Abid Hussein Rasool, Rada Zana Hassan, Li Yuan, Mohammed Hussein A, Wang Yuan, Wang Shaobin, Arandiyan Hamidreza, Tan Xiaoyao, Liu Shaomin
WA School of Mines: Minerals, Energy and Chemical Engineering, Curtin University WA 6102 Australia
Environmental Department, Applied Medical Science, University of Karbala Karbala 56001 Iraq.
RSC Adv. 2020 Feb 25;10(14):8130-8139. doi: 10.1039/d0ra00305k. eCollection 2020 Feb 24.
Aluminum trimesate-based MOF (MIL-96-(Al)) has attracted intense attention due to its high chemical stability and strong CO adsorption capacity. In this study, CO capture and selectivity of MIL-96-Al was further improved by the coordination of the second metal Ca. To this end, a series of MIL-96(Al)-Ca were hydrothermally synthesised by a one-pot method, varying the molar ratio of Ca/Al. It is shown that the variation of Ca/Al ratio results in significant changes in crystal shape and size. The shape varies from the hexagonal rods capped in the ends by a hexagonal pyramid in MIL-96(Al) without Ca to the thin hexagonal disks in MIL-96(Al)-Ca4 (the highest Ca content). Adsorption studies reveal that the CO adsorption on MIL-96(Al)-Ca1 and MIL-96(Al)-Ca2 at pressures up to 950 kPa is vastly improved due to the enhanced pore volumes compared to MIL-96(Al). The CO uptake on these materials measured in the above sequence is 10.22, 9.38 and 8.09 mmol g, respectively. However, the CO uptake reduces to 5.26 mmol g on MIL-96(Al)-Ca4. Compared with MIL-96(Al)-Ca1, the N adsorption in MIL-96(Al)-Ca4 is significantly reduced by 90% at similar operational conditions. At 100 and 28.8 kPa, the selectivity of MIL-96(Al)-Ca4 to CO/N reaches up to 67 and 841.42, respectively, which is equivalent to 5 and 26 times the selectivity of MIL-96(Al). The present findings highlight that MIL-96(Al) with second metal Ca coordination is a potential candidate as an alternative CO adsorbent for practical applications.
基于均苯三甲酸铝的金属有机框架材料（MIL-96-(Al)）因其高化学稳定性和强CO吸附能力而备受关注。在本研究中，通过第二种金属Ca的配位作用进一步提高了MIL-96-Al对CO的捕获能力和选择性。为此，采用一锅法水热合成了一系列MIL-96(Al)-Ca，改变Ca/Al的摩尔比。结果表明，Ca/Al比的变化导致晶体形状和尺寸发生显著变化。形状从不含Ca的MIL-96(Al)中两端由六棱锥封顶的六棱柱形，变为MIL-96(Al)-Ca4（Ca含量最高）中的薄六棱盘形。吸附研究表明，与MIL-96(Al)相比，由于孔体积增加，在高达950 kPa的压力下，MIL-96(Al)-Ca1和MIL-96(Al)-Ca2对CO的吸附能力大幅提高。按上述顺序测量，这些材料对CO的吸附量分别为10.22、9.38和8.09 mmol/g。然而，MIL-96(Al)-Ca4上的CO吸附量降至5.26 mmol/g。与MIL-96(Al)-Ca1相比，在相似操作条件下，MIL-96(Al)-Ca4对N的吸附量显著降低了90%。在100 kPa和28.8 kPa下，MIL-96(Al)-Ca4对CO/N的选择性分别高达67和841.42，分别相当于MIL-96(Al)选择性的5倍和26倍。目前的研究结果表明，与第二种金属Ca配位的MIL-96(Al)是实际应用中潜在的替代CO吸附剂候选材料。
