Fabrication and characterization of a cross-linked two-layer polyetherimide solvent-resistant ultrafiltration (SRUF) membrane for separation of toluene-water mixture

A two-layer polyetherimide ultrafiltration membrane was fabricated by a double-blade casting technique and used for separation of the toluene-water emulsion. The cross-linking process was used to make membranes chemically stable when exposed to solvents. Membranes with different top layer thickness ranging from 40 to 10 mu m were selected for toluene-water separation. These membranes were fabricated in a way that they would have maximum flux while having pore sizes in the tight ultrafiltration range. The results revealed that the two-layer membranes showed higher flux when used for filtration of the toluene-water emulsion so that toluene/water mixture flux increased from 1.27 L m(-2) h(-1) for the single-layer membrane to 3.19 L m(-2) h(-1) for the two-layer membrane with 20 mu m of top layer thickness. Also, toluene rejection improved from 94.11% for the single-layer membrane to 95.25% for the two-layer membrane with 20 mu m top layer thickness. Moreover, the total resistance against water permeation in the two-layer membranes was lower than that in the single-layer membranes. To evaluate the long-term chemical stability of the membranes, they were immersed in a mixture of toluene and water for 5 days. Then again, they were used for filtration of the toluene-water emulsion. It was shown that these membranes could significantly preserve their performance which is a sign of good resistance against tolune. (C) 2021 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.

Automated summary

A two-layer polyetherimide ultrafiltration membrane was fabricated using a double-blade casting technique and showed higher flux and improved resistance when used for separation of the toluene-water emulsion. Results indicated that the two-layer membranes had better performance in terms of flux and chemical stability compared to single-layer membranes.