Synthesis of PANI@α-Fe2O3 /Al2O3 photo-Fenton composite for the enhanced efficient methylene blue removal

Abstract

Abstract In this work, β-FeOOH precursors were grown on flat Al2O3 ceramic matrix by a hydrothermal-assisted sol-gel composite method, followed by heat treatment to obtain α-Fe2O3/Al2O3 photo-Fenton catalysts. The effect of heat treatment temperature on the microstructure and photo-Fenton performance of α-Fe2O3/Al2O3 photo-Fenton catalysts was studied emphatically. The PANI@α-Fe2O3/Al2O3 photo-Fenton composite (PFA-550) were obtained by coating polyaniline (PANI) on the optimized α-Fe2O3/Al2O3 (FA-550) surface via in-situ polymerization, and subsequently used as an anode to assemble a photo-Fenton reactor for the removal of methylene blue (MB). The effect of pH value and applied electric field on MB removal of the photo-Fenton reactor was investigated. It was shown that α-Fe2O3 nanotubes was uniformly distributed over the surface of the flat Al2O3 ceramic in the FA-550 heated at 550°C, which exhibited high photo-Fenton activity. Compared to FA-550, PFA-550 exhibit superior photo-Fenton activity. In addition, PFA-550 have excellent photo-Fenton activity in a wide pH range (pH=3.92~9.21) rather than narrow range (pH=2.0~3.5) in conventional Fenton reaction. The migration of photogenerated electrons(e-) were promoted by external electric field from the surface of PFA-550 to the counter electrode. The removal rate of MB was substantially increased with the effective improvement of the separation of photogenerated e--h+.