Brazilian Palygorskite as Adsorbent for Metal Ions from Aqueous Solution—Kinetic and Equilibrium Studies
2013
Oliveira, Andrea M. B. M. | Coelho, Luiz F. O. | Gomes, Saloana S. S. | Costa, Israel F. | Fonseca, Maria G. | de Sousa, Kaline S. | Espínola, José G. P. | da Silva Filho, Edson C.
Natural palygorskite was used as an adsorbent for the removal of copper, cobalt and nickel from an aqueous solution. All assays were performed under controlled conditions to establish the adsorption capacity of the solid. Initially, the clay was characterized by chemical analysis, XRD, infrared spectroscopy and thermogravimetry. Adsorption experiments for the ions in aqueous solution were carried out by a batch method through which the reaction time, initial concentration of cations, temperature and pH of the aqueous solution were systematically varied. First-order, pseudo-second-order and intraparticle diffusion models were used to describe the kinetic data. The results show that the processes were fitted well by the pseudo-second-order model. Moreover, the equilibrium solid–cation systems followed the Langmuir isotherm model. The results indicate that raw palygorskite could be employed as a low-cost material for the removal of heavy metals from aqueous solution.
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