Biosorption of Pb(II), Zn(II), and Cd(II) from Aqueous Solutions by (Eriobotrya japonica) Loquat Bark

Ammar H. Al-Dujaili; Akl M. Awwad; Nida' M. Salem
The present study investigated the effectiveness of an inexpensive and eco-friendly loquat bark as a biosorbent for the possible removal of toxic lead, zinc, and cadmium ions from aqueous solutions. In this study, the effects of biosorbent dose, pH, initial concentration, contact time, and temperature were examined. The linear Langmuir and Freundlich models were applied to describe the equilibrium isotherms, and both models fitted well. The monolayer adsorption capacity of of Pb(II), Zn(II) and Cd(II) on loquat bark was found as 55.770, 29.447 and 28.802 mg g-1, respectively, at pH 4 and 30oC. Dubinin-Radush Kerich (D-R) isotherm model was also applied to equilibrium data. The mean free energy of adsorption of Pb(II), Zn(II) and Cd(II) (5.596, 3.748 and 3.549 kJ/mol) onto loquat bark, respectively, may be carried out via physisorption mechanism. Loquat bark (LB) was found to remove Pb(II), Zn(II), and Cd(II) ions efficiently from aqueous solutions with selectivity in the order of Pb(II) > Zn(II) > Cd(II).
Keywords: Metal ions, biosorption, loquat bark, isotherms
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