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

Abstract

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.

Graphical Abstract

Keywords:

• nanoclay
• montmorillonite
• atomic absorption spectrometry

Acknowledgements

The authors thank Kathy Severin from the Department of Chemistry at MSU for assistance and allowing access to the GFAAS equipment and Wei Zhang from the Department of Crop and Soil Sciences at the MSU for the use of the Malvern unit and the measurement of the zeta potential. The authors also appreciate the assistance of Carlos Diaz for the GFAAS experiments and Ajay Kathuria for the measurement of SSA.

Funding

This work was financially supported by the Center for Packaging Innovation and Sustainability at the School of Packaging, Michigan State University.