Detection of Heavy Metal Ions using a Composite of Graphene Oxide, Iron Oxide and Metal Organic Framework

Abstract

Heavy metals are non-biodegradable, tend to accumulate in living organisms and cause serious health problems. Therefore, effective treatment of heavy metal ions in aqueous media is critical for public health. For selective and sensitive detection of Pb+2, Hg+2 and Cu2+, glassy carbon electrode was modified by a composite of Graphene oxide, metal organic framework and iron oxide. GO serves as backbone of MOF and iron oxide. It improves conductivity by enhancing electron transfer rate in matrix. Moreover, there are interactions between hydrophilic groups of GO and metal cations. GO, MOF and composite of GO-iron oxide was characterized by FTIR and XRD. The detection performance of electrode modified by composite of GO-MOF-iron oxide and GO-iron oxide was explored by EIS and CV. On introduction of MOF-5 to composite of GO-iron oxide, MOF-5 blocks active sites of composite and deactivate it, as MOF-5 hinders transfer of electron. While composite of GO-iron oxide shows excellent heavy metal ions adsorption, high capacitive current and better sensitivity as compared to composite of GO-MOF-iron oxide. This is all attributed to better electron transport properties, good electronic conductivity and large surface area of GO-iron oxide which lead to excellent catalytic response towards heavy metal ions.