Multiwalled Carbon Nanotubes: Adsorbent for Ruthenium from Aqueous Solution

This paper describes the adsorption behavior of ruthenium on multi walled carbon nanotubes (MWCNTs) from aqueous solution. The adsorption behavior of ruthenium on MWCNTs was studied with respect to contact time, pH, concentration of metal ion, adsorbent dosages and temperature. The equilibrium adsorption data were fitted to Pseudo first order, Pseudo second order, Elovich and Intra-particle diffusion kinetic model as well as Langmuir, Freundlich, Dubinin-Radushkevich and Temkin isotherm models. The Langmuir adsorption isotherm model was found to be best fitted in terms of standard deviation and regression coefficient. The thermodynamics parameter such as Delta H degrees, Delta S degrees, Delta G degrees were also calculated. The endothermic nature of adsorption is indicated by positive value of Delta H degrees and Delta S degrees resulting the randomness at solid solution interface towards favorable adsorption.