Admicelle-air bubble flotation system for rapid and efficient removal of environmental pollutants from waste water

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A microscopic solvent property of surfactant aggregates dynamically sorbed on alumina surfaces (i.e., admicelles) was evaluated by the fluorometric method. From the relationship of emission wavelength and polarity of the selected solvent, sodium dodecylsulfate/alumina admicelles have the hydrophobicity larger than normal micelles. It corresponded to 1-octanol or ethylacetate. Many environmental pollutants including chlorophenols, alkylphenols, polyaromatic hydrocarbons, alkylated tin, formaldehyde, and pesticides were rapidly and effectively collected in the admicelles. The extent of the incorporation was correlated with the aqueous-octanol distribution coefficient, which represents the hydrophobicity of the compound. Highly hydrophobic, hence bio-accumulative compounds were efficiently incorporated and highly concentrated into the admicellar media. The incorporation was quite rapid and efficient because of higher wettability and permeability. Admicelles are also useful for the treatment of large volume samples. Alumina having positive zeta potential became negatively charged particles, when they sorbed anionic surfactant SDS molecules. In the moderate SDS sorption, the alumina particles were quantitatively floated on the solution surface by bubbling. This indicates the possibility of simple and rapid recovery of admicelles. Flotation was achieved within 15 s and the particles were retained on the water surface for several minutes. The proposed admicelle-air bubble flotation system has the high potential, in which different hydrophobic toxic compounds are successfully collected in admicelles and then rapidly separated from the bulk solutions by flotation.