Removal of arsenic(III) oxyanions from wastewater using aminosilane -modified natural and synthetic zeolite

Silanization of the natural and synthetic zeolites as well as their use as adsorbents for removing arsenic(III) oxyanions from wastewater are the topic of this paper. Two types of zeolite were used: natural zeolite-clinoptilolite from Zlatokop deposit, Vranjska Banja, Serbia, previously converted to H+-form and synthetic zeolite, mordenite. The modification was performed with solution (3-aminopropyl) triethoxysilane (APTES). The presence of APTES on the surface of zeolite was confirmed using TG/DSC and FTIR analysis. The results showed that natural aminosilane-modified zeolite has a higher adsorption capacity for arsenic(III) oxyanions compared to mordenite prepared in the same way. The kinetic data follow the Lagergren pseudo-second-order model. This model implies a chemical interaction between AsO33–- ions and functional groups on the silanized zeolite surface.