Adsorption of sodium dodecyl sulfate on hydrotalcite and adsolubilization of 2-naphthol

Adsorption behavior of sodium dodecyl sulfate (SDS) on hydrotalcite was investigated by measuring the amount of SDS adsorbed, zeta potential and pyrene fluorescence spectra of suspensions. The amount of SDS adsorbed increased sharply and then reached a plateau with SDS concentration, accompanying the change of zeta potential from positive to negative. The X-ray diffraction and fluorescence measurements show that the interlayer separation of hydrotalcite increases, while the microenvironment of SDS adsorbed layer becomes hydrophobic with SDS concentration. The amount of 2-naphthol adsolubilized increased considerably at low SDS concentration and then decreased gradually with SDS concentration. In addition, the amount of 2-naphthol adsolubilized increased proportionally with increasing feed concentration of 2-naphthol. (C) 1998 Elsevier Science B.V.