Green Approach to the Synthesis of Nanomaterials and Sustainable Applications of Nano-Catalysts

R.S. Varma
US Environmental Protection Agency, US

Keywords: green chemistry, biorenewable materials, greener nanoparticles, nanotoxicology, sustainable remediation

Summary:

The presentation summarizes synthetic activity for the preparation of nanoparticles involving benign alternatives. Vitamins B1, B2, C, and tea and wine polyphenols which function both as reducing and capping agents, provide extremely simple, one-pot, green synthetic methods to bulk quantities of nanometals in water without the need for large amounts of insoluble templates. A bulk and shape-controlled synthesis of noble nanostructures occurs via microwave (MW)-assisted spontaneous reduction of noble metal salts using aqueous solution of sugars. A general method has been developed for the cross-linking reaction of poly (vinyl alcohol) (PVA) with metallic systems; bimetallic systems,and single-wall carbon nanotubes (SWNT), multi-wall carbon nanotubes (MWNT), and C-60. The strategy is extended to the formation of biodegradable carboxymethylcellulose (CMC) composite films with noble nanometals; such metal decoration and alignment of carbon nanotubes in CMC is possible using MW approach which also enables the shape-controlled bulk synthesis of Ag and Fe nanorods in poly (ethylene glycol). MW hydrothermal process facilitates the efficient formation of magnetic nanoferrites and micro-pine structured catalysts in water from readily available metal salts. Sustainable route to nano particles using polyphenols from winery waste, their applications in catalysis and environmental remediation will be highlighted.