Sorption Equilibrium and Thermodynamic Studies of Zinc (II) Ions from Aqueous Solutions by Bamboo Sawdust

Abstract

Bamboo sawdust is a natural resource and an inexpensive material was used as an adsorbent for removal of zinc (II) ions from aqueous solutions. The zinc (II) ions sorption study has been carried out using batch wise where the influence of physicochemical key parameters such as the solution pH, the contact time, the initial metal concentration, and the adsorbent dosage were considered. Morphological changes observed in scanning electron micrographs of natural and zinc (II) loaded bamboo sawdust confirmed the phenomenon of sorption. Fourier transform infrared spectroscopy (FTIR) of bamboo sawdust before and after sorption confirmed the zinc (II) ions and bamboo sawdust interactions responsible for sorption. Langmuir, Freundlich, and Temkin adsorption isotherm were used to analyze the sorption of zinc (II) ions at different temperatures. The thermodynamic parameters like free energy, enthalpy, and entropy changes for the sorption of zinc (II) ions have also been computed and discussed. The heat of sorption [ΔH = −21.52 kJ/mol] implied that the sorption was exothermic in nature. Bamboo sawdust could be used as an alternative and environmentally friendly adsorbent for removal of zinc (II) ions from aqueous solutions.

Keywords:

• Bamboo sawdust
• isotherm
• sorption
• thermodynamic
• zinc (II) ion

Acknowledgements

The authors acknowledged the Short Term Research Grant Scheme (304/PTEKIND/639062) and Universiti Sains Malaysia for the Fellowship to Nor Syahidah Ghani and the Postdoctoral Fellowship to M. R.