35 No. 2
Materials have always played a central role in human culture and development. Besides wood and other biological materials such as wool, mankind first used materials like flint stone before moving on to metals like bronze and iron. Historians even base their timetable of human development on the materials used at the time, Stone, Bronze, and Iron Ages. The second half of the 20th century is sometimes called the Plastics Age.
Unfortunately, the production and consumption of metals, which are mined, and plastics, mostly made from fossil fuel, are not sustainable in the long term. Even mining fertilizer from deposits of phosphor minerals cannot go on forever. But, as always, there are two sides to the coin. Sustainability involves more than one’s carbon footprint, climate change, or resource depletion. Sustainability is based on three pillars, ecology, economy, and social stability, or the three Ps, people, planet, and profit. With seven billion people on the earth in need of food, water, shelter, and medical treatment—not to mention communication, mobility, and comfort—it will become imperative to develop more sustainable materials to meet these needs.
In Materials for a Sustainable Future, Trevor Letcher and Janet Scott ask, what do we know about these materials today, what do we need to use them in a more sustainable way, or even in a really sustainable way? They tackle these questions from a positive point of view, based on the fact that humankind has always invented new ways and found better solutions to cope with new challenges. They invited 42 authors from 12 countries and all five continents to contribute their knowledge and discuss what should be done in the future. The authors are a good mix of young and experienced scientists, both academic and industrial. The book, supported and sponsored as IUPAC project 2011-042-1-022, was initiated to mark the International Year of Chemistry 2011.
This is not a book you read like a novel from start to end. The 22 chapters go deep into their respective subjects as they stand today, with data and multiple references, but they also provide a good introduction, a look forward, and most of them also a short conclusion. Thus, industrialists, investors, or policy makers will find what they need to know, as will students, teachers, and researchers. It is, as claimed, a readable format for scientists as well as nonscientists.
This book will open the eyes of many a policy maker, when they recognize that there are more challenges than fossil resource depletion, energy and climate influencing gases. The book cover shows a periodic table, where 16 elements are colored red, meaning that they are already very scarce or a rising threat is observed, and many more in yellow, where the availability is limited and a future scarcity of supply is expected. The cover also shows a graph of a bio-refinery scheme. Bi-based value chains are also a major topic in this book.
The book is built on five themes. The first focuses on elements that could soon be in short supply, followed by the second giving a view on sustainability related to biomass, and the third on sustainability related to the feedstock CH4 and CO2. The fourth theme reports on materials related to energy conversion, storage, and distribution. The fifth theme relates sustainability to materials in the urban environment and to water. With limited space, not all topics in the field of sustainability could be included, but the selection covers most of the field.
The chapters focus on single issues related to sustainability, providing detailed information on geology, chemistry, technology, history, and economic data—much more information than expected in a typical handbook. It is clearly a view of today, a snapshot, but always with recent data incorporated.
Chapter 1 discusses base metals and their uses. Copper, lead, zinc, and nickel are treated from mining to consumption data and uses. Also, related greenhouse gas emissions are discussed. The conclusion is that base metals will not be in short supply in the medium term but it is clear that sustainability of production will be governed more by the environmental costs and risk in mining than simply the tonnage remaining.
Rare earths, chapter 2, is a well-discussed topic these days since these materials are key for many electronic applications and for electro mobility, and because political issues impact the world trade. Thus, new sources are being sought, with the number of projects under development outside China rising. The chapter also discusses the increasing interest in finding substitute materials for rare earths.
Chapter 3, which examines the supply of gold, provides some sobering statistics: 168 kt of gold have ever been mined, 104 kt remains in private hands, and it is estimated that only 50 kt remains available in mineral reserves underground. However, demand is rising since gold is also an important material in electronic devices. In the future, it could be especially important to nanotechnology applications.
Platinum group metals, covered in chapter 4, are mainly found in South Africa, with the remaining resources estimated to be around 90 kt globally, compared to an annual production of about 465 t. Sincethese precious metals are very important for catalysis in many ways, they are also of high value for a more sustainable chemistry.
Helium is a strategic element because its cryogenic properties are unique, and for many applications there are no substitutes, as discussed in chapter 5. It is only available from natural gas wells and it might be depleted in 100 years. We should be very careful with the remaining amounts.
In chapter 6 we learn that phosphorus might start to become scarce, even though it is the eleventh most abundant element in the earth’s crust. Given our dependence on phosphorus fertilizer for food production, we will need to make changes to our agriculture, production, wastewater treatment, nutrient recovery, and behavior.
The last chapter under the first theme is on uranium. Nuclear power is viewed very differently around the world. Germany, the home of the reviewer, will terminate all nuclear power generation by 2022 due to the risks involved and unsolved waste questions. Other countries plan to use even more nuclear power. For the authors, nuclear power is a viable strategy to address global climate gas emissions, due to increasing mining efforts, which produce more and more climate gas emissions by themselves.
The biomass theme starts with chapter 8 on aquatic biomass for the production of fuels and chemicals. Producing energy from algae might not be the right path, but for chemicals it is a different story, since high value chemicals can be produced. Chapter 9 discusses using sugarcane as the source for carbon. This well-established route for ethanol production is being extended to other chemicals.
Chapter 10 covers chemicals from biomass at large. The authors clearly state that “bio-based” does not automatically imply “sustainable.” Bio-based chemicals are widely developed. Drop-in solutions, where chemicals from biomass are introduced into existing production pathways, are on the way.
This brings us to the next theme, feedstocks based on CH4 and CO2. Methane for transportation fuel and chemical production is discussed in chapter 11. Natural resources as well as chemical methods of production are discussed. The conclusion is that CH4 will play an important role in future feedstock, either from natural gas or synthetic routes.
In Carbon Capture and Storage, chapter 12, the authors find that the process is not yet feasible, as it costs about 20 percent of energy output. More development of materials and process engineering is needed. Carbon dioxide utilization in the production of chemicals is the topic of chapter 13. The article discusses CO2 as a building block in polyesters and other polymers and the production of fuels. Polycarbonates are the focus of chapter 14 on carbon dioxide in the manufacture of plastics. Carbon dioxide as a sustainable industrial solvent to replace organic solvents (chapter 15) is a well-established technology, which surely will be extended to other processes.
The topic of chapter 16 is battery and fuel cell materials and related issues of energy conversion, storage, and distribution. There is already large-scale production of batteries. The limiting factors are degradation and lifetime.
Materials for photovoltaics are covered in chapter 17. Here, the strong demand will lead to acute supply problems. Substitution, where abundant elements are essential, is a key issue. The dream reaction is water splitting, discussed in chapter 18. In this field we need much more research. Also, the transformation of hydrogen to liquid fuel will become an important focus of research.
The final theme is sustainability related to materials in the urban environment and to water. Chapter 19, which discusses membranes used for water purification, provides a good overview of existing materials and developments.
Glass is not a new material. Nevertheless, new technologies open new opportunities for sustainability, as shown in chapter 20. Examples are thermo-chrome and photo-chrome functionalities and self-cleaning properties. Cost effective solutions must be developed.
The book is well illustrated and chapters are well documented with up to 150 references. Unfortunately, not all figures and tables reveal the data source. The subject index is large and allows easy access to all topics.
The book is valuable in more than one way. It covers a wide field of materials. For a given subject the reader finds extensive data. With a look at the conclusions he or she will get an understanding of what we can do to become more sustainable. It is a large book and not cheap. But the density of information and the different views it provides on an important subject make it worth the money. I thank and congratulate Trevor Letcher and Janet Scott for their effort in publishing this book.
last modified 11 March 2013.
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