Lignin was filled with corn. Na montmorillonite (purified in water), crosslinked with epichlorohydrin at 60 degrees C for 16 h, studied for microstructure, thermal stability and swelling in water and then carbonized in Ar at 500 degrees C for 1 h and used for sorption of Fe3+ and Cu2+ ions from aq. solns. The adsorption capacity of Fe3+ ions (up to 7.5 mg/g) was lower than that known for carbonized biomass. In contrary, the adsorption capacity of Cu2+ ions (21 mg/g) was substantially higher than the literature data (P.J.M. Suhas et al., 2007).