Graphene Oxide as an Adsorbent for Ruthenium from Aqueous Solution

Graphene oxide (GO) was synthesized by modified Hummers method and its adsorption behavior towards ruthenium (III) from aqueous solution was studied w.r.t contact time, pH, ruthenium (III) concentration, GO dosage, temperature and ionic strength. The synthesized GO and ruthenium(III) adsorbed graphene oxide (Ru-GO) were characterized by various techniques such as Fourier Transform Infrared Spectroscopy (FTIR), Raman Spectroscopy, X-Ray Diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS) and Scanning Electron Microscopy-Energy Dispersive X-ray Spectroscopy (SEM-EDS). Pseudo second order kinetics and Langmuir isotherm model were best fitted in terms of standard deviation and regression coefficient. Adsorption of ruthenium (III) was pH dependent and maximum removal occurred at pH=2 with K-d=2.468x10(3) mL. g(-1). Thermodynamic parameters such as enthalpy (Delta H degrees), entropy (Delta S degrees), Gibbs energy (Delta G degrees), activation energy (E-a) and sticking probability (SP*) were also calculated.Moreover, complete desorption of ruthenium (III) on GO could be achieved at an acidity of 8 M HNO3.