Bioinspired Adaptive Ångström-Channels in a Hydrogen-Bonded Metal-Organic Framework for Selective Water Removal From...

The removal of water from light hydrocarbons is a critical yet energy-intensive step in petrochemical processes. Conventional adsorbents often suffer from high regeneration temperatures and undesirable co-adsorption. Inspired by the selective water transport mechanism of aquaporins, we report a hydrogen-bonded metal-organic framework, ZNU-33, featuring bioinspired adaptive one-dimensional channels. The pore walls are decorated with both positively charged (Hbpa⁺) and negatively charged (HEDP^4-) recognition sites. Using in situ single-crystal x-ray diffraction, we captured five phases of ZNU-33, activated (ZNU-33-α), intermediate (ZNU-33-β), partially dehydrated (ZNU-33-γ and ZNU-33-γ2), and fully hydrated ZNU-33, directly visualizing a water‑triggered structural transition. Structural snapshots reveal water uptake proceeding from free-channel water to Cu²⁺ coordination and then to extended hydrogen-bonded water chains. ZNU-33 exhibits high water uptake (9.50 mmol/g at 2.85 kPa and 298 K) and negligible adsorption of CO₂ and all light hydrocarbons. Breakthrough experiments demonstrate efficient water removal under wide flow rates, temperatures, and humidity levels, with water-adsorption capacity recoverable under substantially milder activation conditions than those required by the investigated conventional zeolites. This work not only provides a high‑performance material for selective dehydration, but also establishes a bioinspired adaptive adsorption mechanism for designing water-selective adsorbents.