Comparative adsorption of metal and dye on flake- and bead-types of chitosans prepared from fishery wastes

The adsorption capacities and rates of Cu(II) and a commercial reactive dye RR222 on flake- and bead-types of chitosans prepared from three fishery wastes (shrimp, crab, and lobster shells) were compared at 30°C. It was shown that all equilibrium isotherms could be well fitted by the Langmuir equation. The adsorption capacity of Cu(II) on flake- and bead-types of chitosans appeared to be comparable, but the adsorption capacity of RR222 on bead type was much larger than that on flake type by a factor of 2.0-3.8. The rates of dye adsorption on both types of chitosans indicated different controlling mechanisms. In addition, the bead type of chitosans exhibited a greater rate compared to the flake type. (C) 2000 Elsevier Science B.V.