Contents lists available at ScienceDirect Journal of Environmental Chemical Engineering journal homepage: www.elsevier.com/locate/jece Cyclodextrine-glutaraldehyde cross-linked nanofiltration membrane for recovery of resveratrol from plant extract Hirok Jyoti Borah a , Monti Gogoi a , Diganta B Das b , Swapnali Hazarika a, * a Chemical Engineering Group, Engineering Science & Technology Division, CSIR-North East Institute of Science and Technology (NEIST), Jorhat, 785 006, Assam, India b Chemical Engineering Department, Loughborough University, Loughborough LE11 3TU, Leicestershire, UK ARTICLE INFO Keywords: Resveratrol Cyclodextrin Glutaraldehyde Membrane Nanofiltration ABSTRACT 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 con- centration 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. 1. Introduction Resveratrol, which is a natural phenol and is used as a dietary supplement, is found in many plants such as grapes (1057 μg/100 mL), peanuts (5.1 μg/g), and Itadori plants (68 μg/100 mL) [1,2]. Resvera- trol has chemo-preventive and anti-tumor properties; it also acts as an antibacterial, antioxidant, anthelmintic and insecticide compound [3]. The quantity of resveratrol in its source may change depending on the fertility of the soil and different extraction processes [4]. However, the separation and purification of the biomolecule to its purest form (100 % w/w) from its crude extract is not only a challenging task but also important as increasing interest has been given by the common people for its use in pure form for their medicinal effect as discussed in our earlier studies [1]. In principle, nanofiltration (NF) may be used for purification of resveratrol molecules, but the extent to which this can be achieved is not known. Furthermore, the preparation and character- ization of nanoporous membranes specifically for resveratrol purifica- tion needs to be addressed. In resolving these issues, herein a series of experiments were performed on the preparation of glutaraldehyde cross-linked alpha, beta and gamma-cyclodextrin nanoporous mem- branes and their performances in the separation of resveratrol from plant extract. Nanofiltration (NF) is a pressure-driven membrane process applied in water softening and, analysis of industrial effluents infected by or- ganic impurity, etc. [5,6]. NF membranes have been shown to separate solvents, monovalent ions, a small organic molecule from bivalent ions and larger groups [7]. Numerous analysts have improved various methods for the synthesis of the selective layer through polymerization [8,9]. The pore size of NF is typically 1–10 nm and the membrane can resist small organic compounds and has greater water permeability, lower energy exhaustion, higher flux rates and works at low pressure [10]. The pores of the nanofiltration membranes reject the small un- charged solutes as well as multivalent ions and allow permeation of monovalent ions. These properties make NF membranes suitable in the fractionation and careful elimination of solutes from complex mixtures. The improvement of NF process has led to an observable increase in its utilization in several industries [11]. It is seen that nanofiltration pro- vides an improved understanding of the resveratrol separation process https://doi.org/10.1016/j.jece.2019.103620 Received 9 August 2019; Received in revised form 14 December 2019; Accepted 16 December 2019 ⁎ Corresponding author. E-mail addresses: D.B.Das@lboro.ac.uk (D.B. Das), shrrljt@yahoo.com (S. Hazarika). Journal of Environmental Chemical Engineering 8 (2020) 103620 Available online 17 December 2019 2213-3437/ © 2019 Elsevier Ltd. All rights reserved. T