Lotfi Sellaoui, Felycia Edi Soetaredjo, Suryadi Ismadji, Adrián Bonilla-Petriciolet, Carolina Belver, Jorge Bedia, Abdelmottaleb Ben Lamine, Alessandro Erto
In this study, a bentonite-chitosan composite was tested for the single and binary adsorption of Cd2+ and Pb2+ ions at constant pH (6) and different temperatures (30, 40, and 50 °C). For both adsorbates, the adsorption capacities decreased in binary systems due to an antagonistic adsorption effect. Statistical physics models were used to analyze the adsorption isotherms and to attribute microscopic interpretations to the experimental evidences at a molecular level. Specifically, a monolayer model with one energy and an exclusive extended monolayer model were applied to single and binary adsorption data, respectively. The crossing of the experimental and modelling results proved that Cd2+ ion was more adsorbed in the binary system. The modelling analysis allowed determining that the numbers of ions linked per adsorbent site varied significantly in binary system with respect to single-compound ones, thus confirming that an inhibition effect occured. Finally, the adsorption energy was estimated for both adsorption systems indicating the occurrence of an endothermic adsorption. Moreover, adsorption energies showed concordant trends with the corresponding adsorption capacities of both Cd2+ and Pb2+, hence being able to describe the adsorption phenomena. © 2018 Elsevier B.V.
Unité de Recherche de Physique Quantique, UR 11 ES 54, Université de Monastir, Faculté des Sciences de Monastir, Tunisia; Department of Chemical Engineering, Widya Mandala Surabaya Catholic University, Surabaya, 60114, Indonesia; Departamento de Ingeniería Química, Instituto Tecnológico de Aguascalientes, Aguascalientes, 20256, Mexico; Sección de Ingeniería Química, Facultad de Ciencias, Universidad Autónoma de Madrid, C/Francisco Tomas y Valiente 7, Madrid, 28924, Spain; Dipartimento di Ingegneria Chimica, dei Materiali e della Produzione Industriale, Università di Napoli Federico II, P.leTecchio, 80, Napoli, 80125, Italy