Jacqueline A. Isaacs

ECONOMIC SENSITIVITY FOR END OF LIFE PLANNING AND PROCESSING OF PERSONAL COMPUTERS

As the use of personal computers (PCs) increases, their short life cycle and the fact that they contain many hazardous materials have a significant influence on finding economical and environmentally benign means for their retirement and disposal. Many communities are mandating the recycling of these PCs to recover parts and materials and to minimize the amount of waste landfilled or incinerated. An industry to process end-of-life PCs is evolving to take advantage of this stream of materials. At present, PC recycling is not profitable unless the recycler receives a processing fee. In this paper, the factors that most influence the profitability of end of life processing of PCs are investigated and reported so that PC manufacturers and legislators may better develop products and policies to ensure that there is a viable PCs recycling infrastructure.

Value analysis of disposal strategies for automobiles

Alternative disposal strategies for vehicle design with varying relative proportions of materials, are explored using goal programming to analyze the tradeoffs between technological, economic, and environment factors. Two vehicle designs - one based on a steel unibody and the other more intensively designed with polymer materials - were selected for investigation. The preliminary results indicate that if properly controlled, the current automobile recycling infrastructure in the U.S. can remain economically viable while improving with respect to environmental considerations.

Environmental Assessment of SWNT Production

Assessment of environmental attributes of nanomanufacturing during process development will lead to development of competitive, safe and environmentally responsible manufacturing technologies. An environmental comparison of arc ablation, CVD and HiPco processes was undertaken by developing models for each process. Since no data are yet available for environmental or health impacts of single wall carbon nanotubes (SWNTs), the results from this analysis can only indicate the impact of resource and energy use during processing. Given the potential benefits and concerns over the use of SWNTs, and the fact that many new (and existing) businesses are currently working towards commercialization, assessment of the tradeoffs among the technological, environmental and economic characteristics is critical.

End‐of‐Life Infrastructure Economics for “Clean Vehicles” in the United States

Summary Rising fuel prices and concern over emissions are prompting automakers and legislators to introduce and evaluate “clean vehicles” throughout the United States. Hybrid electric vehicles (HEVs) are now on the roads, electric vehicles (EVs) have been test marketed, and niche vehicles such as high-fuel-economy microcars are being considered for introduction. As these vehicles proliferate and mature, they will eventually reach their end of life (EOL). In the United States, an extensive recycling infrastructure exists for conventional, internal combustion engine (ICE) vehicles. Its primary constituents are the disassembler and the shredder. These industries, as well as battery recyclers, are expected to play integral roles in the EOL processing of clean vehicles. A model of the automobile-recycling infrastructure and goal programming techniques are used to assess the materials streams and process profitabilities for several different clean vehicles. Two-seat EVs with lead-acid or NiMH batteries are compared with two- and four-seat HEVs and microcars. Changes to the nonferrous content in the vehicle bodies are explored and compared for the effect on processing profit-ability. Despite limitations associated with the linearity of goal programming techniques, application of this tool can still provide informative first-order results. Results indicate that although these clean vehicles may not garner the same profit levels as conventional ICE vehicles, they are profitable to process if there are markets for parts and if there are sufficient quantities of nonferrous materials.

Economic Impact of Aluminum‐Intensive Vehicles on the U.S. Automotive Recycling Infrastructure

The use of aluminum alloys in automobile production is growing as automakers strive to lower vehicle fuel consumption and reduce emissions by substituting aluminum for steel. The current recycling infrastructure for end‐of‐life vehicles is mature, profitable, and well suited to steel‐intensive vehicles; increased use of cast and wrought aluminum, however, will present new challenges and opportunities to the disassembler and shredder, who now comprise the first stages of the vehicle recycling infrastructure. Using goal programming techniques, a model of the auto recycling infrastructure is used to assess the materials streams and process profitabilities for several different aluminum‐intensive vehicle (AIV) processing scenarios. The first case simulates the processing of an AIV in the current recycling infrastructure. Various changes to the initial case demonstrate the consequences to the disassembler and shredder profitabilities whenever the price of nonferrous metals changes; greater fractions of the vehicle are removed as parts; the parts removed by the disassembler have increased aluminum content; the quantity of polymer removed by the disassembler is increased; the disassembly costs increase; the disposal costs for shredder residue and hazardous materials increase; the shredder processing costs increase; and different AIV designs are considered. These profits are also compared to those achieved for a steel unibody vehicle to highlight the impact of introducing AIVs into the existing infrastructure. Results indicate that the existing infrastructure will be able to accommodate AIVs without economic detriment.

Life Cycle Impacts and Benefits of a Carbon Nanotube-Enabled Chemical Gas Sensor

As for any emerging technology, it is critical to assess potential life cycle impacts prior to widespread adoption to prevent future unintended consequences. The subject of this life cycle study is a carbon nanotube-enabled chemical gas sensor, which is a highly complex, low nanomaterial-concentration application with the potential to impart significant human health benefits upon implementation. Thus, the net lifecycle trade-offs are quantified using an impact-benefit ratio (IBR) approach proposed herein, where an IBR < 1 indicates that the downstream benefits outweigh the upstream impacts. The cradle-to-gate assessment results indicate that the midpoint impacts associated with producing CNTs are marginal compared with those associated with the other manufacturing stages. The cumulative upstream impacts are further aggregated to units of disability-adjusted life years (DALYs) using ReCiPe end point analysis method and quantitatively compared with the potential downstream DALY benefits, as lives saved, during the use phase. The approach presented in this study provides a guiding framework and quantitative method intended to encourage the development of nanoenabled products that have the potential to realize a net environmental, health, or societal benefit.

