Removal of oxyfluorfen from polluted effluents by combined bio-electro processes

• Published in: Chemosphere (Oxford) 2020-02, Vol.240, p.124912-124912, Article 124912
• Main Authors: Carboneras, M.B., Rodrigo, M.A., Canizares, P., Villasenor, J., Fernandez-Morales, F.J.
• Format: Article
• Language: English
• Subjects: Biological treatment; Bioreactors - microbiology; Boron; Boron-doped diamond; Combined process; Diamond; Electrochemical treatment; Electrodes; Electrolysis - instrumentation; Electrolysis - methods; Halogenated Diphenyl Ethers - chemistry; Halogenated Diphenyl Ethers - metabolism; Herbicide; Kinetics; Oxidation-Reduction; Pesticides - chemistry; Pesticides - metabolism; Sulfates - chemistry; Waste Disposal, Fluid - methods; Water Pollutants, Chemical - chemistry; Water Pollutants, Chemical - metabolism
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/j.chemosphere.2019.124912

In this work, the combination of biological and electrochemical processes to mineralize oxyfluorfen has been studied. First, an acclimatized mixed-culture biological treatment was used to degrade the biodegradable fraction of the pesticide, reaching up to 90% removal. After that, the non-biodegraded fraction was oxidised by electrolysis using boron-doped diamond as the anode. The results showed that the electrochemical technique was able to completely mineralize the residual pollutants. The study of the influence of the supporting electrolyte on the electrochemical process showed that the trace mineral solution used in the biological treatment was enough to completely mineralize the oxyfluorfen, resulting in total organic carbon removal rates that were well-fitted by a first-order model with a kinetic constant of 0.91 h−1. However, the first-order degradation rate increased approximately 20% when Na2SO4 was added as supporting electrolyte, reaching a degradation rate of 1.16 h−1 with a power consumption that was approximately 70% lower. •Low oxyfluorfen concentrations were completely removed by means of bioprocesses.•When operating with high oxyfluorfen concentrations product inhibition appeared.•Electrochemical treatment completely removed the non-biodegraded fraction.•Coupling biological and electrochemical processes ensure oxyfluorfen mineralization.•Na2SO4 as supporting electrolyte increased the first order rate in about 20%.