Clinoptilolite is more appropriate to adsorb molecules whose kinetic diameter is
lower than 3 nm because the most pores are located in the microporous range; molecules
with bigger diameters are not penetrable for the clinoptilolite microporous channels.
The acid treatment increases micropore volumes and the specific surface area of
clinoptilolite; therefore it would improve adsorption efficiency. Heating at 400 °C
eliminates water molecules existing in clinoptilolite channels which may unblock the
channels and increase sorbate penetrating through channels, improving adsorption
efficiency. Nitrogen adsorption method showed that grains of clinoptilolite have
higher specific surface area and pore volume than rock one, thus it may improve adsorption
efficiency. For choosing appropriate physical and chemical modification
methods for each sorbate, all of this characterization, porosity and structural properties
of clinoptilolite should be considered.