Electrochemical generation of ozone for application in environmental remediation

Abstract

This work focuses on the production, in continuous mode, of ozone using a new electrochemical cell, specially designed and manufactured with 3-D printing to produce in a very efficient way high concentrations of this powerful oxidant. The gaseous ozone produced is tested in the degradation of a synthetic waste containing methomyl. The new cell has been characterized in terms of flow distribution, mass transfer, and production of ozone, being able to reach efficiencies as high as 9.5 g/kWh, which may be even competitive with those produced with the corona discharge technology. The prototype manufactured with an electrode area of 1.5 cm2 can produce a stream containing 30 mg/h of O3. This stream can be used to degrade methomyl. However, the direct bubbling was not found to be very efficient and activation of ozone with the simultaneous irradiation of UV light or the dosing of hydrogen peroxide was needed to improve performance, showing important synergism. The efficient removal of methomyl from wastewater opens the window for the development of alternative technologies to direct anodic oxidation based on the production and dosing of gaseous oxidants such as ozone. The operation of these new technologies does not depend on the salts contained in wastewater and prevents the deterioration in the quality of the waste because it does not leave any residue after application in the treated waste.