Mutual-assisted structure of sodium alginate-polyamide membrane for high-efficient dehydration of ethanol

Background: Pervaporation (PV), an environment-friendly and low-cost energy technology, possesses outstanding advantages for the dehydration from organic solution. The structure of the functional selective layer occupies an indispensable role to enhance membrane separation performance. Methods: Here, the sodium alginate (SA) with a polymer network was employed as a scaffold of ethylenediamine (EDA) to successfully prepare a thin-film composite (TFC) PV membrane through the interfacial polymerization (IP) method with trimesoyl chloride (TMC) on a ceramic hollow fiber support. Significant findings: Scanning electron microscopy (SEM), Fourier transform infrared spectrometer (FTIR) and X-ray photoelectron spectrometer (XPS) confirmed the addition of SA in the TFC membrane matrix, and the enhanced interaction between SA and polyamide (PA). Increasing SA concentration influenced the viscosity of solution, which resulted in a thicker functional layer, a lower membrane flux and a better separation perfor-mance. PV experiments were conducted and the prepared TFC membrane exhibited good dehydration perfor-mance with a total flux of 1.49 kg/m2h and a separation factor of 297 for separating 85 wt% ethanol-water mixture at 60 degrees C. The incorporation of SA as a scaffold in the membrane matrix provides a novel means to tailor the functional selective layer for enhancing membrane separation performance.

Automated summary

In this study, a thin-film composite (TFC) PV membrane was successfully prepared by using sodium alginate (SA) as a scaffold on a ceramic hollow fiber support, demonstrating good dehydration performance for separating an 85 wt% ethanol-water mixture. This novel approach of incorporating SA as a scaffold in the membrane matrix provides a promising means to tailor the functional selective layer for enhancing membrane separation performance.