A systematic study and proposed model of the adsorption of binary metal ion solutes in aqueous solution onto activated carbon produced from pecan shells

Adsorption isotherms of a number of binary solute systems have been obtained. The adsorption behavior of these cations in the presence of other metal ions that display strong or intermediate affinities for adsorption sites has been systematically investigated. In this investigation the following factors have been considered: (1) metal ion site competition; (2) charge accumulation near the carbon surface; and (3) speciation of the metal ions. Two multicomponent adsorption models are proposed, and the results are compared to two models presented in the literature. The performance of these models is evaluated by an analysis of error. It is found that models with three interaction parameters generally provide a better fit of the data. In most cases, the proposed two-parameter model gives acceptable results. (C) 2002 Elsevier Science Ltd. All rights reserved.