K-Chabazite Zeolite Nanocrystal Aggregates for Highly Efficient Methane Separation.

Methane (CH 4 ) enrichment and purification is of great significance for increasing the heating value of unconventional natural gas sources and curtailing its effect on global warming. For a long time, commercial adsorbents for CH 4 separation have been hampered by low adsorption capacities, sub-optimal adsorption selectivities, or slow diffusion rates, which have significantly restricted separation productivity. Herein, we report a facile and green seed-passaging method to fabricate donut-like macro-meso-micro hierarchical zeolite K-Chabazite nanocrystal aggregates. This consecutive seed-inducing method requires no organic template. By utilizing this unique nanocrystallization technique, the CH 4 adsorption capacity, gas diffusion rate, and separation productivity of the resultant material are dramatically increased compared with those of commercially available adsorbents, thus setting a new benchmark in CH 4 /N 2 separation. More importantly, production of this adsorbent can be easily scaled-up to the order of 100 kg using readily available raw materials in this environmentally friendly synthetic route, enabling potential industrial implementation.