Kinetic and equilibrium studies of the adsorption of lead (II) ions from aqueous solution onto two Cameroon clays: Kaolinite and smectite

Abstract

The efficiency of the adsorbents; kaolinite (MY22s) and smectite (Sa01) for the removal of lead (II) ions from aqueous solution was investigated. Parameters such as contact time (t) and initial concentration (Co) with a particle size of 80 µm were studied by using a batch scale adsorption technique. This is with the intension of optimising appropriate conditions to be utilised on a commercial scale to decontaminate industrial effluents. Adsorption equilibrium was reached within 60 min for the 50, 70, 90, 110 and 130 ppm initial concentration (Co), of lead (II) ions with a 500 mg weight adsorbent. The adsorption capacity (Qt) of lead ion removal increases with increasing initial concentration, Co of lead (II) ions in solution. The adsorption efficiency or percentage of removal reached 92% for 130 ppm initial concentration, Co, of lead (II) ions with Sa01. Kinetic modelling analysis using the linear correlation coefficient (R2) values showed that the adsorption mechanism follows the pseudo-second order model for the adsorption of lead (II) ions on Kaolinite (MY22s) and smectite (Sa01). The adsorption data were also modelled by using both the Langmuir and Freundlich classical adsorption isotherms. These experimental data fitted the Langmuir isotherm for kaolinite (MY22s) and Freundlich isotherm for smectite (Sa01). Key words: Adsorption, smectite (Sa01), kaolinite (MY22s), lead (II) ions, kinetics, equilibrium adsorption, wastewater treatment.