Efficient capture of PM2.5 by intertwined tubular conjugated microporous polymer-based filters with high stability in a humid environment

Abstract

Airborne particulate matter (PM) has received increasing attention as it causes serious environmental pollution and huge health risk for humans. Herein, we demonstrate the synthesis of tubular conjugated microporous polymers (CMPs) via a one-step cross-coupling reaction for the removal of PM from the air. Tubular CMPs possess a large specific surface area (>484 m² g⁻¹), high physicochemical stability and mechanical flexibility and robustness. Benefiting from their abundant porosity, CMP-based filters show desirable ability for the capture of PM with a high efficiency of greater than 99% for both PM_2.5 and PM₁₀. In combination with their interestingly intrinsic hydrophobicity, a high filtration efficiency for PM_2.5 greater than 99.97% can be obtained even under high-humidity conditions (relatively 96 ± 2%), which can be maintained unchanged during a 12 h continuous test, making them highly advantageous over those hydrophilic filters that usually lose their filtration efficiency in a humid environment. Based on their simple fabrication, inherently hydrophobic wettability and high filtration efficiency, the as-synthesized CMP-based filters would hold great potential as promising filters for PM elimination in a humid environment under harsh conditions by taking the advantage of the intrinsically robust physicochemical properties of CMPs. More interestingly, due to the designable flexibility of CMPs, which makes it possible for fine-tuning their pore size or chemical composition, the tailored-design of advanced CMP-based filters for a specific purpose could be anticipated only by rationally varying the size or structure of their building blocks.