Detection and quantification of montmorillonite nanoclay in water-ethanol solutions by graphite furnace atomic...

Organo-modified montmorillonite (O-MMT) was detected in various water-ethanol solutions by using graphite furnace atomic absorption spectrometry, based on the simultaneous elemental analysis of silicon (Si) and aluminium (Al). The quantification limits of the method were 0.03 mg L⁻¹ for Si and 0.01 mg L⁻¹ for Al, but can be improved to 8 μg L⁻¹ for Si and 3 μg L⁻¹ by using the concentration function of the instrument. A stability test of O-MMT in suspension was conducted by considering the solvent type (i.e., water and/or ethanol) and a surfactant. A good dispersion of O-MMT was achieved in suspensions with water and ethanol at 1:2 (v/v) or with pure ethanol, while the addition of a surfactant improved the dispersion of O-MMT in water. The Si and Al concentrations in the suspensions were correlated with O-MMT concentrations. The Si and Al contents in the O-MMT were determined by using graphite furnace atomic absorption spectrometry to be 22% ± 1.1% and 9.3% ± 0.5% wt/wt, respectively, which was in agreement with values obtained by X-ray fluorescence spectrometry method performed in this study.