Pebax/a-MoS_(2)/MIP-202混合基质膜的制备及CO_(2)分离性能

Preparation of Pebax/a-MoS_(2)/MIP-202 mixed matrix membranes for CO_(2) separation

为了获得高性能的CO_(2)/N_(2)分离膜,把空气中氧刻蚀的二硫化钼(a-MoS_(2))和金属有机框架材料MIP-202通过机械力化学反应制备的双功能填料作为分散相,聚醚嵌段酰胺(Pebax-1657)作为连续相,采用溶液浇铸法制备了Pebax/a-MoS_(2)/MIP-202混合基质膜。采用FT-IR表征了填料的化学结构,借助ATR-FTIR、SEM、TG和力学性能测试表征了混合基质膜的化学结构、微观形貌结构、热稳定性和物理力学性能。研究了水含量、双功能填料配比、含量、膜两侧压差和操作温度对膜气体分离性能的影响,并考察了模拟烟道气(CO_(2)/N_(2)体积比15/85)条件下混合基质膜的长时间运行稳定性。结果表明:在温度为25℃、膜两侧压差为0.1 MPa的操作条件下,a-MoS_(2)与MIP-202质量比为5∶5和双功能填料含量为6%(质量)时,膜的气体分离性能达到最优,CO_(2)渗透性和CO_(2)/N_(2)选择性分别为380 Barrer和124.7,超过了2019年McKeown等提出的上限值。连续测试360 h后,混合基质膜的性能没有明显降低,其平均CO_(2)渗透性和CO_(2)/N_(2)选择性分别为358 Barrer和120.1。这主要是由于a-MoS_(2)和MIP-202协同提高了膜的气体分离性能。

To obtain high-performance CO_(2)/N_(2) separation membranes,a dual-functional filler prepared by mechanochemistry reaction of oxygen-etched molybdenum disulfide(a-MoS_(2))and metal-organic framework material MIP-202 was used as the dispersed phase,and polyether block amide(Pebax-1657)was served as a continuous phase,and Pebax/a-MoS_(2)/MIP-202 mixed matrix membranes(MMMs)were prepared by solution casting.The chemical structure of filler was characterized by FT-IR.The chemical structure,microscopic structure,thermal stability and physical mechanical properties of MMMs were characterized by ATR-FTIR,SEM,TG and mechanical property testing.The effects of water content,dual-functional filler ratio,dual-functional filler content,feed pressure and operating temperature on the gas separation performance of the membranes were studied,and the long-time stability of MMMs under simulated flue gas(CO_(2)/N_(2) volume ratio 15/85)conditions was investigated.The results showed that the best CO_(2) permeability of MMMs was 380 Barrer with a CO_(2)/N_(2) selectivity of 124.7 at 25℃and 0.1 MPa,surpassing the upper bound proposed by McKeown et al in 2019,when the mass ratio of a-MoS_(2) to MIP-202 was 5∶5 and the dual-functional filler content was 6%(mass).The separation performance of MMMs was not significantly degraded over 360 h testing,with an average CO_(2) permeability of 358 Barrer and CO_(2)/N_(2) selectivity of 120.1.This is mainly due to the synergistic improvement of the gas separation performance of the membrane by a MoS_(2) and MIP-202.