Sunlight, Nanoparticles Break Down Pollutants

A class of pollutants that negatively affect hormones can be broken down using nanoparticles and sunlight.

Researchers from the Center for Advanced Materials at the Indian Association for the Cultivation of Science developed the method, which neutralizes bisphenol A (BPA) and other endocrine disruptors. Endocrine disruptors can mimic or block hormones, interfering with humans’ and animals’ reproductive organs and causing other health problems.

The researchers used a reduced graphene oxide composite with silver nanoparticles (rGO-Ag), which can act as an efficient photocatalyst to degrade these pollutants. They developed a “large-scale synthesis method for rGO-Ag,” with which they were able to degrade BPA, phenol and atrazine under UV and visible light.

This chart demonstrates photocatalytic degradation of phenol using an rGO–Ag composite, rGO alone and Ag alone. The control line indicates photolysis without any catalyst.

Earlier approaches to pollutant degradation have worked exclusively with UV light, which makes up just 6 percent of sunlight, whereas visible light makes up 52 percent of the solar spectrum.

The researchers said the silver nanoparticles “offer visible-light-induced excitation of silver plasmons, and conductive rGO offers efficient charge separation and thus induces oxidative degradation of the organic pollutant.”

This new technique could be used to break down other harmful organic compounds, according to the researchers.

The work was funded by India's Department of Science & Technology. The research was published in Applied Materials & Interfaces (doi: 10.1021/am505677x).

For more information, visit www.iacs.res.in.