-CF3-MOF enhanced pervaporation selectivity of PDMS membranes for butanol separation

Direct separating butanol from fermentation broth via pervaporation is considered as the most effective method to realize solvent enrichment, which is dominated by membranes. Herein, MOF (MAF-9) with -CF3 group is doped into PDMS matrix to enhance the butanol pervaporation, especially selectivity. The super-hydrophobicity of MAF-9 caused by -CF3 groups allows the preferential adsorption and permeation for butanol molecules, thus increasing the membrane selectivity; while its appropriate pore diameter renders the exquisite diffusion pathways towards the butanol molecules, thus increasing the membrane flux. Results show that the loading-optimized MAF-9/PDMS MMM has 53 of separation factor and 848 g m(-2) h(-1) of membrane flux, which are increased by 24% and 16%, respectively, compared with pure PDMS membrane. TGA, FT-IR, BET, and XRD are conducted to characterize the thermal stability, morphology and structure of MAF-9; PALS, SEM, AFM, SD and TGA are tested to evaluate the free volume property, morphology, adsorption capacity and thermal stability of membranes, respectively. Conditions including particle loading, feed temperature and feed concentration are also optimized in this study.