Environmental applications of nanotechnology

Environmental applications of nanotechnology

By the AVICENN team – Last modification August 2022

The “promises” of nanotechnology for the environment

Nanotechnologies are often presented as a miracle solution to many environmental problems. In 2009, the Union of Chemical Industries (UIC) stated that “nanomaterials help reduce the environmental footprint of activities: low-energy tires, less energy-consuming vehicles, better insulated homes, more autonomous and less energy-consuming cell phones and computers. (…) Nanotechnologies are increasingly involved in soil and water decontamination, CO2 storage, and the production and storage of renewable energy. At the industrial level, they allow the production of manufactured products while consuming less energy and raw materials“¹Actor’s notebook for the national public debate, Union des Industries Chimiques (UIC), Oct. 2009.

As reported by the President of the National Commission for the National Public Debate on Nanotechnology in April 2010, this view is supported by French research institutions: “What positive aspects can we expect from nanotechnology? According to the CNRS and the CEA, one of the objectives is to contribute to the development of a society that is economical with natural resources and energy, and that has a strong requirement for the preservation of health and the environment²Bilan du débat public sur le développement et la régulation des nanotechnologies, CNDP, April 2010.

Through our web monitoring, we also find numerous announcements of development of so-called “green” nano-applications.³See the bibliography below, heading “elsewhere on the web” as well as the scientific publications of the « NAnoMaterials for Energy applications » research group of the CNRS (GdR Name) created in 2020 in order to develop and exploit the specificities of nanomaterials for the recovery, conversion, transport, and storage of energy.

Vigilance is nevertheless required: in addition to the fact that there are many uncertainties about the risks associated with these developments (see below), some people question the reality and the environmental footprint of these promises.

What are the actual benefits and the ecological impact?

In March 2022, in the magazine La Recherche, Natacha Krins, lecturer at the Laboratoire de Chimie de la Matière Condensée de Paris (LCMCP), shared her concerns about the applications of nanomaterials for energy (in batteries in particular): “We don’t always have a global vision of the issues. We work on extremely technical subjects but of very limited scope in relation to the overall problem” (climate disruption). For example, the origin of raw materials, the recycling, or even the energy management strategy that it could be integrated into”⁴Cf. Ecological transition in research: greener chemistry for a sustainable world, La Recherche, 28 March 2022.

These reflections are in line with the long term concerns expressed by many environmental associations, including the NGOs grouped within the European Environmental Bureau (BEE) and the International Network for the Elimination of Persistent Organic Pollutants (IPEN). They had issued an early warning that the benefits attributed to nanotechnology were often exaggerated, untested and, in many cases, would take years to materialize⁵ Nanotechnology and the environment: a gap between rhetoric and reality European Environmental Bureau (EEB) and the International Persistent Organic Pollutants Elimination Network (IPEN), 2009; Nanomaterials: Health and Environmental Concerns, EEB, 2009.

Do nanotechnologies allow the achievement of greater efficiency with fewer quantities of products? This overlooks the demographic and consumption trends. Friends of the Earth International even fears that nanotechnology will actually increase energy consumption and costs⁶ Nanotechnology, climate and energy: over-heated promises and hot air? Friends of the Earth, November 2010 (see here for a summary in French: Nanotechnologies, climat et énergie).

With the EEB and IPEN ⁷Nanotechnology and the Environment: a gap between rhetoric and reality, European Environmental Bureau (EEB) and the International Persistent Organic Pollutants Elimination Network (IPEN), 2009; Nanomaterials: Health and Environmental Concerns, EEB, 2009, they also point out that the environmental promises associated with nanotechnology often only relate to the use or operation of the products with which they are associated and ignore the environmental footprint of the other stages of the product life cycle – development, manufacture, use, recycling or disposal – where the environment may be impacted.

For example, the research, extraction of raw materials, manufacturing and end-of-life treatment of certain nanomaterials require more sophisticated installations and equipment than traditional processes, and also more energy, more additives (especially water) and sometimes more solvents that are harmful to the environment⁸In a long-term operating scenario, the life cycle assessment of two solar water purification processes, for example, showed a significantly higher environmental impact for the nano-TiO2-based photocatalytic process compared to the conventional approach, due to the high resource consumption in the production of nanoscale titanium dioxide (Untersuchungen des Einsatzes von Nanomaterialien im Umweltschutz, Martens, Sonja, et al (Golder Associates Gmbh), 2010, solicited by: Umweltbundesamt, no. 34/2010, June 2010, Dessau-Roßlau: Umweltbundesamt).

Greenhouse gas emissions generated by the production of certain nanomaterials, nano-silver in particular, may also be more significant⁹Prospective environmental life cycle of nanosilver Tshirts, Walser Tobias et al, ES&T, 2011, 45(10): 4570-4578 and they contribute to global warming and the depletion of the ozone layer.

Moreover, even during their actual use, some products have a low production efficiency, due to a high energy cost for a limited life span (particularly all electronic gadgets, especially smartphones, using micro and nano-electronics).
The high-tech production of carbon-based nanomaterials, such as fullerenes, carbon nanotubes and carbon nanofibers, is currently extremely energy-intensive¹⁰See for example The Potential for Nanotechnology in the Aerospace Industry, Mouser, May 2022. The fuel savings associated with the weight reduction are far from offsetting the energy costs associated with their production. The life cycle impact of carbon nanofibers could be one hundred times greater than that of the materials they replace (aluminum, steel or polypropylene) in the aeronautics or automotive industries, for example¹¹See for example:
– Minimum Energy Requirements for the Manufacturing of Carbon Nanotubes, Gutowski, Timothy G., et al. 2010, IEEE, International Symposium on Sustainable Systems and Technologies,May 16-19, 2010, Washington D.C.
– Carbon Nanofiber Polymer Composites: Evaluation of Life Cycle Energy Use, Khanna, Vikas/Bakshi, Bhavik R., 2009, Environmental Science & Technology, 43(6), 2078-2084.
– Material and Energy Intensity of Fullerene Production, Anctil, Annick, et al. 2011, Environmental Science & Technology, 45(6), 2353-2359..

The energy bill obviously depends on the quantities of nanomaterials produced: when very small quantities are used, for example in the case of carbon nanotubes to produce special plastic films, there can be an energy saving¹²Entlastungseffekte für die Umwelt durch nanotechnische Verfahren und Produkte, Steinfeldt, Michael/Von Gleich, Arnim (Institut für ökologische Wirtschaftsforschung gGmbH FB Umweltökonomie und -politik), 2010, solicited by Umweltbundesamt, no. 33/210, June 2010, Dessau-Roßlau: Umweltbundesamt, but then, the other concern is the risks that nanomaterials may pose.