A Scalable and Cost-Effective Zeolite-Polymer Fiber Sorbent Enabled by Vapor-Induced Cu(I) Activation for Selective Acetylene Capture

Identifying appropriate materials that can simultaneously ensure low production costs, scalability, and retention of intrinsic adsorption capabilities throughout the structuring process remains a significant challenge, thereby limiting the industrial implementation of adsorptive gas separation techniques. We report the first example of the structured fiber sorbents incorporating Cu^I-exchanged Y zeolites (Cu^I@Y), which can form Cu^I-alkyne π-complexes for the selective adsorption of acetylene from C₂H₂/CO₂ mixtures. Cu^I@Y/PVDF fiber sorbents exhibited remarkable adsorption performance, including high C₂H₂ uptake at low partial pressure (0.775 mmol·g^-1 at 10 mbar C₂H₂) and high IAST selectivity (11.7), even after the structuring process. The separation performance was also confirmed by the dynamic breakthrough experiments at 25 °C, demonstrating a separation factor of approximately 3.12 for a ternary C₂H₂/CO₂/He (10/5/85, v/v/v) mixture along with excellent cyclic stability over multiple separation cycles. Notably, Cu^I@Y/PVDF fiber sorbents can be readily fabricated and scaled up using commercially available raw materials, with an estimated production cost of $26 per kilogram. In situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) analyses further supported the presence of Cu^I-alkyne interactions, revealing distinct binding affinities for C₂H₂ and CO₂.