Triclosan degradation by heterogeneous photocatalysis using ZnO immobilized in biopolymer as catalyst

• Published in: Journal of photochemistry and photobiology. A, Chemistry. Chemistry., 2017-07, Vol.344, p.184-191
• Main Authors: Kosera, Vitor S., Cruz, Thiago M., Chaves, Eduardo S., Tiburtius, Elaine R.L.
• Format: Article
• Language: English
• Subjects: Advanced oxidation process; Alginic acid; Alternative energy sources; Biodegradability; Biodegradation; Biopolymers; Catalysts; Chemical compounds; Consumer products; Contaminants; Degradation; Free form; Low concentrations; Photocatalysis; Renewable energy; Sodium alginate; Solar radiation; Studies; Toiletry products; Triclosan; Water treatment; Wurtzite; Zinc oxide; Zinc oxides
• ISSN: 1010-6030; 1873-2666
• DOI: 10.1016/j.jphotochem.2017.05.014

[Display omitted] •Faster triclosan degradation by heterogeneous photocatalysis, using immobilized catalyst.•Good rates of degradation and mineralization of triclosan.•Easy separation of catalyst and application of solar radiation in photocatalysis process. Triclosan (TCS) is compound with bactericidal effect that is frequently used in personal care products. Classified as an emerging contaminant, TCS is found in the environment at low concentrations and it is difficult to degrade by conventional water treatment processes. For this reason, the objective of this work is to evaluate the capacity of heterogeneous photocatalysis in the triclosan degradation using zinc oxide (ZnO) immobilized in sodium alginate. A complete characterization of the free and immobilized forms of ZnO was performed, and its crystalline phase was identified as wurtzite. The determined bandgaps of free and immobilized ZnO were 3.14eV and 3.08eV respectively, involving no change in the bandgap potential of the semiconductor. High efficiency of TCS degradation was obtained (greater than 90%) using free and immobilized catalyst in only 20min of reaction. These results showed that the immobilized semiconductor has practically the same performance as the free form. In addition, studies of degradation were carried out using solar radiation and immobilized semiconductors. In these conditions, high rates of degradation were observed (90% in 90min). The utilization of ZnO immobilized in biopolymer and solar radiation can be an interesting alternative since the use of biodegradable support and alternative energy sources is very attractive from an environmental perspective.