Sustainability Assessment of Nanoscale Zerovalent Iron Production Methods

Nanoscale zerovalent iron (nZVI) is the main nanomaterial used in remediation processes. The aim of this study was to evaluate the sustainability of the nZVI production methods. For this, nine nZVI production methods were selected for analysis. Four kinds of life cycle analysis were performed: life cycle assessment (LCA), life cycle cost (LCC), social life cycle assessment (S-LCA), and life cycle sustainability assessment (LCSA). The LCA was performed in the SimaPro (R) program using the Impact 2002+ method. The LCC was also performed in SimaPro by developing a cost analysis method. For the social analysis, equations were used to calculate the social life cycle score. For the LCSA, the results of the life cycle analyses were normalized, and a weighting factor was defined on the basis of multi-criteria analysis methods. The sustainability score was calculated on the basis of a linear additive model. Scenario and sensitivity analyses were performed, and Monte Carlo simulation was used to quantify the uncertainty of the results. The system limits the stages of raw material extraction, transportation, and nZVI production. The functional unit was 1.00 kg of nZVI produced. The green synthesis method was found to be the most sustainable method, classified as highly sustainable, whereas the micro-emulsion method was found to be the least sustainable method, classified as unsustainable. The scenario analysis showed that overall the Swiss and Canadian scenarios have the highest sustainability index scores, whereas the Indian scenario has the lowest. In addition, the results show low sensitivity to weighting factor variation. In general, this study contributed to the state-of-the-art LCSA application on nanomaterials used in remediation.