Suspension Reactor Studies for the Photocatalytic Degradation of Acetaminophen

Traditional wastewater treatment plants are not generally designed to handle degradation of pharmaceuti-cal-based contaminants, nor do such plants generally incorporate processes that enable complete elimina-tion of pharmaceutical residues. Therefore, pharmaceutical metabolites can be found in groundwater, sur-face water, and even drinking water in low concentrations. Advanced Oxidation Processes (AOPs) are promising to avoid the contamination of agricultural land and aquifers. Here, we focus specifically on the use of photocatalytic degradation processes via titanium dioxide (TiO2) nanoparticles as a photocatalyst, as-sisted by UV radiation and enhanced by H2O2. This degradation approach may allow the degradation of pharmaceutical compounds, such as acetaminophen (ACE), in municipal water treatment plants in which a tertiary treatment phase is suitable. We employ a batch, water-cooled jacketed reactor equipped with a UV lamp containing a TiO2 nanoparticle suspension for the degradation of ACE. We identify favorable condi-tions for contaminant degradation (~63%) at low concentrations of both ACE and titanium dioxide after 90 minutes of treatment. Several combinations of potential AOPs approaches were compared (e.g., UV-C only, UV-C/H2O2, UV-C/H2O2/TiO2 and H2O2 alone). In general, the combined action of the techniques leads to a better degradation of the contaminant. The results suggest AOPs are promising candidates for removal of pharmaceutical metabolites from wastewater effluents.