ROYAL COMMISSION ON ENVIRONMENTAL POLLUTION
CHAIRMAN: SIR JOHN LAWTON –CBE, FRS
Twenty-seventh Report Novel Materials in the Environment: The case of nanotechnology
Presented to Parliament by Command of Her Majesty- November 2008
Introduction and overview
1.1 The discovery, development 1.1 and deployment of novel materials have always been significant factors in the development of human civilisation. Prehistoric and historical epochs are even named according to the new materials (or new uses of materials) that were successively introduced and entered into common use during what we know as the Stone Age, Bronze Age and Iron Age.
1.2 In later eras, new materials have been closely associated with radical change. The development of paper was as important as the printing press in revolutionising communications. The introduction of gunpowder into Europe transformed warfare. In more modern times, gas lighting only became demonstrably superior to oil and candles with the introduction of the gas mantle, composed of novel materials such as thorium and cerium oxides. A hundred years ago electric filament lamps were made possible by other novel and fairly unusual materials, osmium and tungsten. More recently, fluorescent strip lights and compact high efficiency lights use once-novel phosphors to convert the UV produced by the electrical discharge into visible light.
1.3 Regardless of their novelty, materials are fundamental to all areas of technology and economic activity. Manufacturing and construction are entirely dependent on materials, and materials technology affects most economic activities.
1.4 The Royal Commission’s decision to study novel materials was initially motivated by two kinds of concern. First was the potential for releases to the environment arising from increasing industrial applications of metals and minerals that have not previously been widely used. Second was the embodiment of nanoparticles and nanotubes in a wide range of consumer products and specialist applications in fields such as medicine and environmental remediation. As our inquiry progressed, it soon became clear that the bulk of evidence that we were receiving focused on the second of these issues.
1.5 Novel materials and new applications for existing materials are continually being developed in university and commercial laboratories around the world. They are intended either to improve the performance of existing technologies, such as fuel additives to improve the energy performance of cars, trucks and buses, or to make new technologies possible, such as MP3 players and mobile telephones which use trace quantities of exotic minerals. Novel materials are used under controlled conditions in industrial processes to make everyday objects. They are also incorporated in products which find their way into daily use.
1.6 Novel materials include a wide range of industrial products such as polymers, ceramics, glasses, liquid crystals, composite materials, nanoparticles, nanotubes and colloidal materials. In turn, these kinds of materials may be used in a wide range of applications including energy generation and storage, engineering and construction, electronics and display technologies, food packaging, and environmental and biomedical applications.
In the field 1.7 of energy technology for example, the development of more efficient engines, advanced solar photovoltaics, improved batteries and hydrogen storage all offer opportunities for the potentially widespread application of novel materials. Diesel engines are said to be made more efficient by the use of fuel additives, such as cerium oxide. Jet engines can burn fuel at much higher temperatures when rhenium is added to alloys used in their construction. Conductive organic polymers, inorganic semiconductors such as cadmium selenide (in both bulk and nanoparticulate forms) and fullerenes are of interest to manufacturers of solar cells. Various novel lithium compounds are being investigated to achieve improvements in the cathodes of lithium ion batteries found in numerous portable electronic devices, including laptop computers and mobile phones. Hydrogen could be used as an alternative to electricity as an energy source and storage medium. But hydrogen storage as gas or liquid currently presents problems that could potentially be overcome by using inorganic metal hydrides of light elements (along with platinum, palladium, nickel or magnesium as catalysts) or by absorption in high porosity materials with large surface areas, such as nanotubes. There is a similarly wide range of potential applications in many other fields.
1.8 Novel materials are developed in response to a number of different drivers, including the requirement for a specific or improved functionality, increased efficiency, and the need to find substitutes for raw materials that are in short supply or have been found to have adverse effects on the environment or human health. An example of where safer substitutes for existing materials are desirable is the replacement of lead solder in electronic devices. In some cases, the discovery of novel functionality (the ability of a material to behave in a certain way or to ‘do’ something) actually drives a search for profitable applications.
1.9 The improved efficiency and functionality of novel materials can bring tangible environmental benefits, such as those offered by the development of photovoltaics, fuel cells and lightweight composites for cars and aircraft. In all cases, it is unlikely that new materials will be adopted, even in critical areas such as low-carbon energy technology, if the price is too high.
1.10 An example of materials innovation to reduce costs is the search for alternatives to the use of silicon transistors in liquid crystal displays (LCDs). While this technology is well understood, it remains costly and energy intensive, and manufacture of the materials involves the use of highly corrosive chemicals. Conducting polymers, transparent conducting oxides, silicon nanorods and carbon nanotubes are all being explored in the development of printing technologies that could achieve large display area capabilities, high processing speeds and low energy input.
1.11 Price may be only one of a number of constraints on the development and deployment of novel materials. For example, the scarce supply of some elements, such as indium, means that there may not be sufficient availability to realise the potential benefits on a substantial scale.
1.12 When scarce new materials are used in very small quantities, for example as dopants in electronic equipment, the feasibility and cost effectiveness of recycling them is diminished so that increasingly they will be released into the environment.