Synthesis and characterization of graphene oxide (GO) for the removal of lead ions in water

Abstract

The synthesis and characterization of graphene oxide (GO) for water related applications has become an increasing area of research. GO was prepared via Hummer's method, and analysed for structure, morphology, thermal stability, and the ability to remove heavy lead ions from solution. In FTIR analyses, hydroxyl, carboxyl and ester groups were found to be on the structure of GO. XRD showed the interlayer spacing to have increased from graphite to graphene oxide, whereby the average crystallite size of GO was 16.13. Then SEM confirmed the morphology of GO to be exfoliated and wrinkled, with stacked layers. In TGA, EG degraded in a single step, while GO degraded in three distinct steps. When using AAS to analyse the Pb (II) ion intake properties of GO, it showed a maximum adsorption of 98.1% for 600 ppm lead ion solution. The Freundlich isotherm model was consistent with this adsorption, meaning that adsorption took place on a heterogenous surface, on a multilayer basis. The value of n for this isotherm was 0.1474, implying a dominant chemical adsorption. A significant contribution was done to the structure of GO, with its metal adsorption properties clearly portrayed.

Keywords

• Graphene oxide
• Expandable graphite
• Morphology
• Adsorption
• Isotherm modelling