Wednesday, February 21, 2007

Purifying water

Professors work with porous rocks called zeolites

Argen Duncan El Defensor Chieftain Reporter

The work of a New Mexico Tech hydrologist has attracted colleagues from around the world to Socorro.

Professor Robert Bowman, who researches the use of porous rocks called zeolites in water purification, is working with a Fulbright Scholar from Poland for five months and last week hosted a hydrologist from Japan for a few days.

Keiko Sasaki, associate professor at Japan's Kyushu University, and Jolanta Warchol, assistant professor from Poland's Rzeszów University of Technology, both cited Bowman's expertise as the reason for collaboration.

Sasaki wants to use natural zeolite coated with organic material as a chemical filter to remove fluoride and boron from ground water in her country. Boron kills forests and leads to human disease, while fluoride weakens teeth and bones.

Bowman said he was discussing a common interest with Sasaki and giving her advice.

"She's educating me about her research and also water quality problems in Japan," he said.

Sasaki said she came to New Mexico because of Bowman's patent for the zeolite coated with organic material. She wants to try using the highly reactive rock to absorb fluoride and boron, although those substances are more difficult to handle than some contaminants.

"Some modification might be necessary," Sasaki said.

Bowman's modified zeolite now filters out nitrate, chromium, arsenate and similar substances.

"Basically, she's looking at a new application we haven't looked at before," he said.

Sasaki hopes to continue working with Bowman when she returns from her three-night stay in Socorro.

Bowman said he and Warchol would work together on a project of common interest with hopes of publishing the results. The Fulbright organization provides Warchol's salary and Bowman provides facilities.

In Socorro, Warchol plans to investigate the use of modified zeolites in absorbing inorganic, negatively charged ions from streams and to study how the rock selectively removes the particles.

She said the idea of water purification is removing harmful contaminants.

"On the other hand, it's necessary to leave all elements which are necessary for our health," Warchol continued.

Zeolites, found around the world, remove contaminants at much lower cost than the ion exchanges typically used.

Warchol said ion exchanges cost $10 to $15 to clean about a quart of water.

Bowman said natural zeolite costs about 5 cents a pound, and modified zeolite is 25 cents a pound. A pound can treat possibly 500 gallons of water, depending on the contaminants.

Warchol plans to study the mechanisms of the process with math models, either what she developed for her doctorate or more sophisticated ones created later.

Bowman called Warchol's particular modeling a new thrust. His group has done pieces of Warchol's research, but he hopes that, working together, they will be able to understand the process and predict it better.

"Modeling is important for two reasons," Warchol said.

It explains why zeolites do certain things, and if researchers find the proper model, it can be used on a technical level.

"So it means, in other word, we can optimize the process by using just laptops," Warchol said.

Upon her return to Poland, she expects to apply for a grant to work with the zeolites near her university to remove heavy metals from water.

Warchol said she came to Socorro because Bowman is in the top of his field. In her project statement, she also said she needs training from people with experience in hydrology, analytical chemistry, chemical engineering, geology and physics.

"And all these people exist just here," Warchol said in an interview.

aduncan@dchieftain.com

E-mail this story Printer-friendly version