Intensification of peroxone production through the paired generation of hydrogen peroxide and ozone in a continuous flow electrochemical reactor

Abstract

The paired electrochemical production of ozone and hydrogen peroxide is evaluated in a novel 3-D printed electrochemical cell in which the oxidants produced are tested in the removal of fluoxetine hydrochloride (FLX). To properly pair the anodic production of ozone and the cathodic production of hydrogen peroxide in the same cell, that is, with the same intensity in anode and cathode, an innovative composite 3-D gas diffusion cathode was used to decrease the current density (by increasing the effective cathode surface area) in the cathodic compartment, attaining soft operation conditions in this compartment. Meanwhile, a grid DIACHEM® lattice BDD was used in the anode to increase the harsh oxidative conditions in the anodic compartment. The results confirm the viability of pairing both processes. Current intensity positively affects the production of ozone and, less importantly, the production of hydrogen peroxide (because the current efficiency decreases with the intensity), with the contribution of electrolytes containing sulfate and bicarbonates being evaluated in the search of greener processes. The oxidants produced were dosed to solutions containing FLX confirming that the addition of both products (electro-peroxone process) attains a significant improvement in the removal of FLX, which was explained in terms of promoting radical mechanisms for ozone oxidation (peroxone reagent).