Comparison for Adsorption Modeling of Heavy Metals (Cd, Pb, Cu, Zn) from Aqueous Solution by Bio-Formulation

The demand for effective and inexpensive sorbents is increasing in response to the widespread recognition of the deleterious health effects of heavy metals exposure through aqueous solutions. An adsorbent, bio-formulation (BF), was prepared by agricultural waste. The maximal biosorption removal of cadmium (II), lead(II), copper(II), zinc(II) on BF are 99.4, 99.8, 97.6, 98.3% at pH 8, 5, 5, 7, respectively. Freundlich adsorption isotherm is well fitted to the experimental data. The adsorption kinetics of heavy metals reveal that adsorption of heavy metals is very rapid within the first 30 min and equilibrium time is independent of initial concentration. The adsorption process follows second-order sorption kinetics. The biosorption mechanism may be cation exchange effect.