Innovative photoelectrochemical cell for the removal of CHCs from soil washing wastes

• Published in: Separation and purification technology Vol. 230; p. 115876
• Main Authors: Cotillas, Salvador, Lacasa, Engracia, Herraiz-Carboné, Miguel, Sáez, Cristina, Cañizares, Pablo, Rodrigo, Manuel A.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 02.01.2020
• Subjects: Clofibric acid; Diamond; Photoelectrolysis; Soil remediation; Toxicity; Soil remediation; Photoelectrolysis; Diamond; Clofibric acid; Toxicity
• ISSN: 1383-5866; 1873-3794
• DOI: 10.1016/j.seppur.2019.115876

•Novel photoelectrocatalytic cell for the remediation soil washing fluids.•Complete removal of clofibric acid at 10 mA cm−2, with less than 5 kAh m−3.•Efficient mineralization and detoxification regardless light irradiation.•Complete reduction of toxicity during the electrolysis and photoelectrolysis. This work presents a novel photoelectrochemical cell concept for the treatment of soil washing effluents polluted with chlorinated hydrocarbons (CHCs). This cell combines the use of low current densities and the direct irradiation of UV light to the electrodes and the bulk, being easy to be scaled up. To evaluate its performance, the treatment of a soil washing effluent polluted with clofibric acid (~50 mg dm−3) was carried out. The prototype evaluated was equipped with two boron doped diamond (BDD) plates as anodes, two stainless steel (SS) plates as cathodes and a UV lamp located at the bottom. Results show that it was possible to attain a complete abatement and mineralization of the organochlorinated compound at applied electric charges lower than 5 Ah dm−3, regardless the irradiation of UV light. Nevertheless, the removal rate was higher during photoelectrolysis, specially at the beginning of the treatment, which indicates important advantages for the removal of aromatic compounds. In addition, the toxicity of the effluent was dramatically reduced at the end of the process. These results point out the high performance of the novel photoelectrochemical reactor proposed for the complete remediation of soils polluted with CHCs.