Swelling Glass Cleans Toxins In Water

A new glass material engineered by Dr. Paul Edmiston at the College of Wooster has the ability to clean polluted water by absorbing contaminants like a sponge. “Swelling Glass” – glass that swells up like a sponge – could be the key to cleaning up contaminated groundwater. Dubbed “Obsorb”, the material absorbs volatile molecules in water like fuel oil and solvents without sucking up the water itself.

Apart from having unusually useful properties, Obsorb is cheap to implement. It's a reactive glass, allowing it to bind with gasoline and other pollutants containing volatile organic compounds, but it's also hydrophobic, so it doesn't bind with water. So it acts like a “smart” sponge, capable of picking and choosing from contaminated groundwater. Put together like a nano-matrix, the new glass can unfold to hold up to eight times its weight. Once the Obsorb material is full, it floats to the surface and pollutants can be skimmed off. Afterwards, it can be dropped back into the water and reused hundreds of times.

The substance could revolutionize groundwater pollution clean-up because it's relatively low cost and has the ability to rid a site of VOCs that other conventional cleaning methods can't.

Absorbent Materials is well on its way to make Obsorb commercially available. The glass material is currently being tested in pilots across the US, and venture development group Jumpstart LLC recently invested $250,000 in the product. With 4,000 priority contamination sites in the US alone, Obsorb stands to make a big impact on the quality of our water. Obsorb’s unique properties make it ideal for low tech, low-budget cleanups in developing areas as well.

Groundwater Pollution

However, swelling glass is also hydrophobic, meaning that it does not bond with water. At a recent pilot demonstration in Ohio, Obsorb was used in the form of a white powder to suck up a plume of TCE (a volatile organic compound). TCE is particularly difficult and expensive to clean up using conventional means, which is the reason why some contaminated sites are simply shut down, allowing the vapors to dissipate naturally. The process takes decades, so Obsorb is a reactive glass. Unlike conventional glass, it can bond with the chemicals it encounters. However, it is also hydrophobic, meaning that it does not bond with water. Obsorb could provide a low-cost means of recovering sites more quickly.

Low Cost Clean-up

Once full, Obsorb floats to the surface, where it can be skimmed off with something as simple as a coffee filter. After that the pollutants can be retrieved and the glass can be reused hundreds of time. Nano-particles of iron can also be added to convert TCE or PCE (another volatile organic compound) into harmless substances. As a low cost form of cleanup, swelling glass could provide site remediators with yet another in the growing list of non-conventional cleanup tools along with lactate, vitamin B-12, and even cattails.