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1998 Discover Technology Awards: Environment

Jul 1, 1998 5:00 AMNov 12, 2019 4:21 AM


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The world would be a greener place if we derived all the chemicals our industries need from plants. These so-called agrochemicals are generally biodegradable and far less toxic than chemicals derived from oil (petrochemicals), and they are renewable, which means we'd never run out. Unfortunately, agrochemicals cost too much to produce.

Rathin Datta, a chemical engineer at Argonne National Laboratory, has taken a small step toward bringing costs down, at least for one type of agrochemical. Lactate esters, solvents made from cornstarch or sugar, could be widely used in semiconductor chip manufacturing, in stripping paint and de-inking paper for recycling, and in household cleaners and degreasers if only researchers could find a way to make them cheaper than their present price of $1.60 to $2 a pound. The problem has been that conventional processes for making the lactate esters are very inefficient, largely because they lack a good means of separating out the by-products and keeping them from interfering with the reactions.

Then Datta heard about "pervaporation" membranes, which can be used to separate chemicals with small molecules from those with big molecules. After experimenting for two years, he found that with these membranes he could effectively derive his agrochemicals from a broth of fermented cornstarch rich in ammonium lactate. Using heat and catalysts, he first breaks down the mixture into ammonia and lactic acid. Ethanol already present in his brew then reacts with the lactic acid to form the lactate ester. All this time, the membrane lets the water and ammonia by-products escape but keeps the other, active ingredients together in the chamber.

Argonne has licensed the technology to ntec, a technology investment firm in Mt. Prospect, Illinois, which, along with several industrial partners, is developing it. "We hope to have a small-scale plant on-line late in 1999," says Datta. If all goes well, he believes they may then sell lactate esters for $1 a pound or less. At that price, solvents based on lactate esters could replace 80 percent of the 3.8 million tons of solvents now used in the United States each year.


Flywheel BackupActive Power's CleanSourceInnovator: Joe Pinkerton

Flywheels as batteries are not new. Set a disk spinning rapidly on smooth, almost frictionless bearings, and it's not too hard to siphon off its energy as you need it. As simple as they are, however, flywheels so far have been too expensive to replace traditional lead-acid batteries. Joe Pinkerton has made one, called CleanSource, that he says is cheap enough for offices, hospitals, and small institutions that need a backup power source for emergencies. Most companies working on flywheel batteries are targeting satellites, automobiles, and other applications where weight is at a premium, but Pinkerton, the chief executive officer of Active Power in Austin, Texas, took a different tack. "A flywheel is ideally suited for generating high power for short run times," he says, so in late 1995 he set out to build a flywheel device for electrical "glitch protection." Businesses such as chip manufacturers typically use banks of lead-acid batteries to smooth out small fluctuations in electrical service and, in the case of blackout, to provide power for the 15 seconds or so it takes a generator to kick in. For this market, Pinkerton notes, weight isn't a consideration but cost is, and lead-acid batteries are cheap. Pinkerton eschewed the superlightweight, superstrong, and superexpensive composite materials that his competitors use in favor of low-tech steel and old-fashioned clever engineering. Since steel is a magnetic material, Pinkerton made it serve as both motor and generator--it's the unit's only moving part. The vacuum housing does double duty in protecting the flywheel and conducting a magnetic field. By minimizing the number of parts and using nonexotic materials, such as copper and steel, Pinkerton produced a lean, mean flywheel machine. It's significantly easier on the environment, he says, and since it should last 20 years as opposed to 5 for a lead-acid battery, it should be cheaper to operate in the long run as well. The product was unveiled last September. "We are already shipping a couple of systems a week," Pinkerton reports.

Tabula RasaImagex Technologies' Office Paper DecopierInnovator: Sushil Bhatia

When Sushil Bhatia began working with a local recycling committee five years ago, he learned that the toner used by laser printers and copiers is exceptionally difficult to remove. For this reason, each year millions of tons of discarded office paper winds up in landfills. "There must be a better way to handle all this paper waste," he thought.

