Application of beech sawdust for removal of heavy metals from water: biosorption and desorption studies

In this work the efficiency of applying non-modified beech sawdust for the removal of Cu2+ and Cr3+ heavy metal ions from water solutions was examined. Parameters taken into consideration in the analysis of environment conditions were influence of sorbent concentration, initial concentration of metal ions, temperature effect, presence of additional substances in solution (NaCl and MgCl2 inorganic salts and anionic and cationic surface-active compounds). Results of kinetic experiments were described by two models: pseudo-first-order and pseudo-second-order; equilibrium results were approximated with five non-linear isotherm models. Maximum sorption capacity at a temperature of 20 A degrees C and pH 5.0 was 30.22 mg g(-1) for Cu2+ ions and 41.86 mg g(-1) for Cr3+ ions. The positive value of the thermodynamic parameter Delta HA degrees indicates the endothermic nature of the process. Application of 0.1 M HCl as the eluent enables effective desorption of precious metals and reuse of sorbent for purifying water solutions of Cu2+ and Cr3+ ions.