Thermal and structural stability of microporous natural clinoptilolite zeolite

Thermal treatment of zeolites prior to their use as adsorbents is needed to remove adsorbed water from zeolite pores, increasing porosity and surface area without inducing structural deterioration. Here, natural zeolite clinoptilolite (CLI) was thermally treated at 378–1073 K in air atmosphere. Porosity and structural changes after treatments at particular temperatures were investigated with N2 adsorption at 77 K, Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD). Brunauer, Emmett and Teller (BET) surface area reached 60 m2 g−1 and αS surface area reached 80 m2 g−1 after thermal treatment at 473 K due to the evolution of water as evidenced with FTIR spectroscopy. Monoclinic crystal structure of the CLI zeolite was preserved after thermal treatment at ∼873 K as indicated with XRD analysis. The CLI zeolite are structurally stable at ∼873 K, reaching the highest specific surface area at 473 K, thus being promising for future adsorbent applications.