SORPTION OF NEUTRAL RED DYE BY ENTERSORBENT POLYSORB MP FROM AOT MICROEMULSION IN N-DECAN

Sorption of the cationic neutral red dye by Polysorb MP from a microemulsion of 0.25 mol/L AOT in n-decane was carried out at different contents of the aqueous pseudophase. The maximum sorption capacity of the sorbent in the microemulsion exceeded the corresponding one in the aqueous phase by an order of magnitude and amounted to 55 mg/g. A sharp drop in the degree of extraction with an increase in the water content of the microemulsion from 1 to 8 volume percent and the reversibility of sorption processes were demonstrated. Anionic dyes were not extracted by Polysorb MP in the same systems. With increasing water content, the zeta potential of SiO2 particles decreased from 18 to 1 mV. Based on the obtained dependencies, a cation exchange mechanism of microemulsion sorption was proposed, including the exchange of sodium and neutral red cations between micelles adsorbed on the surface of particles and micelles in the bulk of the microemulsion.