Photocatalytic degradation of anti-cancer drugs

Details

Supervisors

Luis Alconero, Patricia ; Janssens, Raphaël

Faculty

Ecole polytechnique de Louvain

Degree label

Master [120] : ingénieur civil en chimie et science des matériaux

Abstract

Antineoplastic drugs are compounds used as anti-cancer treatment. Their toxicity is an issue as they are only poorly eliminated through conventional wastewater treatment. Advanced oxidation processes (AOPs), which have recently emerged as treatment technologies, aim to remove persistent pollutants. In the present work, the removal of anti-cancer drugs by photocatalytic membrane reactor is studied and compared with photolysis and peroxide treatments. 4 drugs were investigated: 5-Fluorouracil, Capecitabine, Cyclophosphamide and Ifosfamide. The study was conducted through kinetics-based, energy-based and economic assessment. Effects of the matrix (wastewater - laboratory grade water) and the presence of catalyst were first studied under irradiation of 2 low pressure (LP) mercury lamps. The addition of 1.5 [g/L] of TiO2 led to an improvement of the kinetics in both laboratory grade water and wastewater, while the passage from laboratory grade water to wastewater led to lower efficiency of both direct photolysis and photocatalysis. Agglomeration of TiO2 in wastewater was also observed in comparison to laboratory grade water. Photolysis and photocatalysis experiments were then performed with a medium pressure (MP) mercury lamp, to investigate the influence of irradiation source on the degradation kinetics. Photolysis showed higher degradation rates than photocatalysis under the irradiation of medium pressure lamps, while both showed improved kinetics in comparison to low pressure lamps based photolysis and photocatalysis. On the other hand, medium pressure lamp based processes were observed to achieve a much less energy efficient degradation than the low pressure lamp based processes. UV(low pressure lamp)/H2O2 experiments, with H2O2 concentration of 0.05 [g/L], were then performed in wastewater. The combination of photocatalyst and hydrogen peroxide was concluded to be inefficient, as proposing lower degradation rates and higher energy demands than UV-photolysis with H2O2 alone. Finally, LP-H2O2 photolysis was shown to be more efficient than direct photolysis and photocatalysis on all three kinetic, energetic and economic aspects.