(25c) Photocatalytic Degradation of Acetaminophen in Dilute Aqueous Solutions

Photocatalytic degradation of acetaminophen in dilute aqueous solution was evaluated using both a catalyst slurry and catalyst immobilized on glass surfaces. Acetaminophen oxidation was studied under various operating conditions to better understand how the reaction conditions impact initial degradation rates and byproduct compositions. Reaction conditions, such as 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 films may eliminate the need to separate fine catalyst particles from the reaction medium, yet few comparisons of their effectiveness to that of slurry reactors are available. Catalyst lifetime, stability on the support, consumption of additional reagents, value and/or safety of the degradation products and energy consumption were considered when comparing various reaction options.