The surface-active (surface tension, adsorption, molecule cross-sectional area in the adsorption monomolecular layer) and colloidal (viscosity, critical micelle concentration, solubilization) properties in aqueous and hydrochloric acid solutions of anionic surfactant alkylbenzenesulfonic acid (ABSA) were studied. Surface activity of ABSA increases in the presence of hydrochloric acid. Two inflections were established on adsorption isotherms with inorganic acid content of 5 and 10 wt. %, which are indicative of stepwise micelle formation. The ABSA dissociation is suppressed in the presence of hydrochloric acid, and therefore it behaves as a nonionic surfactant, forming micelles at lower concentrations. Mixed micelles, formed by dissociated and non-dissociated surfactant particles, are organized with an increase of ABSA content in mixture. The value of the surfactant limiting adsorption increases significantly at small hydrochloric acid amounts in comparison with an aqueous solution. The formed monomolecular layer is denser in the presence of inorganic acid than in an aqueous solution. The solubilization of Sudan I dye in alkylbenzenesulfonic acid increases with increasing in solution acidity. The extremum points on isotherms of solubilizing ability with 5 and 10 wt. % HCl content are observed at surfactant concentrations corresponding to the beginning and end of the formation of micelles containing alkylbenzenesulfonate ion.
The phase state and extraction capacities of aqueous systems based on sulfonol, sodium dodecylsulfate or alkylbenzenesulfonic acid as anionic surfactants and hydrochloric (or sulfuric) acid against the influence of 1,2,3-benzotriazole as an organic complexing reagent were studied. Introduc-tion of 1,2,3-benzotriazole into the systems resulted in its exfoliation in two liquid phases. Optimal concentration parameters of the extraction process in the systems under investigation were found: the total volume of the system (10 ml) contained sulfonol or sodium dodecyl sulfate (0.6 g), alkylbenzenesulphonic acid (0.5 g), and 1,2,3-benzotriazole (0.35 g). The aliquation state was maintained in the following concentration interval of HCl (H2SO4), mol L-1, for the systems with: (a) sodium dodecylsulfate: 0.5-6 (0.5-4), (b) sulfonol: 0.1-4 (0.05-3), (c) alkylbenzenesulfonic acid: 0-4 (0-3). Distribution of 0.01 mol L-1 of Pd(II), Ni(II), Cu(II), Co(II), Zn(II) and Fe(III) ions in the above systems was studied at the optimal components ratios. In the systems containing sodium dodecylsulfate, no quantitative extraction of metal ions was observed. In the systems with sulfonol and alkylbenzenesulfonic acid, practically complete (99.9%) extraction of palladium appeared to be possible in the entire range of acid concentrations; with minimal acid content, over 95% of copper and nickel were extracted. The extraction of palladium ions in the presence of interfering ions was studied. Quantitative recovery of palladium ions was found to not be obstructed by 500-fold molar excess of copper, 300-fold excess of cobalt and 70-fold excess of nickel.
Regularities of the complex formation of scandium with catechol violet in the presence of the cationic surfactant catamine AB in aqueous solutions are considered. The optimum pH interval of scandium complexation with the reagent in systems with and without catamine AB has been determined. The absorption spectra of pyrocatechin vio- let and its complexes with scandium in the double system and in the catamin AB presence at different pH values and surfactant concentrations were taken. The ratio of metal ion and reagent in the forming complex in double and triple systems has been established by methods of saturation and isomolar series. Calibration graphs were constructed, molar light absorption coefficients were calculated, and conditional stability constants of scandium complexes with pyrocate- chin violet were determined by the Babko method.
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