Water Purification System, Materials Library Selected For Discover's Awards

June 7, 1996

By Lynn Yarris, [email protected]


Berkeley Lab scientists have won two of this year's seven 1996 Discover Awards for Technological Innovation. The winners are Ashok Gadgil of the Energy and Environment Division, in the environment category for "UV Waterworks," an ultraviolet-based water purification system; and Xiao-Dong Xiang and Peter Schultz of the Materials Sciences Division, in the computer hardware and electronics category, for "combinatorial synthesis," a high-speed technique for making and testing new materials.

This is the seventh year that Discover magazine has presented its awards, which are intended to "celebrate the outstanding innovations of our time, and specifically, the scientists, engineers, and inventors who too often are the unsung heroes of our technological age." The two 1996 Discover Awards bring the total to four in which Berkeley Lab scientists have played a significant role. The first was in 1993 for the design of the segmented ten-meter mirror of the Keck Telescope which won in the category of sight. The second was for the sulfur lamp which won last year's environment award.

"These honors are a tribute to the innovation and creativity of our scientists and to the breadth and excellence of the work that goes on here," said Berkeley Lab Director Charles Shank. "They are further examples of how national laboratories like Berkeley Lab turn fundamental science into practical solutions."

Secretary of Energy Hazel O'Leary came to the Lab on Tuesday to publicly congratulate the winning scientists and have a personal demonstration of Gadgil's technology.

UV Waterworks is a small, simple device that uses ultraviolet light to quickly, safely, and cheaply disinfect water of the viruses and bacteria that cause cholera, typhoid, dysentery and other deadly diseases.

Unlike other ultraviolet-based water purifiers, UV Waterworks does not require pressurized water-delivery systems and electrical outlets. It is designed to rely on gravity for water flow, which means it can be used with any source of water. It only needs electricity for the UV light, which means it can be powered by a car battery or a 40-watt solar cell.

In developing nations, safe, home-delivered tap water is rare. Each year, waterborne diseases, transmitted mainly through drinking unsanitary water, kill an estimated four million children under the age of five, and make adults sick enough to lose billions of hours of work productivity.

The two most common methods of disinfecting water in developing nations--chlorination and boiling--both have limitations. Chlorine disinfection requires a continual supply of chlorine bleach and trained personnel to make sure chlorine is added to water supplies at effective levels. Boiling is usually done over wood stoves in unvented rooms, which poses health risks of its own and contributes to air pollution and deforestation.

With UV Waterworks, passing water through ultraviolet light inactivates the DNA of pathogens and purifies the water at a cost of about eight cents for every 1,000 gallons. The device can disinfect water at the rate of four gallons per minute, similar to the flow from a typical American bathtub spout.

A pilot project is under way in India and a second project has been proposed for areas in South Africa. Negotiations for licensing the technology to EEG Inc. of Chicago are in their final stages for worldwide use, except in India, where Urminus Industries Ltd. of Bombay already holds the rights.

The combinatorial synthesis technique of Xiang and Schultz promises to dramatically speed the pace of discovery in materials science. It allows researchers to increase the number of chemical compounds that can be created and tested as potential new materials from the current rate of about one a day to as many as 10,000 a day.

Combinatorial synthesis represents a radical departure from so-called "rational" materials design, where researchers try to predict beforehand which specific molecular structures will yield desired properties. With combinatorial synthesis, the strategy is one of sheer numbers--thousands of potential structures are created and screened to find those with the properties being sought.

Schultz, who is also a professor of chemistry at Berkeley, took the idea for combinatorial synthesis from the human immune system. The immune system maintains a library of roughly one trillion differently shaped antibodies each made up of different combinations of protein chains. When faced with an invading agent, such as a virus, the immune system selects the antibodies from this combinatorial library that happen to bind to the virus and creates multiple copies to fight the infection. Schultz used the technique to invent "catalytic" antibodies--antibodies that, because of their shape, promote certain chemical reactions--for which he received the 1995 Wolf Prize in Chemistry.

Though biotechnology researchers have used a combinatorial approach to screen for potentially useful drugs, this is the first time the strategy has been applied to materials.

To create a "combinatorial" library of advanced materials, Xiang and Schultz deposit thousands of distinct combinations of metal-oxide molecules onto a one-inch square grid. The materials are deposited in a checkerboard pattern as thin-film squares and different metal ingredients are stenciled onto the grid through cut-out "masks." Because a different mask is used for each ingredient, each square in the grid receives a unique combination.

Given the millions of potential compounds that exist just from the combination of the five elements that can form metal-oxides, there is an enormous advanced materials "universe" waiting to be discovered. Working at Berkeley Lab's Molecular Design Institute, Xiang and Schultz have already used their combinatorial synthesis technique to discover 26 new magnetoresistive materials.

Symyx Technology, a California start-up corporation, has licensed the combinatorial synthesis technology from the Berkeley Lab for commercial development.