Photocatalytic Degradation of Methylene Blue using Fe2O3-TiO2/Kaolinite under Visible Light Illumination

Abstract

<p>Combining TiO₂ and a semiconductor with a smaller band gap, such as Fe₂O₃, to form a heterojunction composite can increase its photocatalytic activity. In this work, the Fe₂O₃-TiO₂/kaolinite composites were successfully synthesized by ultrasonic-assisted coprecipitation using titanium-tetraisopropoxide (TTIP) dan Fe (NO₃)₃.9H₂O as precursors. Using kaolinite as a matrix also increases the photocatalyst’s surface area. The obtained Fe₂O₃-TiO₂/kaolinite composites were characterized. The crystal phase was characterized using X-Ray Diffraction and resulted in anatase with a crystallite size average of 9,7 nm. Fourier Transform Infrared Spectrophotometer (FTIR) shows the peak at a wavenumber 574-1210 cm⁻¹ ascribed TiO₂ and Fe₂O₃ incorporated into kaolinite. The Optical properties show the absorption edge of Fe₂O₃-TiO₂/kaolinite is redshift toward the visible light region. The result showed that the photocatalytic activity of Fe₂O₃-TiO₂/kaolinite composites with heterostructure was more active than the corresponding Fe₂O₃ or pure TiO₂ in the degradation of methylene blue under visible light illumination, which can degrade 83% for 180 minutes. Fe₂O₃ and kaolinite cause its synergistic effect as supporting materials. Furthermore, it indicates that the recombination of photo hole and photoelectron charge pair can be minimized. The Fe₂O₃-TiO₂/kaolinite composite is a promising photocatalyst to degrade organic pollutants for wastewater treatment.</p>