Study of structural properties of ion treated and mechanically deformed commercial bentonite

(ii) Argon-ion treatment. X-ray diffraction analysis showed that the mean d (001) montmorillonite lattice spacing shifted from 1.50 to 1.35 nm, whilst the peak intensity decreased and broadened, with a decrease of the crystallite size in the 001 direction. SEM showed an increased presence of sub-micrometric rounded particles at the surface of the treated samples than for the untreated ones. DSC indicated a decrease in water content after the gas treatment. Laser diffraction showed that the ion treatment increased the number of submicron-sized particles with a concomitant reduction of the number of particles with bigger sizes, leading to an increase of the volumetric surface. These very preliminary results suggest that ionised argon treatment performed in a controlled environment can be exploited to reduce the amount of interlayer water molecules in montmorillonite, to modify its surface characteristics and particle size distribution in a way to increase the specific surface without particle agglomeration or compaction. Applications to other clay minerals (for example, talc and kaolinite, etc.) are envisaged and in progress. Hence, both mechanical deformation and interactions of particular ionised gases can induce significative changes of the physical and chemical properties of bentonite and other clay minerals and further systematic studies are in progress in order to evaluate the potentiality for low-cost industrial applications.