Monitoring simultaneous photocatalytic-ozonation of mixture of pharmaceuticals in the presence of immobilized TiO2 nanoparticles using MCR-ALS: Identification of intermediates and multi-response optimization approach

作者：Fathinia Mehrangiz; Khataee Alireza^*; Naseri Abdolhosein; Aber Soheil

来源：Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy , 2015, 136: 1275-1290.

DOI：10.1016/j.saa.2014.10.014

• Photocatalysis
• Ozonation
• Multivariate curve resolution
• Nanocatalyst
• Multi-response optimization
• Pharmaceutical

The present study has focused on the degradation of a mixture of three pharmaceuticals, i.e. methyldopa (MDP), nalidixic acid (NAD) and famotidine (FAM) which were quantified simultaneously during photocatalytic-ozonation process. The experiments were conducted in a semi-batch reactor where TiO2 nanoparticles (crystallites mean size 8 nm) were immobilized on ceramic plates irradiated by UV-A light in the proximity of oxygen and/or ozone. The surface morphology and roughness of the bare and TiO2-coated ceramic plates were analyzed using scanning electron microscopy (SEM) and atomic force microscopy (AFM). An analytical methodology was successfully developed based on both recording ultraviolet-visible (UV-Vis) spectra during the degradation process and a data analysis using multivariate curve resolution with alternating least squares (MCR-ALS). This methodology enabled the researchers to obtain the concentration and spectral profiles of the chemical compounds which were involved in the process. A central composite design was used to study the effect of several factors on multiple responses namely MDP removal (Y-1), NAD removal (Y-2) and FAM removal (Y-3) in the simultaneous photocatalytic-ozonation of these pharmaceuticals. A multi-response optimization procedure based on global desirability of the factors was used to simultaneously maximize Y-1, Y-2 and Y-3. The results of the global desirability revealed that 8 mg/L MAD, 8 mg/L NAD, 8 mg/L FAM, 6 L/h ozone flow rate and a 30 min-reaction time were the best conditions under which the optimized values of various responses were Y-1 = 95.03%, Y-2 = 84.93% and Y-3 = 99.15%. Also, the intermediate products of pharmaceuticals generated in the photocatalytic-ozonation process were identified by gas chromatography coupled to mass spectrometry.

• 出版日期2015-2-5