HYDROTHERMAL SYNTHESIS OF KA (LTA-TYPE) ZEOLITE FROM ANGREN KAOLIN: STRUCTURAL, MORPHOLOGICAL, AND ADSORPTION CHARACTERIZATION

Abstract

This study explores Angren kaolin as a low-cost local raw material for the synthesis of KA zeolite (LTA-type). A multi-step activation process using oxalic acid was applied to remove impurities and enhance reactivity. Hydrothermal synthesis yielded highly crystalline KA zeolite, whose structural and adsorption properties were thoroughly investigated. XRD analysis confirmed the formation of an ordered crystalline lattice, while FTIR spectra revealed characteristic Si–O–Si and Al–O vibrations and the presence of double four-ring (D4R) units typical of LTA-type zeolites. BET and DFT analyses demonstrated a well-developed porous structure and strong adsorption capacity: BET surface area was 8.475 m²/g, DFT surface area 19.575 m²/g, maximum adsorption volume 149.00 cc/g, and average pore diameter 121.955 Å. These findings confirm the high hydrophilicity and efficiency of KA zeolite as an adsorbent. The study provides a scientific basis for utilizing Angren kaolin in zeolite synthesis and highlights the strategic importance of local resources for future industrial-scale applications.