The influence of structural and processing parameters of modifiers on the interlayer structure of modified montmorillonite

Abstract

This study mainly focused on exploring the influence of different processing methods on the structure, physical and chemical characteristics and adsorption ability of modified montmorillonites. The effect of three different modifiers with different chain lengths such as 12-aminododecanoic acid (ADA), 1,12-diaminododecane (DDC) and octadecylamine (ODC) on the d-spacing of montmorillonite was studied in detail. FT-IR spectra and N₂ adsorption isotherms were used to confirm the formation of modified montmorillonites. XRD experiments were carried out and the influence of structural and processing parameters of the modifiers on the interlamellar spacing of modified montmorillonites was studied. It was found that the ODC modifier with a longer carbon chain comparatively enhanced the interlamellar spacing than that of other modifiers. The influence of HCl, the amount of modifiers and temperature on the interlayer structure was also discussed. Upon modification, the peak around 2θ = 6.8° due to [001] plan was shifted to lower 2θ values and the corresponding interlamellar spacing was increased from 1.39 nm to 2.97 nm. The adsorption behavior of the modified montmorillonites for both inorganic and organic pollutants was also discussed based on structural and surface properties. The observed log K_OM values for the distribution of organic pollutants onto modified montmorillonites are comparatively larger in this study indicating that these modified montmorillonites are superior to both natural soil systems as well as literature studies reported so far.