Periodic bipolar operation of Ti/RuO2-IrO2-RhOx electrodes for in-situ polymeric product desorption in recalcitrant contaminant degradation: From pseudocapacitive stabilization to model simulation

Anodic oxidation has been recognized as an attractive technique for wastewater treatment. However, polymeric product (PP) adsorption still remains to be an obstacle because currently available exogenous PP removal methods are either laborious or costly. To overcome such a problem, a Ti/RuO2-IrO2-RhOx has been artfully designed for periodic bipolar operation to realize in-situ PP desorption herein. Due to the RhOx-bridged pseudocapacitance enhancement, the electrochemical stability reduction problem of the conventional electrode in bipolar operation could be substantially eliminated. The PP adsorption mainly impacted the interfacial charge transfer of the electrode instead of the mass transfer of contaminant from the solution toward the electrode surface. Delightedly, the bipolar operation could effectively in-situ regenerate the poisoned electrode from PP adsorption due to the combined effects of OH- dissolution and H(2 )stripping, thereby essentially promoting the deep mineralization of degradation intermediates rather than further polymerization, with this promotion degree influenced by four factors (current density, initial contaminant concentration, bipolar frequency, and contaminant types). This further encouraged the successful establishment of a new bipolar completely mixed (BCM) model for theoretical guidance of efficient PP desorption during various contaminant degradation. This work might open up a brand new avenue for poisoned electrode in-situ regeneration from detrimental PP adsorption and provide mathematical model guidance for PP desorption.