Fate of nanoparticles depends on properties of water carrying them

May 4th, 2008 - 12:31 pm ICT by admin  

Washington, May 4 (ANI): A new study has found that the fate of nanoparticles spilled into groundwater, depends on the properties of water carrying them.

Researchers at the Georgia Institute of Technology in the US carried out the study.

They found out that the environmental fate of carbon-based nanoparticles and the ability of municipal filtration systems to remove them from drinking water, depends on subtle differences in the solution properties of the water carrying the particles.

In slightly salty water, for example, clusters of Carbon 60 (C60) would tend to adhere tightly to soil or filtration system particles. But where natural organic compounds or chemical surfactants serve as stabilizers in water, the C60 fullerene particles would tend to flow as easily as the water carrying them.

According to Kurt Pennell, a professor in the School of Civil and Environmental Engineering at the Georgia Institute of Technology, “In some cases, the nanoparticles move very little and you would get complete retention in the soil.”

“But in different solution conditions or in the presence of a stabilizing agent, they can travel just like water. The movement of these nanoparticles is very sensitive to the solution conditions,” he added.

Researchers want to know more about the environmental fate of nanoparticles to avoid creating problems like those of polychlorinated biphenyls (PCBs), in which the harmful effects of the compounds were discovered only after their use became widespread.

“We want to figure out now what will happen to them and how toxic they will be in the environment,” said Pennell.

To study the flow and retention of the nanoparticles in simulated soil and filtration systems, Pennell’s research team filled glass columns with either glass microbeads or sand, and saturated the columns with water.

They then sent a “pulse” of water containing C60 nanoparticles through the columns, followed by additional water containing no nanoparticles.

They measured the quantity of nanoparticles emerging from the columns and analyzed the sand and glass beads to observe the quantity of C60 retained there. They also extracted the contents of the columns to measure the distribution of retained nanoparticles.

“In sand, we saw a uniform distribution of the nanoparticles throughout the column, which suggests that under the circumstances we examined, there is a limited retention capability due to filtration,” explained Pennell. “Once that capacity is reached, the particles will pass through until they are retained by other grains of soil or sand,” he added.

According to Pennell, the study findings suggest that the predictions of “filter theory” will have to be modified to explain the transport of nanoparticles in soil. (ANI)

Related Stories

Tags: , , , , , , , , , , , , , , , , , , ,

Posted in National |