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Membrane with high performance for dye/salt mixed solutions effective separation is desired for textile wastewater treatment. In this paper, a carboxylated poly(aryl ether nitrile) (PEN-COOH) tight ultrafiltration membrane was prepared to fractionate dye/salt by non-solvent induced phase separation with PEG6000 as additive. Due to the synergistic effect of the strong electricity absorption of inherent -CN on poly(aryl ether nitrile) and the ionization of -COOH, PEN-COOH membrane surface showed a strong electronegativity, which was beneficial to the efficient dyes removal by electrostatic repulsion effect. Meanwhile, it was conducive to moderately reducing the membrane denseness to improve permeability. Dextran solute retention experiment showed that PEN-COOH membrane had a molecular weight cut-off of 31,000 Da, corresponding to an effective surface average pore of 7.7 nm. It had a hydraulic permeability of 2.9 L m−2 h−1 bar−1. Compared with those membranes prepared by commercially available materials, PEN-COOH membrane showed unparalleled separation performance advantages. Its pure water flux reached 401.2 L m−2 h−1, while maintaining high retention efficiency of electronegative dyes (> 99%) and low rejection rate of salts (< 10%) under 0.1 MPa driving pressure. PEN-COOH membrane also showed good anti-dye-fouling durability and excellent dye separation performance under varied pH, temperature and pressure, making it a promising membrane for textile wastewater treatment. [Display omitted] • A PEN-COOH TUF membrane was prepared for efficient fractionation of dye/salt mixed solutions. • The strong electronegativity and high porosity ensured excellent dye rejection performance of PEN-COOH membrane. • It owned a PWF of 401.2 L m−2 h−1, complete retention of electronegative dye and low salt rejection rate. [ABSTRACT FROM AUTHOR]

A porous hollow polysulfone (donated as PHPSF) microspheres were prepared by non-solvent-induced phase separation using PEG as a porogen. The influence of the molecular weights (Mw) of PEG on the morphology and porous structure of the microspheres were investigated. As the Mw of PEG increasing from 600 to 10,000 g·mol–1, the viscosity of the system increases, leading to the increase of the viscosity difference between the dispersed phase and the continuous phase, and a delay in phase separation. Hence, the diameter and shell thickness of the obtained microspheres increase with the porosity reducing. Moreover, when the Mw of PEG is below 4000, the low |Δδ| between PEG and solvent is conducive to the formation of microporous structure with narrow pore distribution. The as-prepared PHPSF microspheres exhibit a separation efficiency of 6 times for MB than that of the original PSF microspheres. In addition, a reusability of 5 times of PHPSF is achieved even in the harsh acid or alkali condition. These results clarify the relationship between the different Mw of PEGs and microspheres morphology. Therefore, this kind of PHPSF microspheres holds a promising for the water organic pollution treatment. [Display omitted] • Porous hollow polysulfone (PHPSF) microspheres were prepared by the non-solvent-induced phase separation. • The porosity, macro/micropore size, diameter, pore morphology and specific surface area of the PHPSF microsphere is influenced by the molecular weight of PEG. • PHPSF microspheres have sub-micron surface pores and a honeycomb core-shell structure, showing high MB efficiency, excellent reusability and good mechanical/chemical stability. [ABSTRACT FROM AUTHOR]