Mechanical Activation as a Method to Regulate Morphology, Texture and Surface Functional Composition of Carbon-Mineral Materials Derived from Sapropel

Abstract

Data on the synthesis of carbon-mineral materials (CMM) through carbonization of native sapropel after preliminary mechanical activation (MA) in the air environment are presented. The effect of MA parameters (time, the size and acceleration of milling bodies) on the fractional composition and morphology of sapropel is investigated. MA for 5‒10 min promotes the dispersion of sapropel particles, while a further increase in treatment time causes their partial agglomeration. It is demonstrated that preliminary MA of native sapropel leads to changes in the texture parameters and acidity of the surface of CMM obtained after the carbonization stage. An increase in specific surface area from 90 to 560 m²g^-1 is observed, with an increase in the adsorption pore volume from 0.16 to 0.52 cm³g^-1 as a result of an increase in the fraction of micropores in the formed CMM. Despite this fact, CMM samples still contain large pores, and the fraction of meso- and macropores is 70%. In addition, a decrease in pH of the point of zero charge occurs as a consequence of an increase in the content of acidic oxygen-containing groups. The discovered effect is essential for the formation of sapropel-based materials with required properties and for broadening their application area.