The growing prevalence of microplastics in water supplies worldwide has fostered development of numerous remedial treatment schemes. Many of these are cost-prohibitive, difficult to scale up or contribute additional pollution by use of plastic filters. proposed so far are costly or difficult to scale up. A new approach based on the use of renewable and biodegradable materials offers a more sustainable as well as efficient means of capturing these contaminants, which endanger human health.

A bio-based material termed bioCap was developed for this application by researchers from Sichuan University (China), Southwest Minzu University (China), University of British Columbia (Canada) and Chengdu University (China). The engineered material exploits the properties of sawdust and natural polyphenols, which generate strong molecular interactions with polymer particles, including many microplastics.

A sawdust substrate was fortified by the addition of tannic acid, an abundant forestry byproduct, and tested for microplastics removal in a fixed-bed column. The bioCap system was demonstrated to trap 95.2% to 99.9% of plastic particles — including polystyrene, poly(methyl methacrylate), polypropylene, polyvinyl chloride, polyethylene terephthalate and polyethylene — in a column of water.

Examination of the organs from two groups of mice fed either bioCap-treated or untreated water for one week revealed that those exposed to treated water bioaccumulated significantly fewer microparticles.

This bio-based microplastic-capturing approach is described in Advanced Materials.