Glauconitic clay of El Gidida, Egypt: evaluation and surface modification

Three samples of glauconitic material from El Gidida, Egypt were evaluated in terms of the mineralogical and chemical composition, crystal morphology, surface area and porosity. The effect of heat treatment and acid activation on the surface area, pore volume and microporosity of glauconitic clay was investigated. Data obtained by using Scanning Electron Microscope (SEM), X-ray diffraction (XRD), X-ray Florescence (XRF), and Infrared (IR) spectroscopy, reveal that the glauconitic material of El Gidida area is di-octahedral with an iron-rich illite-smectite mixed layer composed of a range of expandable layers (<10–40%), in addition to variable percentages of kaolin and quartz. As the relative amounts of kaolin and quartz increased, illite-smectite mixed layers decreased. Low K2O content in glauconitic material is related to the composition of the parental glaucony mineral phase as well as to destabilization of glauconite. Morphologically, glauconite pellets consist of spheroidal aggregates of very fine particles, arranged parallel to each other, and separated by debris. However, many of the platelets are bent and curly, generating numerous mesopores. The surface area and pore volume ranged between 147–80 m2/g and 0.341–0.164 cm3/g, respectively. Details of the above characterization studies are given in this paper.