REUSABLE ADSORBENTS FOR DILUTE-SOLUTION SEPARATION - 1 - ADSORPTION OF PHENANTHRENE ON SURFACTANT-MODIFIED ALUMINA

Activated gamma-alumina surface was modified by adsorption of an anion ic surfactant, sodium dodecylsulfate (SDS) from the aqueous phase. Typ ical S-shaped isotherms of surfactants on mineral oxides were observed for the adsorption of SDS on alumina. The formation of surfactant agg regates (hemi-micelles) on the surface made the alumina hydrophobic an d increased the capacity of the oxide surface for an organic compound, namely, phenanthrene (PHE). The sorption of phenanthrene was directly related to the concentration of surfactant adsorbed. The partitioning of phenanthrene normalized to the adsorbed surfactant concentration w as independent of pH. The linear sorption constant for a number of org anic compounds was correlated to the octanol-water partition constant and activity coefficient in water, which are indicators of compound hy drophobicity. It is suggested that the ability to easily regenerate a modified alumina surface could be exploited in using it for wastewater treatment of contaminants at dilute concentrations. (C) 1998 Elsevier Science B.V.