Farshid Kazemi - Department of Applied Chemistry, Mashhad Branch, Islamic Azad University, Mashhad, Iran
Hasan ali Zamani - Department of Applied Chemistry, Mashhad Branch, Islamic Azad University, Mashhad, Iran
Mohamad Reza Abedi - ۲Department of Applied Chemistry, Quchan Branch, Islamic Azad University, Quchan, Iran
Mahmoud Ebrahimi - Department of Applied Chemistry, Mashhad Branch, Islamic Azad University, Mashhad, Iran

In this study, a photocatalyst based on the combination of a polyoxometalate (۱۲-tungstosilicic acid) and a nanoparticle (α-Fe۲O۳) was prepared to investigate its ability to degrade Tramadol from water samples. The structure, morphology, and functional groups of the synthesized photocatalyst (α-Fe۲O۳/ ۱۲-tungstosilicic acid) were characterized using SEM images, EDX pattern, TEM image, FAM images, and FTIR spectra. Due to the high surface-to-volume ratio in nanoparticles and high intramolecular charge transfer by polyoxometalates, the combination of α-Fe۲O۳ nanoparticles and ۱۲-tungstosilicic acid as a photocatalyst exhibits a high photodegradation efficiency in a suitable time toward the tramadol degradation. Besides, several factors affecting the degradation process of Tramadol with the prepared photocatalyst were evaluated using an experimental design method based on Box-Behnken design to reduce the number of experiments and study the interaction between the factors. In optimal conditions, the tramadol concentration, pH of the sample solution, photocatalyst amount, and the hydrogen peroxide concentration were optimized, which were ۹۰.۰ mg L-۱, ۳۰۰ mg L-۱, ۷.۶, and ۰.۶ mg L-۱, respectively. The study of the photocatalyst activity and the degradation kinetics for the tramadol photodegradation as a pharmacological contaminant in a water sample under ultraviolet irradiation exhibited that the synthesized photocatalyst had a high photodegradation efficiency with a pseudo-first-order rate constant of ۰.۰۲۳۲ min-۱ for a photodegradation time of ۷۰ min.  

Polyoxometalates, Tramadol, Photodegradation, α -Fe۲O۳ nanoparticles, ۱۲-tungstosilicic acid