Fabrication of tight GO/PVDF hollow fiber membranes with improved permeability for efficient fractionation of dyes and salts in textile wastewater

In this study, a graphene oxide/polyvinylidene fluoride (GO/PVDF) tight hollow fiber membrane (HFM) with improved permeability was fabricated via one-step direct spinning process to fractionate the dyes and salts (NaCl and Na2SO4) in textile wastewater. Scanning electron microscopy (SEM) indicated that the GO/PVDF HFM possessed a smooth and tight outer selective layer and a relatively porous and loose inner surface. The optimized HFM not only possesses a small mean pore radius of 1.14 nm, but also has a high pure water flux of 24.8 L/m(2)center dot h center dot bar. The stronger negative charge (- 40 mV at pH = 7) was obtained by the GO/PVDF HFM. Due to the synergistic effects of size exclusion and charge repulsion, the resultant HFM exhibited excellent rejection for dyes (i.e., close to 100% for Congo red and Methyl blue, 98.9% for Eriochrome black T) and low salts rejection (i.e., 1% for NaCl, 11% for Na2SO4). Besides, with appropriate addition of hydrophilic GO to the doped solution, the resultant membrane exhibited good hydrophilicity, antifouling property and excellent stability. The newly developed tight HFM would be of great significance for effective fractionation and treatment of textile wastewater.

Automated summary

A GO/PVDF tight hollow fiber membrane (HFM) was developed via one-step direct spinning process for fractionation of dyes and salts in textile wastewater. The optimized HFM showed small pore radius, high pure water flux, strong negative charge, excellent rejection for dyes, and low salts rejection. Additionally, the membrane exhibited good hydrophilicity, antifouling property, and stability, making it significant for effective treatment of textile wastewater.