This Biodegradable Sponge Collects Loose Microplastics—But There's a CatchResearchers in China have developed a self-assembling and biodegrada...

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This Biodegradable Sponge Collects Loose Microplastics—But There's a CatchResearchers in China have developed a self-assembling and biodegrada...
This Biodegradable Sponge Collects Loose Microplastics—But There's a Catch
Researchers in China have developed a self-assembling and biodegradable sponge that snags microplastics floating in water. Based on early tests, it's possible that the sponge could help clean up our irrigation channels, lakes, and oceans—but there's a catch. The materials used to make the sponge could introduce a host of environmental and ethical problems of their own.

In a paper for Science Advances, environmental biotechnologists at Wuhan University write that their sponge "can remove 98.0 to 99.9% of microplastics in four types of real water and maintains a high removal efficiency of up to 95.1 to 98.1% after five adsorption cycles." Thanks to its ultra-fine framework—which makes the sponge look a bit like a melamine cleaning pad—the sponge physically intercepts tiny pieces of plastic as they float in irrigation, pond, lake, and ocean water. Because many microplastics come from products that contain chemical surfactants or anionic initiators (which are used to polymerize tires, packaging, medical equipment, and more), they tend to be negatively charged; the sponge's positively charged material allows it to catch onto opposing shreds of plastic waste.

An image of a scientist holding a baking sheet-sized white sponge, next to another image of cubes of white sponge.
Credit: Hongbing Deng/University of Wuhan

But the material that comprises the sponge itself could be an issue. Called Ct-Cel, the sponge consists of chitin and cellulose. While the researchers used cotton plants to obtain the sponge's cellulose—a carbohydrate found in all plants, making it the most abundant organic compound on Earth—they got the chitin, a natural biopolymer, from squid carcasses. This is referred to as "squid bone" in the researchers' paper; more specifically, the chitin comes from the squid's gladius, or the semi-transparent, rigid material that supports the squid's body.

Attached link

https://www.extremetech.com/science/this-biodegradable-sponge-collects-loose-microplastics-but-theres-a-catch?utm_source=flipboard&utm_content=topic/environment

Taxonomy