Bondarieva A. Porous Ceramic Materials Based on Clay of Ukraine

The thesis focuses on creating novel functional materials using inexpensive and accessible raw materials to protect natural water systems from contamination by arsenic (V) and chromium (VI) compounds. Porous ceramic materials were obtained using natural clay minerals, specifically kaolinite, montmorillonite, and saponite. The minerals were structurally adjusted and then modified with zero-valent iron, ferrihydrite, iron/cobalt oxyhydroxides, and organosilicon compound on their surfaces. The following methods were used: X-ray diffraction analysis to control the monominerality of samples of natural clay minerals and determine the phase composition of synthesized porous ceramic materials; IR spectroscopy to control the processes of structure formation and surface modification of ceramic matrices; X-ray fluorescence analysis to determine the elemental composition of the samples under study; low-temperature nitrogen adsorption/desorption method to determine the characteristics of the porous structure; thermogravimetric analysis to determine the temperature indicators of phase and structural transitions in samples; scanning electron microscopy with energy dispersive X-ray spectroscopy to study the surface morphology of materials; inductively coupled plasma atomic emission spectrometry to determine the initial and equilibrium concentrations of heavy metals in solution. The work first investigates the peculiarities of structure formation and determines the possibilities of controlling the parameters of the porous structure of layered silicates in the processes of obtaining powdered ceramic matrices and granulation. The sorption properties of iron-containing ceramic materials in relation to arsenic and chromium compounds were studied. Proposes a basic technological scheme to produce a composite based on natural raw materials (saponite clay from the Tashkiv deposit) and iron/cobalt oxyhydroxides. The method of utilisation of the spent sorbent using ceramic technology was chosen. It is shown that the utilisation of spent sorbents using of this technology leads to a strong binding of toxicants in the ceramics matrix and makes it impossible to leach them into the environment. The total volume of the thesis is set out on 160 pages of printed text and includes an introduction, five chapters, general conclusions, a list of references and 1 appendix. The work is illustrated with 24 tables and 63 figures. The list of references includes 193 items.