Hybrid [polysulfone-Zero Valent Iron] membranes: Synthesis, characterization and application for AsIII remediation

Hybrid polysulfone membranes decorated with Zero Valent Iron (ZVI) nanoparticles were prepared and evaluated for As-III uptake. The hybrid polysulfone/ZVI membranes were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM-EDX), transmission electron microscopy (TEM), mercury intrusion porosity measurements, thermal gravimetric analysis (TGA) and differential thermal analysis (DTA). The membranes are characterized by a macroporous structure with ZVI particles dispersed both inside the pores as well as at their surface. Electron Paramagnetic Resonance (EPR) spectroscopy reveals that the surface sulfide groups of polysulfone are readily accessible by extrinsic Cu-II cations. Moreover the polysulfone/ZVI membranes have a considerable electron-donating capacity to surface-adsorbed atoms, thus they are able to reduce Cu-II to Cu-I, and inhibit oxidation of ZVI from Fe-0 to Fe3+. As a result, the Zero Valent Iron particles are stabilized against oxidation by ambient air and show appreciable As-III adsorption capacity (26.6 mg g(-1)). This renders them a significant stability, thus they can be reused at least four times for As-III adsorption with a loss less than 1% of their As-uptake capacity. Based on a theoretical Surface Complexation Model we provide a consistent interfacial/structural picture that describes quantitatively all observed phenomena. (C) 2015 Elsevier B.V. All rights reserved.