Directional Control of the Structural Adsorption Properties of Clays by Magnetite Modification

This article presents the results of the study on the effect of nanomagnetite modification on textural characteristics of clay matrices, adsorption properties, and parameters of the spent sorbents separation. The nitrogen adsorption-desorption method has shown that the obtained magnetic nanocomposite sorbents have large specific surface areas (in 1.2-2 times more) than the initial clays due to the formation of the secondary porous structure on the surface and in macropores of clay matrices. The best adsorption properties with respect to dyes belong to magnetic sorbents with nanomagnetite content of 7wt.%. The additional modification of the third phase of graphene-like molybdenum disulphide into magnetic sorbents leads to the significant increase in the sorption capacity of both cationic (up to 1100mg/g) and anionic (up to 1830mg/g) dyes. The conducted investigations of the total acidity and acid-base sites on the surface of clay, magnetite-modified clay, and molybdenum disulfide-modified magnetic sorbent indicate the significant influence of the Lewis base cites on the adsorption properties of these materials.