Hematite (Fe2O3)-modified biopolymer for Rhodamine B degradation under visible light

Abstract

This study deals with the preparation of a novel biomaterial by incorporating the hematite α-Fe2O3 onto crushed leaves of the Washingtonia filifera palm tree in their raw state and in extracted cellulose from the same plant. The incorporation of α-Fe2O3 was accomplished by hydrothermal route at 200 °C. The palm leaves, extracted cellulose, and synthesized products were characterized by thermal analysis (TG) and FT-IR spectroscopy. The latter revealed peaks at 524 and 449 cm−1 for the synthesized material, attributed to vibrational deformation of the inorganic Fe-O bond. In contrast to the TG profile of raw palm leaves, the thermogram of the composite degrades in a single step at 343 °C. This one-step decomposition clearly indicates the chemical modification of our cellulose matrix and confirms the successful incorporation of the hematite α-Fe2O3 into the lignocellulose. The second part is devoted to α-Fe2O3 working as sensitizer in photocatalysis, it was characterized optically (Eg = 1.94 eV) and electrochemically with a flat band potential of −0.53 VSCE. The conduction band (−0.73 V SCE ) is more cathodic than the potential of the O2/O2 •− couple (−0.52 V SCE ) and should reduce dissolved oxygen into reactive O2 •− radical. The as-prepared materials were successfully tested in the photocatalytic degradation of Rh B (10 ppm) and the result gave an abatement of 60% on α-Fe2O3/lignocellulose under visible light irradiation (LED lamp) with a flux of 23 mW cm−2. The kinetic obeys a first-order model with a half photocatalytic-life of ∼ 7 h.