环糊精增强马来酸酐接枝聚丙烯膜的制备及H2/CH4分离性能

Preparation of cyclodextrin enhanced maleic anhydride grafted polypropylene membranes and H2/CH4 separation performance

摘要:

焦炉气的主要成分为氢气（H2）和甲烷（CH4）,实现两种气体的分离具有重要的工业价值。以马来酸酐接枝聚丙烯（MAPP）作为H2分离复合膜的基体材料，以倍他环糊精（β-CD）、乙二胺改性倍他环糊精（mβ-CD）为填料，乙基环己烷（EC）和N,N-二甲基乙酰胺（DMAC）为溶剂，采用溶液共混法，分别制备系列β-CD/MAPP膜、mβ-CD/MAPP膜。采用FTIR、XRD、TGA、SEM对制备的膜材料进行表征，基于膜材料的H2/CH4分离性能测试，考察β-CD和mβ-CD添加量（以MAPP为基准的质量百分数）对β-CD/MAPP膜、mβ-CD/MAPP膜的H2渗透率、H2/CH4分离选择性的影响。由于CD分子具有中空腔体结构疏松了膜微结构，提高了CD/MAPP膜的H2渗透率；CD与MAPP间良好的键合作用，进一步改善了CD/MAPP膜的H2/CH4分离选择性。结果表明，β-CD和mβ-CD加入可以提高MAPP膜的H2/CH4分离性能；随着β-CD添加量（25%、50%、75%）的增加，β-CD/MAPP膜的H2渗透率逐渐从448 mol/(m2·s)增加至519 mol/(m2·s)，H2/CH4分离选择性先增加后减小，β-CD添加量50%制备的β-CD/MAPP膜具有最高的H2/CH4分离选择性（66.6），为MAPP膜的H2/CH4分离选择性（11.7）的5.7倍；随着mβ-CD添加量（25%、50%、75%）的增加，mβ-CD/MAPP膜的H2渗透率逐渐从410 mol/(m2·s)增加至489 mol/(m2·s)，H2/CH4分离选择性先增加后减小，mβ-CD添加量50%制备的β-CD/MAPP膜具有最高的H2/CH4分离选择性（73.7），为MAPP膜的H2/CH4分离选择性（11.7）的6.3倍；相同填料添加量（25%、50%、75%）情况下，β-CD/MAPP膜较mβ-CD/MAPP膜的H2渗透率高，但H2/CH4分离选择性低。

Abstract:

The main components of coke oven gas are hydrogen (H2) and methane (CH4), and separating the two gases has important industrial value. Maleic anhydride grafted polypropylene (MAPP) was used as the matrix of the H2 separation composite membrane. Beta-cyclodextrin (β-CD) and ethylenediamine-modified beta-cyclodextrin (mβ-CD) were used as fillers. Methylcyclohexane (EC) and N,N-dimethylacetamide (DMAC) were used as solvents. A series of β-CD/MAPP membranes and mβ-CD/MAPP membranes were prepared by the solution blending method. The prepared membranes were characterized by FTIR, XRD, TGA, and SEM. Based on the H2/CH4 separation performance test of the membranes, the effects of the addition amounts of β-CD and mβ-CD (mass percentage based on MAPP) on the H2 permeability and H2/CH4 separation selectivity of β-CD/MAPP membranes and mβ-CD/MAPP membranes were investigated. CD molecules have a hollow cavity structure, which loosens the membrane microstructure and improves the H2 permeability of the CD/MAPP membranes. The good bonding between CD fillers and the MAPP matrix further improves the H2/CH4 separation selectivity of the CD/MAPP membranes. The results show that the addition of β-CD and mβ-CD can improve the H2/CH4 separation performance of the MAPP membrane. With the increase of β-CD addition (25%, 50%, 75%), the H2 permeability of β-CD/MAPP membranes gradually increased from 448 mol/(m2·s) to 519 mol/(m2·s), and the H2/CH4 separation selectivity first increased and then decreased. The 50%β-CD/MAPP membrane had the highest H2/CH4 separation selectivity (66.6), which was 5.7 times that of the MAPP membrane (11.7). With the increase of mβ-CD addition (25%, 50%, 75%), the H2 permeability of mβ-CD/MAPP membranes gradually increased from 410 mol/(m2·s) to 489 mol/(m2·s), the H2/CH4 separation selectivity first increased and then decreased. The 50%β-CD/MAPP membrane had the highest H2/CH4 separation selectivity (73.7), which was 6.3 times that of the MAPP membrane (11.7). Under the same filler addition amounts (25%, 50%, 75%), the H2 permeability of the β-CD/MAPP membranes was higher than that of the mβ-CD/MAPP membranes, but the H2/CH4 separation selectivity was lower.