Chemists remove microplastics using okra

Extracts of okra and other slimy plants commonly used in cooking can help remove dangerous microplastics from wastewater, scientists said Tuesday.

The new research was presented at the meeting of the American Chemical Society, and offers an alternative to the synthetic chemicals currently used in treatment plants that can themselves pose risks to health.

"In order to go ahead and remove microplastic or any other type of materials, we should be using natural materials which are non-toxic," lead investigator Rajani Srinivasan, of Tarleton State University, said in an explainer video.

Okra is used as a thickening agent in many cuisines a stew from Louisiana. It's also a staple of cuisine in South Asia, where it's called bhindi.

Srinivasan's past research had examined how the goo from okra and other plants could remove textile-based pollutants from water and even microorganisms, and she wanted to see if that would equally apply to microplastics.

Ingested microplastics -- defined as pieces five millimeters or smaller -- have been shown to harm fish in several ways, from disrupting their reproductive systems to stunting growth and causing liver damage.

Srinivasan and colleagues set about investigating how extracts of supermarket-bought okra, aloe, cactus, and fenugreek, tamarind and psyllium would perform.

They tested chains of carbohydrates, known as polysaccharides, from the individual plants, as well as in combination, on various microplastic-contaminated water, examining before and after microscopic images to determine how many particles had been removed.

They found that polysaccharides from okra paired with those from fenugreek could best remove microplastics from ocean water, while polysaccharides from okra paired with tamarind worked best in freshwater samples.