Bhatia, president of Imagex Technologies in Framingham, Massachusetts, did some research. The difficulty with copiers and laser printers, he found, is that "the toner is embedded deeply in the paper because of the heat and pressure used in the process." Newsprint ink, by contrast, lies mostly on the surface, which is why it rubs off on your hands but makes newspapers easier to recycle. So Bhatia and a team of researchers found a chemical that sunders the bond between the toner and the paper. In demonstrations, Bhatia placed a piece of paper on a heated surface, brushed a milky liquid containing the secret chemical over the paper, and in a few seconds brushed the printing away. Imagex is now building a prototype "decopier" that, while it would look much like a photocopy machine, would work in reverse: a printed page will be fed in, and a few seconds later, out will pop a crisp, blank sheet.

By September 1997, Bhatia had figured out how to decopy paper from 15 different copiers in addition to overhead slides. He envisions his Office Paper Decopier being put to work mainly in large companies. By decopying and reusing white paper instead of throwing it away, a big office could in theory cut paper costs by 70 percent or more. Also, Bhatia says, a personal decopier could be very attractive to the security-conscious who worry that their shredded documents might be pieced back together. Decopy them first and they'll be gone for good.

Bug LightOak Ridge National Laboratory's Critters on a ChipInnovator: Michael Simpson

Two years ago Michael Simpson was building integrated circuits--that is, chips--with built-in light sensors. Then Gary Sayler, a colleague of his at Oak Ridge National Laboratory, mentioned that he had genetically engineered bacteria to light up when exposed to certain kinds of pollution. "It hit me immediately," Simpson recalls. "We needed to put these two things together and make an instrument out of them."

By January 1997, Simpson had whipped up his first crude coupling of life and nonlife by placing a drop of water containing some of Sayler's bacteria on a slide on top of a silicon chip. When exposed to naphthalene, a component of jet fuel, the bacteria glowed blue-green and the chip sent out a signal reporting the chemical's presence. Simpson dubbed the invention "critters on a chip." Now Simpson is trying to keep the critters alive for a month or more. He hopes to freeze-dry them so that they can be stored and revived as needed--you'd just add water. And he is building a collection of bacteria engineered to detect a range of chemicals.

Simpson believes the chips will help find oil, discover new drugs, and control industrial pollution. He envisions researchers ultimately being able to scatter hundreds of the chips around a clean-up site, where they will detect the levels of various pollutants and report them via built-in transmitters.

Sucking Up MercuryPacific Northwest National Laboratory's Mesoporous Silica for Mercury RemovalInnovator: Xiangdong Feng

For years researchers have been tantalizingly close to an effective way to take mercury out of polluted water. One promising method involves the use of long molecules that can grab the mercury as it flows by. The problem is, even when you manage to anchor a multitude of these molecules to some common material, such as silicon, so that they stand shoulder to shoulder like the pile of a lush carpet, they still won't grab enough mercury to make the method efficient. It works, but it's slow and expensive.

In late 1996 the solution came to Xiangdong Feng of Pacific Northwest National Laboratory in Richland, Washington, as he was pondering the properties of mesoporous silica--a spongelike rock made of the same substance as sand, riddled with microscopic holes, or pores, that form tiny tunnels. In particular, he was thinking of how much surface area exists in even a very small volume of the material--a five-gram pebble contains a veritable football field within. "I thought, 'Why don't we combine these things?'"

For the next few months, Feng and his colleagues experimented with techniques for coating the pores of mesoporous silica with carpets of carefully designed molecules. By filtering water through grains of this material, Feng says, he has been able to remove mercury from water in tests. Eventually, he says, it should be possible to reduce the presence of mercury to a few parts per trillion, compared with a few parts per billion for current techniques, and do it more quickly as well. In addition, Feng says his invention can remove just about any pollutant or heavy metal from contaminated water: "People say I should quit my day job and start mining for gold."

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