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Separation Science and Technology, Vol.40, No.5, 959-990, 2005
The adsorption of heavy metals by tochilinite, an iron sulfide material produced by chemical precipitation: Analysis using a simple theory of chemisorption
This paper describes the adsorption of heavy metals Cd, Ph, Cu, and Zn by a tochilinite-like material composed of alternating layers of Fe1-xS and Fe(OH)(2). The layers are thin, being of atomic dimension. The material was produced by chemical precipitation together with some magnetite, Fe3O4, which renders the material magnetic. The results were analyzed with a simple chemisorption model which contained two parameters g(=mass of the heavy metal adsorbed/mass of adsorbent added) and C, a kinetic term with dimensions, 1.mg(-1).h(-1)., h is the time elapsed in hours. The fitting procedure works well with values of g > 1, in some cases. However, according to the simple theory g and C should be constant independent of M-A, the mass of adsorbent added: the constancy predicted was not observed. From the variation of g and C with M-A the conclusion was that for a more complete understanding of the adsorption process, in addition to chemisorption adsorption-desorption processes must be included.