Biosorption of heavy metals using fresh water algae

Biosorption of lead (II) ions onto rhizoclonium species was investigated with the variation in the parameters of pH, contact time, biosorbent dosage and lead (II) concentrations and temperatures. Fourier transform infra-red analysis of algae with and without biosorption revealed the presence of O-H stretching vibration at 3402cm⁻¹ and it shifted to 3371cm⁻¹, which indicates the biosorption of Pb (II) ions. The lead (II) biosorption equilibrium was attained within 30 min. The equilibrium experimental data were tested using the most common isotherms. The results are best fitted by the Freundlich model among two-parameter models isotherm models for Pb (II). The kinetic data were fitted by pseudo-first-order and pseudo-second-order. From the results obtained, the pseudo-second-order kinetic model best describes the biosorption of lead ions. The thermodynamic parameters (ΔG°, ΔH° and ΔS°) were calculated and it was found that the adsorption process is spontaneous and endothermic and is favored at higher temperature.