Contribution to the study of some physical and chemical properties of Syrian diatomaceous earth

Abstract

This study investigates the physicochemical properties of Syrian diatomaceous earth sourced from the upper layer (2 m depth) of the Khneifis phosphate mine in Palmyra, Homs Governorate, Syria. Comprehensive characterization using SEM, EDX, FTIR, XRD, TGA, and BET analyses revealed an amorphous silica (opal-A) content exceeding (80%), with a hierarchical porous structure exhibiting specific surface area of (37.6 m²/g) and total pore volume of (60.5 µl/g). The material demonstrates Type IV adsorption isotherms with H3 hysteresis, indicating mesoporous (64.25%) and macroporous (10.04%) characteristics ideal for filtration and adsorption applications. SEM analysis confirmed preservation of centric diatom frustule morphologies at various magnifications, while EDX quantified major elemental composition                                         (Si: 35.23 wt%, O: 50.18 wt%) with minor (Al, Fe, Ca, and P impurities). FTIR spectra identified characteristic Siloxane vibrations (Si-O-Si) (1045, 812 cm⁻¹) and surface silanol groups (Si-OH( (3393 cm⁻¹), and TGA showed 2.96% total weight loss up to 950°C, confirming Syrian diatomaceous earth thermal stability.