Arsenate and Chromate Removal with Cationic Surfactant-Loaded and Cation-Exchanged Clinoptilolite-Rich Tuff vs Montmorillonite

Abstract

Using a laboratory set-up, sorption of chromate and arsenate from aqueous solutions with the octadecylammonium acetate (ODA)-modified clinoptilolite was examined. In the experiments, a natural montmorillonite was compared with organically, i.e. surfactant-loaded clinoptilolite and with some inorganically substituted (Ag, Pb)-monoforms. The arrangements of the surface-attached ODA chains have been an important factor for the difference in the adsorption states of the guest species (oxyanions). A novel nanostructure inorganic-organic composite prepared has been investigated using SEM, thermogravimetry, UV-VIS diffuse reflectance and powder XRD spectral analytical methods. Finally, adsorption isotherms for the system studied have been measured. An approach for regeneration of exhausted surfactant-immobilized clinoptilolite with inorganic salt solutions under dynamic regime has been proposed.