Template-assisted fabrication of polyether ether ketone hollow fiber membrane for highly efficient separation of binary dye mixtures

Poly(ether ether ketone) (PEEK) is among the most reliable membrane materials in membrane-based separation processes due to its excellent properties especially under harsh environment. Successfully implementing the controllable construction of the pore structure into the fabrication process of PEEK hollow fiber membranes (HFMs) can make a significant contribution to addressing the issue of membrane selectivity and permeability. Herein, we developed a flexible route for manufacturing PEEK HFMs by melt-spinning technology combined with the template-assisted crystallization process. This route effectively reduced the amount of organic solvent in the membrane preparation process, and the crystallization induced strategy remarkably improved the connectivity of membrane pore structure and fixed pore structure of PEEK HFMs. Furthermore, we conducted a comprehensive investigation into the separation mechanism and performance stability of the prepared membranes in binary dye mixtures. The results unveiled that the suitable pore structure of the PEEK HFMs that maintained a high salt permeability with a high dye retention, synergized with strong negative charge contributed to excellent performance in dye/salts or dye/dye binary mixtures separations. A long-term stability of PEEK HFMs for treatment of the simulated textile wastewater with rejection coefficient of above 99% to dyes like congo red (CR) and a low NaCl rejection (<10%) indicated that PEEK HFMs have a bright prospect in dye/salt separation for water purification and resource reclamation.