Zeta potential study of natural- and acid-activated sepiolites in electrolyte solutions

Abstract

Detailed characterisation of natural sepiolite from the Eskisehir region of Turkey was performed using X-ray diffraction, X-ray fluorescence, field emission scanning electron microscopy, specific surface area (BET method), Fourier transform infrared spectra, derivative thermogravimetry (DTG) and differential thermal analysis. Electrokinetic properties of natural- and acid-activated sepiolites were investigated as a function of the concentration of various electrolytes, such as NaCl, KCl, LiCl, CaCl 2, MgCl 2, NaNO 3, Na 2CO 3, FeCl 3 and Al(NO 3) 3. While mono and divalent cations and anions did not change the surface charge of natural- and acid-activated sepiolite, trivalent cations changed the surface charge from negative to positive. Acid-activated sepiolite samples shifted towards the positive region in nearly all electrolyte solutions when compared with the natural sepiolite. © 2011 Canadian Society for Chemical Engineering © 2011 Canadian Society for Chemical Engineering.