Tag Archives: Jim Hannah

Removing pollutants from water with nano-brushes

The Jan. 16, 2012 news item ( by Jim Hannah) on Nanowerk about nano-brushes and water pollution reminded of an MIT (Massachusetts Institute of Technology) event at the last Venice Biennale, which featured a demonstration of nanotechnology-enabled oil-absorbing robots (my Aug. 26 2010 posting includes a video of the MIT project, Seaswarm).

Here’s an overview of the situation, from the news item,

The need to efficiently purify water is mushrooming into a massive global issue as human and industrial consumption of water grows.

The United Nations estimates that about 1.1 billion people currently lack access to safe water. Several forecasts suggest that freshwater may become the “oil” of the 21st century – expensive, scarce and the cause of geo-political conflicts.

In the United States, aging water-treatment infrastructure is struggling to keep up with growing threats to the clean-water supply, making water purification a major energy expense. Technologies like the “nano-brush” may provide some relief.

Dr. Sharmila Mukhopadhyay of Wright State University (Ohio, US) is working on the problem with her research team and they are developing (from the news item),

… near molecular-sized “nano-brushes.”

These fuzzy structures have bristles made up of thousands of tiny, jellyfish-like strands. The increased surface area of the bristles, with proper coatings, allows them to behave like powerful cleaners that kill bacteria and destroy contaminants that pollute water.

Here’s a brief description of how this would work,

Different materials can be broken down into nano-particles and then attached to the bristles of the brushes.

For example, particles of silver kill bacteria on contact without being dispersed as pollutants in the water. Particles of palladium break up carbon-tetrachloride and other water pollutants. And particles of titanium oxide can zap pollutants when activated by sunlight.

Mukhopadhyay plans to attach three or four different kinds of water-purifying particles to the nano-brushes. “So simultaneously you can combine multiple environmental cleanup applications into one single component,” she said.

They have been testing this solution in the lab and they appear to be confident that it will be deployed in the field in the next few years. I’m thrilled that the nanoparticles being used for the cleanup don’t become pollutants themselves (at least, not so far).