by Marcia Goodrich
Assume for the sake of argument that you wanted to mop up a really, really big oil spill. Say it’s in a massive body of water teeming with life that abuts hundreds of miles of white-sand beaches and sensitive wetlands. What would you look for in a detergent?
First of all, it should be a super-foamy surfactant, says Gerard Caneba. That foam should be stable, able to hold up its suds in the face of lots of gunk. It should also be really safe, so that fish, turtles, jellyfish, and toddlers wouldn’t sicken or die if they were to accidently swallow the stuff.
It would be nice if it were cheap too.
“We’re working on something like that,” says Caneba, a professor of chemical engineering at Michigan Tech. “We think it could be used in the Gulf. This is the most stable foam around. If you want an analogy, bubble gum is made of this.”
Caneba’s surfactant is a simple chemical, vinyl acetate-acrylate salt, transformed from a polymer dubbed VA/AA using a process he developed: free- radical retrograde-precipitation polymerization. The FRRPP-made foam is so stable that it can push crude oil off the surface of water onto a solid structure. Any remaining oil is broken into tiny droplets that could be gobbled up by microbes. “It’s not a true emulsifier,” Caneba explains. “It doesn’t keep on creating contaminated water with emulsified crude oil.”
So far, toxicity tests on the vinyl acetate-acrylate salt have shown no ill effects. It is inexpensive, about two dollars a pound. It’s easy to make, and it’s amazingly efficient. “You can push one volume of oil with one volume of a 1 percent solution of the surfactant,” he says. “You could move the oil somewhere and then suck it up.”
Caneba had originally developed VA/AA and the vinyl acetate-acrylate salt to recover petroleum from existing oil fields. Now, as the Gulf of Mexico slowly recovers from the worst oil spill in history, he hopes VA/AA and its chemical cousins may some day have another application: making the water safe again, for both people and pelicans.
Surfactant: a two-sided chemical, one water-loving and one oil-loving, that reduces the surface tension between oil and water. In the case of Caneba’s vinyl acetate-acrylate salt, the oil-loving half does not adhere well to the oil, so the foam can push the oil away from water.
Free-radical retrograde-precipitation polymerization (FRRPP): a novel, ef̀cient process for synthesizing many different types of polymers. Caneba has authored a scholarly book on the subject, Free-Radical Retrograde-Precipitation Polymerization (FRRPP):Novel Concept, Processes, Materials, and Energy Aspects, published in 2010 by Springer.
VA/AA: Vinyl acetate-acrylic acid-based block copolymer, a precursor to the vinyl acetate-acrylate copolymer salt surfactant originally developed by Caneba to recover petroleum from depleted oil fìelds.