Phenanthrene degradation using Fe(III)-EDDS photoactivation under simulated solar light: A model for soil washing effluent treatment

• Published in: Chemosphere (Oxford) Vol. 236; p. 124366
• Main Authors: Tao, Yufang, Brigante, Marcello, Zhang, Hui, Mailhot, Gilles
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.12.2019; Elsevier
• Subjects: Advanced oxidation processes; Chemical Sciences; Ferric Compounds - chemistry; Iron complexes; Phenanthrenes - chemistry; Photochemistry; Soil - chemistry; Soil depollution; Solar Energy; Sulfate radical; Advanced oxidation processes; Sulfate radical; Iron complexes; Soil depollution; Photochemistry
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/j.chemosphere.2019.124366

In this work, for the first time, the nonionic surfactant polyoxyethylene-(20)-sorbitan monooleate (Tween 80, C64H124O26) aided soil washing effluent was treated by enhanced activation of persulfate (PS) using Fe(III)-EDDS (EDDS: ethylenediamine-N, N-disuccinic acid) complexes under simulated solar light irradiation. The performance of this system was followed via the production and reactivity of radical species (SO4-, HO, Cl2-) and degradation of phenanthrene (PHE) used as a model pollutant in soils. Different physico-chemical parameters such as the concentration of reactive species and pH were investigated through the PHE degradation efficiency. The second-order rate constants of the reactions for generated radicals with PHE and Tween 80 in solution were identified through competitive reaction experiments under steady-state conditions and application of nanosecond laser flash photolysis (LFP) as well. A kinetic approach was applied to assess the selectivity and reactivity of photo-generated radicals in aqueous medium in order to explain the observed degradation trends. This work proposes an innovative technology of management of soil washing solutions using Fe(III)-EDDS complexes and solar light for the activation of persulfate. •Soil washing effluent is treated by a novel application involving Fe(III) complexes and persulfate.•Primary photo-redox process of Fe(III)-EDDS governs the efficiency of PHE degradation.•The presence of TW80 is the crucial factor governing the degradation of PHE.•The reactivity of radical species on PHE is modified in the presence of TW80.•The presence of chloride ions can significantly improve the PHE removal in this system.