The present research was undertaken to study the potential efficiency as adsorbents of three acid activated carbons, prepared from plant biomass of colas edulis shell (CAH), pentaclethra macrophylla husk (GAH) and aucoumea klainenea sawdust (QAH), for the removal of Pb (II) ions from aqueous solution, by the means of batch technique. The study was managed using pH, concentration of lead solution, adsorption process equilibrium time and temperature as parameters. The adsorption increased with the increase in pH. The Pb (II) concentration to the equilibrium on the acid activated carbons surface for CAH (765 mg/g) is higher than for GAH (743 mg/g) and than of QAH (671 mg/g). The experimental data were found to fit both Freundlich and Langmuir isotherms. CAH (3.52 mg/g) was found to possess a more large heterogeneous surface capacity than GAH (2.19 mg/g) and QAH (1.43 mg/g) for Pb (II) ions adsorption, according to the Freundlich model. The testing of Langmuir model had given QAH (42.19 mg/g) higher monolayer surface capacity than GAH (27.25 mg/g) and CAH (22.62 mg). Adsorption kinetics was found to follow well the pseudo-second-order than the pseudo-first-order models. The adsorption process was found to be realized spontaneously between 308 and 318K.
Key words: Adsorption, lead (II), acid activated carbons, isotherm models, kinetic equations.
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