Aqueous precipitation

Several groups of workers have applied ion chromatography to the analysis of rain [31-34]. 

Xiang and Chang [32] used ion chromatography to determine sodium, potassium and ammonium ions in rain water. 

Small et al. [6] used this technique to determine ammonion ion in rain. Kadowaki [35] applied ion chromatography for the determination of sodium, potassium, ammonium, calcium and magnesium in rainwater samples. The method was compared to atomic absorption spectrometry and found to be less influenced by interferences. 

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Molten salt extraction residues are processed to recover plutonium by an aqueous precipitation process. The residues are dissolved in dilute HC1, the actinides are precipitated with potassium carbonate, and the precipitate redissolved in nitric acid (7M) to convert from a chloride to a nitrate system. The plutonium is then recovered from the 7M HNO3 by anion exchange and the effluent sent to waste or americium recovery. We are studying actinide (III) carbonate chemistry and looking at new... 

The most important synthetic routes to iron oxide pigments involve either thermal decomposition or aqueous precipitation processes. A method of major importance for the manufacture of a-Fe203, for example, involves the thermal decomposition in air of FeS04-7H20 (copperas) at temperatures between 500 °C and 750 °C. The principal method of manufacture of the yellow a-FeO(OH) involves the oxidative hydrolysis of Fe(n) solutions, for example in the process represented by reaction (1). 

Finally, control of fluorapatite particle size (from 15 nm to 200 pm) and morphology can be achieved by varying precipitation conditions using aqueous precipitation from a micro-emulsion or by biomimetic synthesis in a gelatin matrix [129],... 

Figure 8. Molecular arrangements in aqueous precipitates of insulin and lecithin-car diolipin (13). Left the lipid bilayer structure used in the preparations center the precipitate formed by a 9/1 molar ratio of lecithin-cardiolipin and right the precipitate formed by a 6/4 molar ratio.

Figure 9. Molecular arrangements in aqueous precipitates of bovine serum albumin and lecitnin-cardiolipin (14). Center lipid bilayers and left ana right two alternative structures of the precipitates based on the x-ray diffraction spacings.

Pure fluorite type Ce02 is obtained straightforwardly via solid state thermal decomposition or aqueous precipitation. In the recent years, novel s)mthetic routes and techniques have been applied for the synthesis of nanoceria. In this section, the synthesis through aqueous and nonaque-ous solution-based methods as well as the dry and post annealing routes toward ceria nanomaterials are illustrated with examples. And the related systems as well as the simulation works providing instructive results are also discussed. 

Catalyst. One catalyst, prepared to contain equi-atomic amounts of lead, magnesium, and aluminum, was prepared for this study. Synthesis was accomplished by the hydrotalcite preparation procedure reported by Reichle 12). It is a standard aqueous precipitation and crystallization procedure that avoids filtering and washing problems associated with gel precipitates. A solution of Pb, Mg, and Al nitrates was added under agitation to a solution of NaOH and Na2C03 and maintained at 70 C for thirty hours. This caused precipitation of crystalline material. 

Dudeney, A.W.L. et al.. An aqueous precipitation-phase extraction route to hydrous zirconia particles, Posvder Technol., 65, 207, 1991. 

The three other boehmites were generated by aqueous precipitation. Two of them were provided by LA ROCHE CHEMICALS (B2 and B4) and one by PROCATALYSE (B3). They were chosen because they cover a large set of peptization properties in the reproducible peptization test described below. 

Since the reactants are both ionic species, the expert system will check for aqueous precipitation reactions. In this case, using solubility rules, the expert system predicts logically, but incorrectly, that iron(III) carbonate will precipitate from the solution. In fact, if a precipitate is formed, it is more likely to be iron(III) hydroxide, since iron(III) ion and carbonate ion are both rather susceptible to hydrolysis. Rules have not yet been established to predict when hydrolysis of the components will override precipitate formation. 

Hence, these calcium phosphate phases are members of the same family and their expression in aqueous precipitates is strictly governed by extraneous factors such as supersaturation, temperature and pH level. It is well known that OCP is a transitional state during the formation of HAp in vitro (Brown and Chow, 1986) and that its nucleation rate is substantially higher than that of HAp (Lu and Leng, 2005 Ito et al., 2014). In vivo proliferation and differentiation studies on murine bone marrow stromal ST-2 and primary calvarial osteoblastic cells support the conclusion that OCP promotes appositional bone formation more significantly than hydrolysed Ca-deficient hydroxyapatite, at least in its early stages up to 12 weeks (Suzuki et al., 2006). 

L. Vayssieres, C. Chaneac, E. Tronc, and J. P. JoUvet. Size tailoring of magnetite particles formed by aqueous precipitation An example of thermodynamic stability of nanometric oxide particles. J. Colloid Interface Sci., 205 205-212, 1998... 

As a solution-based materials synthesis technique, the microemulsion-mediated method [10-18] offers the unique ability to effect particle synthesis and particle stabilization in one step. The solubilized water droplets serve as nanosize test tubes, thus limiting particle growth, while the associated surfactant films adsorb on the growing particles, thereby minimizing particle aggregation. The purpose of this chapter is to review the literature on the microemulsion-mediated synthesis of metal hydroxides and oxides the definition of a metal is extended here to include the semimetal silicon. Since metal oxides are frequently produced by decomposing metal salts, aspects of the literature on microemulsion-derived metal salts are also considered. In principle, any previously established aqueous precipitation chemistry can be adapted to the microemulsion synthesis technique. Accordingly,... 

Evaluate the environmental impacts of MOX fuel fabrication that uses a process of aqueous precipitation and granulation ... 

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