Local Cuban bentonite clay: composition, structure and textural characterization

The physic and chemical characterization of the bentonite clay from Chiqui Gómez deposit, central Cuba, (Cuban clay) shows that it is mainly constituted by sodium montmorillonite (>90%), with a structural formula for one-layer unit determined as (Na3.99Al0.01)(Al1.11Fe3+0.49Mg0.18Ti0.07)(Ca0.24Na0.15K0.01)O10(OH)2. Cuban has specific surface area 80 m2g-1, pore volume about 0.0776 cm3g-1, 61% porosity both N2 adsorption-desorption isotherms exhibit hysteresis loop IV type. thermogravimetric analysis (TGA) studied mineral presents first endothermic peak, characteristic montmorillonite, in 48.1 ºC others less accentuated (80.8, 94.0, 119.8 ºC) corresponds to loss water, can be extended up 250 ºC. FT-IR spectra show existence Si-OH, Al-Al-OH, Al-Fe-OH, Al-Mg-OH Si-O-Si functional groups all samples, bands between 1,120 461 cm-1 correspond phyllosilicate structures OH stretching vibrations were observed. pH at point zero charge (pHPZC) obtained value 8.1, which allows classified basic.