Energy recovery in wastewater decontamination: Simultaneous photocatalytic oxidation of an organic substrate and electricity generation

The contemporary removal of organic pollutants from aqueous solution and electricity generation is studied in the present work by means of an experimental device resulting from the combination of a photocatalytic reactor and an electrochemical cell. The proposed system relies on the capability of Cu²⁺ ions to reduce in the presence of TiO₂, (solar) UV radiations and a sacrificial organic agent. In the anodic solution of the combined photoreactor-cell, Cu⁰ is oxidized to Cu²⁺ and the latter is reduced again to the lowest oxidation state. The use of different sacrificial agents ranging from formic acid (FA) to glycerol (GLY) to glucose (GLU) is investigated along with the adoption of two different cathodes for the cell, the first based again on the couple Cu²⁺/Cu⁰ and the second on the couple O₂/H₂O.