Reduction and adsorption of Pb2+ in aqueous solution by nano-zero-valent iron—A SEM, TEM and XPS study

This study reports the synthesis, characterisation and application of nano-zero-valent iron (nZVI). The nZVI was produced by a reduction method and compared with commercial available ZVI powder for Pb2+ removal from aqueous phase. Comparing with commercial ZVI, the laboratory made nZVI powder has a much higher specific surface area. XRD patterns have revealed zero-valent iron phases in two ZVI materials. Different morphologies have been observed using SEM and TEM techniques. EDX spectrums revealed even distribution of Pb on surface after reaction. The XPS analysis has confirmed that immobilized lead was present in its zero-valent and bivalent forms. ‘Core–shell’ structure of prepared ZVI was revealed based on combination of XRD and XPS characterisations. In addition, comparing with Fluka ZVI, this lab made nZVI has much higher reactivity towards Pb2+ and within just 15 min 99.9% removal can be reached. This synthesized nano-ZVI material has shown great potential for heavy metal immobilization from wastewater.