Science Wednesday: Nano Goes for the Green

Each week we write about the science behind environmental protection. Previous Science Wednesdays. While Kermit the Frog’s famously laments that it is not easy being green, it is becoming increasingly clear that we have no choice but to develop innovative and creative ways to minimize our impact on the environment. For the past 35 years or so, I’ve been involved in searching for ways that science—chemistry in particular—can help.

Chemistry has become so important to modern life that it’s virtually at the center of everything we make. That’s why the development of “green chemistry” is so important. The 12 principles of green chemistry have been laid out very clearly, focusing on reducing, recycling, or eliminating the use of toxic materials in chemical synthesis or manipulations.

The first wave of green chemistry research focused primarily on replacing the use of toxic, volatile organic solvents by using microwaves, ultrasound, and photochemistry. Now, I’m excited to be involved in the next generation of green chemistry research, exploring the use of nanomaterials (particles 100 nanometers or smaller—a nanometer is about 100,000 times smaller than the width of a human hair).

One big question we asked ourselves was “why not use a single compound that nature uses to build nanomaterials from a single, environmentally-benign source?” Turns out it was a good question. We discovered that we can use almost anything to reduce metal salts, including vitamins (B1, B2, and C), tea and wine polyphenols, and natural surfactants, to their nano forms. This newer thinking provides a simple, one-pot, greener synthetic alternative to bulk quantities of nanomaterials, as compared to conventional methods that use toxic reagents.

We also discovered that we could easily synthesize noble, uniform-size nanostructures using microwave (MW) heating (yes, the same used in the kitchen). Using this technology, we’ve developed extremely strong and light materials by cross-linking polymer matrices into carbon nanotubes.

What’s next? How about making biodegradable cellulose composite films with nanometals? We figured out how to do that heating the salts with carboxymethylcellulose (CMC), essentially the same compound found in the diet supplement Metamucil, facilitates the alignment of carbon nanotubes.

image of authorGreen chemistry means green jobs, too. We are already working with VeruTEK, a Connecticut-based company this is using patented nanotechnology for green environmental remediation (clean up) by using zerovalent iron, also known as ‘iron nanoparticles’. They have created lots of Green jobs while targeting pollutants in soil and water.

About the author: Dr. Rajender (Raj) S. Varma was recently awarded the Visionary of the Year Award at the Green Technologies fo rthe Environment Conference held in Bloomfield, Ct. Varma is a research chemist with EPA’s National Risk Management Research Laboratory.

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