Supramolecular Composite Materials Based on Cobalt(II) Ferrite and Biochar for Purifying Aqueous Solutions from Chromium(VI) Ions

The possibility of synthesizing supramolecular composite organo-inorganic materials based on cobalt(II) ferrite and biochars from rice husk and sunflower husk is studied. It is established that the morphology of the biochar determines the structural characteristics of the composite. The synthesized materials are characterized by X-ray phase analysis, BET, and scanning electron microscopy. Cobalt(II) ferrites crystallize on the surface of the carbon carrier in the form of a film, whose crystallite size is 80–96 nm, which is lower than for CoFe₂O₄, obtained using sol-gel technology. It is established that the synthesized composites exhibit significant catalytic activity in the process of decomposition of hydrogen peroxide and sorption of chromium(VI) compounds from an aqueous solution. The increase in the sorption capacity is associated with the formation of the Fenton system Fe³⁺/Fe²⁺. The obtained results can be used for the synthesis of innovative products from agricultural waste and their use in water treatment processes.