摘要/Abstract
变压吸附（PSA）制取O2的核心是吸附剂.近年来，金属有机骨架（MOFs）被认为是一种具有广阔应用前景的新型吸附剂.通过水热法制备了MIL-101（Cr）/氧化石墨烯（GO）.结果表明，MIL-101（Cr）/GO-15具有更高的比表面积（3486 m2·g-1）和更大的孔体积（2.39 cm3·g-1），因此也表现出更高的O2吸附量（0.54 mmol·g-1）.进一步根据理想吸附溶液理论（IAST）预测了其在O2/N2体积比为1：4混合气体中的O2/N2选择性为1.2，相比MIL-101（Cr）提高了17.65%.同时，MIL-101（Cr）/GO-15的循环利用性能更佳，经过三次O2吸脱附循环后，依然拥有高达80%的O2吸附量，具有较好的循环再生性能.
关键词: O2/N2分离, 金属有机骨架, MIL-101(Cr)/GO, 循环再生性能
The pressure-swing adsorption (PSA) technology is the promising approach for O2/N2 separation because of its low cost and facile manipulation, in which adsorbents dominate the separation performance. In recent years, metal-organic frameworks (MOFs) have been recognized as the most potential adsorbents in gas adsorption and separation due to their ultrahigh surface area. In this work, MIL-101(Cr) with different weight percentages of graphene oxide (5%, 15% and 35%) was prepared by growing MIL-101(Cr) on pre-synthesized GO materials. The final product was activated under vacuum at 180℃ for 12 h. Structure characterization of different MIL-101(Cr)/GO composites revealed that MIL-101(Cr)/GO-15 with 15% GO additive exhibited the highest specific surface area (3486 m2·g-1) and pore volume (2.39 cm3·g-1) compared with pristine MIL-101(Cr) and the composites with 5% and 35% GO additives. The high surface area and pore volume are beneficial for the O2 uptake of MIL-101(Cr)/GO-15. Compared with the O2 uptake of MIL-101(Cr)/GO-5 (0.35 mmol·g-1) and MIL-101(Cr)/GO-35 (0.31 mmol·g-1), MIL-101(Cr)/GO-15 exhibited the highest uptake of 0.54 mmol·g-1. Further pore size distribution analysis demonstrated that the enhanced O2 uptake of MIL-101(Cr)/GO-15 can be ascribed to its increased fraction of mesopores. On the other hand, O2/N2 selectivity of different MIL-101(Cr)/GO composites was also calculated according to ideal adsorbed solution theory (IAST), from which it was found that MIL-101(Cr)/GO-15 displayed the highest O2/N2 selectivity (1.2) in a binary gas mixture with the volume fraction of O2/N2=1/4. Compared with pristine MIL-101, O2/N2 selectivity of MIL-101(Cr)/GO-15 was increased by 17.65%. Recyclability is one of the most important criteria to evaluate the gas adsorption performance of adsorbents. Therefore, the recyclability of MIL-101(Cr)/GO-15 was tested by measuring the O2 adsorption and desorption isotherms for three cycles. It was revealed that 80% of O2 uptake of MIL-101(Cr)/GO-15 was remained after three adsorp-tion/desorption cycles, implicating the outstanding recyclability of MIL-101(Cr)/GO-15.
Key words: O2/N2 separation, metal-organic framework, MIL-101(Cr)/GO, recyclability
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