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Tiny spheres to trap water contaminants developed

Press Trust of India  |  Washington 

Scientists have created tiny spheres that can catch and destroy (BPA), a used to make that often contaminates

is commonly used to coat the insides of cans, bottle tops and supply lines, and was once a component of baby bottles. While that seeps into and drink is considered safe in low doses, prolonged exposure is suspected of affecting the health of children and contributing to high blood pressure.

Scientists at in the US have developed something akin to the Venus' flytrap of particles for remediation.

The micron-sized spheres resemble tiny flower-like collections of dioxide petals.

The supple petals provide plenty of surface area for researchers to anchor -- a benign sugar-based molecule often used in and drugs.

It has a two-faced structure, with a hydrophobic (water-avoiding) cavity and a hydrophilic (water-attracting) outer surface.

is hydrophobic and naturally attracted to the cavity. Once trapped, reactive oxygen species (ROS) produced by the spheres degrades BPA into

In the lab, the researchers determined that 200 milligrams of the spheres per litre of contaminated water degraded 90 per cent of BPA in an hour, a process that would take more than twice as long with unenhanced dioxide.

"Most of the processes reported in the literature involve nanoparticles," said Danning Zhang, a graduate student at

"The size of the particles is less than 100 nanometers. Because of their very small size, they're very difficult to recover from suspension in water," said Zhang, of the study published in the journal

While a 100-nanometer particle is 1,000 times smaller than a human hair, the enhanced dioxide is between 3 and 5 microns, only about 20 times smaller than the same hair.

"That means we can use low-pressure microfiltration with a membrane to get these particles back for reuse. It saves a lot of energy," Zhang said.

Since ROS also wears down cyclodextrin, the spheres begin to lose their trapping ability after about 400 hours of continued ultraviolet exposure, Zhang said. However, once recovered, they can be easily recharged.

"This new material helps overcome two significant technological barriers for photocatalytic water treatment," said Pedro Alvarez, from

(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)

First Published: Sun, October 07 2018. 16:50 IST
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