Silver and manganese co-doped titanium oxide aerogel for effective diclofenac degradation under UV-A light irradiation

Abstract

The photodegradation of diclofenac from aqueous medium under UV-A light condition has been essayed using co-doped with manganese and silver TiO2 photocatalysts. X-ray diffraction, Raman spectroscopy, Scanning electron microscopy, Transmission electron microscopy, High resolution transmission electron microscopy, Energy dispersive X-ray, N2 adsorption-desorption measurements at 77 K, UV–Visible diffuse reflectance, X-ray photoelectron spectroscopy and photoluminescence analyses were used to characterize the materials. A high surface specific area of 165 m2/g, low band gap energy (2.7 eV) and effective charge separation were obtained for the 0.5%Ag-0.6%Mn/TiO2 photocatalyst. The results of the photocatalytic experiments showed that co-doping improved the photocatalytic activity of TiO2. In particular, TiO2 co-doped with 0.6 mol% Mn and 0.5 mol% Ag exhibited the maximum diclofenac removal (86%) after 4 h under UV-A light irradiation. The photodegradation rates followed a first order kinetics according to the Langmuir-Hinshelwood model, being the highest apparent rate of 0.0064 min−1. The photocatalytic performance appears as related to the specific surface area, the low optical band gap energy, the creation of surface oxygen vacancies and the efficient separation of photogenerated electron-hole pairs.