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This work studies in detail the photo-Fenton degradation process of Paracetamol (PCT) on an annular pilot-plant reactor using Computational Fluid Dynamics (CFD). A cylindrical lamp emission model was originally implemented over the structure of the OpenFOAM(R) platform and a multicomponent reaction mixture model was used to compute the temporal evolution of the different species at each point of the reactor. Once the proposed model was experimentally validated, the influence of different operating conditions (i.e. different strategies for hydrogen peroxide (H 2 O 2 ) dosage, use of low recirculation flow rates (Qr), and a completely uncovered lamp setup) was studied. The results of the analysis showed that a double addition of H 2 O 2 (50% before the tank and 50% before the reactor) significantly reduces the reaction times of the process. Moreover, the overall PCT degradation rate does not change when Qr is increased, thus allowing the system to be operated with a recirculation flow three times lower than that the one used in the experiments. Thereby, the developed model allows identifying the reaction conditions that maximize the overall PCT conversion, making efficient use of H 2 O 2 (main chemical reagent) and reducing the electrical energy consumption (recirculation flow) by operating the system under conditions present in large-scale photochemical reactors.

Different visible light responses of commercial TiO2photocatalysts are assessed for theirapplication in air decontamination. To do that the modified TiO2catalysts were immobi-lized on borosilicate glass plates according to a dip coating method. Then, the photocatalyticperformance of these plates was evaluated in a continuous gas flat plate photoreactor irra-diated with visible light lamps using two representative air pollutants: nitrogen oxide andacetaldehyde. Working under visible light, the modified TiO2catalysts were compared bymeans of efficiency parameters: the true quantum efficiency, which relates the moles ofdegraded pollutant with the moles of the absorbed photons, and the apparent photonicefficiency, which relates the moles of degraded pollutant with the moles of incident pho-tons. Also, the photocatalytic pollutants degradation by immobilized modified TiO2could berelated with their optical properties, finding a clear correlation between them. These resultsare useful to decide which TiO2will be more efficient for a full scale air decontaminationprocess under visible light illumination. Fil: Ballari, Maria de Los Milagros. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; Argentina Fil: Carballada, J.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; Argentina Fil: Minen, Romina Inés. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; Argentina Fil: Salvadores, Federico. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; Argentina Fil: Brouwers, H. J. H.. Eindhoven University of Technology; Países Bajos Fil: Alfano, Orlando Mario. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; Argentina Fil: Cassano, Alberto Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; Argentina

The present study aims at proposing a kinetic model that can capture the complexity and non-linear nature of the Fenton and photo-Fenton processes in the degradation of a model pollutant. Moreover, the proposed model is also able to account for the effect of the Local Volumetric Rate of Photon Absorption (LVRPA), depending on the radiation field within the annular photoreactor and consequently including the reactor dimensions and lamp characteristics. Paracetamol (PCT) was selected as model pollutant, because it is widely used as antipyretic and analgesic. Three kinetic parameters, accounting for the Fenton-like reaction and the hydroxyl radical attack to hydrogen peroxide and paracetamol, were estimated. Mean Square Error (MSE) and Root Mean Square Error (RMSE) were calculated to validate the model reliability.

The present work evaluates the enhancement of the photocatalytic inactivation of bacterial spores employing TiO2 films with silver deposits compared to TiO2 films without metal deposition. Bacillus subtilis spores spread over TiO2 films with different silver contents were irradiated with artificial UV-A light. The performances of the coatings were evaluated by the quantum efficiency parameter, which relates the inactivation rate with the radiation absorption rate by the coating. Spectral diffuse transmittance and reflectance measurements of the films were carried out to evaluate the fraction of energy absorbed by the coatings. TiO2 and Ag/TiO2 films characterization also included X-Ray Diffraction (XRD), Atomic Force Microscopy (AFM), X-ray photoelectron spectroscopy (XPS), and Scanning Electron Microscopy (SEM). A notable increase in the photocatalytic inactivation was observed by increasing the silver content of the coatings, reaching a maximum quantum efficiency with the sample containing 1.09 wt.% Ag/TiO2. The addition of higher amounts of silver rendered lower inactivation, thus indicating the existence of an optimum Ag/TiO2 relation. Fil: Zacarias, Silvia Mercedes. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Santa Fe. Instituto de Desarrollo Tecnológico Para la Industria Química (i); Argentina Fil: Satuf, María Lucila. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Santa Fe. Instituto de Desarrollo Tecnológico Para la Industria Química (i); Argentina Fil: Vaccari, María C.. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas; Argentina Fil: Alfano, Orlando Mario. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Santa Fe. Instituto de Desarrollo Tecnológico Para la Industria Química (i); Argentina

