Photocatalytic degradation of saccharin under UV‐LED and blacklight irradiation

Abstract

AbstractBACKGROUNDThe photocatalytic treatment of the artificial sweetener saccharin (SAC), an emerging environmental contaminant, was investigated. UVA irradiation was provided by an environmentally friendly light‐emitting diode (UV‐LED), whose efficiency was compared with a conventional blacklight fluorescent lamp (UV‐BL).RESULTSThe effect of the initial SAC concentration (2.5–10 mg L‐1), TiO2 concentration (0–500 mg L‐1), water matrix (absence/presence of humic acids), and treatment time on process efficiency was evaluated. Under the best conditions assayed ([SAC]0 = 2.5 mg L‐1, [TiO2] = 250 mg L‐1), SAC was degraded within 20 and 90 min under UV‐LED and UV‐BL irradiation, respectively. Liquid chromatography‐high resolution mass spectrometry (LC‐HR/MS) revealed that SAC degradation proceeds via hydroxylation of the phenyl ring, cleavage of C–N bond and further oxidation reactions. Finally, UV‐LED was found to be up to 16 times more energy efficient than UV‐BL.CONCLUSIONSIn all cases, UV‐LED achieved higher photocatalytic efficiency, in terms of organic degradation, and was found to be significantly more energy and cost efficient than conventional UV‐BL irradiation source, thus rendering LED‐photocatalysis a sustainable technology for the treatment of persistent contaminants. © 2017 Society of Chemical Industry