Hybrid Chitin-Coffee Ground Biochar Foam for Microplastic Adsorption

Microplastics threaten ecosystems and human health. Based on the existing microplastic adsorption solutions, we hypothesized a sustainable filtration method based on a hybrid chitin-coffee ground biochar foam made of β/α-chitin foam from waste seafood and coffee ground biochar from used coffee grounds to adsorb microplastic particles in water would be efficient. The hybrid chitin-coffee ground biochar foam achieved consistently high adsorption efficiency in seawater and showed strong performance for fluorescent PS microspheres larger than 1 μm in deionized water, river water and seawater. This adsorption performance resulted from the combined effects of electrostatic attraction, hydrogen bonding, hydrophobic, and π–π interactions. This study demonstrates that waste-derived materials were able to offer a low-cost, environmentally friendly, and efficient solution for microplastic adsorption from water.