Electron microscope image of an SU-102 crystal. The dark areas are 1nm-wide pores. Image: Tom Willhammar.
Electron microscope image of an SU-102 crystal. The dark areas are 1nm-wide pores. Image: Tom Willhammar.

Researchers from Stockholm University in Sweden have developed porous crystals made from pomegranate extract that can capture and degrade pharmaceutical molecules found in local municipal wastewater. The researchers report this work in a paper in Nature Water.

Pharmaceutical compounds act on the human body to improve our health, but they can also have unintentional adverse effects on wildlife if they escape into the environment, as happens when they’re flushed away in wastewater. Hence wastewater-treatment plants are facing the challenge of removing emerging organic contaminants (EOCs) such as active pharmaceutical ingredients, which will require new materials and technologies.

One strategy for removing pollutants from water is by using porous materials that behave like sponges. Metal-organic frameworks (MOFs) are a type of nanoporous material made of metal ions and organic molecules. Most MOFs are synthesized using synthetic organic molecules. But now researchers from the Department of Materials and Environmental Chemistry at Stockholm University have managed to synthesize new porous MOFs using a naturally occurring molecule found in plants – ellagic acid.

“Ellagic acid is one of the main building units of naturally occurring polyphenols known as tannins, which are common in fruits, berries, nuts and tree bark,” says Erik Svensson Grape, a PhD student in the Department of Materials and Environmental Chemistry and first author of the paper. “By combining ellagic acid, which was extracted from either pomegranate peel or tree bark, with zirconium ions, we developed a new highly porous MOF which we named SU-102.”

To test the performance of SU-102, the researchers applied the new MOF to water that had already been purified at a local wastewater-treatment facility. The results showed that SU-102 could extract many of the pharmaceutical pollutants that were not fully removed by the wastewater-treatment process. In addition to capturing the pharmaceutical pollutants, SU-102 could also break them down using light, in a process known as photodegradation.

“This has been a very exciting project as we got the opportunity to work directly with water samples from the treatment plant, thereby finding an application where our material could be put to use towards a very pressing environmental issue,” says Grape. “We hope one day that SU-102 will be used on a bigger scale and also for other environmental applications.”

This story is adapted from material from Stockholm University, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.