New data the kaolinite-potassium acetate complex

The intercalation complex of kaolinite and potassium acetate (KAc) was stud ied by HTXRD, IR spectroscopy and DTA-TG. The HTXRD patterns indicate that the 14.06 Angstrom basal spacing of the complex contracts to 11.77 Angstrom and 9.35 Angstrom after heating at 60 degrees C. The DTA-TG data indicate that water is present in these new complexes, the decomposition of which oc curs between 290 degrees C and 400 degrees C. Modifications observed in the high-frequency region of the spectra obtained after heating suggest that K ions occupy the ditrigonal holes in the OH surface of the kaolinite layers , whereas water is probably located between the KAc layer and the OH surfac e of the kaolinite. This structural arrangement would favour the H-bonding between inner-surface OH groups and water and justifies the presence of new bands at lower frequencies. Electrostatic interactions between the keyed K ions and O of the inner OH groups would justify the modifications of the 3 619 cm(-1) OH-stretching band.