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To prepare a new type of composite membrane with high flux and good dye removal performance, hyperbranched polyester (HPE) was selected as the reactive macromonomer and a cross-linked HPE skin layer was successfully formed on the PVC-UF membrane via one-step acteal reaction between HPE and glutaraldehyde (GA) from aqueous emulsion. The resultant membranes were characterized using ATR-FTIR, FESEM, surface zeta potential and CA, while the effects of GA concentration and heat treatment time on their performance were evaluated by permeate flux and rejection rate of sunset yellow (SY). The obtained HPE-M5 membrane exhibited a SY rejection rate of 96.4% and a permeate flux of 237.6 L m − 2 h − 1 at 0.4 MPa. Due to the good stability and the feasibility of backwashing treatment, the prepared composite hollow fiber membrane has a promising perspective of application in dye removal. [ABSTRACT FROM AUTHOR]

High-efficient separation of molecules is of great significance in food, biotechnology, pharmaceutical and dairy industries. To this end, cationic hyperbranched poly (amido-amine)s (HBPs) with different numbers of quaternary ammonium groups were employed as a new kind of 3D spherical macromonomers to fabricate nanofiltration (NF) membranes, through interfacial polymerization (IP) between cationic HBPs and trimesoyl chloride (TMC) on a polyvinyl chloride ultrafiltration (PVC-UF) hollow fiber membrane surface. Apart from the inner voids inside cationic HBP molecules for fast transport of water molecules, sizes and charge properties of the outer voids between cationic HBP molecules can be modulated by changing the numbers of quaternary ammonium groups on cationic HBP molecule surfaces for enhancing both high permeability and selectivity (water permeance and MgCl 2 rejection rate of the resultant NF membrane are up to 310.5 L m−2 h−1 MPa−1 and 92.0% respectively). Based on the separation mechanism of combined steric and Donnan effects, the resultant NF membrane exhibits ultrahigh retentions to molecules with high molecular weights (MWs) or positive charges, thus molecular-level selectivity to VB12/VB2 (neutral molecules with distinct MWs) or VB1/VB2 (cationic/neutral molecules with similar MWs) can be achieved. [Display omitted] • Cationic HBPs were synthesized as a novel kind of macromonomers for IP. • Nanochannel in NF membrane selective layers were engineered by cationic HBPs. • HBP-TAC2/TMC membrane exhibits higher water permeability and MgCl 2 rejection. • Separation of molecule mixtures can be achieved based on steric and Donnan effects. [ABSTRACT FROM AUTHOR]