Abstract
This study reports a systematic investigation of fine-tuning the filtration performance of nanofiltration membranes with biophenol coatings to produce solvent-resistant membranes with 390-1550 g mol-1 molecular weight cutoff (MWCO) and 0.5-40 L m-2 h-1 bar-1 permeance. Six kinds of inexpensive, commercial biophenols (dopamine, tannic acid, vanillyl alcohol, eugenol, morin, and quercetin) were subjected to identical oxidant-promoted polymerization to coat six kinds of loose asymmetric membrane supports: polyimide (PI), polyacrylonitrile (PAN), polysulfone (PSf), polyvinylidene difluoride (PVDF), polybenzimidazole (PBI), and polydimethylsiloxane (PDMS). The coatings were characterized by Fourier-transform infrared spectroscopy (FTIR), and the morphologies were characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The long-term stability of 42 membranes were tested in 12 organic solvents, including emerging green solvents MeTHF and Cyrene. The biophenol coatings led to tighter membranes with a decrease in MWCO of 12-79% at a penalty of a 22-92% permeance decrease in acetone.