Preparation Of Metal Or Metal Oxide / Carbon Composites And Their Analytical Separation Applications

Graphene, a single or several layered graphites, possesses an intriguing two-dimensional nanostructure with excellent mechanical, thermal and electrical properties. As a kind of one-dimensinal nanomaterial, carbon nanotube has great chemical, electrical, mechanical properties. In this paper, graphene, carbon nanotube and metal composites were used in the adsorption and SERS detection. The main contents of this article are as follows:The extensive use of heavy metals in industrial processes has resulted in environmental contamination. Heavy metal ions specifically binding to proteins, nucleic acids, and small metabolites in living organisms, have caused serious health problems of animals and human beings. In this work, A highly reductive and magnetic graphene/Fe₃O₄ composite（abbreviated as HR-M-GO/Fe₃O₄） was synthesized via graphene oxide（GO） oxidizing FeCl₂ in situ. Due to rich ferrous ions in the composite, the resulting HR-M-GO/Fe₃O₄ shows extraordinary removal capacity for Cr（VI）. The chemical mechanism of Cr（VI） removal by HR-M-GO/Fe₃O₄ is investigated by X-ray photoelectron spectroscopy. As a perspective, the novel Fe2+-rich magnetic graphene composites with excellent performance could also be applied in the treatment of other metallic ions in wastewater.High level of sodium thiocyanate in milk and infant formula will increase the risk of goiter for bottle-fed infants. In this work, we report a simple, environmentally friendly method for preparing a novel Au dotted magnetic graphene sheet（Au-MGS）. To prepare the magnatic graphene, FeCl₂ is oxidized by graphene oxide in situ to magnetic nanoparticles deposited on graphene sheets. Inositol hexakisphosphate（IP6） serves as a bridging agent and a stabilizer. Au NPs is dotted onto the magnetic graphene network with the help of IP6. As a surface-enhanced Raman scattering（SERS） substrate material, the limit of detection for sodium thiocyanate reaches 100 n M. Therefore, Au-MGS can be developed as a smart SERS substrate for sodium thiocyanate detection.Malachite green（MG） is a synthetic triphenylmethane dye that has been extensively used in aquaculture or food industry as an effective anti-microbial agent. Because of its potential teratogenicity, genotoxicity and carcinogenicity, the use of MG has been banned in different parts in the world. Adjusting the ratio of the amount of gold nanoparticles and carbon nanotube, we prepared an ultrasensitive SERS substrate. We have shown that in carbon nanotube/gold composites（CNT-Au）, gold nanoparticles are in close contact, forming several hot spots and providing a significant enhancement of the SERS signal. As a SERS substrate, the limit of detection for MG reached 0.1 ppb. Therefore, CNT-Au can be developed as a smart SERS substrate for MG detection.