Vermiculite-based Sorbents Modified with Compounds of Various Natures

The aim of this work was to investigate the effect of organic and inorganic modifying agents on the internal structure and surface properties of vermiculite from the Kovdor deposit in an alkaline medium. Vermiculite from the Kovdor deposit was treated with various compounds in an alkaline medium (sodium hydroxide, sodium stearate) with successive addition of copper chloride and potassium hexacyanoferrate(II) solutions. According to powder X-ray diffraction data, the introduction of stearate ion leads to an increase in the interplanar spacing compared to pristine vermiculite. The increase in the coherent scattering region attests to an increase in the degree of crystallinity and considerable interaction of the modifying agent with the surface. The subsequent addition of potassium hexacyanoferrate(II) leads to further increase in the interplanar spacing because of the bulky hexacyanoferrate ion; however sharp decrease in the coherent scattering region indicates exfoliation of the layered silicate, which leads to a decrease in the surface area due to increasing content of amorphous structure.