abstract
Batch stirred tank experiments were carried out to study the application of ETS-4 microporous titanosilicate for Hg2+ ions removal from aqueous solution. The effect of operational conditions was assessed and it was proved that Hg2+ uptake (%) increases with increasing contact time, increasing ETS-4 mass and decreasing initial Hg2+ concentration. It was confirmed that stirring rate does not affect the Hg2+ removal by ETS-4 as long as it is high enough to break the diffusion resistance. Two simplified models, the pseudo first-order and the pseudo second-order equations, were used to describe the kinetics of the sorption process and better fittings were obtained by the last one. The Bt versus t plots indicated that film diffusion is the rate-limiting step of the removal of Hg2+ by ETS-4. Langmuir, Freundlich and Dubinin-Radushkevich isotherm equations fitted quite well the equilibrium data and the Langmuir maximum capacity of ETS-4 was found to be 246 mg g(-1) at 21 degrees C. (C) 2009 Elsevier B.V. All rights reserved.
keywords
ACTIVATED CARBONS; MERCURY IONS; METAL-IONS; HG(II) IONS; ADSORPTION; BIOSORPTION; SORPTION; WATER; CADMIUM(II); ISOTHERMS
subject category
Engineering
authors
Lopes, CB; Otero, M; Lin, Z; Silva, CM; Rocha, J; Pereira, E; Duarte, AC
our authors
Carlos Manuel Silva
Associate Professor
Cláudia Batista Lopes
Assistant Researcher
João Rocha
Full Professor
Zhi Lin
Principal Researcheracknowledgements
We thank the FCT (Fundacao para a Ciencia e a Tecnologia, Portugal) and FEDER for financial support. This research was supported by a FCT PhD grant (SFRH/BD/19098/2004) funding C.B Lopes.