Search

Nanotechnology has created numerous opportunities for the development of novel thin film nanocomposite (TFN) membranes. In this study, we prepared a novel β-cyclodextrin based nanosheets (β-CDNSs) with a lateral size of approximately 200–400 nm and thickness of ∼10 nm through the interfacial polymerization method and used it as the nanofillers in aqueous phase to prepare advanced nanofiltration (NF) membranes. The high microporosity, organic attribute, hydrophilic COOH and reactive OH groups present in β-CDNSs are conducive to the microstructural parameters fine-tuning of the resultant TFN membranes. The optimal membrane TFN-0.02 presented the PA selective layer with thinner thickness, less crosslinking degrees, prominent globule microstructures, and increased hydrophilic properties. As a result, it achieved a remarkable enhancement in pure water permeability (21.46 L m−2 h−1 bar− 1, versus 8.79 L m− 2 h− 1 bar− 1, nearly 2.4-fold increase), high rejection of divalent salt (above 98% for Na 2 SO 4) and an outstanding selectivity of α NaCl/Na2SO4 = 50.27. Moreover, the tailored membrane TFN-0.02 exhibited superior resistance towards four typical organic foulants BSA, LYZ, DTAB and SDS. Overall, this work provides insightful guidance for the design of novel organic nanomaterials with desired properties for greatly enhanced separation performances of as-fabricated membranes. [Display omitted] • Novel β-CD nanosheets with plenty of carboxyl groups were prepared by IP method. • β-CDNSs possess high microporosity, organic attribute, reactive hydroxyl groups. • The PA layer gave thinner, less-crosslinked, protuberant globule microstructure. • The membrane showed much enhanced water flux and mono-/divalent salt selectivity. • The membrane exhibited superior resistance towards four typical organic foulants. [ABSTRACT FROM AUTHOR]

The integration of high permeability and exceptional selectivity, thereby overcoming the conventional "trade-off" effect, remains a persistent challenge for the practical implementation of organic solvent nanofiltration (OSN) membranes. Herein, at the molecular level of design, we utilized the 5,5′-diamino-2,2′-biphenol (amino-BIPOL) and diacyl chloride as IP monomers to prepare OSN membranes with high perm-selectivity. The amino-BIPOL, a contorted biphenol molecule with four reactive sites, serves as a molecular-level unit to hinder efficient packing of polymer chains and induce the formation of interconnected micropores in the resulting polyesteramide layers. By employing diacyl chloride terephthaloyl dichloride (TPC) and isophthaloyl dichloride (IPC) as the oil-phase cross-linker, two kinds of TFC membranes were prepared. The resulting membranes both present smooth surface morphology, with ultrathin and high microporous selective layer allowing for efficient mass transfer. Specifically, the methanol permeance of amino-BIPOL/TPC and amino-BIPOL/IPC membrane reaches up to 15.1 and 15.6 LMH/bar, while maintaining a molecular weight cut-off (MWCO) value of 300 and 373 Da, respectively. Overall, this work illustrates the different oil-phase cross-linkers will result in diverse nanofilm microstructure and thus with distinct perm-selectivity properties, offering new insights for the design and modification of advanced OSN membranes. [Display omitted] • Amino-BIPOL and diacyl chloride were used to prepare TFC OSN membranes by IP method. • The membranes present high micropores and ultrathin characteristics. • Two oil phase cross-linker result in nanofilms with diverse cross-linked network. • The optimal membrane shows methanol permeance of 15.1 LMH/bar and MWCO of ∼300 Da. [ABSTRACT FROM AUTHOR]