Assessment of samarium biosorption from aqueous solution by brown macroalga Turbinaria conoides

In the present research, a brown marine macroalga (Turbinaria conoides) was employed as a novel biosorbent for the sequestration of samarium ions from aqueous solutions. The influence of solution pH, initial Sm(III) concentration and contact time on Sm(III) removal were investigated. The biosorbent was characterized through Fourier transform infrared spectroscopy, potentiometric titration, scanning electron microscopy and energy-dispersive X-ray spectroscopy analysis. Equilibrium experimental results were fitted to isotherm models such as the Langmuir, Freundlich and Redlich-Peterson to obtain the characteristic parameters of each model. The pseudo-first-order and pseudo-second-order kinetic models were used to analyze the experimental kinetic data. The Langmuir and Redlich-Peterson isotherms were found to best fit the equilibrium data and the biosorption kinetics followed the pseudo-second-order model. From the Langmuir isotherm model, the maximum biosorption capacity was found to be 151.6 mg/g at the solution pH 4.0. Desorption experiments revealed that 0.1 M HCI was efficient with good recovery of Sm(III) ions with desorption efficiency of 99.2%. (C) 2017 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.