Nickel adsorption by magnetic alginate microcapsules containing an extractant.
Résumé
The adsorption of heavy metals on biomaterials was investigated by studying the potential of alginate microcapsules contg. an extractant (Cyanex 272) and magnetic nanoparticles (g-Fe2O3) for the adsorption of Ni(II) from aq. solns. A two-stage kinetic behavior was obsd. with 70% of the max. sorption capacity achieved within 8 h. An increase in Ni removal with increase in pH occurred, the max. uptake capacity being »0.42 mmol g-1 at pH 8. The adsorption isotherm (pH »5.3) was obtained in a wide range of initial Ni concns.; the exptl. data were fitted by a Langmuir model and the q max value was estd. to be 0.52 mmol g-1. Moreover, including magnetic particles in the microcapsules allowed easy isolation of the beads from the aq. solns. after the sorption process. Magnetic microcapsules are then suitable for the development of efficient biosorbents for removal and recovery of heavy metals from wastewater using magnetic sepn.