The dynamic interfacial tensions (IFTs) of three different types of surfactant solutions, cationic surfactant hexadecyl trimethylammonium (CTAB), anionic surfactant sodium dodecyl benzenesulfonate (SDBS), and non-ionic surfactant Triton X-100 (TX-100), against model oil containing oleic acid (OA) have been investigated by a spinning drop interfacial tensiometer. The influences of the OA concentration and addition of alkali have been studied. The experimental results show that OA added to the oil phase has a significant effect on interfacial behaviors of surfactant solutions. An obvious synergistic effect on reducing IFT can be observed for low-concentration cationic surfactant CTAB solution because the tight mixed adsorption films will be formed through electrostatic attraction between CTAB and OA molecules. However, the synergistic effect will disappear at a high surfactant concentration by the formation of mixed micelles. For the anionic surfactant SDBS system, the mixed adsorption of SDBS and OA molecules leads to a limited decrease of equilibrium IFT as a result of electrostatic repulsion. The hydrophilic group EO chain of TX-100 extends into the aqueous phase and the interfacial film becomes tight with an increasing bulk concentration. As a result, OA shows little effect on the equilibrium IFTs at a high TX-100 concentration. The alkali in the aqueous phase will react with OA in the oil and produce anionic surfactant sodium oleate (SO), which destroys the synergistic effect between CTAB and OA molecules. With an increase of the OA concentration, the dynamic characteristic of IFT has been enhanced and the transient IFTs decrease obviously because more SO molecules have been produced.
Zheyu Huang,Jingzhong Kuang,Weiquan Yuan,Mingming Yu,Xiaoyuan Wang
Centering on the roles of ultrasound in flotation kinetics, adsorptions of sodium oleate and scheelite, heat of adsorption and mineral surface properties, we investigated the effects of ultrasonic pre-treatment on scheelite surface dissolution, as well as properties and microstructure of sodium oleate solution. As a result, the ultrasonic treatment of sodium oleate or scheelite promoted the adsorption of sodium oleate on the surface of scheelite, which improved adsorption heat, thermal reaction rate, surface hydrophobicity , flotation rate and recovery rate of scheelite. However, the ultrasonic treatment effect of sodium oleate was better than that of scheelite. The dissociation of sodium oleate molecules was promoted by the ultrasound reduces the surface tension of collector solution to enhance its solution activity. In the meantime, the agglomeration structures of sodium oleate were disrupted by ultrasonication to form a small or single molecular structure, which helped accelerate the solute migration speed and reduced induction time between sodium oleate and scheelite. Ultrasonic treatment removed the adhesion of fine particles on the surface of scheelite and the severely corroded mineral surface, which accelerated the dissolution and increased the number of Ca 2+ reactive sites.
危险品化学品经营许可证（带存储）