Ammonium sulfate-mediated

The first report of microemulsion-mediated synthesis of an iron oxide phase was by Inouye et al. [46]. The microemulsion-plus-reactant method (C of Fig. 3) was used by bubbling molecular oxygen into a ferrous ion-containing microemulsion. Microemulsions based on either AOT (i.e., AOT/hydrocarbon/water, where the hydrocarbons were cyclohexane, hexane, or heptane) or potassium oleate (i.e., potassium oleate/ -hexane///-hexanol/water) were used the aqueous pseudophase consisted of a ferrous ammonium sulfate solution (5x10 and 10 M). Electron microscopy revealed needle-shaped primary particles that aggregated into cubic clusters ( 80 nm). It was concluded from the particle shape and elec-... 

Yamada et al. (1978) demonstrated again this transfer in the following way. Microsomes labeled with were prepared by feeding [ Cjacetate to endosperm tissue slices from 4-day-old castor bean seedlings and incubated with unlabeled mitochondria from the same tissues. The loss of C lipids from microsomes was accompanied by an increase in lipids in mitochondria. The addition of a 105,000-g supernatant, and a further pH 5.1-treated supernatant prepared from castor bean endosperms at the same stage, markedly enhanced the lipid transfer from microsomes to mitochondria. The activity of the added fraction was precipitated by ammonium sulfate and lost after pepsin or heat treatment. Thus it was concluded that in castor bean endosperms phospholipids were transferred from the endoplasmic reticulum to mitochondria and that this exchange was mediated by a protein contained in the cytosol. In castor bean tissues, the transfer of lipids was limited to phospholipids (Table III). 

Facilitated transport of penicilHn-G in a SLM system using tetrabutyl ammonium hydrogen sulfate and various amines as carriers and dichloromethane, butyl acetate, etc., as the solvents has been reported [57,58]. Tertiary and secondary amines were found to be more efficient carriers in view of their easy accessibility for back extraction, the extraction being faciUtated by co-transport of a proton. The effects of flow rates, carrier concentrations, initial penicilHn-G concentration, and pH of feed and stripping phases on transport rate of penicillin-G was investigated. Under optimized pH conditions, i. e., extraction at pH 6.0-6.5 and re-extraction at pH 7.0, no decomposition of peniciUin-G occurred. The same SLM system has been applied for selective separation of penicilHn-G from a mixture containing phenyl acetic acid with a maximum separation factor of 1.8 under a liquid membrane diffusion controlled mechanism [59]. Tsikas et al. [60] studied the combined extraction of peniciUin-G and enzymatic hydrolysis of 6-aminopenicillanic acid (6-APA) in a hollow fiber carrier (Amberlite LA-2) mediated SLM system. 

Sayari et al [202,203] extended the LCT technique to the synthesis of mesostructured zirconium oxide. The use of long chain quaternary ammonium salts or primary amines as templates led to the formation of hexagonal and lamellar Zr02 phases, respectively. Zr(S04)2 was used as zirconium source, which provided a highly acidic medium, pH < 1.5. Consistent with the synthesis conditions and EDX analysis data a S X I mechanism where the surfactant-inorganic interaction is mediated by sulfate anions was proposed. Unfortunately, both structures collapsed upon removal of the surfactant either by high temperature calcination or by solvent extraction [203]. However, the hexagonal form was successfully... 

Microbially catalyzed processes often have a lag time before a significant effect can be observed (Ehrlich, 1996) obviously a problem in temporal upscaling of short time experiments. Figure 13.1 shows the temporal development of sulfate and ammonium concentrations measured in wells upstream and within the pilot scale Fe reactive barrier at the Rheine site (NRW, Germany). A site description and monitoring results are reported elsewhere (Ebert et al., 1999A, B). A most probably microbially mediated sulfate reduction with subsequent sulfide precipitation accounts for the decrease in sulfate concentration within the reactive barrier over a period of several months. Sim-... 

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