CHAPTER 2:Environmentally Friendly Preparation of Metal Nanoparticles

This chapter summarizes the “state of the art” in the exploitation of various environmentally-friendly synthesis strategies, reaction precursors and conditions to manufacture metal and metal oxide nanoparticles in the most widely followed ‘bottoms-up’ approach. The use of various organisms, such as plants, bacteria, fungi, yeasts, etc. in the eco-friendly preparation of metal nanoparticles under mild reaction conditions and without (if possible) the use of hazardous chemicals is described including recent advances in terms of synthesis precursors, shape control and surface functionalization. Detailed examination of numerous syntheses examples and case studies is presented, with current limitations and possible advancements that are necessary in developing large-scale continuous preparation of metal nanoparticles utilizing wastes and “sacrificial” organisms. The alternative greener processes should eliminate the use of toxic reagents and organic solvents and ensure that very little or no hazardous by-products are formed during the synthesis process. The ideal protocol should provide better control of shapes, sizes and dispersivity of metal nanoparticles and reduces the need for purification of the manufactured nanoparticle, which in turn eliminates the use of extensive amounts of organic solvents and manipulation of nanoparticles that are hazardous to the environment.