Hydrophobicity desorption efficiency

Incorporated multivalent complex anions in PXV matrix were desorbed by the decrease of cationic charge density of PXV. About half or all of cationic charges of PXV were reduced when potentials were stepped to -0.70 V and -1.20 V, respectively. At -0.70 V, Fe(CN)0 " was desorbed theoretically (about 50%), but desorption efficiency of Mo(CN)84 at -0.70 V was half as much as that of Fe(CN)0 system. This might correspond to the strength of the interaction between PXV matrix and complex anions, or the hydrophobicity of Mo(CN)8. ... 

For metal desorption from the biomass certain dilute solutions of mineral acids like hydrochloric acid, sulfuric acid, acetic acid and nitric acid were used [219, 76]. Batch system was carried out to study the desorption of the adsorbed Hg (II) from the biosorbent - immobilized and heat inactivated Trametes versicolor and Pleurotus sajur-caju [8]. Hg (II) ions adsorbed onto the biosorbents were eluted with 10 mmol dm HCl and the results showed that more than 97% of the adsorbed Hg (II) ions were desorbed from the biosorbents. In order to evaluate the feasibility of applying the prepared biosorbents in the heavy metals removal processes, the metal desorption efficiency from loaded biosorbents, and the reusability of the biosorbent in repeated adsorption-desorption operations were determined. The charged species exhibited desorption-resistance fraction whereas the desorption of the neutral form was completely reversible. The difference in sorption and desorption between the neutral and charged species is attributed to the fact that the anionic species sorbs by a more specific exothermic adsorption reaction whereas the neutral form partition by the hydrophobic binding to the soil [206]. Desorption of soil-associated metal ions and possible mechanisms have received considerable attention in literature [148],... 

Micelles forming above the c.m.c. incorporate hydrophobic molecules in addition to those dissolved in the aqueous phase, which results in apparently increased aqueous concentrations. It has to be noted, however, that a micelle-solubilised chemical is not truly water-dissolved, and, as a consequence, is differently bioavailable than a water-dissolved chemical. The bioavailability of hydrophobic organic compounds was, for instance, reduced by the addition of surfactant micelles when no excess separate phase compound was present and water-dissolved molecules became solubilised by the micelles [69], In these experiments, bacterial uptake rates were a function of the truly water-dissolved substrate concentration. It seems therefore that micellar solubilisation increases bioavailability only when it transfers additional separate phase substrate into the aqueous phase, e.g. by increasing the rates of desorption or dissolution, and when micelle-solubilised substrate is efficiently transferred to the microorganisms. Theoretically, this transfer can occur exclusively via the water phase, involving release of substrate molecules from micelles, molecular diffusion through the aqueous phase and microbial uptake of water-dissolved molecules. This was obviously the case, when bacterial uptake rates of naphthalene and phenanthrene responded directly to micelle-mediated lowered truly water-dissolved concentrations of these chemicals [69]. These authors concluded from their experiments that micellar naphthalene and phenanthrene had to leave the micellar phase and diffuse through the water phase to become... 

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