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New Mexico State University

New Mexico State University

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Students investigate methods to remove arsenic and fluoride from water

Skills learned while studying to become a chemical engineer are something Arley Torres can take back home and share with her community in Palomas, Mexico.



Left to right: Laura Nunez, Ryan McCool, Shuguang Deng, Mahesh Arcot Dhanushkodi and Arely Torres demonstrate an experiment in a chemical engineering lab at NMSU. (NMSU photo by Darren Phillips)

Torres is working alongside two other junior chemical engineering students at New Mexico State University, Ryan McCool and Laura Nunez, and a Las Cruces High School student, Mi Deng, to clean up drinking water in the border region.

"I have a personal interest in our water treatment project because I am from Mexico and the project involves USA-Mexico border water treatment," Torres said.

The students hope to find a cost-efficient method of reducing the high levels of arsenic and fluoride in Columbus, N.M., and Palomas, Mexico, drinking water.

Laura Nunez, Ryan McCool, Shuguang Deng, Mahesh Arcot Dhanushkodi and Arely Torres

"We will work as a team to solve this problem," said McCool.

The NMSU team is one of 42 funded by the U.S. Environmental Protection Agency to participate in the People, Prosperity and the Planet National Student Design Competition. Their project, Drinking Water Purification for USA-Mexico Border Region, was awarded $10,000. The students will prepare over the next eight months for the national design competition.

Competitors must develop progressive solutions to environmental issues while considering the economic impact. This year's teams will work on developing alternative energy sources, providing clean water to rural communities, new methods of recycling, novel options for green buildings, designing sustainable buildings, and more. The competition will take place at the National Mall in Washington, D.C., on April 25 and 26, 2007.

Small communities along the border are suffering from a lack of practical water purification methods. Columbus, N.M., residents are allowed five gallons of water per day because the community cannot afford a big water purification facility, said Shuguang Deng, chemical engineering associate professor and head of the student research team.

"I think if you have a big household that's not enough water. A lot of families just drink the contaminated water they have and they don't really know that there's a problem with that," he said.

High quantities of arsenic and fluoride in water are harmful when consumed and used for cleaning. Arsenic can cause cancer and fluoride can cause bone density problems, Deng said.

The engineering students are working with mesoporous alumina, a material they hope will absorb arsenic from well water. The different sizes of pores found in the various mesoporous alumina materials make it a great candidate for sucking up harmful water pollutants.

"If the pore size is too small or too large it may not be useful. So we are trying to make them at a more optimal range for the removal of those pollutants," Deng said.

The student research group hopes to manufacture a sol-gel derived mesoporous alumina-based absorbent that will have the right size pores.

The common method of water filtration in the border region is called reverse osmosis. Reverse osmosis uses pressure created by water to push more water through a membrane that extracts pollutants. Mesoporous alumina differs from reverse osmosis because it does not need to be powered and it does not use two gallons of water to purify just one gallon.

The team is now researching a clever way to remove fluoride. Deng said the students maybe able to remove fluoride by modifying the sol-gel alumina's surface area.

"The problem is we have a good adsorbent for arsenic but not for fluoride. The mesoporous method is not yet very effective for removing fluoride," Deng said. "We may end up with a mixed bed packed with two adsorbents: sol-gel alumina for arsenic and another adsorbent for fluoride."

To have a chance of winning the EPA National Student Design Competition, the NMSU chemical engineering students must find a method for removing fluoride from water. Top winners will be given an additional $75,000 to make their projects marketable.

"This project is important to the people in those small villages who definitely need quality drinking water and it also maybe to many other big utility companies," Deng said. "We are developing something which could be potentially more cost-effective."

As for Aley Torres, she's just glad to have the opportunity to work on the project. "If we do a good job and it gets implemented, I will feel like I did something positive for the community as well as for my family."