Solubilization experimental study

The cleaning process proceeds by one of three primary mechanisms solubilization, emulsification, and roll-up [229]. In solubilization the oily phase partitions into surfactant micelles that desorb from the solid surface and diffuse into the bulk. As mentioned above, there is a body of theoretical work on solubilization [146, 147] and numerous experimental studies by a variety of spectroscopic techniques [143-145,230]. Emulsification involves the formation and removal of an emulsion at the oil-water interface the removal step may involve hydrodynamic as well as surface chemical forces. Emulsion formation is covered in Chapter XIV. In roll-up the surfactant reduces the contact angle of the liquid soil or the surface free energy of a solid particle aiding its detachment and subsequent removal by hydrodynamic forces. Adam and Stevenson s beautiful photographs illustrate roll-up of lanoline on wood fibers [231]. In order to achieve roll-up, one requires the surface free energies for soil detachment illustrated in Fig. XIII-14 to obey... 

The product is equal to the equilibrium constant X for the reaction shown in equation 30. It is generally considered that a salt is soluble if > 1. Thus sequestration or solubilization of moderate amounts of metal ion usually becomes practical as X. approaches or exceeds one. For smaller values of X the cost of the requited amount of chelating agent may be prohibitive. However, the dilution effect may allow economical sequestration, or solubilization of small amounts of deposits, at X values considerably less than one. In practical appHcations, calculations based on concentration equihbrium constants can be used as a guide for experimental studies that are usually necessary to determine the actual behavior of particular systems. 

GE Amidon, WI Higuchi, NSF Ho. Theoretical and experimental studies of transport of micelle-solubilized solutes. J Pharm Sci 71 77-84 (1982). 

A Representative List of Experimental Studies Exploring Emulsion System for Drug Solubilization... 

This observation suggests that nanotubes may interact physically through either wrapping or covering of nanotube surface by solubilized polymeric chain of PAni. Another possibility offers a n-n chemical interaction of planner surface of nanotube with quinoid ring of PAni chain [20]. More experimental study needs to be carried out to clarify the origin of this phenomenon. 

Experimental studies concerning crystallization from W/O microemulsions use thermal analysis methods to characterize the microemulsions themselves, to determine thermodynamic parameters of crystallization, and to characterize the final products. A large number of studies are concerned with the state of water in ionic [109] and nonionic [110] W/O microemulsions. It has been shown that because of the close proximity of the interface, the properties of the water molecules are quite different from those of water in the bulk, and this difference in itself may have a profound effect on the solubilization and crystallization of solutes. The problem is discussed in detail in two other chapters (by Schulz et al. and by Garti et al.) in this book and will not be reiterated here. In this presentation we describe (1) calorimetric studies of the formation of nanosized inorganic crystallites and (2) the use of TG and DSC in the characterization of a water-soluble organic compound crystallized in a W/O microemulsion. 

A second step of this approach is an extensive study of the enzymes responsible for the lipid biosynthesis. As most of the synthesizing machinery is located in membranes, this step requires a solubilization and purification of the enzymes followed by a theoretical and experimental study of the functioning of the reconstituted enzymes and the modulation of their activity by the surrounding lipids. 

Some researcher groups (Chiou et al. 1985 Condo and Jonston 1992 Condo et al. 1994 Wissinger and Paulaitis 1991) conducted experimental studies on the measurements of Tg of PS and poly(methyl methacrylate) (PMMA) as affected by the solubilization of CO2 at elevated pressures and temperatures, and they interpreted the experimental results with theory. Some investigators (Chiou et al. 1985 Condo and Jonston 1992 Wissinger and Paulaitis 1991) observed that the Chow theory (1980) predicts experimental results reasonably well for low concentrations (e.g., up to approximately 12 wt %) of CO2, while others (Condo et al. 1994) observed that the theory of Condo et al. (1992) predicts experimental results reasonably well for concentrations of COj as high as 20 wt %. Figure 13.14 compares theory with experiment on the extent of... 

Since very often the physicochemical properties of solubilizates are modified when they are entrapped in reversed micelles, almost all the experimental techniques can been used, and have been used, to study solubilization [28,31,118-122]. 

Zhong et al. (2003) studied the apparent solubility of trichloroethylene in aqueous solutions, where the experimental variables were surfactant type and cosolvent concentration. The surfactants used in the experiment were sodium dihexyl sulfo-succinte (MA-80), sodium dodecyl sulfate (SDS), polyoxyethylene 20 (POE 20), sorbitan monooleate (Tween 80), and a mixture of Surfonic- PE2597 and Witconol-NPIOO. Isopropanol was used as the alcohol cosolvent. Eigure 8.20 shows the results of a batch experiment studying the effects of type and concentration of surfactant on solubilization of trichloroethylene in aqueous solutions. A correlation between surfactant chain length and solubilization rate may explain this behavior. However, the solubilization rate constants decrease with surfactant concentration. Addition of the cosolvent isopropanol to MA-80 increased the solubility of isopropanol at each surfactant concentration but did not demonstrate any particular trend in solubilization rate of isopropanol for the other surfactants tested. In the case of anionic surfactants (MA-80 and SDS), the solubility and solubilization rate increase with increasing electrolyte concentration for all surfactant concentrations. 

Example 8.6 A Nuclear Magnetic Resonance Study of Solubilization in a Reverse Micelle. Let 5 be the chemical shift produced by the proton of a solubilized molecule and differentiate between the experimental shift (subscript exp) and the 5 s produced by molecules in bulk (subscript 0) or micellar (subscript m) environments. Arguing by analogy with the derivation of Equation (24) shows that... 

Three 1-D column studies were conducted to investigate the effects of EtOH addition (0, 5, and 10% wt) on the micellar solubilization of residual PCE by 4% Tween 80 in a uniform porous medium. The applied Darcy velocities ranged from 3. 3 to 4.9 cm/hr. Periods of flow interruption (8 and 15 hours) were utilized to evaluate PCE mass transfer under no flow conditions. A summary of the experimental conditions and physical... 

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