Efficient Separation of Acetylene and Carbon Dioxide in a Decorated Zeolite

Abstract

The almost identical molecular sizes and volatilities of acetylene and carbon dioxide make their separation extremely challenging in industry. Reported here is the efficient separation of acetylene and carbon dioxide (v/v=2/1, which is relevant to that in the industrial cracking stream) in faujasite zeolites decorated with atomically‐dispersed copper(II) sites under ambient conditions. In situ neutron powder diffraction and inelastic neutron scattering confirm that the confined copper(II) site displays chemoselective yet reversible binding to acetylene, whereas adsorbed carbon dioxide molecules are stabilized by weak host–guest supramolecular interactions with the framework oxygen centers, thus resulting in the efficient separation of these two gases under flow conditions. A designed adsorption‐purging‐desorption system based upon Cu@FAU is established for the recovery of high purity acetylene (98–99 %) from the mixture of acetylene and carbon dioxide, offering an unprecedented separation factor of 22.2 with an effective dynamic uptake of acetylene of 1.51 mmol g−1 at 298 K.

Confinement in a Zeolite and Zeolite Catalysis

“…Subsequently, a more generalized hydrothermal route to zeolites with confined cations has been explored by employing functionalized silanes to complex the cations and meanwhile act as the templates to stabilize the surrounding zeolite framework. With the rational screening of functionalized silanes, several bivalent cations confined in FAU zeolites, i.e., Ni@FAU, Cu@FAU, and Zn@FAU, have been prepared, and the cation sites are uniform enough for Rietveld refinement. , The key point for the successful confining of isolated cations in zeolite lies in the synchronism between the decomposition of the cation complex and the anchoring of coordinated unsaturated sites by framework oxygen. That is, there should be two available framework oxygen atoms from [AlO 4 ] units to stabilize the bare bivalent cations from complex decomposition.…”

Optimal Pore Chemistry in an Ultramicroporous Metal–Organic Framework for Benchmark Inverse CO2/C2H2 Separation

“…In the context of C 2 H 2 and CO 2 separation, the acidic H atoms with positive charge in C 2 H 2 are capable of interacting strongly with these active sites, resulting in high C 2 H 2 /CO 2 selectivity [6] . However, since CO 2 is the main contaminant in C 2 H 2 (3 % and even up to 50 %), [2e] CO 2 ‐selective sorbents are preferred for C 2 H 2 purification because they will permit the direct isolation of C 2 H 2 as a pure raffinate product. This will also efficiently leverage extensive industrial expertise in light‐product‐focused adsorptive cycles [1c, 2c] .…”

Amino‐Functionalised Hybrid Ultramicroporous Materials that Enable Single‐Step Ethylene Purification from a Ternary Mixture

“…Physisorbents offer potential to greatly reduce the energy footprint of separation processes [3, 8] . Nevertheless, despite advances in gas purification from binary mixtures using physisorbents under ambient pressure and temperature, [9] including C 2 H 4 , [10] C 2 H 4 purification from ternary C2‐CO 2 mixtures remains an unmet challenge [11] . This is largely a consequence of the similar physicochemical properties (molecular sizes and boiling points, Scheme S1) of the three components [11a, 12] and the absence of physisorbents that selectively exclude C 2 H 4 .…”