TITLE:
Equilibrium Sorption of Lead and Nickel from Solutions by Flame of the Forest (Delonix regia) Pods: Kinetics and Isothermic Study
AUTHORS:
Aiyesanmi Ademola Festus, Okoronkwo Afamefuna Elvis, Akinmolayan Bolanle Morayo
KEYWORDS:
Equilibrium Sorption; Delonix regia; Lead; Nickel; Isotherms; Kinetics; Pseudo Second Order; Langmuir
JOURNAL NAME:
Journal of Environmental Protection,
Vol.4 No.3,
March
18,
2013
ABSTRACT: Batch adsorption techniques were used to study the biosorption of Lead and Nickel from aqueous solutions by Flame of the forest pods. The effects of optimum pH, contact time, metal ion concentration, biosorbent dose, biosorbent particle size and the presence of sodium, calcium and magnesium interfering ions on the sorption were investigated. Experimental results showed that Delonix regia biomass was effective in removing these metals from aqueous solutions as the equilibrium biosorption of both metals was attained within 60 minutes of interaction with 98% of the metals removed within this period. Sorption of these metals was dependent on pH as maximum removal was attained at pH 4 and pH 5 for Lead and Nickel ions respectively. Adsorption experiments showed that the process followed the pseudo second order kinetic model with high r2 (0.9999) and the equilibrium data fitted well with Langmuir and Freundlich isotherm models. The presence of competing ions impacted negatively on the sorption process irrespective of the type used. 27% and 36% of lead (II) were recovered from the spent biosorbents with 1 MHCl and disodium salt of EDTA solutions respectively.