Efficient removal of Pb(ii) from aqueous solution using zinc oxide/graphene oxide composite

Abstract

Due to the rapid development of industrialization over the years, the enhancement on heavy metals removal technology are becoming more urgent. Graphene oxide (GO) gained attention as adsorbents due to high surface area and high affinity towards heavy metals removal. However, its tendency for agglomeration and difficulty in phase separation urges more researches done to address its drawback. Zinc oxide (ZnO), a versatile nanomaterial, has been discovered to have high affinity towards heavy metals removal, tendency to spread out across GO sheet and ease of handling. Therefore, in this study, zinc oxide/graphene oxide nanocomposites (ZnO/GO) were synthesized as adsorbents for the removal of Pb(II) from aqueous solution. The synthesized composite was characterized using Fourier-transform Infrared Spectrometry (FT-IR), Scanning Electron Microscopy (SEM) and X-ray Diffraction (XRD), and had confirmed the chemically bonding of ZnO on GO. From the batch test, the optimum adsorbent dosage and initial pH for Pb(II) adsorption using ZnO/GO were 0.16 g/L and at pH 5, respectively, with the adsorption capacity of Pb(II) at 418.78 mg/g. The most rapid adsorption had occurred in the first 30 minutes, and the equilibrium time was achieved at 160 minutes. Also, Pb(II) adsorption had followed the pseudo-first order kinetic model. Therefore, ZnO/GO is thought to be a newly promising adsorbent in removing Pb(II) ion from the aqueous solution.