cross-linking of graphene oxide by eosin y for application in mixed-matrix nanofiltration membranes

In this study, nanofiltration membranes were developed from sulfonated polyethersulfone using a combination of the phase inversion method and immersion technique in a non-solvent environment. polyvinylpyrrolidone (pvp) was employed as the pore-forming agent, with dimethylacetamide (dmac) serving as the solvent. the inherent hydrophobicity of these membranes, attributed to their sulfonated polyethersulfone composition, was mitigated by the introducing graphene oxide nanoparticles. additionally, eosin y monomers were introduced into the graphene oxide to enhance the dispersion of graphene oxide nanosheets. various characterization techniques, including electron microscopy, fourier-transform infrared (ft-ir) spectroscopy, energy-dispersive x-ray (edx) spectroscopy, permeability tests, salt rejection, flux measurements, contact angle analysis, and water content assessment, were applied to achieve the modified membranes. the electron microscopy images illustrated the formation of porous voids beneath the surface and wider channels within the modified membranes. ft-ir analysis showed the presence of functional groups (o=c-br) in the eosin y-go nanosheets. the introduction of eosin y-go nanosheets led to noticeable changes in permeation rate, with increased salt rejection, particularly sodium sulfate (na2so4). moreover, nanoparticle inclusion significantly improved hydrophilicity and enhanced water content. furthermore, the adding the nanoparticles resulted in an increase in porosity and pore size. ultimately, correction sample includes 0.01 wt% of nanoparticles exhibited superior performance, particularly in terms of salt permeability and sodium sulfate (na2so4) passage, compared to other samples. this optimal nanoparticle concentration highlights a key finding of the study.