Natural plant extracts remove up to 90% of microplastics from water, — research

American researchers have found that natural polymers derived from okra and fenugreek are extremely effective in purifying water from microplastics.

Natural plant extracts of okra and fenugreek effectively trap microplastic particles and can remove up to 90% of it from sea, freshwater and groundwater. In early experiments, a research team led by Rajani Srinivasana studied the properties of okra, fenugreek, and tamarind extracts. It turned out that these natural polymers trap microplastic particles, causing them to stick together and settle to the bottom. 

To produce the polymers, the researchers soaked chopped okra pods and mixed fenugreek seeds in containers of water overnight. The dissolved extracts were removed and dried into powders. These powdered extracts contained polysaccharides, which are naturally occurring polymers.

Initial tests demonstrated that one gram of either powder per liter of water was most effective at capturing microplastics.

• Dried Okra Extract — removes 67% of microplastics from water within an hour;
• Dried fenugreek extract — 93% microplastic from water within an hour;
• Mixture of equal amounts of okra and fenugreek — 70% microplastic with water in 30 min;

These polymers demonstrated significantly greater efficiency than the synthetic polyacrylamide polymer used for wastewater treatment. The researchers also tested the effectiveness of plant extracts of okra and fenugreek on real microplastic-contaminated water.

To do this, they collected samples from water bodies throughout the state of Texas and tested them in the laboratory. The effectiveness of removing plastic from water depended on the source from which the samples were taken. In particular, okra extract removed up to 80% of microplastics from seawater, fenugreek removed —80-90% of microplastics from groundwater, and a mixture of the two removed up to 77% of microplastics from freshwater. According to the researchers, the different efficiencies of the okra and fenugreek polymers are due to the fact that each water sample contained different types of microplastics, different shapes and sizes.

The results of the study are published in the journal ACS Omega

Source: SciTechDaily