Poly(vinyl alcohol)-crosslinked thin-film composite pervaporation membrane with robust butanol dehydration performance

• Pervaporation membranes fabricated using PVA and TMC were applied for n-butanol dehydration. • Optimization of interfacial polymerization parameters was carried out. • The tuned membrane showed a remarkable performance for n-butanol/water separation. Herein, a poly(vinyl alcohol) (PVA)-based polyester thin-film composite (TFC) membrane was constructed for the pervaporation (PV) dehydration of n-butanol/water mixture. PVA was crosslinked with trimesoyl chloride (TMC) via interfacial polymerization (IP) using hydrolyzed polyacrylonitrile (HPAN) as membrane support. The resulting membranes were subjected to a series of PV tests to explore the influence of varying IP parameters and PV operating conditions on the membrane separation performance. Characterization techniques including attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy, water contact angle analysis, field emission scanning electron microscopy (FESEM), and atomic force microscopy (AFM) were carried out to evaluate the surface properties of the membrane. ATR-FTIR analysis detected absorption bands associated with the trimesoyl ester, validating the formation of a TMC-based polyester membrane. The PVA-TMC/HPAN membrane demonstrated higher hydrophobicity, improved surface roughness, and thicker permselective layer compared to the unmodified PVA/HPAN membrane. The most desirable IP parameters for the fabrication of the PVA-TMC/HPAN membrane were established to be 1.00 wt.% PVA, 7.5-minute PVA immersion time, 1.00 wt.% TMC, and 40-minute reaction time. Consequently, the PVA-TMC/HPAN membrane exhibited a permeation flux of 219.6 g∙m −2 ∙h −1 with a 99.84 wt.% water concentration in permeate for the separation of 90/10 wt.% n -butanol/water solution at 25 °C. Lastly, the PVA-TMC/HPAN membrane showed a long-term stable PV performance at 40 °C for a duration of 7 days. This study offers an insight into the enhanced dewatering of aqueous n -butanol solution through pervaporation using TMC-modified PVA TFC membrane.