Life Cycle Assessment (LCA) of nanocompounds synthesis based on magnetite (Fe3O4) nanoparticles: conventional and microfluidic methods

Abstract

In the face of escalating industrialization and its consequent pollution, the global community is increasingly invested in exploring efficient solutions for the removal of toxic pollutants from wastewater. Our research group, Biomicrosystems, has focused on exploring the use of nanocompounds based on magnetic nanoparticles as a potential solution for wastewater treatment. These nanocompounds have shown promising capabilities in remediating pollutants due to their large surface area and high reactivity. Incorporating microfluidic technologies into the use of these nanocompounds has gained popularity due to their potential for environmental detection, operational cost, lower investment, and reduced infrastructure requirements. Therefore, the chapter two of this dissertation focuses on a specific approach, which involves the modeling and evaluation of six different micromixer designs specifically intended specifically for wastewater treatment. These micromixers are meticulously assessed based on their velocity profiles, pressure drops, and flow patterns under controlled mixing conditions. Additionally, a comprehensive life cycle assessment (LCA) analysis is conducted to understand the environmental impact of these micromixers and assess the sustainability of the mixing process. Magnetite nanoparticles (MNPs) are the most used nanoparticles in our research group for manufacturing nanocompounds. They have garnered particular attention for their cost- effectiveness, ease of manufacture, modifiability, and magnetic recoverability. However, the potential of MNPs for environmental remediation largely depends on assuring efficient synthesis methods that avoid substantial environmental impacts. Microfluidic techniques have emerged as a promising approach for the controlled and efficient production of MNPs with improved properties. In that context, chapter three of this dissertation proposes three uniquely configured micromixers (serpentine, triangular, and 3D), each designed to facilitate controlled growth and nucleation processes for the formation of uniformly sized and crystalline MNPs. Experiments confirm that these micromixers effectively synthesized MNPs with homogeneous morphologies, particle size distributions, and crystalline structures. A subsequent comparative LCA, considering water and energy consumption, demonstrates the micromixers superior environmental performance compared to conventional batch co-precipitation synthesis. Chapter four extends this research by conducting an exhaustive LCA on MNPs production at laboratory and industrial scales using micromixers. This analysis highlighted the potential of these microfluidic platforms to enable a sustainable MNPs synthesis process and their viability for large-scale production. As a result, this dissertation delves into the synthesis of MNPs with an emphasis on enhancing their efficacy and sustainability in environmental applications. A comprehensive understanding of the sustainability performance of the synthesis methods of MNPs can be achieved by integrating environmental, economic, and exergetic analyses. The LCA methodology appears well-suited to evaluate potential environmental impacts associated with such manufacturing methods. However, a comprehensive analysis should also consider the economic aspects to ensure the viability and overall economic sustainability of these manufacturing process. Therefore, conducting an economic analysis provides valuable information into the financial feasibility of sustainable practices. Additionally, an exergetic analysis provides insights related to the quantification of the exergy losses at each stage of the process, helping identify areas for improvement, optimize energy usage, and minimize resource consumption. Consequently, chapter five presents a comparative assessment at an industrial scale, evaluating the environmental, economic, and exergetic feasibility of MNPs production, illuminating both the advantages and challenges of implementing micromixers for large-scale MNPs production. In conclusion, this dissertation provides invaluable insights for industries seeking to adopt sustainable and efficient manufacturing processes for MNPs. By providing comprehensive analysis and practical recommendations, this research contributes substantially to the transition towards environmentally friendly and resource-efficient production methods.