Electrospun membrane composed of poly[acrylonitrile-co-(methyl acrylate)-co-(itaconic acid)] terpolymer and ZVI nanoparticles and its application for the removal of arsenic from water
We present a facile approach to immobilizing nanoscale zero valent iron (nZVI) particles onto an electrospun membrane based on poly[acrylonitrile-co-(methyl acrylate)-co-(itaconic acid)] (hereinafter referred to as AN/MA/IA). The nZVI particles were synthesized under a nitrogen atmosphere by reducing Fe(III) cations with sodium borohydride NaBH4 in the presence of an AN/MA/IA membrane as a supporting scaffold. The synthesized nZVI particles are uniformly distributed into the membrane with a mean diameter ranging from 70 to 100 nm. The AN/MA/IA/nZVI membrane was characterized using SEM-EDX, XRD, XPS, TGA, ATR-FTIR, field dependent magnetization measurements using a super conducting quantum interference device (SQUID) magnetometer and Mössbauer spectroscopy. XRD analysis, Mössbauer spectroscopy and magnetization measurements confirmed the presence of the nZVI supported AN/MA/IA membrane, but XPS analysis showed that the surface of the nZVI particles oxidized to iron oxide forms, suggesting a core shell structure of nZVI on the membrane. We show that the composite AN/MA/IA/nZVI membrane can effectively remove As(III) and As(V) from water with a sorption capacity of 46.7 mg g−1 and 46.4 mg g−1 for As(III) and As(V), respectively. Inner-sphere surface complexation, oxidation and reduction reaction, ion exchange, electrostatic repulsion and functional group interaction are discussed as the major mechanisms involved in the arsenic removal by the functionalized membrane. The repeated cycles of adsorption/desorption and regeneration using 0.1 M NaOH signifies the AN/MA/IA/nZVI membrane as an efficient material for the removal of arsenic contamination from water.