Characterisation of a laboratory electrochemical ozonation system and its application in advanced oxidation processes

An electrochemical reactor for oxygen/ozone production was developed using perforated planar electrodes. An electroformed beta-PbO2 coating, deposited on a platinised titanium substrate, was employed as anode while the cathode was a platinised titanium substrate. The electrodes were pressed against a solid polymer electrolyte to minimise ohmic drop and avoid mixing of the gaseous products (H-2 and O-2/O-3). Electrochemical ozone production (EOP) was investigated as function of current density, temperature and electrolyte composition. Electrochemical characterisation demonstrated ozone current efficiency, F EOP, ozone production rate (g h(-1)), v(EOP), and grams of O-3 per total energy demand (g h(-1) W-1), v(EOP) increase on decreasing electrolyte temperature and increasing current density. The best reactor performance for EOP was obtained with the base electrolyte (H2SO4 3.0 mol dm(-3)) containing 0.03 mol dm(-3) KPF6. Degradation of reactive dyes used in the textile industry (Reactive Yellow 143 and Reactive Blue 264) with electrochemically-generated ozone was investigated in alkaline medium as function of ozone load (mg h(-1)) and ozonation time. This investigation revealed ozonation presents very good efficiency for both solution decolouration and total organic carbon (TOC) removal.