UV-based Advanced Oxidation Processes for Albendazole Degradation

Pharmaceuticals are complex molecules with different physicochemical and biological properties and functionalities. Although they are present in the aquatic environment in low (ng/L) concentrations, they are continually being released into the environment what can lead to unwanted effects on the living organisms. Many studies showed that the main points of collection and subsequent release of pharmaceuticals into the environment are wastewater treatment plants, suggesting that their upgrade and implementation of advanced treatment technologies are required. One of the possible solutions for degradation and/or removal of pharmaceuticals from the wastewaters is the use of advanced oxidation processes (AOP) as an additional treatment step. In this study the degradation of albendazole (ALB) was investigated using three UV based processes (with 185/254 and 365 nm radiation sources): (i) UV photolysis, (ii) UV photocatalysis (UV light + TiO2 nano film) and (iii) UV+O3 process. Screening of albendazole and related degradates was performed using liquid chromatography tandem mass spectrometry (HPLC- MS/MS) and ultra high performance liquid chromatography quadrupole time-of-flight mass spectrometry (UHPLC-QTOF-MS) with direct injection. The fastest degradation of ALB, for both UV-C and UV-A radiation, was obtained by UV+O3 process with removal efficiency higher than 90%, achieved in 10 minutes. Although the slowest degradation of ALB was obtained using UV-A processes, they have a potential for practical use since they could use natural solar radiation as a source of UV-A radiation and therewith significantly reduce the price of the treatment step.