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[Display omitted] • Surface tuned PDMS-PVDF membranes prepared trifunctional and tetrafunctional crosslinker. • Hydrophobic enrichments due to long alkyl or fluoroalkyl group at the membrane surfaces confirmed. • Among different series, highest pervaporation performance delivered by fluoroalkyl tuned PDMS-PVDF membrane. • Stabilized flux of 0.30 LMH and IPA content in permeate >99.95% were achieved in PV test using the PDMS PFTES membrane. An energy-efficient pervaporation (PV) facile approach was designed to remove isopropanol during α, ω-diol production. Accordingly, a series of polydimethyl siloxane (PDMS) membranes were prepared by tuning their surface chemistry through trifunctional (PFTES and OTMS) and traditional tetrafunctional (TEOS) crosslinkers and casting on a polyvinylidene fluoride (PVDF) membrane. Additional hydrophobic tail enrichment on the membrane surface because of alkyl (OTMS) and fluoroalkyl (PFTES) groups from the tri-functional crosslinker was confirmed by FTIR, XPS, and DSC. TGA and XRD revealed that the tetra crosslinking site promoted a denser structure across the membrane than the trifunctional crosslinker. In the water contact angle measurements of the different series of membranes, the contact angle was proportional to the hydrophobic site. When a series of PDMS membranes were tested for PV of the novel feed PDO/IPA (90/10 w/w) system, the highest flux was delivered from the fluoroalkyl type crosslinked membrane, which was attributed to its superior hydrophobicity and amorphous nature, with excellent IPA selectivity from all the membranes. As a result, a stabilized flux of 235.8 g/m2h and excellent separation factor (IPA content in permeated >99.95%) in a 40 h continuous PV test was achieved using the PDMS PFTES membrane. [ABSTRACT FROM AUTHOR]

[Display omitted] • Hydrophilic surface modification of HNT performed bydopamine. • TGA, FE-SEM, TEM and XPS analysis conducted to confirmed the PDA modified HNT surfaces. • 5wt.% PDA/HNT incorporated PVA/PVAm membrane showed optimized pervaporation output. • PDA modified HNTs show effective filler for separation of alcohols in pervaporation. In reference, the mussel-encouraged surface adhesion chemistry, dopamine oxidative auto-polymerization on the surface of halloysite nanotubes (HNTs) was performed to confer hydrophilicity to the HNTs. The additional hydrophilic moieties with surface coating by polydopamine (PDA) was assured with transmission electron microscopy (TEM), thermogravimetric analysis (TGA), and X-ray photoelectron spectroscopy (XPS) techniques. A PDA/HNT-incorporated polyvinyl alcohol/polyvinyl amine (PVA-PVAm) membrane was fabricated for the pervaporation-dehydration of isopropanol/water (IPA/water), and the filler dispersion, crystallinity, and hydrophilicity of the membrane were confirmed by field-emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), and contact angle measurements, respectively. The pervaporation test was performed with membranes having different PDA/HNT contents, where the flux increased from 0.19 to 0.39 kg/m2h, and the separation factor decreased from 479 to 63 with the 80/20 (w/w, IPA/water) feed mixture at 40 °C. Compared to the unmodified HNT-incorporated membrane, the membrane with 5 wt.% PDA/HNT exhibited superior performance. Upon increasing the feed (85/15 IPA/water w/w) temperature from 40 to 70 °C, the flux of water and IPA increased from 0.062 to 0.13 kg/m2h and 0.000063 to 0.00144 kg/m2h, respectively. The apparent energy of activation calculated using the Arrhenius equation was positive for both IPA and water. The higher energy required for permeation of IPA (99.65 kJ/mol) compared to water (22.69 kJ/mol) is attributed to facile permeation of water compared to IPA through the hydrophilic channel created by PDA-HNT. In long-term operation (120 h), the IPA and water flux of the 5 wt.% PDA/HNT-incorporated PVA-PVAm membrane was maintained using a feed composition of 80/20 (w/w %) IPA/water at 40 °C, indicating remarkable reusability of the membrane. [ABSTRACT FROM AUTHOR]

Conventional distillation failed to separate a ternary azeotropic mixture of ECH, IPA and water (50/30/20 w/w, %) exist in the epoxy resin manufacturing process. Thus, we prepared a PVA-tetraethyl orthosilicate organic–inorganic hybrid membrane and modified the membrane by layer-by-layer deposition of a PVAm/silicotungstic acid polyelectrolyte for the pervaporation (PV) dehydration of ECH/IPA/water mixtures. In PV experiments at 30 °C, the flux decreased from 0.14 to 0.05 kg m−2 h−1 and separation factor increased from and 2099 to 13,320 with TEOS addition in the PVA membrane was observed. And for the layer by layer deposition on PVA-TEOS (4) membranes flux increased and separation factor decreased from 0.14 to 0.28 kg m−2 h−1 and 2099 to 416 with the number of layer of deposition were observed respectively. On varying the feed water content from 20 to 10 wt. %, the pervaporation flux at 30 °C decreased from 0.22 to 0.0066 kg m−2 h−1 and the separation factor increased from 1061 to 9094 was observed. By applying the Arrhenius equation, permeation activation energies of ECH and IPA (97.42 and 111.96 kJ mol-1, respectively) are higher than that of water (40.88 kJ mol−1) were reported for the layer by layer membrane. [ABSTRACT FROM AUTHOR]