A Spectroscopic and Microscopic Study on the Extraction Behavior of a Probe Dye, Neutral Red, by Aerosol OT in the Isooctane/Water System

Abstract

In the extraction system using Aerosol OT (AOT) in isooctane, the distribution of AOT between the isooctane and aqueous phases depended on the concentration of inorganic electrolytes, salts and/or acids. A colored dye, neutral red, was selected as a probe molecule, which exists in red cationic and yellow nonionic forms in acidic and alkaline regions, respectively. The extraction was investigated in the acidic region in detail. At lower NaCl concentrations, the cationic neutral red existed in the aqueous phase. At higher NaCl concentrations, the cationic neutral red was extracted into the isooctane phase. At intermediate NaCl concentrations, a small amount of third phase appeared in the interfacial region and almost all of the cationic neutral red was extracted into it.Observation by optical microscopy gave geometric information about the third bicontinuous microemulsion phase as well as microemulsions or emulsions formed in the isooctane and aqueous phases.

<i>In Situ</i> Microscope Measurements of the Formation of Nanometer-Sized Gold Particles at the Dodecane/Water Interface through the Direct Reduction of Aqueous Tetrachloroaurate(III) by Hydrophobic <i>dl</i>-α-Tocopherol in the Presence of 1,10-Phenanthroline

“…Observation by optical microscopy was carried out with a fabricated thin-layer two-phase microcell, as shown in Figure 1 [12][13][14]. Briefly, a thin glass plate (0.14 mm in thickness), a glass plate (1 mm in thickness) with a hole (3 mm in diameter), and a glass plate (1 mm in thickness) with a hole (7 mm in diameter) were assembled in this order.…”

Effect of Diethanolamine on The Extraction Properties of Reverse Micelles with Sodium Bis(2-ethylhexyl) Sulfosuccinate

“…Hence, reverse micellar solutions have been extensively investigated as media for the extraction of proteins and enzymes from aqueous solution [2][3][4][5][6][7][8][9][10][11][12][13][14][15]. The extraction of proteins is controlled by the interaction between reverse micelles and proteins, such as electrostatic interaction between the ionic surfactant and the charged surface of the protein, hydrophobic interaction between the interface of the reverse micelles and the hydrophobic part of the proteins, and the steric exclusion effect from the micelles [16,17].…”