Abatement of ibuprofen by solar photocatalysis process: Enhancement and scale up Fabiola Me ´ ndez-Arriaga a , M. Ignacio Maldonado b , Jaime Gimenez a, *, Santi Esplugas a, **, Sixto Malato b a Chemical Engineering Department, University of Barcelona, Marti i Franque `s 1, 08028 Barcelona, Spain b Plataforma Solar de Almerı´a-CIEMAT, Carretera Sene ´s km 4, 04200 Tabernas (Almerı´a), Spain 1. Introduction New emerging contaminants have attracted special attention: the pharmaceutical compounds [1]. Non-Steroidal Anti-Inflamma- tory Drugs (NSAIDs), as ibuprofen (IBP), are widely used and prescribed as analgesic and antipyretic medicaments. The rank of IBP prescriptions dispensed in USA was placed 17th in 2005 [2]. Unfortunately the extensive use of IBP has enclosed a secondary effect: IBP has been detected in water and the ecotoxicological impact on the microbiological systems can provoke irreversible harmful effects on bioreceptors. For example Richards and Cole [2] report the toxic response from the FETAX test (Frog Embryo Teratogenesis Assay-Xenopus) as effect of several concentrations of IBP after 96 h of exposition: 30 mg/L showed inhibition on the growth of embryos, >70 mg/L no survival embryos were detected. Concentration of IBP has been reported in the range of 0.01–990 mg/ L. The wastewater treatment plants are not able to eliminate IBP completely; however, this drug reaches an important removal by biological oxidation, in some cases more than 70% [3]. Even relatively acceptable removal efficiencies can be assumed, the harmful presence of IBP, as consequence of metabolic, photolytic and/or attenuation processes [4], remains along its occurrence in environment also at low concentrations. Several typical strategies for IBP removal from water have been reported, for example ozonation, chlorination, etc. However, the secondary products after such treatments increase the toxic properties of the processed effluent. On the other hand advanced oxidation processes (AOPs) are non-classical water remediation techniques which promote miner- alization of the pollutants and/or biodegradable byproducts through radical-species. Some of them are able to take the advantage to employ solar renewable energy, for instance the heterogeneous photocatalysis with semiconductors like titanium dioxide (TiO 2 ). Solar energy contains energy capable to generate electron/hole pairs (e  /h + ), especially the UV energy with wavelength below 387 nm. The e  /h + react with adsorbed water or oxygen on the surface of the catalyst producing the powerful oxidative specie  OH, which carries out the photocatalytic degradation of organic compounds. Thus, this process improves the cost-effectiveness through photoactivation with solar irradiation. There are some reports about the degradation of pharmaceu- tical compounds like antiepileptic, beta blockers, cholesterol, triglyceride reducers, steroid hormones, ionated X-ray contrast media, etc. by heterogeneous photocatalysis [1], most of them at lab-scale and by using electric sources of irradiation. And only few works are available with solar energy at large-scale [5], however their results are promising. The aim of this work is to study the degradation of the pharmaceutical pollutant ibuprofen using photocatalysis and solar irradiation in three different pilot plants located in Barcelona University and in Solar Platform of Almeria (PSA), Spain. The effect of TiO 2 loading, initial IBP concentration and extra-oxidant agent on the IBP removal and mineralization has been studied in order to obtain the irradiated-time required to reach a biodegradable dissolution able to be coupled to a biological reactor. Catalysis Today 144 (2009) 112–116 ARTICLE INFO Article history: Available online 23 February 2009 Keywords: Ibuprofen Solar photocatalysis NSAID remediation PPCP emerging contaminants ABSTRACT The aim of this work is to evaluate the degradation of the emerging pharmaceutical contaminant ibuprofen (IBP) in water by heterogeneous photocatalysis in three different solar pilot plants. IBP and TOC removal increase directly proportional to concentration of catalyst (TiO 2 ). The addition of H 2 O 2 increases the removal efficiency. The complete IBP removal and decrease of TOC to sufficient extent was stated in optimal experimental conditions and biodegradability and average oxidation state (AOS) results conducted suggest a post-biological treatment of solution. Surface responses obtained from the experimental results, for different initial IBP and TiO 2 concentrations used, can allow to predict time needed for a sufficient TOC removal to reach sufficient biodegradability. ß 2009 Elsevier B.V. All rights reserved. * Corresponding author. Tel.: +34 93 402 12 93; fax: +34 93 402 12 91. ** Corresponding author. Tel.: +34 93 402 12 90; fax: +34 93 402 12 91. E-mail addresses: j.gimenez.fa@ub.edu (J. Gimenez), santi.esplugas@ub.edu (S. Esplugas). Contents lists available at ScienceDirect Catalysis Today journal homepage: www.elsevier.com/locate/cattod 0920-5861/$ – see front matter ß 2009 Elsevier B.V. All rights reserved. doi:10.1016/j.cattod.2009.01.028