Electrochemical treatment of flutriafol wastewater using a novel 3D macroporous PbO2 filter: Operating parameters, mechanism and toxicity assessment

In order to break the high operating cost bottleneck of electrochemical treatment of aqueous flutriafol (FTF), an emerging fungicide, a novel three-dimensional ordered macroporous PbO2 (3DOM-PbO2) filter was designed to facilitate mass transfer. The effects of operating parameters, including current density, flow rate and initial concentration on FTF electrooxidation performance were investigated using conventional flat Ti/PbO2 (F-Ti/PbO2) and 3DOM-PbO2 filters, with primary objective being the development of appropriate parameters for FTF treatment. The results indicated that the FTF removal efficiency on 3DOM-PbO2 filter was improved by 2.8 times compared to that on F-Ti/PbO2 at 5 inA cm(-2), 10 ml s(-1) and 100 mg L-1 FTF. The corresponding electrical energy consumption was reduced by 2.7 times, 'TOC removal and mineralization current efficiency were enhanced by 4.9 and 4.8 times, respectively. Furthermore, aromatic intermediates, nitrogenous compounds and carboxylic acids were identified as main byproducts using experimental method combined with quantum chemical calculations. Then, a possible pathway of FTF degradation on 3DOM-PbO2 was proposed. Finally, the acute toxicity results showed that toxicity of the byproducts first increases and then decreases through the proposed route. LC50,48 h value of FTF wastewater increased 35%-70% on the 3DOM-PbO2 filter, indicating a significant biodegradability enhancement.