Removal of cadmium (II) from aqueous effluents by sorption on Romanian silver fir tree bark (Abies alba Mill.) wastes

In last decades the search for new low cost sorbents that have heavy metal ions binding capabilities is a hot topic in the field of clean-up technologies. In this study,  wastes of  Romanian silver tree (Abies alba) bark  were explored for first time as green and economical sorbent for the removal of Cd(II) ions from aqueous solutions.  The effect of various experimental parameters such as initial solution pH, sorbent dose, initial Cd(II) concentration, temperature and contact time has been investigated under batch conditions. 

The Langmuir and Freundlich models were used to describe the equilibrium isotherms and both models have been fitted very well. According to the evaluation using the Langmuir equation, the maximum sorption capacity of Cd (II) ions on Abies alba bark waste was found to be 11.98
mg g^-1 at 293 K. The thermodynamic parameters showed that the process of Cd(II) sorption on silver fir tree bark was feasible, spontaneous and endothermic. Kinetic data were properly fitted with the pseudo–second order model. The obtained results strongly suggest that Romanian silver tree (Abies alba) bark is eligible as an efficient sorbent for the decontamination of toxic metals from wastewaters.