ACID ACTIVATION OF PRRENJAS CLAY MINERAL

Abstract

Prrenjas clay mineral is found in southeast Albania and has a high content on bentonite. The
influence of the sulphuric acid activation on the composition, structure and surface properties of
Prrenjas clay mineral is investigated in this study by means of elemental chemical analysis, X-Ray
Diffractometry, IR Spectroscopy and gas adsorption-desorption measurement. H2SO4
concentrations of 0.143 M, 0.232 M, 0.371 M, 0.537 M, 0.734 M, 0.927 M and 1.456 M were used in
the treatment of samples. The treatment by increasing the acid concentration brings the leaching of
Al3+, Fe2+, Mg2+ from the clay structure. The specific surface area and the pore volume of the clay
samples increases respectively from 83 m2/g and 0.069 cm3/g for the untreated clay to 420 m2/g and
0.384 cm3/g for the clay mineral treated with 1.456 M H2SO4 solution. New mesopores were created
during the acid activation mainly in the range of 2 – 8 nm. For the samples treated with 0.927 M
and 1.456 M solutions the increase in specific surface area and pore volume is very high. The
cationic exchange capacity decreases steadily with the concentration of H2SO4 used for the
treatment.