Authors:J. Galán, J. Del Castillo, A. González-Pérez, V. Fuentes-Vázquez, and J. Rodríguez
The specific conductivities of dodecylpyridinium chloride have been
determinated in water-butanol/pentanol/hexanol solutions in the temperature
range of 10 to 35C, and butanol, pentanol and hexanol concentrations
up to 0.05 mol kg–1.
data the temperature dependence of the critical micelle concentration, (cmc),
was determined. The molar fraction of alcohol in the micelle was estimated
using the theory suggested by Motomura et al.
for surfactant binary mixtures. The standard Gibbs free energy of solubilization
of alcohols in the micelles was worked out using the phase separation model.
Authors:J. Galán, A. Gonzáles-Pérez, J. Del Cactillo, and J. Rodríguez
Electrical conductivity of aqueous solutions of dodecylpyridinium chloride and bromide have been determined. From these data
the critical micelle concentration (cmc) was determined. The thermal properties as standard Gibbs free energy, enthalpy and entropy of micellization was estimated
from a uncharged-phase separation model and enables to obtain another properties like heat capacity of micellization and the
relevant parameters in the minimum of temperature dependence of cmc. The enthalpy-entropy compensation was shown for the studied compounds.
As a part of a research program on the treatment of radioactive process waste waters, sorbent macroflotation was tested to remove Co(II) from dilute aqueous solutions. Activated charcoal was used as the sorbent, and gelatin, cetylpyridinium chloride, dodecylamine or N-dodecylpyridinium chloride (NDPC) as the collector. In addition to the effect of the collector type on the percent removal, the effects of the pH, the charcoal and collector doses, the metal ion concentration, the ionic strength and the use of combinations of NDPC with other reagents have been investigated. At the optimum conditions removals better then 97% could be achieved in the pH range of 7.5–10.0 with NDPC plus a low concentration of a low-molecular-weight polyacrylamide. The results obtained are discussed in terms of hydrolysis of the metal ion and the electric state of both the charcoal and collector.
Ion, precipitate and adsorbing colloid flotation of cobalt(II) have been investigated at different pH values, using N-dodecylpyridinium chloride (DPCl), A strong cationic surfactant, and sodium lauryl sulfate (NaLS), a strong anionic surfactant, as collectors. In case of adsorbing colloid flotation, hydrous manganese dioxide was used as an adsorbent. The precipitate flotation curves experimentally obtained with the two tested collectors were compared with the corresponding theoretical one calculated from the data published for Co(II) hydrolysis. The effects of the collector concentration, ageing of the water-MnO2–Co(II) system, bubbling time period, cobalt(II) concentration and foreign salts on the percent removal of Co(II) by adsorbing colloid flotation using DPCl as collector were determined. Removals approaching 100% could be achieved under the optimum conditions.