The growing use of microscopic particles in everyday consumer and industrial products has been subject to considerable study – but much less research has been devoted to the end-of-life and recycling implications of nanomaterials.
Nanomaterials are used in a wide variety of consumer products and industrial applications, many of which have reached their end-of-life. Studies have shown, however, that these tiny particles can have toxic effects, which makes the development of appropriate recycling strategies imperative.
More than 11 million tonnes of nanomaterials are placed on the market each year but this number can only be a rough estimate, say experts. Their global value is expected to grow from US$ 14.7 billion in 2015 to more than US$ 55 billion by 2022, according to Allied Market Research.
‘Nano’ is everywhere
‘Every 18 months in Europe, we see a doubling in consumer products that claim to contain nanomaterials,’ says Steffen Foss Hansen, associate professor at the Technical University of Denmark and co-founder of The Nanodatabase, which was set up in 2012.
‘But there is a lack of access to information about how many nanomaterials are produced, how much is used, by whom, and where,’ he adds. ‘We have been calling for regulation for a long time in this area, as any kind of risk assessment starts with knowing what is out there.’
The largest application for the technology is electronics, followed by energy, but ‘nano’ is everywhere: carbon nanotubes are used in batteries, sporting goods, composite plastics, concrete and ceramics; nano-titanium dioxide is used in paints, coatings, building materials, textiles and metals; nano-silver is used in textiles, kitchenware and coatings.
Because some of these products have reached their end of life, development of appropriate waste management strategies is critical, according to a report on waste and nanomaterials from the Organisation for Economic Co-operation and Development (OECD), which was published in 2016.
What’s the real impact?
Most nanomaterials are based on metals on a molecular scale: one nanometer is one billionth of a metre, which is 10 000 times smaller than the diameter of a human hair. At this scale, the material is no longer effectively a metal but a chemical that may have novel properties compared to its bulk form.
That is also the reason why nanomaterials have become so popular. Wind turbine blades with a coating that contains carbon nanotubes produce 30% more power than conventional blades. Nano-silver acts as an anti-bacterial agent in textiles but the particles are deadly to micro-organisms if they get into the soil.
Few studies have concerned the presence of nanomaterials in recycled products. One concluded that ‘less than 10% of nanomaterials from different products will be recycled back to the production and manufacturing chain’. Another predicted that ‘about 40-47% of nanomaterials in construction ends up in recycled materials.’
Fuente: RECYCLING INTERNATIONAL