Improving treatment of VOCs by integration of absorption columns into electrochemical cells using 3-D printing technology

Abstract

This work is focused on the evaluation of the performance of a novel integrated electrochemically assisted absorption reactor. This reactor combines a PEM cell (equipped with Nafion 117 membranes, boron doped diamond anode and titanium cathode) and a packed absorption column into a one compartment device that helps to maximize the use of electrogenerated oxidants by promoting the oxidation of gaseous pollutants. The device has been made using 3D printing technology with a clear Formlabs resin as printing material. Benzene was used as model of volatile organic compound (VOCs). Results demonstrate that this technology prevents wasting of ozone and obtains high efficiencies in the removal of benzene. As well, it is shed light on the mechanisms of benzene absorption and degradation in the liquid phase and on the effect of the current density on the efficiency of the process. Maximum removal efficiencies of nearly 60% are attained working at 50 mA·cm−2 with a moderate energy consumption. Lower degradation at higher current densities is explained in terms of the benzene desorption from liquid to gas phase provoked by the intense gas generation at the electrochemical cell (mainly H2 and O2). These results demonstrate the viability of this new reactor for the removal of VOC's.