Abstract
Selective separation of lignin depolymerization products is key to fractionating and isolating high-value aromatic compounds from the depolymerization process. The primary aim of this study was to synthesis graphene oxide (GO) membranes for selective separations of lignin oligomeric units from polar organic solvent-water media. GO membranes were synthesized on a polymeric substrate by a shear assisted casting of aqueous GO dispersion using a wire-wound rod. Deposited GO was then reduced to different extents by controlled thermal incubation, and the impact on membrane performance was investigated. The extent of reduction of GO was established by extensive characterization with FTIR, XPS, Raman Spectroscopy, XRD, and contact angle measurements. Impressive performance with the rejection of over 70% for the model compound trimer BMP (2,6-bis[(2-hydroxy-5-methyl phenyl) methyl]-4-methylphenol) was achieved compared to only 20% rejection for the dimer GGE (guaiacylglycerol-β-guaiacylether) with isopropanol-water (90–10% by volume) as a solvent. This corresponds to an encouraging selective separation with selective permeation of dimer (GGE) 3.5 times higher compared to trimer (BMP). rGO membranes exhibited a stable performance over 84 h of operation at a shear rate of 1.1 Pa in a cross-flow mode of operation. Selective separation of GO can be effectively modulated by controlling the O/C ratio by the extent of reduction of GO; indeed, the retention of trimeric compounds increased with increasing GO reduction. The remarkable performance of GO membranes could enable energy-efficient fractionation of lignin oligomeric compounds from polar organic solvents.
Original language | English |
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Article number | 115865 |
Journal | Separation and Purification Technology |
Volume | 230 |
DOIs | |
State | Published - Jan 2 2020 |
Bibliographical note
Funding Information:This research was supported by the National Science Foundation under Cooperative Agreement No. 1355438, and by NIH-NIEHS-SRC (Award number: P42ES007380). Authors acknowledge the help of Dr. Nicolas Briot from Electron Microscopy Center and Xiaobo Dong, at University of Kentucky for characterization of the membrane. Authors also acknowledge the intellectual contributions made by Dr. Andrew Colburn at various stages in conducting the presented research.
Funding Information:
This research was supported by the National Science Foundation under Cooperative Agreement No. 1355438 , and by NIH-NIEHS-SRC (Award number: P42ES007380 ). Authors acknowledge the help of Dr. Nicolas Briot from Electron Microscopy Center and Xiaobo Dong, at University of Kentucky for characterization of the membrane. Authors also acknowledge the intellectual contributions made by Dr. Andrew Colburn at various stages in conducting the presented research.
Publisher Copyright:
© 2019 Elsevier B.V.
ASJC Scopus subject areas
- Analytical Chemistry
- Filtration and Separation