Simple and effective chitosan based films for the removal of Hg from waters: Equilibrium, kinetic and ionic competition
authors Rocha, LS; Almeida, A; Nunes, C; Henriques, B; Coimbra, MA; Lopes, CB; Silva, CM; Duarte, AC; Pereira, E
nationality International
journal CHEMICAL ENGINEERING JOURNAL
author keywords Mercury; Chitosan films; Chemical modification; Competitive ions; Remediation; Natural waters
keywords METAL-IONS; AQUEOUS-SOLUTIONS; MERCURY IONS; WASTE-WATER; ADSORPTION; BIOSORPTION; MEMBRANES; MODELS; BIOSORBENTS; ADSORBENT
abstract The efficiency of chitosan cross-linked with genipin (Chg) and cross-linked with genipin and grafted with caffeic acid (Ch(g+car)) to remove Hg(II) from waters was investigated. An optimal dose of 50 mg L-1 for both chitosan films was selected based on the equilibrium removal percentage and on the contact time required to attain the equilibrium. The sorption extent was dependent on the initial Hg(II) concentration (C-Hg,C-0), with removal efficiencies varying between 79% and 82% for C-Hg,C-0 = 0.05 mg L-1 and between 89% and 94% for C-Hg,C-0 = 0.50 mg L-1. Under ion competition, the Ch(g) and Ch(g+caf) films showed to be effective and selective for mercury in multimetallic solutions containing also cadmium and lead. In the case of natural river and seawaters, the mercury speciation played an important role in the overall sorption process, reducing the percentage removal of Hg. In terms of modeling, the kinetic data were well described by pseudo-first and pseudo-second order models, depending on the experimental conditions. The diffusion models suggested that the entire sorption process of Hg(II) by both Chg and Chg+caf films was essentially controlled by pore diffusion. The equilibrium data were well described by the Sips isotherm, and the estimated capacity was 2.2 and 4.0 mg g(-1) for Chg and Ch(g+caf) films, respectively. In the whole, the results showed that the sorption efficiency was improved by grafting caffeic acid to the polymeric chains of chitosan cross-linked with genipin. (C) 2016 Elsevier B.V. All rights reserved.
publisher ELSEVIER SCIENCE SA
issn 1385-8947
year published 2016
volume 300
beginning page 217
ending page 229
digital object identifier (doi) 10.1016/j.cej.2016.04.054
web of science category Engineering, Environmental; Engineering, Chemical
subject category Engineering
unique article identifier WOS:000378181400022
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