Sorbent Mass Variation Method: A New Possibility for the Determination of Binding Isotherms.

Measurement of equilibrium mass fraction of a surfactant as a function of the sorbent mass fraction was performed on gel sorbent-solution systems in order to determine binding isotherms and to calculate fundamental characteristics of the solvation layer. With application of this new method, it was possible to calculate specific solvation/sorption capacity and absolute average local composition of the solvation layer. It has been pointed out by systematic variation of the composition (hydrophobicity) and degree of cross-linking of the gel sorbents that the ratio of components in the solvation layer can be constant in a given range of equilibrium mass fraction of the sodium dodecyl sulfate (SDS) and that the specific solvation/sorption capacity of gel sorbents can be much greater than that of activated carbon type adsorbents. On the basis of a mixed sorbent model, it turned out from calculations that there is no preferential binding of SDS close to the chemical cross-links and that the surfactant molecules prefer vinyl acetate groups as binding sites. The density of cross-links regulates the aggregation number of the bound surfactant as well. For loose gels, both binding isotherms and swelling curves show that the surfactant-polymer interaction is a strongly cooperative process. The result of these experiments may influence the general concept of solvation/sorption isotherms and all related phenomena

Use of Gamma-Valerolactone as an Illuminating Liquid and Lighter Fluid

The sulfuric acid-catalyzed conversion of paper wastes in gamma-valerolactone (GVL) or dioxane leads to the formation of levulinic acid (LA) and formic acid (FA), which can be converted to GVL by transfer-hydrogenation using the Shvo catalyst in situ or separately. The isolation of LA and FA was assisted by the neutralization of the sulfuric acid with ammonia to form a biphasic system. While the ammonium sulfate and most of FA and some of LA were in the aqueous phase, the organic solvent-rich phase contained most of the LA and some of the FA. GVL was used as an illuminating liquid in glass lamps for hours without the formation of noticeable smoke and/or odor even in a small room. While neat GVL can be used for the safe but somewhat slow lighting of charcoal, the ignition with different mixtures of GVL (95 or 90 vol %) and ethanol (5 or 10 vol %) was reduced to a convenient few seconds. Ignition tests of charcoal combined with emission analyses revealed that by increasing the ethanol content to 10 vol % the relative VOC emission can be decreased by 15% compared to the commercial lighter fluids