Métodos de produção no nanoferro aplicado na remediação: análise da sustentabilidade do ciclo de vida

Abstract

The nano-scale zero-valent iron (nZVI) is the main nanomaterial used in the remediation. Thus, the objective of this work is to analyze the sustainability throughout the life cycle of the nZVI production methods used in the remediation of contaminated sites. The work takes place in three main stages: identification and characterization of production methods; Analysis of the environmental (LCA), Economic (LCC) and social (SLCA) life cycle of production methods; and sustainability analysis. The characterization of the production methods was carried out through a systematic bibliographic review. For the analysis of sustainability the methods were selected considering the application and technology criteria used. LCA and LCC were performed using the Simapro® Life Cycle Assessment tool. The SLCA was carried out considering the stakeholders. The system boundaries of the three life cycle analyses include the stages of raw material extraction and manufacturing. The functional unit considered is 1.00 kg of nZVI produced. The sustainability analysis was carried out through a multi-criteria and Multi-attribute analysis. Nine nZVI production methods were identified and characterized, comprising the different process configurations. Of these, three methods were selected to evaluate the sustainability: milling, liquid chemical reduction with sodium borohydride, and chemical gas reduction with hydrogen gas. In LCA the method of reduction with sodium borohydride generated the lowest environmental impacts, the use of renewable energy sources contributed to the improvement of the environmental aspects of the methods. In LCC the hydrogen gas reduction method resulted in the highest costs. The scenario of the energy costs of the methods has a direct influence on the total production costs. In the SLCA the milling method resulted in the highest social indexes, and the data are sensitive to different social scenarios. In the sustainability analysis of the life cycle the method of reduction with sodium borohydride is the most sustainable. The sustainability index is influenced by the scenarios considered, in addition, the consideration of different specialists becomes important in a more accurate and comprehensive evaluation of the sustainability of the methods.