New Insights to Characterize Mineralogical and Physicochemical Properties of Nanoporous and Nanostructured Bentonites (Montmorillonites)

Abstract

Bentonite is rich in montmorillonite, which is a nanostructured and nanoporous member of smectite group. Mineralogical and physicochemical properties of bentonites play a key role in choosing appropriate bentonites for different applications. Scanning electron microscopy (SEM) reveals the morphological form and size of mineral phase of the studied bentonite samples. X-ray diffraction (XRD) analysis showed that the studied bentonites predominantly consist of montmorillonites accompanying other impurities such as quartz, calcite, and plagio feldspar. The amount of organic components CHNO (carbon, hydrogen, nitrogen, and oxygen) in the samples was so low that it had no significant effect on the result of XRF analyses. X-ray fluorescence (XRF) analysis showed that there was a large amount of Al₂O₃ in sample ES3 and this large amount of Al₂O₃ indicates a greater amount of montmorillonite in this sample compared to that in sample GH1. Due to a larger amount of CaO, the type of GH1 montmorillonite is Ca-montmorillonite and due to a lower amount of CaO compared to that of Na₂O the type of ES3 montmorillonite is Na-montmorillonite. This study aims at examining a novel insight to characterize bentonites to find out the mineralogical and physicochemical properties of studied samples.

Keywords:

• bentonite
• characterization
• instrumental analyses
• mineralogy
• nanostructured and nanoporous montmorillonite

Acknowledgments

The late professor Seyed Hamid Jazayeri is highly acknowledged for his contribution in initiating Bentonite research through my M.Sc. and Ph.D studies. I acknowledge the critical reading of the manuscript and suggestions by H. Azimi, which significantly improved the manuscript. Special thanks are given to A. Kyanpisheh, M. Kyanpisheh, and M. Faryadi for providing the laboratory facilities and their assistance.

Notes

*TFeO = FeO + Fe₂O₃.