Paracetamol Mineralization by Advanced Electrochemical Oxidation Processes for Wastewater Treatment

Abstract

Environmental Context.Even after passing through water treatment plants, discarded pharmaceuticals have been linked with poisoning aquatic life. A simple and reliable method for treating household wastewater would alleviate this issue. Using the common pain reliever paracetamol as a model, the simple combination of dissolved iron and copper with ultraviolet light is shown to fully decompose (‘mineralize’) this drug into simple inorganic components, which represents an improvement over current treatments with ozone or peroxides, that achieve only partial mineralization. Paracetamol solutions at pH 3.0 have been efficiently mineralized by environmentally clean electrochemical methods such as electro-Fenton and photoelectro-Fenton processes using a cell with a Pt anode and an O2-diffusion cathode for H2O2 electrogeneration. This species reacts with added Fe2+ giving hydroxyl radical as main oxidant. Photoelectro-Fenton with Fe2+, Cu2+, and UVA light as catalysts leads to complete mineralization due to the removal of the final carboxylic acids (oxalic and oxamic). When catalysts are used separately, both acids or part of them remain in solution, giving a partial (> 65%) mineralization.