Adsorption and Desorption studies of <i>Delonix regiapods</i> and leaves: Removal and recovery of Ni(II) and Cu(II) ions from aqueous solution
Abstract. In this study, the adsorption of Ni(II) and Cu(II) ions from aqueous solutions by powdered pods and leaves of Delonix regia was investigated by batch adsorption techniques. The effects of operating conditions such as pH, contact time, metal ions concentration and the presence of sodium ions interfering on the sorption process were investigated. The results obtained showed that the equilibrium sorption was attained within 30 min of interaction and the adsorption process followed the pseudo-second-order kinetic model for all the metal sorption with the exception of Cu(II) sorption on the leaves. The equilibrium data fitted well with both the Langmiur and Freundlich Isotherms; the desorption study revealed that the percentage of metal ions recovered from the pods were higher than the leaves at various concentration of nitric acid. This study has proven that Delonix regia biomass, an agro-waste could be used for removing Ni(II) and Cu(II) ions from wastewater.