High-Throughput Removal of Micro(Nano)Plastics With 99.8% Rejection From Water Using Cationic Cellulose Filter-Paper...

Efficient and rapid methods for removing micro(nano)plastics are lacking. Herein, we fabricated a cellulose filter-paper composed of cationic and uniform microfibers through precise regulation of the fiber morphology and surface chemical structure. The cationic filter-paper composed of microfibers with a diameter of 2 µm and a zeta potential ≥54 mV can retain 99.8% of micro(nano)plastics (size of 0.1-100 µm) in water, with fluxes reaching 25866 L·m^-2·h^-1 for microplastics and 3158 L·m^-2·h^-1 for nanoplastics, which are 17.5 times that of conventional filter paper (with retention rates of 61.0% and 12.2% for microplastics and nanoplastics, respectively) and 21.2 times that of microporous membrane (0.22 µm) (with a retention rate of 51.9% for nanoplastics). Synergistic effect of electrostatic interaction, hydrogen-bonding interaction, and physical blocking enable this cationic filter-paper to efficiently retain micro(nano)plastics. The filter is eco-friendly cellulose, which avoids secondary pollution. Due to the solvent resistance and high stability of cellulose, the filter-paper is recycled by dissolving and removing the retained micro(nano)plastics with organic solvents. The retention performance of the filter paper remains effective after 10 cycles of use. The precise regulation of the morphology and chemical structure of natural polymer provides a sustainable and rapid solution for the efficient removal of micro(nano)plastics.