Thermal Regeneration Model for Spent Montmorillonite Sorbent

The regeneration possibilities of montmorillonite after repeated heating in the temperature range of 300 °C - 450 °C were investigated. A simple technique for thermal regeneration of spent montmorillonite sorbent was developed. Powder X-ray diffraction (PXRD), thermogravimetry/differential thermal analysis (TG/DTA), wavelength dispersion X-ray fluorescence spectrometry (WDXRF) and visible light spectrometry were employed for sample characterization. Heating at 300 °C allowed successful repeating of regeneration, at which the montmorillonite structure could be restored after several heating cycles. However, regeneration at about 450 °C resulted only in partial regeneration of montmorillonite structure. After three regeneration cycles at 450 °C the pseudo-illitization was irreversible.