Synthesis, Surface Characterization and Photocatalytic Activity of TiO2 Supported on Almond Shell Activated Carbon

Three types of photocatalysts were synthesized by metal organic chemical vapor deposition and impregnation methods using the almond shell activated carbon as support. These photocatalysts denoted by (TiO 2 /ASAC (V), TiO 2 /ASAC (I1) and TiO 2 /ASAC (I2)) were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), diffuse reflectance spectroscopy (DRS) and nitrogen adsorption–desorption isotherms. SEM observation shows that TiO 2 was deposited on activated carbon surface. XRD results confirm that TiO 2 existed in a mixture of anatase and rutile phases. The DRS spectra show the characteristic absorption edge of TiO 2 at approximate 380 nm corresponding to the optical band gap of 3.26 eV. Besides, FTIR spectrum indicated the presence of (Ti–O) groups. The specific surface area of photocatalysts decreased drastically in comparison with the original activated carbon. The catalysts were very efficient for the photodegradation of total organic carbon (TOC) from industrial phosphoric acid solution under UV irradiation. The kinetics of photocatalytic TOC degradation was found to follow a pseudo-first-order model. The prepared TiO 2 /ASAC showed high photoactivity for the photodegradation of TOC in the following order: TiO 2 /ASAC (V) > TiO 2 /ASAC (I1) > TiO 2 /ASAC (I2) > ASAC > TiO 2 (P25).