MIL-100 (Fe) integrated fibrous polyvinyl alcohol graft on cellulose acetate towards the development of green membranes; Application in multi solute rejection

Biodegradable cellulose acetate (CA) based membrane is grafted with poly(vinyl alcohol) (PVA) which is stabilized by citric acid (ca) (via electrospinning) and cured thermally to obtain water stable, robust cross-linked CA membrane. A high surface area metal organic framework (MOF) namely MIL-100(Fe) is electrospun with PVA nanofiber to achieve more functionalized nanocomposite grafting. Thermal curing allows cross-linking between the functional groups of CA, PVA and MOF which facilitates grafted PVA nanofibers to remain intact on the CA surface during filtration. The physicochemical properties and morphology of composite membranes are determined using various spectroscopy and microscopy tools. The performance of electrospun membrane composites were assessed for the treatment of humic acid (HA), heavy metal ions, dyes and sulfate salts. The results indicate that the hydrophilicity of membranes enhanced significantly upon coating a MOF functionalized nanofiber layer on CA membrane. The prepared composite membranes show rejection efficiency of > 90% for HA, Pb2+ and Cd2+ and nearly 70% for MgSO4 and Na2SO4 salts. Remarkable flux up to ten times more than the recently reported nanofiber reinforced membranes is achieved. In summary, this study provides an insight into designing of effective CA membranes by engineering various MOF - electrospun nanofibers for greater permeability and removal of various solutes.