UV and solar photo-degradation of naproxen: TiO2 catalyst effect, reaction kinetics, products identification and toxicity assessment

• Type: Article in International Scientific Journal
• Date: 2016

Authors

Nabil Jallouli (Author) Other; Kais Elghniji (Author) Other; Olfa Hentati (Author) Other; Ana Rita Ribeiro (Author) FEUP; Adrián M. T. Silva (Author) FEUP; Mohamed Ksibi (Author) Other

Journal

Title: Journal of Hazardous Materials

Vol. 304

Pages: 329-336

ISSN: 0304-3894

Publisher: Elsevier

Indexing

ISI Web of Knowledge - 29 Citations

Scopus - 58 Citations

INSPEC

Associated Projects

LSRE-LCM - Laboratório de Processos de Separação e Reação - Laboratório de Catálise e Materiais

Other information

Authenticus ID: P-00G-W46

DOI: 10.1016/j.jhazmat.2015.10.045

Abstract (EN): Direct photolysis and TiO2-photo catalytic degradation of naproxen (NPX) in aqueous solution were studied using a UV lamp and solar irradiation. The degradation of NPX was found to be in accordance with pseudo-first order kinetics, the photocatalytic process being more efficient than photolysis. The NPX removal by photolysis (pH(initial) 6.5) was 83% after 3 h, with 11% of chemical oxygen demand (COD) reduction, whereas the TiO2-UV process led to higher removals of both NPX (98%) and COD (25%). The apparent pseudo-first-order rate constant (k(app)) for NPX degradation by photolysis ranged from 0.0050 min(-1) at pH 3.5 to 0.0095 min(-1) at pH 6.5, while it was estimated to be 0.0063 min(-1) under acidic conditions in photocatalysis, increasing by 4-fold at pH 6.5. Ultra High Performance Liquid chromatography (UHPLC) coupled with a triple quadrupole detector and also a hybrid mass spectrometer which combines the linear ion trap triple quadrupole (LTQ) and OrbiTrap mass analyser, were used to identify NPX degradation products. The main intermediates detected were 1-(6-methoxynaphtalene-2-yl) ethylhydroperoxide, 2-ethyl-6-methoxynaphthalene, 1-(6-methoxynaphtalen-2-yl) ethanol, 1-(6-methoxynaphtalen-2-yl) ethanone and malic acid. Solar photocatalysis of NPX showed COD removals of 33% and 65% after 3 and 4 h of treatment, respectively, and some reduction of acute toxicity, evaluated by the exposure of Eisenia andrei to OECD soils spiked with NPX-treated solutions.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 8