Daily Archives: November 30, 2011

Nanotechnology and the Environment

Scientists working on the EC-funded research project Monacat,  are looking at how nanomaterials can remove water pollutants such as nitrates. “Nitrate reduction has been studied for decades; it’s very hard to do and it isn’t commercially viable,” says Alexei Lapkin, professor of chemical engineering at the University of Warwick, who works on Monocat.  Nitrates taken into the body through water can block oxygen transport. In severe cases this can starve tissues and organs of oxygen and lead to conditions including heart defects in babies. Nitrate levels are therefore strictly regulated, with an estimated €70bn–€320bn (£60bn –£274bn) spent every year across the EU removing nitrogen waste from water. The Monocat project has developed reactors coated with carbon nanotubes and nanofibres that could potentially remove nitrate pollutants at much lower costs. Lapkin says the most successful reactors will soon be chosen for patenting and further development.

Another European project, NanoGLOWA, is using nanotechnology to tackle global warming. The project aims to develop nanomembranes that can remove carbon dioxide from power plant emissions more efficiently than current methods. These membranes use nanomaterials to physically separate or chemically react with the carbon dioxide in flue gas streams.

As well as cleaning up fossil fuel use, nanotechnology is improving the viability of clean energy. Today, the most widespread photovoltaic solar cells are made of polycrystalline silicon and are relatively expensive, but nanotechnology is working to drive the costs of solar power down.  “It’s quicker and easier to grow a small crystal than a large one, and nanocrystals can be made in large quantities by simple chemical routes,” explains Jason Smith, leader of the Photonic Nanomaterials Group, University of Oxford. Photovoltaic cells made by “printing” nanoparticle inks are already commercially available.  “So far they have reached 17% efficiency,” says Smith. Normal polycrystalline silicon cells are about 20% efficient. “This is a pretty impressive achievement and demonstrates that nanomaterials can be almost as efficient as the standard polycrystalline silicon cells, while produced at a fraction of the cost.” An important next stage of the research will be to continue to improve the efficiency of these cheap nanoparticle cells…

“We will need at some point to replace internal combustion and diesel engines,” says Duncan Gregory, professor of inorganic materials at the University of Glasgow. “Hydrogen is an ideal fuel since one can extract a large amount of energy from it, and the process is green.”  However, storing hydrogen as a gas is both inconvenient and dangerous. “Solid-state storage, by which hydrogen is stored within a host solid, could overcome these problems, in principle making it possible to store a much higher amount of hydrogen in a relatively unreactive form,” Gregory says. He and his team have patented a nanomaterial called lithium nitride, similar in structure to carbon nanotubes and nanofibres, which may provide a way to store hydrogen safely inside a solid.

 

“It might be this material or similar that provides the breakthrough, or a completely different way of thinking,” says Gregory. “How soon this technology becomes ready depends on what the political will for change is. In these challenging economic times, real-terms government spending on research has fallen. Thankfully, energy remains a high UK research priority that will be essential, given all our environmental, economic and political concerns.”

New forms of glass that control the heat, light and glare passing through a surface are emerging. But these are based on nanotechnology procedures that, in some cases, have been around for decades.

Excerpt, Penny Sarchet, Essential matter, Guardian, Nov. 25, 2011