uranium remains in the effluent. 

Metal-complexation/SFE using carbon dioxide has been successfully demonstrated for removal of lanthanides, actinides and various other fission products from solids and liquids (8-18), Direct dissolution of recalcitrant uranium oxides using nitric acid and metal-complexing agents in supercritical fluid carbon dioxide has also been reported (79-25). In this paper we explored supercritical fluid extraction of sorbed plutonium and americium from soil using common organophosphorus and beta-diketone complexants. We also qualitatively characterize actinide sorption to various soil fractions via use of sequential chemical extraction techniques. 

Adsorption by carbon, which is one of the oldest adsorption methods used, has been reviewed and evaluated for the preconcentration of trace metals (794). Many authors have discussed the preparation of activated charcoal and carbon from a wide variety of usually local sources. The applications to water treatment are far too numerous to mention other than a few. Jo (795) carbonized a resin and a gum and hydrated the residue above 600 C to produce an adsorbant selective for cadmium(II). Kuzin et al, 196) used deashed active carbon and oxidized carbon for the quantitative sorption of copper, lead, zinc, and nickel from nearly neutral solutions containing 1-2 M alkali-metal halide. Pearson and Siviour (797) converted the metal-ion species to amine complexes before adsorbing these onto carbonaceous materials such as brown charcoal char or cellulose. Mercury vapor can be removed from a solution by reduction followed by passage of a nitrogen stream and adsorption by activated charcoal (798). Activated carbon, which had been oxidized with nitric acid, has been used to extract several metals including divalent nickel, cadmium, cobalt, zinc, manganese, and mercury from fresh water, brine, and seawater (799, 200). 

Separation of Pu and Am from nitrate-nitric acid feed was achieved with a SLM in which DHDECMP or n-octylphenyl N,N-diisobutylcarbamoyl methylphosphine oxide (CMPO) as the carriers (7). After transport of the Am into the 0.25 M oxalic acid strippant, it was recovered by sorption on an inorganic ion exchanger. 

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