A common mineral similar to rust, fashioned into a powder of tiny crystals, could provide a simple, inexpensive method for removing hazardous levels of arsenic from drinking water.
November 10, 2006 (Press Release) --
A common mineral similar to rust, fashioned into a powder of tiny crystals, could provide a simple, inexpensive method for removing hazardous levels of arsenic from drinking water, researchers at Rice University in Houston are reporting today.
That would help reduce the risk of cancer for tens of millions of impoverished villagers in China and southeast Asia, where high levels of arsenic occur naturally in many water supplies, the researchers said in telephone interviews.
Arsenic contamination is also a threat to water supplies in parts of Latin America, Africa and the United States, where the Environmental Protection Agency this year lowered the allowable arsenic levels in municipal water systems to 10 parts per billion, down from 50 parts per billion.
The research, being reported in the journal Science, is the latest of numerous investigations into the environmental uses of nanotechnology — the manipulation of materials so tiny that they are measured in nanometers, or billionths of a meter. At such small scales, common materials often begin to exhibit novel properties.
In this case, the researchers made crystals of a rustlike mineral called magnetite. They found that when the crystals were smaller than 40 nanometers wide, they were much more sensitive to low-strength magnetic fields than would have been expected based on the behavior of larger particles.
At 12 nanometers wide, the researchers found, the magnetite particles could bind up to 100 times as much arsenic as the larger iron particles currently used in filters, yet still be extracted from test liquids with inexpensive magnets that are widely used as computer components.
While the particles’ performance has been tested only in laboratories, the researchers said it seemed likely that removing arsenic could be as simple as pouring a small amount of magnetite powder into a pot of well water and waiting briefly while bound arsenic was pulled to the bottom by a simple magnet.
Communities with centralized water systems might use filters rather than magnets to collect the particles, because such technology is already in place to collect contaminants from those systems, according to Vicki L. Colvin, a chemistry and chemical engineering professor who is director of Rice’s Center for Biological and Environmental Nanotechnology.
The researchers said further research was needed to determine whether the magnetite would be an improvement on other nanoscale minerals already used in such systems, including zirconium, aluminum, iron and manganese compounds.
Even if Mr. Tomson’s cost estimates are correct, researchers still have to demonstrate that the technology can be used safely. For example, no one knows the risks of the arsenic residue being consumed by accident or leaching from landfills back into water supplies.
Author: BARNABY J. FEDER
Source: http://www.nytimes.com/
That would help reduce the risk of cancer for tens of millions of impoverished villagers in China and southeast Asia, where high levels of arsenic occur naturally in many water supplies, the researchers said in telephone interviews.
Arsenic contamination is also a threat to water supplies in parts of Latin America, Africa and the United States, where the Environmental Protection Agency this year lowered the allowable arsenic levels in municipal water systems to 10 parts per billion, down from 50 parts per billion.
The research, being reported in the journal Science, is the latest of numerous investigations into the environmental uses of nanotechnology — the manipulation of materials so tiny that they are measured in nanometers, or billionths of a meter. At such small scales, common materials often begin to exhibit novel properties.
In this case, the researchers made crystals of a rustlike mineral called magnetite. They found that when the crystals were smaller than 40 nanometers wide, they were much more sensitive to low-strength magnetic fields than would have been expected based on the behavior of larger particles.
At 12 nanometers wide, the researchers found, the magnetite particles could bind up to 100 times as much arsenic as the larger iron particles currently used in filters, yet still be extracted from test liquids with inexpensive magnets that are widely used as computer components.
While the particles’ performance has been tested only in laboratories, the researchers said it seemed likely that removing arsenic could be as simple as pouring a small amount of magnetite powder into a pot of well water and waiting briefly while bound arsenic was pulled to the bottom by a simple magnet.
Communities with centralized water systems might use filters rather than magnets to collect the particles, because such technology is already in place to collect contaminants from those systems, according to Vicki L. Colvin, a chemistry and chemical engineering professor who is director of Rice’s Center for Biological and Environmental Nanotechnology.
The researchers said further research was needed to determine whether the magnetite would be an improvement on other nanoscale minerals already used in such systems, including zirconium, aluminum, iron and manganese compounds.
Even if Mr. Tomson’s cost estimates are correct, researchers still have to demonstrate that the technology can be used safely. For example, no one knows the risks of the arsenic residue being consumed by accident or leaching from landfills back into water supplies.
Author: BARNABY J. FEDER
Source: http://www.nytimes.com/
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