The market for nano-based consumer products has grown significantly in recent years. In light of the promising future projections of nano-based industries, proactive measures are necessary to make nanotechnology sustainable. One effective approach for achieving long-term sustainability is to use inherently safe materials, production processes and recycling strategies, based on the principles of green chemistry and engineering.  In recent years, so-called 'green' methods for nano-synthesis have been explored using natural, bio-based alternatives to harmful industrial chemicals. However, the sustainability of these 'green' synthesis processes has not been critically studied from a life cycle perspective. To address this issue, we conducted a screening-level life cycle assessment (LCA) of several metallic nanoparticle synthesis methods. We also assessed the uncertainties in different scale-up scenarios, improvements in process efficiencies and reductions in energy requirements due to maturing of technology. We found that �green� synthesis methods can have major environmental impacts which can vary significantly from process-to-process. In many cases, 'green' methods can have more adverse impact than conventional processes.  Besides improved synthesis methods, novel strategies for nanowaste management are required to sustain the growth of nano-based applications. The limitations of analytical tools for real-time, on-site monitoring of nanomaterial emissions and the lack of adequate data make nanowaste management challenging. Nanowaste streams can also contain significant amounts of precious metals; recovering these precious metals can help reduce the life cycle impacts of different nanotechnologies. At present, existing environmental regulations do not address the specific challenges associated with nanowaste management or recycling. To address this problem, we are developing a laboratory-scale protocol for reclaiming precious metals from nanowaste. Besides the experimental studies, we are also conducting scenario analyses of metallic nano-synthesis with and without recycling to identify the environmental hotspots therein and to estimate the life cycle impacts of reclaiming precious metals from nanowaste.

Life cycle assessment of nanotechnology: Environmental impacts of nanomaterial production and precious metal recovery from nanowaste

248th National Meeting (2014)

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