Tannic acid oxidation by Electroperoxone

Abstract

The electro-peroxone (E-peroxone) process as an advanced oxidation process integrates the ozonation and electrooxidation processes in a system. The process produces in situ H2O2 on the cathode surface by using sparged oxygen that releases during ozone generation. E-peroxone provides highly oxidative reaction conditions due to the further reaction of H202 with ozone to produce OH center dot radicals. In this study in which oxidation of tannic acid was carried out, 10% more dissolved organic carbon mineralization was provided by converting the ozonation system to E-peroxone. While H2O2 did not directly involve in the oxidation of tannic acid, the molecular ozone reaction dominated the oxidation at the early stage of the reaction. The OH center dot radicals produced were involved in oxidation and resulted in the formation of less ozone-reactive structures (ie carboxylic acids). However, the superiority of the E-peroxone process to form more OH center dot radicals was limited due to the low pH of tannic acid. The change of ozone dose and applied flow density were other parameters affecting the oxidation efficiency.