Flotation of polycyclic aromatic hydrocarbons coprecipitated with aluminum hydroxide containing sodium dodecyl sulfate and magnesium

A simple and efficient method for concentrating polycyclic aromatic hydrocarbons (PAHs) in water was developed. Al(III) and an anionic surfactant, sodium dodecyl sulfate (SDS), were added into the aqueous sample solution. Subsequently, the solution pH was adjusted to 7 by adding 2 and 0.1 mol/L sodium hydroxide solutions to form aluminum hydroxide precipitaties. Hydrophobic PAHs were well incorporated into the hydrophobic media of the precipitates. The recoveries of PAHs were improved by the addition of Mg(II). Based on the fluorescent spectra of a molecular probe, N-phenyl-1-naphthylamine (PN), the hydrophobicity of aluminum hydroxide containing SDS and Mg(II) corresponds to that of 1-propanol. The precipitates were rapidly collected by flotation. The combination of coprecipitation and subsequent flotation was useful for concentrating PAHs prior to their HPLC analysis.