Environmental Life Cycle Assessment of a Carbon Nanotube-Enabled Semiconductor Device

Carbon nanotubes (CNTs) demonstrate great promise in a variety of electronic applications due to their unique mechanical, thermal, and electrical properties. Although commercialization of CNT-enabled products is increasing, there remains a significant lack of information regarding the health effects and environmental impacts of CNTs as well as how the addition of CNTs may affect the environmental profile of products. Given these uncertainties, it is useful to consider the life cycle environmental impacts of a CNT-enabled product to discover and potentially prevent adverse effects through improved design. This study evaluates the potential application of CNT switches to current cellular phone flash memory. Life cycle assessment (LCA) methodology is used to track the environmental impacts of a developmental nonvolatile bistable electromechanical CNT switch through its fabrication, expected use, and end-of-life. Results are reported for environmental impact categories including airborne inorganics, land use, and fossil fuels, with the largest contributions from gold refining processes and electricity generation. First-order predictions made for the use and end-of-life (EOL) stages indicate that the CNT switch could provide potential improvements to reduce environmental burden during use, although CNT release could occur through existing EOL processes.

NanoEHS – defining fundamental science needs: no easy feat when the simple itself is complex

Nanotechnology is no longer in its infancy and has made significant advances since the implementation of the National Nanotechnology Initiative (NNI) in 2000. Incorporation of nanotechnology in many fields including information technology, medicine, materials, energy, catalysis and cosmetics has led to an increase in engineered nanomaterial (ENM) production, and consequently, increased nanomaterial use. In comparison, the generation of concrete and consistent evidence related to the environmental health and safety of nanomaterials (NanoEHS) is lacking. The main factors contributing to the slower progress in NanoEHS versus conventional EHS are related to the complexity, property transformations, life cycles and behavior of nanomaterials even in carefully controlled environments. Therefore, new systematic, integrated research approaches in NanoEHS are needed for overcoming this complexity and bridging current knowledge gaps. A workshop on “NanoEHS: Fundamental Science Needs” brought together scientists and engineers to identify current fundamental science challenges and opportunities within NanoEHS. Detailed discussions were conducted on identifying the fundamental properties that are critical in NanoEHS, differentiating between conventional and NanoEHS studies as well as understanding, the effect of dynamic transformations on nanometrology, role of dosimetry and mechanistic data gaps in nanotoxicology. An important realization that even simple nanoscale materials can be complex when considering NanoEHS implications was noted several times during the workshop. Despite this fact, a number of fundamental research areas to further the scientific foundation to address NanoEHS needs are suggested.

Characterization of Potential Exposures to Nanoparticles and Fibers during Manufacturing and Recycling of Carbon Nanotube Reinforced Polypropylene Composites.

Carbon nanotube (CNT) polymer composites are widely used as raw materials in multiple industries because of their excellent properties. This expansion, however, is accompanied by realistic concerns over potential release of CNTs and associated nanoparticles during the manufacturing, recycling, use, and disposal of CNT composite products. Such data continue to be limited, especially with regards to post-processing of CNT-enabled products, recycling and handling of nanowaste, and end-of-life disposal. This study investigated for the first time airborne nanoparticle and fibers exposures during injection molding and recycling of CNT polypropylene composites (CNT-PP) relative to that of PP. Exposure characterization focused on source emissions during loading, melting, molding, grinding, and recycling of scrap material over 20 cycles and included real-time characterization of total particle number concentration and size distribution, nanoparticle and fiber morphology, and fiber concentrations near the operator. Total airborne nanoparticle concentration emitted during loading, melting, molding, and grinding of CNT-PP had geometric mean ranging from 1.2 × 10(3) to 4.3 × 10(5) particles cm(-3), with the highest exposures being up to 2.9 and 300.7 times above the background for injection molding and grinding, respectively. Most of these emissions were similar to PP synthesis. Melting and molding of CNT-PP and PP produced exclusively nanoparticles. Grinding of CNT-PP but not PP generated larger particles with encapsulated CNTs, particles with CNT extrusions, and respirable fiber (up to 0.2 fibers cm(-3)). No free CNTs were found in any of the processes. The number of recycling runs had no significant impact on exposures. Further research into the chemical composition of the emitted nanoparticles is warranted. In the meanwhile, exposure controls should be instituted during processing and recycling of CNT-PP.

Integrating life cycle assessment into managing potential EHS risks of engineered nanomaterials: reviewing progress to date

The 2011 National Nanotechnology Initiative’s Environmental Health and Safety Research Strategy stressed the need for research to integrate life cycle considerations into risk management and, then, to better integrate risk assessment into decisionmaking on environmental, health, and safety (EHS) dimensions of nanomanufacturing. This paper reviews scholarly articles published 2010–2015 that in some way apply life cycle analysis to nanotechnology to assess the extent to which current research reflects the priorities lain out in the NNI report. As the NNI’s focus was primarily on the “responsible development of nanotechnology” we also focus our examination on the ways in which LCA, in concert with other methodologies, can provide utility to decision makers facing the challenge of implementing that broad goal. We explore some of the challenges and opportunities inherent in using LCA, a tool built to optimize manufacturing decisions, as a guide for policy formulation or tool for policy implementation.