Characterization of Ashaka and Tango Bentonites surfaces after modification with Benzyl dimethyl dodecyl and dimethyl dioctadecyl ammonium chlorides.

Abstract

Bentonites from Ashaka and Tango of Gombe State, Nigeria were surface modified with two different surfactants viz; Benzyl dimethyl dodecyl and dimethyl dioctadecyl ammonium chlorides by cation exchange method. The surfaces of the modified products were characterized by means of Fourier-transformed infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The FTIR spectra of the modified bentonites showed the C-H asymmetric (υasCH2), symmetric (υsCH2) stretching and bending (δ) vibrations (2926, 2920, 2918; 2851 and 1469cm-1) in methylene groups of surfactant alkyl chains respectively. The basal spacing of the unmodified bentonite samples, determined by means of X-ray diffraction (XRD) was 15.23 Å and 12.99 Å and after modification with benzyl dimethyl dodecyl ammonium it increased to 20.07Å and 19.62Å while with dimethyl dioctadecyl ammonium it increased to 21.79Å and 26.75Å. Results of the SEM images revealed rougher surfaces with uniformly dispersed small particles of grain-like structures characteristic of the organomodified bentonites.Keywords: Basal spacing, Cation exchange, Organobentonites, Quaternary ammonium surfactants, Surface modification