Characterisation of Green Nanomaterials

Green synthesis of nanoparticles is becoming popular due to its sustainability, eco-friendly and inexpensive approach. Production of submicron-sized particles from the biogenic sources is referred as green-mediated synthesis. Different kinds of green metal nanoparticles available are Ag, Au, Cu, Cd, Pt, Pd, Fe, and other metal oxides include ZnO, CeO2, TiO2, ZrO2, In2O3, Cu2O and CuO, PbS, Fe3O4. These nanoparticles are characterised for its surface morphology and its compositional structure. The common techniques employed for characterisation of metal and metal oxide nanoparticles include UV-visible absorption spectroscopy, X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, energy dispersive spectroscopy (EDAX), atomic force microscopy (AFM), scanning electron microscope (SEM), transmission electron microscope (TEM), etc. The main characteristics that determine the properties and functionality of green nanomaterials are particle size, size distribution, crystallinity, specific surface area, surface morphology and elemental composition. Characterisation of green nanoparticles is significant to study about the nature, behaviour and functional properties of synthesised green nanoparticles (NPs). These NPs are well known for its antimicrobial and antioxidant effects as they have potential applications in food processing as in food packaging, food quality analysis and food/drug delivery systems. In order to find potential applications of green nanomaterials, characterisation of these nanoparticles is significant. This chapter essentially focusses on various characterisation techniques for the green-synthesised nanomaterials.