Without chemical carriers

Emulsion liquid membranes have been formulated for the removal of species without chemical carriers. These systems rely on solubility differences between permeant species. The first work performed by Li (73) dealt with the separation of a bineiry mixture of aromatic eind paraffinic hydrocarbons. The hydrocarbons were encapsulated in an aqueous liquid membrane forming an emulsion which was distributed in a hydrocarbon solvent and mixed. The aromatic hydrocarbons preferentially permeated through the aqueous liquid membrane phase due to solubility differences. Cahn and Li (7 ) describe a liquid membrane formulation for phenol removal in which sodium hydroxide is encapsulated by an organic liquid membrane. The resulting membrane phase is mixed with a continuous aqueous phase containing phenol. 

Since disperse dyes diffuse very slowly into PES fibers, efforts have been made to increase the rate of dye strike by chemical or physical alteration of the fiber. The fiber is also modified to reduce the pilling tendency, to increase shrinkage and elasticity, and to reduce flammability. Such modified fibers exhibit improved dye receptivity. Fibers with improved dyeability can be dyed with disperse dyes at boiling temperature without a carrier or with basic dyes when they are modified with acidic components (5-sulfoisophthalic acid). Fibers of this type are used if dyeing cannot be carried out easily above 100°C (e.g., in the case of floor coverings, articles made of PES-wool blends, stretch materials, and cord). Strongly crimped PES bicomponent fibers are produced for special purposes. These fibers are normally also dyeable at the boil and without a carrier [136, 137, 138],... 

As for fish and Daphnia, the difficulties most overlooked in producing reliable toxicity data for algae arise from frequently testing concentrations of contaminants above their water solubility. The uncritical use of solvent carriers may introduce additional effects (Calleja and Persoone, 1993). The testing of nominal doses without chemical analyses of the actual contaminant concentrations in the tests causes major uncertainties in the experimental EC50 data. 

The second task is the one most frequently met in monitoring work. It can be solved in many different ways, but basically there are two typical approaches (1) To add inactive carrier in known amounts, allow for isotope exchange, separate, and purify until further purification does not influence the characteristics of the radiation, and measure the radioactivity and chemical yield the measurement of radioactivity in this case need not be discriminatory. (2) Without chemical pretreatment, to measure the intensity at one energy only (if no other radionuclides emitting at the same energy are present) or to use the difference in half-lives to differentiate between two (or more) radionuclides, as shown in Figure 3. 

Iodine The samples contained no radioactive iodine isotopes other than and they were therefore analyzed only by ICP-MS and without chemical separation. However, the following radiochemical method was also developed for the samples. Some Na2S03 was added to the solution to reduce iodine to iodide. Then iodide carrier was added in a concentration of M. An equal amount of 0.1 M NaN02 was added to oxidize iodide... 

The combustion of zirconium in an oxygen stream in the presence of tungsten granules and a chemical carrier (carbon-rich steel) yields excellent results (72)(73). The tungsten is oxidized without splashing and the exothermy of the reaction guarantees its fusion, while keeping the reaction mixture at a temperature above 3000 C. 

Epoxides such as ethylene oxide and higher olefin oxides may be produced by the catalytic oxidation of olefins in gas-liquid-particle operations of the slurry type (S7). The finely divided catalyst (for example, silver oxide on silica gel carrier) is suspended in a chemically inactive liquid, such as dibutyl-phthalate. The liquid functions as a heat sink and a heat-transfer medium, as in the three-phase Fischer-Tropsch processes. It is claimed that the process, because of the superior heat-transfer properties of the slurry reactor, may be operated at high olefin concentrations in the gaseous process stream without loss with respect to yield and selectivity, and that propylene oxide and higher... 

It is clearly impossible to give a comprehensive overview of this rapidly expanding field. I have chosen a few experts in their field to discuss one (class of) transport protein(s) in detail. In the first five chapters pumps involved in primary active transport are discussed. These proteins use direct chemical energy, mostly ATP, to drive transport. The next three chapters describe carriers which either transport metabolites passively or by secondary active transport. In the last three chapters channels are described which allow selective passive transport of particular ions. The progress in the latter field would be unthinkable without the development of the patch clamp technique. The combination of this technique with molecular biological approaches has yielded very detailed information of the structure-function relationship of these channels. 

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