Self-assembled ionic nanofibers derived from amino acids for high-performance particulate matter removal

Particulate matter (PM) is a primary contributor to air pollution, which is a serious threat to humans. It remains challenging to develop green high-performance air filters. Bio-based fibers as air-filtration materials are drawing much more attention. In this work, the first demonstration of applying absolutely ionic nanofibers derived from renewable phenylalanine methyl ester hydrochloride to produce high-performance air filters is successfully shown by employing a simple and convenient in situ ionic self-assembly approach. These bio-based filters exhibit exceptional comprehensive PM filtration performance, where the average PM removal efficiencies are above 99.5% and the pressure drops are 5 Pa resulting in record high quality factor (QF) values above 1 Pa-1. Quantum-chemistry calculations were performed to evaluate the surface properties of the ionic fibers. The devised amino acid-based PM filter may be used as a high-efficiency green filter.