Precise controlling pore size distribution at sub-angstrom scale in granular novel carbon molecular sieves derived from coconut shell for separating ethylene and ethane
Granular carbon molecular sieves (CMSs) with sub-angstrom molecular recognition accuracy were synthesized from coconut shells via a chemical-free, eco-friendly method. The resulting CBCMS-800 exhibits a C2H4 uptake of 2.15 mmol/g at 298 K and 100 kPa while nearly excluding C2H6, achieving a C2H4/C2H6 uptake ratio of 15.36 and a molecular recognition resolution of 0.28 Å. Breakthrough curves confirm excellent separation performance. The evolution of pore size distribution (PSD) in amorphous CMS was elucidated through multiple characterization techniques, revealing that elevated temperature radiation induces both pore creation and shrinkage. A three-region model explains the sub-angstrom sieving mechanism. The precise PSD control at sub-angstrom scale, combined with low cost and structural stability, positions CBCMS-800 as a promising candidate for industrial C2H4/C2H6 separation, offering a sustainable alternative to cryogenic distillation and costly MOFs.