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• Smooth (R a less than 2 nm) surface of the GQDs-interlayered membrane was achieved. • The 25 nm-thick skin layers of the GQDs-interlayered membranes. • The GQDs-PEI interlayer covalent bonded between substrate and skin layer. • The prepared membrane maintained stable performance in DMF for 45 days at 80 °C. Novel thin film nanocomposite (TFN) organic solvent nanofiltration (OSN) membranes with sandwich-like structure were developed via interfacial polymerization (IP) using both low concentration m-phenylenediamine (MPD) and trimesoyl chloride (TMC), on graphene quantum dots (GQDs)-polyethyleneimine (PEI) modified polyimide substrate surface, and followed by post-IP crosslinking and solvent activation. Such GQDs-interlayered OSN membranes have exhibited a remarkable reduced thickness (about 25 nm) and an ultra-low average surface roughness (less than 2 nm) of their IP skin layers, respectively. Both material features are rarely reported in literature. Meanwhile, our GQDs-interlayered OSN membranes have shown an increased Rhodamine B (479 Da) rejection (from 87.4% to 98.7%) and an increased ethanol permeance (from 33.5 to 40.3 L m−2 h−1 MPa−1) compared with the pristine OSN membrane. Superior solvent resistance was demonstrated after long immersion in pure N , N -dimethylformamide (DMF) at room temperature for 81 days, and at 80 °C for 45 days, and after a long-term consecutively filtration with Rose Bengal (1017 Da) DMF solution at 25 °C for 5 days, without scarifying solute rejection. Antifouling properties during the long-term filtration were also indicated. This paper presents a novel GQDs-interlayered strategy in developing high-performance TFN membranes for OSN application. [ABSTRACT FROM AUTHOR]

This study describes the preparation and characterisation of MIL-53(Fe) and its effect on the performance of forward osmosis (FO) membranes. The cellulose acetate (CA)/MIL-53(Fe) hybrid membranes were fabricated using the method of phase inversion by dispersing MIL-53(Fe) in a CA casting solution. To improve the selectivity and permeability performance of FO membranes, the effects of MIL-53(Fe) content, casting solution temperature, coagulation bath temperature, and annealing temperature were studied. Results from scanning electron microscopy, membrane porosity, atomic force microscopy, and water contact angle tests of all the membranes show that the structural properties of the CA/MIL-53(Fe) hybrid membranes were optimised. The results of the FO performance tests, including the values of water flux and reverse salt flux, indicate improvement in the selectivity and permeability properties of the CA/MIL-53(Fe) hybrid membranes. Under the conditions of deionised water as the feed solution and 1 M NaCl solution as the draw solution, the water flux and reverse salt flux of the CA/MIL-53(Fe) hybrid membranes reached 34.9 L/(m2·h) and 2.02 g/(m2·h), respectively, in comparison with CA membranes. This study demonstrates that MIL-53(Fe) can improve the desalination performance and structural properties of FO membranes. • MIL-53(Fe) with high porosity was used to fabricate cellulose acetate (CA)/MIL-53(Fe) hybrid membranes for the first time. • Optimal experimental conditions of CA/MIL-53(Fe) hybrid membranes were conducted. • The water flux and reverse salt flux of CA/MIL-53(Fe) hybrid membranes were improved compared to CA membranes. • Effect of MIL-53(Fe) on structural properties of CA membranes was widely discussed. [ABSTRACT FROM AUTHOR]

Solvent resistant nanofiltration (SRNF) membranes are highly demanded in processing organic solutions especially those contain large molecules with molecular weight between 200 to 2000 Da, yet they have some drawbacks such as relatively poor solvent resistance and low solvent permeance. The current work presented an innovative class of amino-functionalized graphene quantum dots (aGQDs) embedded thin film nanocomposites (TFN) for SRNF membranes which were prepared via interfacial polymerization (IP) and subsequent steps (chemical imidization, crosslinking, and solvent activation). The prepared membranes enabled covalent interactions not only between the IP skin layer and the substrate, but also between the IP layer and the embedded aGQDs. The ethanol permeance and surface porosity increased by 44% and 69%, respectively, with the embedment of aGQDs under the optimal conditions, while the Rhodamine B (RDB, 479 Da) rejection maintained essentially stable above 99%. Furthermore, our novel membranes exhibited excellent long-term stability, with a rejection of over 99% for Rose Bengal (RB, 1017 Da) during the continuous filtration of 100 mg L−1 RB/ N , N -dimethyl formamide (DMF) solution at room temperature for more than 768 h. They also exhibited good organic solvent resistance and high-temperature tolerance in both DMF and NMP solvents, with a RDB rejection of over 99% and an ethanol permeance of about 38 L m−2 h−1 MPa−1 after being immersed in DMF at 80 oC for 248 h, and a RDB rejection of over 99% and an ethanol permeance of about 41 L m−2 h−1 MPa−1 after being immersed in NMP at 80 oC for 232 h. The results demonstrated that the aGQDs-embedded TFN OSN membrane has vast potential in SRNF applications. Image 1 • (PI-aGQDs/PI) XA membrane was prepared via IP, imidization, crosslinking, activation. • The (PI-aGQDs/PI) XA SRNF membrane owns a wholly covalent bonding chemical structure. • aGQDs improve greatly the surface morphology and performance of the SRNF membrane. • The SRNF membranes kept >99% RB rejection in filtration of DMF at 25 oC for 30 days. • The SRNF membranes kept good solvent resistance in DMF and NMP at 80 oC for 10 days. [ABSTRACT FROM AUTHOR]