Collivignarelli MC, Abbà A, Carnevale Miino M, Arab H, Bestetti M, Franz S. Decolorization and biodegradability of a real pharmaceutical wastewater treated by H
2O
2-assisted photoelectrocatalysis on TiO
2 meshes.
JOURNAL OF HAZARDOUS MATERIALS 2020;
387:121668. [PMID:
31784132 DOI:
10.1016/j.jhazmat.2019.121668]
[Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Revised: 11/06/2019] [Accepted: 11/10/2019] [Indexed: 05/27/2023]
Abstract
In recent years, photoelectrocatalysis (PEC) for the treatment of industrial wastewaters (IWWs) has been repeatedly proposed. However, despite the number of tests reported in literature, only a few of them were conducted on real IWWs. In this study, real pharmaceutical IWWs showing an intense recalcitrant color were treated by PEC and H2O2-assisted PEC (UV/TiO2/Bias and UV/H2O2/TiO2/Bias, respectively) on TiO2 meshes having sub-micrometric features obtained by Plasma Electrolytic Oxidation. Photolysis (UV), chemical oxidation (H2O2) and H2O2-assisted photolysis (UV/H2O2) were tested in the same reactor for comparison. The configuration UV/H2O2/TiO2/bias showed the best results in term of decolorization efficiency and rate, where decolorization was 55 % (single-step H2O2 dosing) and 44 % (three-step H2O2 dosing), after 2 h of contact time. In the same contact time, UV and UV/TiO2/Bias processes did not give decolorization. A more effective COD removal was measured for the PEC processes, UV/H2O2/TiO2/Bias (-24 %) and UV/TiO2/Bias (-20 %), while COD removal by UV was almost 0 %. Correspondingly, the SOUR values showed that PEC combined with a single-step H2O2 dosage was the most effective configuration, leading to the highest biodegradability of the treated IWW with respect to the other processes. The energy consumption analysis demonstrated that PEC+H2O2 (single-step dosage) optimized energy costs.
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