Highly Efficient and Long-Lifetime Ozone Water Production System Realized Using a Felt Separator

Abstract

The efficiency of ozone production using a conventional polymer electrolyte system with Pt electrodes decreased from 15 to 2% after operating for 100 h. The degradation of the system was caused by Pt black particles concentrated on the cathode side of the Nafion 117 membrane. The particles reacted with the membrane and produced holes on its cathode-side surface. To prevent the decomposition of the membrane, a felt separator made of polyethylene terephthalate (PET) was inserted between the Nafion 117 membrane and the cathode Pt electrode, and dilute NaCl or solutions of 0.01–1 M were circulated through the cathode to compensate for the low conductivity of the PET separator. As a result, a high current efficiency of more than 20% and a lifetime longer than 150 h have been achieved in the electrolysis system. The PET felt separator captured Pt black particles and prevented the membrane from decomposition. However, the lifetime of ozone in anode water was much shorter than that obtained using a conventional electrolyte system. A similar lifetime to that in the conventional system was obtained by substituting the PET felt separator with a quartz filter.