Metal-polyphenol dual crosslinked graphene oxide membrane for desalination of textile wastewater

With the fast development of textile industry, the increasing discharge of textile wastewater is posing a grand challenge to the environmental safety. Graphene oxide (GO) nanosheet with excellent physicochemical properties and lamellar structure, is regarded as an ideal membrane material for the rejection of dyes. However, the selectivity and long-term course of GO-based membranes are largely limited due to the narrow interlayer distance as well as poor aqueous solution stability. To address such situations, a series of GO-based membranes (Fe/GO-TAx) were prepared using coordinated tannic acid-functionalized GO (GO-TA) nanosheets with FeIII ions in this study. The results indicated that Fe/GO-TAx membranes exhibited greater interlayer distance and higher hydrophilicity, as well as a decreasing trend of negative surface charge. Furthermore, the Fe/GO-TA20 conferred a superior dye/salt selective sieving mechanism with a high separation factor and a permeability of 61.2 L m−2 h−1 bar−1 (approximately 6-times higher than the pristine GO membrane). Importantly, the fabricated Fe/GO-TA20 membrane exhibited inherent removals for organic dyes, and more than 99% removals were achieved in the test. These findings were expected to provide some simple but practical strategies for the fast fabrication of two-dimensional laminar structure GO separation membranes to achieve excellent sieving of high-salinity textile wastewater.