Mass transport and pervaporation recovery of aniline with high-purity from dilute aqueous solution by PEBA/PVDF composite membranes

Abstract

Poly(ether block amide)(PEBA)/poly(vinylidene fluoride)(PVDF) composite pervaporation membrane was prepared for recovering of high-purity aniline from dilute aqueous solution, and the resistance-in-series model was set up for the simulation of the present pervaporation. Based on the mass transport model, the thickness of PEBA selective layer was determined by considering the boundary concentration polarization. It is found that the selective layer membrane with a thickness of 20 μm would almost have no diffusion barrier in the liquid phase at 80 °C when Re was above 1000. Meanwhile, based on the studies on the effects of feed concentration as well as temperature on the separation performance of PEBA/PVDF composite membrane in terms of permeation flux, selectivity and permeance, it is also found that the total permeation flux could reach as high as 6420 g/(m2 h) with a corresponding separation factor of 35 at a feed concentration of 3 wt% and a feed temperature of 80 °C, indicating the excellent performance of the as-prepared composite membrane for aniline separation. Furthermore, the performance of the composite membrane for the removal of aniline from wastewater was investigated using a batch pervaporation-fractional condensation (PVFC) experimental system, by which the concentration of the feed could be reduced to 550 ppm after 5.5 h of treatment, and accordingly, 65 wt% of the aniline in the feed was recovered in the first condenser as its high-purity form at an initial aniline concentration of 30,000 ppm.