Structure influence of hyperbranched polyester on structure and properties of synthesized nanofiltration membranes

• Different generation HPE was used to fabricate NF membranes.
• Effect of HPE structure on NF membranes structure was studied.
• Effect of HPE structure on NF membranes properties was studied.
• Anionic and cationic dyes were used to evaluate properties of NF membranes.

Nanofiltration (NF) membranes have been prepared by interfacial polymerization of hyperbranched polyester with different number of terminated hydroxyl groups and trimesol chloride (TMC). Surface morphology and chemical structure of the different membranes were characterized by Fourier transforms infrared spectrometry (FTIR-ATR), scanning electron microscopy (SEM), atom force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). Molecular weight cut-off (MWCO) and surface zeta potential of the NF membranes were evaluated. The effect of pH value, operation pressure and salt concentration on rejection properties were also assessed. Nanofiltration properties were determined with organic anionic and cationic simulated dye wastewater. It was found that all NF membranes surface presented negative charge and had a MWCO of 4–6 kDa. Rejection properties of the NF membranes were affected by the dye charges, dye concentration and salt concentration.

Hyperbranched polyester (HPE) with different number of terminated hydroxyl groups (16, 32 and 64) was used as reactive monomer to prepare nanofiltration membrane by interfacial polymerization. Surface morphology and chemical structure of different membranes were characterized. Nanofiltration properties were performed with anionic and cationic simulated dye wastewater. The rejection of dye molecules was determined mainly by sieving effect. It was found that the structure and properties of NF membranes were affected obviously by HPE structure. All nanofiltration membranes presented negative charge and had a high MWCO. Rejection properties of the nanofiltration properties to dye were affected by dye charge, dye concentration and salt concentration.Figure optionsDownload high-quality image (77 K)Download as PowerPoint slide