Abstract
The use of coconut bagasse as an adsorbent for the treatment of Cu(II)
ions from aqueous solutions has been investigated. The adsorbent was
characterized by infrared spectroscopy, including zeta potential and pH
effects. To assess the possibility of removing Cu(II) from aqueous
solutions by this sorbent the effects of contact time, initial metal ion
concentration, and temperature were studied at pH 5.5. Kinetic studies
showed that the amount adsorbed increased with initial Cu(II)
concentration, and the equilibrium was established in 120 min. The
kinetic data were analyzed using a pseudo second-order equation.
Adsorption equilibrium data were investigated using the Langmiur,
Freundlich, D-R, Temkin and Halsey isotherm models. The adsorption of
Cu(II) on the coconut bagasse was endothermic (Delta H degrees 86.2
kJ/mol), resulting in an increase in entropy (Delta S degrees 339
J/mol/K) and a decrease in Gibbs free energy (Delta G -16.34 to -22.44
kJ/mol) in the temperature range of 301-313 K. A reduction in adsorption
capacity with an increase in heat of adsorption revealed an ion exchange
mechanism for Cu(II) adsorption.
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