Evolution of molecular structure and conformation of n-alkylammonium intercalated iron rich bentonites

Clay-surfactant hybrids were prepared from three montmorillonites of different cation exchange capacity (CEC) and iron-content using n-alkylammonium surfactants with varying alkyl chain length from C10 to C16. Structure of clay-surfactant hybrids were evaluated using basal spacing from XRD, organic loading from Thermogravimetric Analysis (TGA) and conformational analysis from FTIR. It was found that the structure of the clay-organic hybrid depends mostly on CEC and marginally on iron-content. The systematic study of structural evolution and comparable swelling nature of clay-surfactant hybrids of the low-CEC, high iron-variety indicates its potential industrial application like high-CEC montmorillonite.

► Clay-surfactant hybrids prepared from montmorillonites with different cation exchange capacity and iron-content. ► Structure of clay-surfactant hybrids for n-alkylammonium surfactants (C10–C16) studied with XRD, TG and FTIR. ► Structure evolution of the hybrid depends mostly on CEC and marginally on iron-content. ► Hybrids show comparable organophilicity. ► Clay-surfactant hybrids of low-CEC, high iron-variety can find commercial application like high-CEC montmorillonites.