LCA applied to nano scale zero valent iron synthesis

Abstract

Purpose Application of zero valent iron nanoparticles is an innovative technology for ground water treatment and soil remediation. There are several methods to synthesise nano scale zero valent iron (nZVI), namely through bottom-up methods which consists on chemical reactions using strong reducing agents. In this work, the environmental impacts and costs were determined for two methods, namely the traditional one that uses sodium borohydride and the green method that uses extracts obtained from natural products. Methods The consideration of environment and economic aspects in the earlier stages of the synthesis processes and in the development of new materials is of great importance since it can help to decide if alternative methods are promising and should be further developed aiming more sustainable processes. In this work, life cycle assessment (LCA) was used as an ecodesign strategy evaluating environmental performance of the two synthesis methods, identifying critical stages of the synthesis processes of nZVI. An economic evaluation and a sensitivity analysis considering a different scenario for electricity production were also performed. Results and discussionThe results obtained in this study showed that the green synthesis method presents lower environmental impacts than the traditional one, roughly 50% lower in the first scenario. In the second scenario, environmental impact of green synthesis corresponds to 38% of the environmental impact of traditional synthesis. In the green method, the critical stage is the extraction process which is closely related to the electricity production. In the traditional method, the reactant use is the critical stage that is related to the production of sodium borohydride. The economic evaluation indicated that the traditional synthesis method is much more expensive than the green synthesis (roughly eight times higher). Conclusions From the results obtained, it is possible to conclude that the green synthesis method presents lower environmental impacts in both scenarios and lower costs than the traditional synthesis.

Sustainable Synthesis of Nanoscale Zerovalent Iron Particles for Environmental Remediation

“…Martins et al. applied lifecycle assessment as an eco‐design strategy to evaluate the environmental performance of green syntheses of nZVI and identify the critical stages of the synthetic processes . Benign syntheses appear to have a lower environmental impact than traditional methods.…”

Green synthesis of nanoparticles for the remediation of contaminated waters and soils: Constituents, synthesizing methods, and influencing factors

“…The use of green materials also fits well with the environment industry's paradigm shift toward nature based solutions (Song et al, 2019). The benefit of green synthesis was exemplified by Martins et al (2017), who used life cycle assessment (LCA) to reveal a 50% reduction in the total environmental impact of a green synthesized nano scale zero (EGCG, 36-40%), (-)Epigallocatechin (EGC 0.7%-2.3%) and (-)Epicatechin (EC 0.5-2.2%), which have bactericidal and antioxidant properties (Ahmmad et al, 2013). The ability of tea extract in the reduction of Fe was illustrated by Hoag et al (2009), who showed that as the reaction between Fe(NO 3 ) 3 and a tea extract occurred, the UV absorbance spectra shifted and the mixture changed from yellow to dark brown (Fig.…”

Environmental Sustainability Evaluation of Iron Oxide Nanoparticles Synthesized via Green Synthesis and the Coprecipitation Method: A Comparative Life Cycle Assessment Study

“…The environmentally friendlier compounds used in the green synthesis showed promising results compared to other green methods reported in the literature. 5 , 48 …”

“…The production of these compounds involves fossil fuel extraction, refining, and combustion, promoting the release and emission of solid, liquid, and gaseous wastes into the environment. 48 The contribution of iron(III) was related to a possible release of iron ions, 49 and the large amount used for the reduction to iron(II), considering that the latter compound was replaced by the C. citratus extract in the green synthesis. However, the low value was related to the iron(III) salt precursor composition since it was composed of chlorides instead of more toxic compounds such as sulfates.…”