Life cycle assessment as a tool to enhance the environmental performance of carbon nanotube products: a review

The importance of evaluating the environmental performance of emerging carbon nanotube (CNT) products from a life cycle perspective is emphasized in this work. Design, development and deployment of CNT products offer many potential benefits to society, but not without negative impacts on public health and the environment. Cradle-to-grave life cycle assessments (LCAs) of CNT products should be performed to ensure that the negative impacts of these products do not transcend the benefits offered by them. Although the application of LCA to CNT products is still emerging, the review conducted by the authors of existing studies suggests that the manufacturing stage in a CNT product life cycle can dominate the environmental impacts, largely as a result of the energy-intensive processes involved in the production of both the CNTs themselves as well as subsequent consumer products. Furthermore this work highlights several key challenges currently encountered with the application of LCA to CNT products, including a lack of data availability and uncertainties associated with estimation of certain impact characterization factors (due to qualitative nature of CNTs). Finally, improving the environmental performance of CNT products using LCA will involve a collaborative effort early in the design process between technology developers and LCA practitioners.