Cyclodextrine-glutaraldehyde cross-linked nanofiltration membrane for recovery of resveratrol from plant extract

Resveratrol has antibacterial, antioxidant, anthelmintic and insecticide properties. While the demands for use of resveratrol have been increasing, its separation and purification from its crude extract have not matured well-enough yet. Though nanofiltration (NF) can be used for the purification of the resveratrol molecules yet the extent to which this can be achieved is not known. In addressing this, glutaraldehyde cross-linked alpha, beta and gamma-cyclodextrin NF membranes were prepared and studied for their performances in the separation of resveratrol from plant extract. Beta CD-Glu cross-linked membranes are thermally stable up to the temperature of 516 °C and it is hydrophobic in nature. The interplay of the effects of various permeation parameters on flux and rejection rate has been established. The permeation flux reached 11.35 mmol.m-−2. h-1 for a feed concentration of 0.76 mmol.L-1 solution and the maximum % rejection of 98.02 % was eventually recorded for beta CD-Glu cross-linked membrane. The concentration of resveratrol in the feed solution also plays a prominent role in altering the percentage of separation of resveratrol from its crude extract. The transport of resveratrol was explained with a model of solute transport inside the membrane pores which depends on the hydrogen bonding contribution between the solvent, solute and membrane. Overall, it was observed that the rejection decreased when the feedstock flow rate goes up, which indicated that the permeation flux increases. The membrane has a high enrichment of resveratrol separation.