(50e) Polyarylester Nanofiltration Membranes with Solvent Resistance

Nanofiltration (NF) membranes have numerous applications for the separation of chemicals with low molecular weights from organic solvents and the separation of aqueous solutions [1]. The challenge is to develop organic solvent nanofiltration (OSN) membranes with excellent separation that are effective in diverse organic solvents [2]. Lignin and its derivatives exhibit excellent anti-solvent property since they have abundant hydroxyl groups [3]. Therefore, we are motivated to develop new NF membranes with solvent resistance by employing natural polyphenol materials into membrane surfaces.

In our study, we initially synthesized a composite nanofiltration (NF) membrane by employing ammonium lignosulfonate (AL) and trimesoyl chloride (TMC) as monomers on a crosslinked polyetherimide (C-PEI) membrane via interfacial polymerization, and assessed the separation performance in polar aprotic solvents, including THF, DMSO, DMAc and DMF, respectively. It is shown that the AL-TMC membranes had adequate rejection but low permeance in organic solvents. To enhance the permeance, we adopted two kinds of new monomers, vanillic alcohol (VA) and guaiacol (GA), which possesses the molecular structure similar to a subunit of AL, to synthesize respectively the VA-TMC and the GA-TMC NF membranes. Through ATR-FTIR, ¹³C-NMR, XPS, SEM and AFM, we observed that TMC reacts with VA to form ester bonded structures on the C-PEI support. The VA-TMC NF membrane is composed of polyarylester and exhibits effective separation performance in DMSO. The optimal membrane NF-2VA has a DMSO permeance of approximately 21 L m^-2 h^-1 MPa^-1, a rejection of 89% for Brilliant Blue R-250 and a rejection of 81% for clindamycin phosphate. While the optimal GA-TMC membrane (NF-3GA) has the permeance of 73.05 Lm^−2 h^−1 MPa^-1 and 99% rejection of RB in THF. Such polyarylester NF membranes can be effectively used for the recovery of drug residues from organic solvents in the pharmaceutical industry.

Acknowledgement

This work was supported by the National Key Research and Development Program (2016YFC1201503), NSFC (21621004) and the Program for Changjiang Scholars and Innovative Research Team in University (IRT_15R46).

References

[1] P. Marchetti, M.F. Jimenez Solomon, G. Szekely, A.G. Livingston, Molecular separation with organic solvent nanofiltration: a critical review, Chemical reviews, 114 (2014) 10735-10806.

[2] P. Vandezande, L.E.M. Gevers, I.F.J. Vankelecom, Solvent resistant nanofiltration: separating on a molecular level, Chemical Society Reviews, 37 (2008) 365-405.

[3] A. Duval, M. Lawoko, A review on lignin-based polymeric, micro- and nano-structured materials, Reactive and Functional Polymers, 85 (2014) 78-96.