Nanoporous Carbon@Graphene Oxide – Mesoporous Silica Composite as an Absorbent for the Removal of Hg (II) from Aqueous Solution

Abstract

Heavy metal, especially mercury (Hg), and agricultural waste pollution is now a serious threat to the environment and human life because of the rapid urbanization and industrialization. In order to handle these toxic pollutant particles or their ions, researchers have attempted to develop several adsorbent materials with change of shape, size, architecture, surface charges, and surface biomolecules. With a view of enhancing the efficiency of adsorbent materials, the present study deals with graphene oxide mesoporous silica incorporated nanoporous carbon (NC) derived from palm kernel shell waste towards Hg (II) adsorption. The composite material were characterized via BET specific surface area (1020 m²/g), field emission scanning electron microscopy (FESEM), and X-ray diffraction analysis (XRD). The NC@GO-MS composite was most suitable for the adsorption of Hg (II) under the influences of pH, adsorbent dosage, initial concentration and contact time. The maximum adsorption efficiency of Hg (II) (212.8 mg/g) was achieved at a pH 4, while Langmuir model fit the equilibrium sorption data best and was fitted with a pseudo-second order kinetic model. Moreover, thermodynamic studies indicated that, the enthalpy, entropy, and Gibbs free energy values show that the adsorption is compatible with spontaneous, favorable, and endothermic reactions. Therefore, based on the results, the synthesized NC@GO-MS composite can serve as a promising candidate for wastewater treatment considering its efficiency, inexpensive, and environmentally friendly source.