A novel technique for fabrication of rod-like shape zeolite LTA and hydroxysodalite by extrusion of bentonite powder: Effects of technical factors on structural characteristics

Abstract

The current investigation proposes a novel method for the fabrication of zeolite-based packed beds by extrusion of a paste, containing Ca-bentonite, boehmite, and sodium hydroxide, as rod-like shape. The formed precursor was heated at 800 °C to reinforce the extrudates, aged at different times, 3–24 h, and converted to the zeolite structure by recrystallization in the hydrothermal condition, 3–9 h. The obtained results showed that aging, and recrystallization times affect the crystalline phase structure, morphology of particles, textural properties, and cation exchange capacity (CEC) as characterized by X-ray diffractometry, field emission electron microscopy, and N2 adsorption–desorption isotherms. The thermally treated extrudates could be converted to zeolite LTA, and or hydroxysodalite (HS), depending on aging, and recrystallization times. It is necessary to age the treated extrudates in 9 h, and control the recrystallization time within 3 h to achieve zeolite LTA with a proper CEC, 232 mg g−1. Contrarily, the choice of inverse conditions, leads to create a mesoporous HS with a broad pore size distribution, 2–50 nm.