Engineered Removal of Trace NH3 by Porous Organic Polymers Modified via Sequential Post‐Sulfonation and Post‐Alkylation

Abstract

AbstractAlthough NH3 is damaging to human health and the environment, a smart synthetic route toward adsorbents with controllable adsorption and desorption properties at ultralow concentrations remains unexplored. Herein, double postsynthetically modified porous organic polymers, obtained via post‐sulfonation and post‐alkylation, are reported. The sulfonated adsorbent, 1S, exhibits a record‐high NH3 capacity (4.03 mmol g−1) at ≈500 ppm. Notably, the polymer can capture NH3 even at a ppb concentration level. Hydrophobization of the sulfonated materials with alkyl chains affords cost‐effective and scalable adsorbents (1SCx and 1ESCx), which possess a high contact angle (≈120°) with water, thus resulting in rapid desorption kinetics and exceptional recyclability under dry and humid conditions at room temperature. This is the first demonstration of this design strategy for the control of the desorption of NH3 among porous adsorbents.