Photodegradation of 17α-ethinylestradiol on Ag3PO4 crystals treated at different temperatures

Abstract

The incorrect disposal of medicines can trigger an imbalance in the ecosystem of rivers and lakes, as well as human and animal health. Therefore, the heterogeneous photocatalysis technique is a promising technology to minimize or even eliminate these pollutants from aquatic systems. Silver phosphate crystals (Ag3PO4) have excellent photocatalytic and bactericidal properties. For the synthesis of crystals of silver phosphate, the method of preparation used was precipitation at room temperature, followed by heat treatment at 100, 200, 300, 400, and 500 ºC for six h. The X-ray Diffraction data show structures with excellent crystallinity, remaining even after temperature variation. Scanning electron microscopy images exhibited a variation in the morphology of the materials with increasing temperature. Diffuse reflectance spectroscopy revealed the materials optical band energy values ranging from 2.33 to 2.41 eV. On the other hand, the Raman and Infrared spectra showed a reduction in the bands referring to the phosphate groups. The Ag3PO4 crystals heat treated at 200 and 500 ºC showed the better performance for the photodegradation of 17α-ethinylestradiol (EE2) with highest kinetic constant (7.42x10− 3 min− 1) and TOF (3.11x10− 4 min − 1) values for photocatalyst test carried out on crystals heat treated at 200 ºC.