Removal of trivalent chromium ions from aqueous solutions by sodium polyacrylate beads

Abstract

In the present study, the performance of sodium polyacrylate beads on the removal of trivalent chromium Cr (III) from aqueous solutions was evaluated using several techniques such as Fourier Transformed Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Analysis (EDAX), Inductively Coupled Plasma (ICP) and Atomic Adsorption Spectroscopy (AAS). On one hand, the characterization of dry PANa beads was carried out through FTIR and the surface morphology was analyzed by SEM and EDAX methods in order to show the loading of heavy metal on PANa beads. On the other hand, the effect of contact time, initial pH solution, initial Cr(III) concentration, adsorbent mass and temperature on the adsorption capacity of PANa was studied. All results have shown that the adsorption equilibrium was reached at about 60 minutes with an adsorption efficiency close to 90 %. Also, the study of the reliability of PANa beads was effectuated using 0.01 M nitric acid solution through six cycles of adsorption/desorption which were determined in order to study the reliability of PANa over time and to test their efficiency in industrial applications. Finally, the obtained thermodynamic parameters (ΔG°, ΔH° and ΔS°) indicate that the adsorption process is spontaneous and endothermic.