It is known that
the polyamide (PA) barrier layer’s inherent microstructure
and surface physicochemical properties of thin film composite nanofiltration
membrane are crucial for its separation performance. Herein, we designed
and synthesized a new zwitterionic aromatic diamine monomer 3-(4-(2-((4-aminophenyl)amino)ethyl)morpholino-4-ium)propane-1-sulfonate
(PPD-MEPS) through a three steps reaction, and this hydrophilic molecule
was incorporated into the active layer to tailor the poly(piperazine-amide)-based
nanofiltration membranes with significantly improved water permeability
and antifouling properties. As a p-phenylenediamine
(PPD) derivative, PPD-MEPS possesses two active amine units, which
can react with trimesoyl chloride in the organic phase during the
interfacial polymerization reaction process. Thus, the super-hydrophilic
zwitterions were not only on the membrane surface but also across
the whole PA layer to facilitate water molecule transportation. The
successful augmentation of zwitterions into the PA layer was well
illustrated by attenuated total reflectance–Fourier transform
infrared spectroscopy (ATR–FTIR) results and X-ray photoelectron
spectroscopy analysis. With increasing loading content of PPD-MEPS
in PIP aqueous solution, the as-fabricated nanofiltration membranes
(NFMs) exhibited higher hydrophilicity, increased active layer thickness,
and molecular weight cut off. When the zwitterionic monomer reached
60% to PIP for NFM-4, the water permeability went up to 9.82 L m–2 h–1 bar–1, increasing
by 45%; meanwhile, the Na2SO4/NaCl selectivity
increased from 2.54 to 4.03. In addition, the fouling experiments
illustrated that the fouling resistance of the zwitterion-modified
NFMs to bovine serum albumin was significantly improved.
Organic solvent nanofiltration (OSN) is an emerging membrane separation technology, which urgently requires robust, easily processed, OSN membranes possessing high permeance and small solutes‐selectivity to facilitate enhanced industrial uptake. Herein, we describe the use of two 2,2′‐biphenol (BIPOL) derivatives to fabricate hyper‐crosslinked, microporous polymer nanofilms through IP. Ultra‐thin, defect‐free polyesteramide/polyester nanofilms (≈5 nm) could be obtained readily due to the relatively large molecular size and ionized nature of the BIPOL monomers retarding the rate of the IP. The enhanced microporosity arises from the hyper‐crosslinked network structure and monomer rigidity. Specifically, the amino‐BIPOL/PAN membrane exhibits extraordinary permselectivity performances with molecular weight cut‐off as low as 233 Da and MeOH permeance of ≈13 LMH/bar. Precise separation of small dye mixtures with similar M.W. based on both their charge and molecular size are achieved.
Highly permeable organic solvent nanofiltration (OSN) membranes are desired to be used in an efficient and energy-saving chemical separation process. Herein, we fabricated high-flux OSN membrane by synthesizing 7,7'-dihydroxy-2,2'-binaphthol (7,7'-OH-BINOL)...
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.