Comparison of Photoreactor Designs for Oxidation of Dilute Aqueous Waste Contaminants

The viability of photocatalytic reactions in advanced oxidation processes for removal of dilute aqueous contaminants was evaluated using a variety of reaction systems.  Using acetaminophen as analyte, the oxidation reaction was studied using various operating conditions and reactor designs to better understand how the reaction conditions impact conversion and potentially, product selectivity.  Catalyst concentration, reagent concentration, metal loading on the catalyst, oxygen purging, solution pH, solution temperature, addition of oxidant, batch versus continuous operation, light intensity and semiconductor stabilization were investigated.  Literature results for reaction intermediates and reaction kinetics were used to interpret experimental results.  A main focus was optimization of reaction conditions that can make photocatalytic oxidation of dilute aqueous contaminants more sustainable and economical.  Catalyst stability, consumption of additional reagents, value and/or safety of the degradation products and energy consumption were considered for the various reaction options.