Sekaran et al.[301] used buffing dust, waste generated from leather
industry, for the removal of dyes. The adsorption capacity of buffing
dust was found to be 6.24 mg/g at pH 3.5 and 30 ◦C for acid
brown dye. The removal of methylene blue from aqueous solutions
by adsorption on tanned solid wastes was studied by Tahiri et al.
[302]. The maximum adsorption capacity was found ca. 84 mg of
methylene blue for each gram of buffing dust.