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

Abstract

Although 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.

Advanced Materials for NH3 Capture: Interaction Sites and Transport Pathways

“…A record-high NH 3 capacity (4.03 mmol g −1 ) at 500 ppm was achieved, and it adsorbed 0.48 mmol g −1 even at a concentration of 800 ppb. Simultaneously, the hydrophobic nature of alkyl chains offers rapid desorption kinetics and exceptional recyclability under dry and humid conditions at room temperature [ 103 ].

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A Mini-Review on NH3 Separation Technologies: Recent Advances and Future Directions

“…Lee et al synthesized a microporous amic acid polymer with both Brønsted acidic and hydrogen-bond sites for efficient adsorption of NH 3 . Since then, a lot of other POPs with Brønsted acidic or hydrogen-bond sites were developed for the adsorption of NH 3 . − …”

“…Therefore, the interaction of metal ions with NH 3 does not affect the major frameworks of POPs, and the POPs do not have the problems of framework collapse after NH 3 adsorption Table summarizes the functional types and NH 3 adsorption capacities of representative POPs reported in the literature. − …”

Ionic liquid-functionalized metal organic frameworks and their composite membranes for enhanced proton transport

“…In this context, as a promising alternative solid electrolyte for PEMFCs, porous materials garnered attention due to their intrinsic advantages, such as well-ordered structure, large surface area, and pore functionalization. 17–21 These materials hold diverse potential applications in areas such as mixed gas separation, 22–24 toxic gas removal, 25–30 sensing, 31,32 light-mediated catalysis, 33–37 and therapy. 38–41 In particular, metal–organic frameworks (MOFs) with well-organized internal conduction pathways and a large pore volume containing numerous water molecules to facilitate the formation of hydrogen bond networks have been extensively investigated.…”