The molality dependence of specific conductivity of pentadecyl bromide, cetylpyridinium bromide and cetylpiridinium chloride
in aqueous solutions has been studied in the temperature range of 30–45 °C. The critical micelle concentration (cmc) and ionization
degree of the micelles, β, were determined directly from the experimental data. Thermal parameters, such as standard Gibbs free energy
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.
Authors:A. Tabak, B. Afsin, S. F. Aygun, and E. Koksal
Organobentonites were synthesized by treating Na-bentonites (Wyoming and Reşadiye) with cetylpyridinium chloride (CPC) using ion exchange method. The difference in the basal spacing by 0.65 Å and a higher mass loss by 13.32% of organobentonite (Wyoming) in the temperature range 200–550°C comparing with that of organobentonite (Reşadiye) were in conformity with the CEC values of organobentonites. The HOH stretching and bending peaks of bentonites became sharper following the treatment with the organo-cation. The intensity decrease of the Al–OH band for organobentonite (Reşadiye) and in particular, the significantly higher amount of m-cresol retained by the organobentonite of lower CEC than that by the organobentonite (Wyoming) indicate the influence of the CP cation on the adsorption process.
Thin-layer chromatography (TLC) of fifteen amino acids was performed using silica gel and alumina impregnated with micellar solutions of cetrimide and cetylpyridinium chloride as stationary phases and aqueous solutions of dextrose as mobile phases. TLC system comprising of silica gel impregnated with micellar solution of cetrimide (5.0 mM) as stationary phase and 40% (
) aqueous solution of dextrose as mobile phase was found the most favourable for the separation of amino acids. Impregnation of silica gel with the micellar solution of cetrimide brings about a substantial change in the mobility of lysine. Separation of lysine (ketogenic) from arginine (glucogenic) is important physiologically. Surface modification of silica gel on impregnation, as indicated by FTIR and SEM studies, was responsible for improved chromatographic performance. The effect on the separation of the presence in the sample of heavy metal cations, as impurities, was examined. Limits of detection for lysine and arginine were 0.17 μg and 0.12 μg, respectively. For validation, the stability of the mixture and the reproducibility of the chromatographic properties Δ
, separation factor (
), and resolution (
) were calculated. The proposed method is simple, rapid, and free from use of volatile organic solvents.
dissolved in 15 mL of water. To this solution, 0.6 g of cetylpyridiniumchloride dissolved in 30 mL of water was added slowly. The mixture was stirred vigorously for 4–5 h at 40 °C. A white solid was filtered off and then washed with an excess amount of