Laminated Adsorbents with Very Rapid CO2 Uptake by Freeze-Casting of Zeolites

作者：Ojuva Arto^*; Akhtar Farid; Tomsia Antoni P; Bergstrom Lennart

来源：ACS Applied Materials & Interfaces, 2013, 5(7): 2669-2676.

DOI：10.1021/am400122r

• freeze-casting
• zeolite 13X
• shaping
• structured
• laminate
• adsorbent
• hierarchical
• carbon dioxide
• CCS
• gas separation
• uptake kinetics

Structured zeolite 13X monoliths with a laminated structure and hierarchical macro-/microporosity were prepared by freeze-casting aqueous suspensions of zeolite 13X powder, bentonite, and polyethylene glycol. Colloidally stable suspensions with a low viscosity at both room temperature and near freezing could be prepared at alkaline conditions where both the zeolite 13X powder and bentonite carry a negative surface charge. Slow directional freezing of the suspensions led to the formation of well-defined and thin lamellar pores and pore walls while fast freezing resulted in more cylindrical pores. The wall thickness, which varied between 8 and 35 mu m, increased with increasing solids loading of the suspension. Thermal treatment at 1053 K of the freeze-cast bodies containing between 9 and 17 wt % bentonite resulted in mechanically stable zeolite 13X monoliths. The monoliths displayed a carbon dioxide uptake capacity of 4-5 mmol/g and an uptake kinetics characterized by a very fast initial uptake where more than 50% of the maximum uptake was reached within 15 s. Freeze-cast laminated zeolite monoliths could be used to improve the volumetric efficiency and reduce the cycle time, of importance in, for example, biogas upgrading and CO2 separation from flue gas.

• 出版日期2013-4-10