Lotfi Sellaoui, Felycia Edi Soetaredjo, Suryadi Ismadji, Yacine Benguerba, Guilherme L. Dotto, Adrián Bonilla-Petriciolet, Alírio Egídio Rodrigues, Abdelmottaleb Ben Lamine, Alessandro Erto
The adsorption of Pb(II) and Hg(II) ions on bentonite-alginate composite (BAC) is investigated in both single-compound and binary systems, at three different temperatures. For a better interpretation and comparison, all the adsorption equilibrium isotherms are recorded under identical conditions. A simple examination of all adsorption equilibrium isotherms shows that the bentonite-alginate composite is more effective for Pb (II) adsorption than for Hg (II) and the adsorption capacity is reduced in binary system, reflecting a competitive effect between the Pb (II) and Hg (II). To explain the single and binary processes and the corresponding mechanisms, Hill and competitive Hill models are applied. The adsorption geometry can be determined at different temperatures by an estimation of the number of ions captured per BAC adsorbent site. Based on these models, it is shown that the affinity sequence in all adsorption systems is: Pb (II) - Hg (II). This behavior can be explained and corroborated by an energetic analysis deduced from these models. Finally, in order to deepen the interpretation of single-compound and binary adsorption, the conductor-like screening model (COSMO-RS) was tested and applied to calculate the total interaction energies between heavy metals and BAC adsorbent. The evaluation of energies deduced from COSMO-RS model indicated that the electrostatic misfit interaction energy may play the main role in the heavy metals ions adsorption in tested systems. © 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, 601-14, Indonesia; Department of Processes Engineering, Universite Ferhat Abbas, Setif–1, Setif, 19000, Algeria; Laboratoire de Génie des Procédés Chimiques, Université Ferhat Abbas, Sétif–1, Sétif, 19000, Algeria; Environmental Processes Laboratory, Chemical Engineering Department, Federal University of Santa Maria–UFSM, 1000, Roraima Avenue, Santa Maria, 97105–900, RS, Brazil; Instituto Tecnológico de Aguascalientes, Aguascalientes, 20256, Mexico; Laboratory of Separation and Reaction Engineering - Laboratory of Catalysis and Materials (LSRE-LCM), Faculdade de Engenharia, Universidade do Porto, Rua Dr. Roberto Frias s/n, Porto, 4200-465, Portugal; Dipartimento di Ingegneria Chimica, dei Materiali e della Produzione Industriale, Università di Napoli Federico II, P.leTecchio, 80, Napoli, 80125, Italy