Chemistry is the only science and industrial sector that can transform molecules and materials. As such chemistry is the basis for our high living standard, the high quality of health, and key for future sustainable development in general. About 20 years ago the 12 principles of green chemistry have been introduced based on preliminary work by OECD, European Union, the U.S. Environmental Protection Agency and many individuals. This was a big step forward to enable chemistry to deliver greener chemical products. The principles address the chemical products and their synthesis to reduce waste generation and energy need, reduction of toxicity and environmental burden by individual chemicals. However, there are some shortcomings. It is not clear how many of the twelve principles have to be met to call a chemical "green" or better "greener" and how much greener it will or should be. A principle states to use renewables. However, renewables aren't endlessly available, need energy and auxiliary chemicals too for extraction and processing, generate waste and impact the environment. The same holds for the products made of them. Some can be as toxic as non-renewables and. Furthermore, metals and other elements are not renewable but are indispensible for (electro)mobility, communication, renewable energy etc.. How to deal with them? Often there are competing demands for certain resources (e.g. biomass, renewable energy, a certain metal) for different products and applications. Many problems are just arising as the concentration of a certain compound to too high at a certain place. Therefore, it is important be aware of total substance, material and products flows and a broader systems thinking, also to as possibly linked rebound effects or transfer of problems to other environmental media, regions, other stakeholders or into the future. Therefore a broader view is needed.
The framework of circular economy was developed by the Ellen-MacArthur Foundation the European Union and others. Still increasing visible environmental pollution, especially by macro plastics and e-waste, triggered it. The increasing shortage of fossil resources as well as the increasing need for metals and other elements ("critical resources") such as phosphorous which are indispensible for high technology products such as batteries is another driver. Recycling and reuse of products and waste, which, however, is well known since decades, is at the core of chemistry in a circular economy, including the products ("resources") renewed by nature. Thereby pollution of the environment as well as savings of resources is possible. Whilst overcoming some of the limitations of green chemistry, chemistry for a circular economy is faced with its own challenges. Chemistry in a circular economy comes along with the need for interdisciplinary cooperation between chemists and product designers, architects, users of the products and many others. This has to be included into education too. Products have to be designed for circulation and recycling from the very beginning. Circulation and recycling also needs much energy. The substance flows, material flows and product flows have to be depolluted. In any case there are unavoidable losses of substances and materials according to the inescapable laws of thermodynamics (dissipation). There is no endless circulation and recycling. The bigger, the more dynamic, and the more diverse the flows are the bigger are the losses. Not all products can be circulated. Furthermore, sustainability depends on how and when to use products.
Therefore, to meet the goals of sustainability also needs the inclusion of alternative business models for chemical products, ethics and social issues among many others when it comes to the extraction of resources and the use of products. Chemistry for sustainability ("sustainable chemistry") starts with understanding the service and function needed. They can sometimes be met without the use of chemicals or at least less chemicals e.g. by different behaviour, education and training, different design of products or buildings. To enable chemistry to contribute in a sustainable manner to sustainable development, e.g. as set by the Sustainable Development Goals of the United Nations, a more holistic framework and understanding is needed - sustainable chemistry - that uses green chemistry and chemistry adapted to a circular economy but overcomes their above mentioned challenges and shortcomings as both are not sustainable per se.
Figure 1: Conventional Chemistry, Green Chemistry, Chemistry for a Circular Economy, and Chemistry for Sustainability
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European Union (2015) Closing the loop – An EU action plan for the circular economy. COM/2015/0614 final. https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:52015DC0614
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Kümmerer, K., Dionysiou, D. D., Olsson, O., Fatta-Kassinos, D. (2018) A path to Clean Water. Science 361 (6399), 222-224. DOI: 10.1126/science.aau2405
Leuphana University Lüneburg
Klaus Kümmerer is professor for Sustainable Chemistry and Material Resources, director of the Institute of Sustainable and Environmental Chemistry at the public Leuphana University Lüneburg (Germany) and director of Research and Education of the International Sustainable Chemistry Collaborative Centre (ISC3) in Bonn (Germany). His interdisciplinary research and teaching is focused on Sustainable Chemistry, Sustainable Pharmacy, Material Resources, Aquatic Environmental Chemistry, and Time and Sustainability. He received several awards for his interdisciplinary work. Klaus Kümmerer served and is serving in many national and international boards including of the German Chemical Society, the German Science Foundation, the Global Chemical Outlook by UNEP and the EU Technology Platform SusChem Europe. He also (co)organizes/ed and chairs several international and national conferences. He is founding editor and editor-in-chief of Sustainable Chemistry and Pharmacy, and Current Opinion in Sustainable Chemistry journals as well as associate editor of Chemosphere and Environmental Pollution. He published extensively in peer reviewed scientific journals edited more than 10 scientific books. His work was featured in TV, radio, internet, newspapers and chemistry journals such as CE&N.