abstract
The synthetic microporous titanosilicate material ETS-4 has been used for the removal of Hg2+ and Cd2+ from water. Batch stirred experiments were carried out to study the equilibrium and the kinetics of the removal of Hg2+ and Cd2+ from water. It has been demonstrated that ETS-4 has a great affinity for both these metal cations even when their initial concentrations are low. The uptake rates for both Hg2+ and Cd2+ were well described by the pseudo-second order model which constants confirmed that the kinetics of the removal of Cd2+ is faster than that of Hg2+. However, at the equilibrium, ETS-4 has a higher capacity to remove Hg2+ than Cd2+. Adsorption isotherms for both Hg2+ and Cd2+ were well fitted to Langmuir isotherm and the corresponding monolayer capacities of ETS-4 are 0.43 and 0.24 mu mol mg(-1), respectively, which are quite consistent with those predicted by the pseudo-second order kinetic equation. Hence, the contribution of this work is to support the use of this material for the removal of Hg2+ and Cd2+ from water. (C) 2009 Elsevier B.V. All rights reserved.
keywords
HEAVY-METALS UPTAKE; AQUEOUS-SOLUTION; ACTIVATED CARBONS; IONS REMOVAL; WASTE-WATER; COPPER IONS; ADSORPTION; MERCURY(II); SORPTION; CADMIUM
subject category
Engineering; Water Resources
authors
Otero, M; Lopes, CB; Coimbra, J; Ferreira, TR; Silva, CM; Lin, Z; 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 Fundacao para a Ciencia e a Tecnologia (FCT) and FEDER for financial support. This research was supported by a FCT PhD grant (SFRH/BD/19098/2004) funding C.B. Lopes.