Conjugated microporous poly(aniline)s for removal of low-concentration formaldehyde

Removal of indoor formaldehyde is important but challenging due to the very low concentration. Here, we showed the applicability of a new class of conjugated microporous poly(aniline)s (CMPAs) in this formaldehyde capture. The unique properties of rich ultramicroporosity and benzenoid amine (–NH–) groups made the resulting CMPAs ideal platforms for the efficient low-concentration formaldehyde adsorption, through the interaction between benzenoid amine groups and formaldehyde via Mannich reaction and H-bond in the ultramicropore. They therefore exhibited ultrafast adsorption, receiving > 80% removal efficiency for ca 0.7 ppm formaldehyde within 60 min, and benchmarking storage capacity, achieving ca. 2679.68 mg·g⁻¹ for CMPA-2. Our CMPAs also worked well in a self-assembled air clean unit, keeping kinetically reducing average 98% of formaldehyde after treatment of 4000 BV polluted air (with ca. 25 ppm formaldehyde) without break-through. Outcomes highlighted the potential of CMPAs for the clean-up of airborne formaldehyde for human health protection in next generation.