Enhancement of photocatalytic degradation of Malachite Green using iron doped titanium dioxide loaded on oil palm empty fruit bunch-derived activated carbon

Abstract

Iron-doped titanium dioxide loaded on activated carbon (Fe-TiO₂/AC) was successfully synthesized from oil palm empty fruit bunch (OPEFB) using sol-gel method. The properties of the synthesized pure TiO₂, Fe-doped TiO₂, AC, TiO₂/AC and Fe-TiO₂/AC were examined by various techniques such as field emission scanning electron microscopy (FE-SEM), Fourier-transform infrared spectroscopy (FT-IR), UV-Vis diffuse reflectance spectroscopy (UV-Vis DRS) and nitrogen adsorption-desorption analyses at 77 K. FE-SEM revealed that Fe-doped TiO₂ particles were dispersed homogeneously on the AC surface. FT-IR demonstrated high surface hydroxylation after Fe doping on TiO₂ and UV-Vis DRS showed that Fe-TiO₂/AC had the lowest band gap energy. Catalytic performance results proved that Fe dopants could restrict the recombination rate of hole and electron pairs, whereas AC support improved the Malachite Green (MG) adsorption sites and active sites of the hybrid catalyst. Photocatalytic degradation of 100 mg/L MG in the presence of 1.0 g/L 15 wt% Fe-TiO₂ incorporated with 25 wt% AC, initial solution pH of 4 and 3 mM H₂O₂ could achieve the highest removal efficiency of 97% after 45 min light irradiation. This work demonstrates a promising approach to synthesis an inexpensive and efficient Fe-TiO₂/AC for the photocatalytic degradation of organic dye.

Keywords: Activated carbon; Fe dopant; Oil palm empty fruit bunch waste; Photocatalytic degradation; Titanium dioxide.