Crystal morphology and differential meso-micro pore-volume distribution patterns of clinoptilolite fractions

Abstract

Analysis of scanning electron microscope (SEM) morphology and pore - volume distribution of commercial clinoptilolite fractions have been conducted experimentally using an analyzer by measuring the N2 adsorption isotherm. The commercial material was fractionated by sieving through different sieves viz., \125 l (Z1; fine fraction), 125–250 l (Z2; medium fraction) and 250 l (Z3; coarse fraction). All three fractions exhibited type IV isotherm of IUPAC. Adsorption hysteresis (H3) suggested that the pores are slit - shaped even though the pores are multi - shaped in reality. SEM results have shown, the morphology of clinoptilolite having particle size grains of 396 nm (fine fraction, 125 l sieve), 488 nm (medium fraction, 125–250 l sieve) and 541 nm (coarse fraction, 250 l sieve) with layered structure. However, medium fraction has exhibited incomplete hexagonal structure too. The meso–micro pore - volume distribution of the fractions were calculated from the hysteresis loop according to the adsorption curves of Barret, Joyner and Halenda. There was only a minor change in pore volume to each incremental pore volume for the coarse clinoptilolite fraction.