O’Carroll: Environment, just one beneficiary of nanotechnology revolution

Nanotechnology has generated significant public and scientific excitement due our abilities to design and synthesize nanoparticles at the nano scale.

A nanoparticle is considered a particle with one of its three dimensions less than 100 nanometres.

There are a wide variety of engineered nanoparticles on the market or currently in development. They are designed to have a wide range of very unique properties that are much more significant than larger particles of the same composition.

For example carbon nanotubes, which are sheets of rolled carbon, are light weight with significant strength. This makes them very useful in composite materials such as tennis racquets and bicycles.

Given their unique properties they have also been used for drug delivery.

Quantum dots, made of binary alloys such as cadmium and selenide, are biomedical sensors. Silver and gold nanoparticles have a wide range of commercial applications, including use of silver nanoparticles for antimicrobial applications (e.g., in socks) and nanogold for electronics.

From this, it is readily apparent that nanotechnology is significantly impacting our day-to-day lives. In the environmental community there is considerable interest in harnessing the tremendous potential of nanotechnology for environmental restoration and water purification.

Environment Canada estimates 29 per cent of the population consumes groundwater as their domestic water, so protection of this resource is essential to the health and well-being of Canadians.

Historically, the subsurface was thought to act as a natural filter of wastes injected into the ground. The potential for these wastes to persist in the subsurface for decades, potentially contaminating drinking water sources was ignored.

Oils are one class of waste liquids that were subject to improper disposal practices. These liquids are extremely difficult to remove from subsurface aquifers (zone below the ground with considerable amounts of water that can be pumped out).

Nanoiron particles are one promising innovative groundwater remediation technology that can convert these contaminants into less toxic or nontoxic materials. They are particularly useful because of their size – a single human hair is 500 to 5,000 times as wide. At that scale, they can move through microscopic flow channels in soil and rock, reaching and destroying groundwater pollutants that larger particles cannot.

We have had tremendous success in laboratory experiments using nanoiron to rapidly degrade a wide range of environmental pollutants.

However one problem has hampered the widespread implementation of nanoiron is poor subsurface mobility. That is when nanoiron is injected into the subsurface it did not originally flow through microscopic flow channels in soil and rock, as anticipated.

To overcome this problem we have developed formulations and processes that make nanoiron mobile in the subsurface.

One part of this recipe has been the use of starches or flour in our nanoiron in our formulation. We are currently working with researchers at the University of Toronto to take the nanoiron that we have developed in our laboratories to the field scale.

In November 2010 and February 2011, we took our technology to the field to clean up two contaminated sites.

At the first field experiment, we injected 1,000 litres of a nanoiron solution into a very contaminated region in the subsurface. Continued site monitoring has found considerable decreases in subsurface contaminants. The second field trial was equally successful.

This work has generated significant public and media attention.

We are very excited with these success stories and anticipate moving forward with commercial applications of nanoiron.

Nanotechnology holds unbelievable potential that will revolutionize the products we use on a daily basis. With these advances comes significant potential for nanotechnology-based technologies to improve the environment.

Watch tonight: Western Professor Dennis O’Carroll discusses the nano revolution, and his field tests with nanoiron, on The Nature of Things, airing at 8 p.m. Thursday, Oct. 27 on CBC-TV.