The unique chemical and physical properties of nanoscale materials have led to important roles in several scientifi c and technological fi elds. Environmental chemistry processes have benefi ted from the enhanced reactivity of nanoscale particles relative to their bulk counterparts with contaminants. Here, we describe recent advances in the synthesis and characterization of metallic and bimetallic nanoparticles that have been effective toward degrading toxic organohalide contaminants. We then review the degradation mechanisms involved in the reactions of nanoscale particles with organohalides via reduction pathways. We also discuss an emerging area -the degradation of organohalides via multi-electron transfer pathways.

Engineered nanoparticles (ENPs) are known to possess unique size and shape dependent chemical and physical properties. As a result of their properties, ENPs have been effective in several important applications including catalysis, sensor design, photonics, electronics, medicine, and the environmental remediation of toxic pollutants. Such properties and applications have led to an increase in the manufacture of ENPs and a rise in their presence in consumer products. The increase of ENPs in consumer products presents several opportunities and challenges, and necessitates a proactive study of their health and safety. This article highlights some recent work in which we have studied the effect of exposure of well-defined ENPs to pesticides and the effect of pH and dissolved organic matter. We also summarize our work and that of others who have studied the toxicity of ENPs with microorganisms. The results provide insights on the need for green manufacturing strategies of ENPs, their use and safe disposal practices.

The design and synthesis of well-defined metallic and bimetallic nanoparticles (NPs), their characterization, and the assessment of how their size and shape-dependent properties influence their applications are important areas of investigation for advancing green technologies that protect the environment. This chapter reviews recent advances in the design and synthesis of metallic, bimetallic and semiconductor nanoparticles and their emerging applications in the production of energy and chemicals from biorenewable materials. This contribution focuses on nanoparticle-mediated processes for biomass transformation that include hydrogenation, hydrogenolysis, decarboxylation, small molecule oxidation, conversion of cellulosic materials, hydrocarbon formation, and production of fuel cells. These processes all have significant potential for development of green technologies.

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