LCA of metal nanomaterial production

The use of engineered nanomaterials (ENMs) in commercial product has reached a new stage, where consumers in their daily life are frequently encountered with products containing this new material class. Metal and metal-oxide nanomaterials are among the most commonly used ENMs in products. Potential life cycle impacts arise from all life cycle stages of the ENM products. Currently there are many unknowns related to the inputs and outputs from production of ENMs and the potential impacts that arise from that and we need to better understand and map the impacts that arise from the raw material extraction and
manufacturing of ENM products. Further in the life cycle, i.e. the use and disposal, additional difficulties are observed in accounting for potential impacts e.g. the potential health impacts related to release of nanoparticles. This case study considers the production of ENM (Ag, ZnO and Mg(OH)2 applied as additives in
polypropylene (PP), and the production of PP with conventional additives that provide similar properties as the ENMs. Different scenarios of nanoproducts consisting of metal ENMs and PP were compared with current use of additives in PP products through a detailed cradle-to-gate LCA study. The results show that the ENMs do not contribute substantially to the impact profile of nanoproducts, but the PP plastic has the main responsibility. The main reason is the rather low amounts of ENM added. Further the comparison showed that nanoproducts have less impacts associated to them compared to the PP products containing
conventional additives due to the improved material functionality and properties that ENMs contribute to.