A goo made from kitchen ingredients like okra and fenugreek is as effective at removing microplastics from water as an industry standard.
Microplastics are fragments of plastic smaller than 5 millimetres across that pollute water sources across the world. Their possible health effects are a cause of concern, although we still know little about their impact in the body. They can be removed from water supplies by using a fossil fuel-based gel, polyacrylamide, but this can be toxic to humans under certain conditions.
Now, at the University of Texas and her colleagues have created sustainable, plant-based alternatives, which are as effective in laboratory studies and non-toxic to humans.
Advertisement
Srinivasan and her colleagues crushed up plant-based ingredients commonly used as recipe thickeners, such as okra, fenugreek, prickly pear cactus, aloe vera and tamarind, and extracted long carbohydrates known as polysaccharides.
They then dried the extracts to form a powder. When added to water, it acts as a flocculant, making the microplastics clump together in a goo that sinks to the bottom.
Srinivasan and her team used various combinations of the extracts on seawater and freshwater samples and found that certain mixtures, such as okra and fenugreek, trapped as many microplastics as the polyacrylamide gel or more.
鈥淚 wanted something that could be used around the world and that was easily available,鈥� says Srinivasan. She聽and her team presented the research at the American Chemical Society Spring 2022 conference in San Diego, California on 22 March.
One advantage of using the plant-based extracts is that they can be used in pre-existing microplastic filtering infrastructure. But further work will be needed to see how the production process might be scaled up, says Srinivasan.
鈥淚t is nice that they introduced a kind of extra sustainability element into the research by using a plant-based flocculant,鈥� says at the University of Surrey, UK. But he adds that the researchers need to prove their materials work with a wide range of real-world microplastics of different sizes.
