Photocatalytic degradation of metoprolol in aqueous medium using a TiO2/ natural zeolite composite

Abstract

Photodegradation of metoprolol using a TiO2 and Mexican natural zeolite composite (T/MZ) was studied. The photocatalyst was successfully synthesized by physical mixing method where commercial TiO2 Degusa P25 was supported on thermochemical modified clinoptilolite. X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy and Fourier transform infrared spectroscopy confirmed the TiO2 incorporation over the clinoptilolite surface without structural changes of the zeolite. Point of zero charge of 6.2 was found for the T/MZ, while the bandgap energy of 3.15 eV was obtained by UV–Vis diffuse reflectance spectroscopy. Photodegradation tests of metoprolol as a model emerging pollutant were carried out, finding that the T/MZ composite to have superior degradation percentages thant the commercial TiO2 P25 for all the pH values tested (3–9), which demonstrates a synergistic effect between the semiconductor material and the zeolitic support. Finally, it was found that the kinetics degradation of metoprolol follows the Langmuir, Hinshelwood, Hougen and Watson (LHHW) model.