Application of soluble bio-organic substances (SBO) as photocatalysts for wastewater treatment: Sensitizing effect and photo-Fenton-like process
Soluble bio-organic substances (SBO) isolated from urban biorefuses have been investigated in photocatalytic processes for wastewater treatment using a cationic dye, namely crystal violet (CV) as target compound. The SBO have been found to enhance the photobleaching of CV solutions with an optimal SBO concentration of ca. 20 mg L−1. Mechanistic investigation based on chemical probes and changes in the absorption spectrum of CV in the presence of SBO seems to indicate that a complex formed between sensitizer and substrate plays a major role in the process. SBO have also been tested for the implementation of photo-Fenton processes at circumneutral media: the observed pseudo first order rate constants for CV decoloration was higher for UV/SBO/Fe(II)/H2O2 (5.5 × 10−3 min−1) than for UV/Fe(II)/H2O2 (1.5 × 10−3 min−1). A modified mechanism, in which HO are less relevant that at the acidic medium, is in agreement with results of experiments carried out with chemical probes.
Graphical abstractFigure optionsDownload full-size imageDownload high-quality image (118 K)Download as PowerPoint slideHighlights► The use of SBO isolated from urban wastes for water treatment has been explored. ► SBO are able to catalyze photobleaching of crystal violet. ► A CV–SBO complex might play a major role in the process. ► SBO favored neutral photo-Fenton processes.
Journal: Catalysis Today - Volume 209, 15 June 2013, Pages 176–180