Improving pressure durability and fractionation property via reinforced PES loose nanofiltration hollow fiber membranes for textile wastewater treatment

Loose nanofiltration (NF) hollow fiber membranes with excellent dye rejection and high inorganic salt transmission are promising for textile wastewater treatment. Herein, a novel kind of reinforced PES loose NF hollow fiber membranes with robust twisted fiber bundle was fabricated by a facile dry-wet spinning process. The SEM results indicate that the favorable interfacial bonding layer was formed between the separation and supporting layer for the sake of endowing the membranes with high longitudinal strength and lateral pressure resistance. For one thing, the tensile strength of the PST membranes was up to 185.7 MPa, a considerably higher than FEP hollow fiber membrane prepared by melt spinning process (18.5 MPa). Moreover, the PST-1 membranes show almost no deformation, compared to sever deformation of FEP hollow fiber membrane after 100 h at high pressure operation. For another, the prepared PST membranes display stable pure water flux of 52.3 L·m−2·h−1 under 0.6 MPa. Specifically, the PST membranes exhibit excellent fractionation efficiency of dye/salt mixtures, along with high dye rejection of 99.9% and low salt rejection (<7%). These results indicate that the robust reinforced PES loose NF hollow fiber membranes with permeation stability have great potential application for practical textile wastewater treatment.