Electrospun Fe-supported silica membrane for the Fenton-like oxidation of Bisphenol A

Abstract

A self-standing silica membrane was successfully fabricated through the combination of the sol-gel/EISA synthesis and the electrospinning process. The membrane was doped with 5 wt% Fe (Fe-SiO2) by the wet impregnation method. The material was characterized by SEM/EDS, TEM, TGA, FTIR, XRD, Mössbauer spectroscopy and N2 adsorption-desorption at -196 ºC techniques, exhibiting a nanofibrous structure with micro- and meso-porosity, a large specific surface area (260 m2/g) and phases of amorphous SiO2 and hematite (Fe2O3). Fe-SiO2 was tested as a catalyst in the Fenton-like oxidation of the emerging pollutant, Bisphenol A (BPA). The material displayed promising activity, achieving complete BPA removal and high mineralization levels (46 and 60 % at 70 and 80 ºC, respectively). Over 45 % mineralization was retained after six consecutive cycles at 80 °C, with Fe leaching below discharge limits. The oxidation process involved a combined Fenton-like homogeneous/heterogeneous mechanism. The loss of activity was attributed to Fe leaching and silica dissolution at higher temperatures, followed by coagulation and precipitation due to interactions with organic intermediates, leading to the blockage of reaction sites. The material may hold promise as a catalyst for wastewater treatment.