Modeling of zinc adsorption onto clinoptilolite in a slurry bubble column
2013
Vivacqua, Vincenzino | Xu, Wanjing | Hébrard, Gilles | Li, Loretta Y. | Grace, John R. | Dept Chem & Biol Engn ; University of British Columbia [Canada] (UBC) | Laboratoire d'Ingénierie des Systèmes Biologiques et des Procédés (LISBP) ; Institut National de la Recherche Agronomique (INRA)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse) ; Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS) | Dept Civil Engn ; University of British Columbia [Canada] (UBC)
This paper presents experimental results and a successful model for zinc removal from Acid Rock Drainage by adsorption on clinoptilolite. The experiments were conducted in a slurry bubble column of 0.09 m inner diameter and 1.4 m height, loaded with 100 g of clinoptilolite particles of diameter 0.3-1.4 mm/kg liquid. Aqueous zinc ion concentrations were determined before and during the adsorption tests. Zeolite was then regenerated by a sodium chloride solution, whose zinc concentration was determined against time. The Langmuir isotherm model was fitted to the experimental results under batch conditions to characterize the adsorption capacity of the solid surfaces. A global kinetic model with mass transfer to the particles and uptake on adsorption sites facilitates interpretation of the ARD slurry bubble column adsorption-desorption results. Due to air injection, perfect mixing could be assumed. The effect of particle size on the forward rate constant k(f) of the adsorption process is important. The model is also applied to the sorbent regeneration by zinc desorption to provide a complete description. Consistent with the model, external mass transfer is not rate-limiting in this adsorption-desorption process. (C) 2013 Elsevier Ltd. All rights reserved.
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