Photocatalytic Treatment of Pharmaceuticals in Real Hospital Wastewaters for Effluent Quality Amelioration

• Main Authors: Panagiotis-Spyridon Konstas, Christina Kosma, Ioannis Konstantinou, Triantafyllos Albanis
• Format: Article
• Language: English
• Published: MDPI AG 2019-10-01
• Series: Water
• Subjects: hospital wastewater; pharmaceutical compounds; photocatalysis; tio₂; g-c₃n₄; srtio₃/g-c₃n₄; transformation products; metabolites
• Online Access: https://www.mdpi.com/2073-4441/11/10/2165

The presence of pharmaceutically active compounds (PhACs) in the wastewater effluents has confirmed that conventional wastewater treatment technologies are not sufficiently effective in the pharmaceuticals’ removal. The objective of the present study was to evaluate and compare the photocatalytic degradation of PhACs using TiO₂-P25, graphitic carbon nitride (g-C₃N₄, CN) and a heterojunction of perovskite strodium titanate and graphitic carbon nitride SrTiO₃/g-C₃N₄ (20% g-C₃N₄, 20CNSTO) photocatalytic materials, in hospital wastewater effluents, by simulated solar irradiation. The experiments were performed by using real wastewater samples collected from the university hospital wastewater treatment plant (WWTP) effluent of Ioannina city (Northwestern Greece) and inherent pharmaceutical concentration levels. The analysis of the samples was accomplished by solid phase extraction followed by liquid chromatography-Orbitrap high-resolution mass spectrometry. In the cases of TiO₂ and CN, more than 70% of the initial concentration (e.g., venlafaxine) was degraded after 90 min, while 20CNSTO presented lower photocatalytic performance. Furthermore, some compounds were sporadically detected (e.g., fluoxetine) or their concentrations remained stable during the photocatalytic treatment time period (e.g., trimethoprim). In total 11 transformation products (TPs) were formed along the degradation processes and were identified by using liquid chromatography high resolution mass spectrometry.