Lee J.-YZhan J.-YAng M.B.M.YYeh S.-CTsai H.-AJeng R.-J.RU-JONG JENG2021-08-052021-08-05202113835866https://www.scopus.com/inward/record.uri?eid=2-s2.0-85101300033&doi=10.1016%2fj.seppur.2021.118470&partnerID=40&md5=713d3656e4bdd14ff286d2ab5888cc1chttps://scholars.lib.ntu.edu.tw/handle/123456789/577197In this study, spirobisindane-functionalized graphene oxide (SFGO)/polyimide (Matrimid? 5218, i.e. M) solutions are spin-coated onto a polysulfone support to produce SFGO@M nanocomposite membranes for alcohol dehydration by pervaporation. Compounds 3,3,3′,3′-tetramethyl-1,1′-spirobisindane-6,6′-diol (TSD) and 4,4′-((3,3,3′,3′-tetramethyl-2,2′,3,3′-tetrahydro-1,1′-spirobi[indene]-6,6′-diyl)bis(oxy))dianiline (TTSD) are synthesized based on a conversion reaction from bisphenol A (BPA). Both TSD and TTSD contain spirobisindane structure, which is inspired by the structural unit from polymers of intrinsic microporosity. The fine structural characteristics of SFGO@M membranes are evaluated using positron annihilation lifetime spectroscopy. The membrane free volume increases in the following order: M < GO@M < BPA-GO@M < TSD-GO@M < TTSD-GO@M. These results reveal that SFGO affected the fine structural characteristics of membranes in a more significant manner when compared with GO@M and BPA-GO@M. Moreover, TSD-GO@M and TTSD-GO@M exhibit different levels of dehydration performance when tested on different alcohol feed solutions. After TTSD modification on GO, the membrane performance increased from 619.3 ± 124.0 g?m-2h?1 for the pristine sample, to 915.5 ± 44.8 g?m-2h?1 for TTSD-GO@M, and the water concentration in the permeate is maintained as high as 99 wt%. Furthermore, the modified membranes are stable under broad operating conditions with high potential for long-term use. ? 2021 Elsevier B.V.Dehydration; Evaporation; Graphene; Nanocomposites; Pervaporation; Positron annihilation spectroscopy; Dehydration performance; Functionalized graphene; Membrane performance; Nano-composite membranes; Polymers of intrinsic microporosities; Polysulfone supports; Positron annihilation lifetime spectroscopy; Structural characteristics; Membranes[SDGs]SDG6[SDGs]SDG13journal article10.1016/j.seppur.2021.1184702-s2.0-85101300033