The photocatalytic activity under UV and visible irradiation of a series of CeO2–TiO2 composite materials prepared by microemulsion and subsequently calcined at 500 °C was evaluated using acetaldehyde as a model pollutant. The activities of three composite catalysts containing 2.5, 5 and 25 M% of ceria, as well as a nano-titania reference are compared by means of efficiency parameters; the quantum (or true) efficiency, as well as the photonic (or apparent) efficiency were evaluated. To this end, the lamp emission properties, as well as the radiation field interaction with the catalyst inside the reactor were modeled and numerically calculated. For the evaluation of the radiation absorbed by the catalysts, the optical properties of the materials were measured and a radiative transfer model that considers all potential optical events was built up. The stability of the systems under reaction conditions was also studied. Overall, the results evidence that the composite containing 2.5 Ce mol% outperforms titania by a factor of at least 2, irrespective of the illumination source used in the experiment. This shows the potential of the CeO2–TiO2 composites, a highly active and stable system, for sunlight optimum profiting., M.J. Muñoz-Batista and A. Kubacka thank MINECO for support thought the predoctoral FPI and postdoctoral “Ramón y Cajal” programs, respectively. M.J. Muñoz-Batista would like to thank MINECO for a grant-in-aid (EEBB-I-13-06684) allowing his stay at Santa Fe, Argentina. Financial support by MINECO is also acknowledged (project CTQ2010-14872/BQU). Also, the authors acknowledge financial support from the Universidad Nacional del Litoral, Agencia Nacional de Promoción Científica y Tecnológica, and Consejo Nacional de Investigaciones Científicas y Técnicas of Argentina.

A kinetic model of the photocatalytic inactivation of Escherichia coli in an annular wall reactor is presented. The model is based on a reaction scheme that involves a series of events in which bacteria are progressively damaged and eventually led to cell lysis. The model explicitly takes into account radiation absorption effects. Photocatalytic inactivation experiments were carried out in a photoreactor operated in a closed recirculating circuit with a reservoir tank and irradiated with a 6 W black light lamp situated in the axis of the reactor. Immobilization of TiO2 Aeroxide P25 has been carried out by the dip-coating procedure onto the inner-tube wall of the annular reactor. Experimental results for different TiO2 layer thicknesses were used to estimate the kinetic parameters of the model. Good agreement between model predictions and inactivation experiments was achieved in the whole range of TiO2 thicknesses studied. Fil: Marugán, Javier. Universidad Rey Juan Carlos; España Fil: van Grieken, Rafael. Universidad Rey Juan Carlos; España Fil: Pablos, Cristina. Universidad Rey Juan Carlos; España Fil: Satuf, María Lucila. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; Argentina Fil: Cassano, Alberto Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; Argentina Fil: Alfano, Orlando Mario. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; Argentina

A model of a bench-scale, annular, continuous flow reactor for the photocatalytic disinfection of water, operated under conditions of no perfect mixing is presented. The performance of the photoreactor has been simulated following a predictive procedure, with no adjustable parameters, based on the intrinsic kinetics and the information about the geometry, irradiation source and operation conditions (catalysts concentration and its properties as well as the initial concentration of bacteria). The only experimental information required to be determined at laboratory scale are the kinetic parameters of a mechanistic model that takes into account the explicit dependence of the reaction rate with respect to the local volumetric rate of photon absorption (LVRPA) and the optical properties of the catalyst. The proposed model predicts an optimal catalyst concentration in the range 0.1–0.2 × 10−3 g cm−3, with a significant decrease in the disinfection efficiency for higher catalyst loadings. Important resistances to the mass transport are detected at high TiO2 concentrations, as a result of the low diffusion coefficient of the employed microorganism (Escherichia coli). Operating under the optimal catalyst concentration, model predictions show satisfactory agreement with experimental results extracted from the custom-built bench scale reactor. Fil: Marugán, Javier. Universidad Rey Juan Carlos. Escuela Superior de Ciencias Experimentales y Tecnología. Departamento de Tecnología Química y Ambiental; España; Fil: Van Grieken, Rafael. Universidad Rey Juan Carlos. Escuela Superior de Ciencias Experimentales y Tecnología. Departamento de Tecnología Química y Ambiental; España; Fil: Pablos, Cristina. Universidad Rey Juan Carlos. Escuela Superior de Ciencias Experimentales y Tecnología. Departamento de Tecnología Química y Ambiental; España; Fil: Satuf, María Lucila. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - CONICET- Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química (i); Argentina; Fil: Cassano, Alberto Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - CONICET- Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química (i); Argentina; Fil: Alfano, Orlando Mario. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - CONICET- Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química (i); Argentina

This study is focused on the kinetic modelling of the photocatalytic inactivation of bacteria with suspended TiO2. A rigorous model based on a proposed reaction mechanism and accounting explicitly for the rate of photon absorption has been developed. The application of the general kinetic expression to limiting cases suggests that the interaction bacteria–catalyst can be considered to be weak. In contrast, a complex dependence on the radiation absorption rate must be taken into account, as very different radiation conditions may coexist inside the photoreactor, with high absorption rates in the region near to the radiation entrance window and much lower values on the opposite side of the photoreactor. The model has been successfully validated by experimental data, being able to reproduce the evolution of the concentration of viable bacteria in a wide range of values of TiO2 concentration, irradiation power and initial concentration of bacteria with a normalized root mean square logarithmic error of 5.3%. The values of the kinetic parameters are independent of the specific reactor setup or the operating conditions and therefore, the model can be used in a predictive way for photoreactor design and scaling-up, as well as for the optimization of other reactor configurations. Fil: Marugan, Javier. Universidad Rey Juan Carlos; España Fil: Van Grieken, Rafael. Universidad Rey Juan Carlos; España Fil: Pablos, Cristina. Universidad Rey Juan Carlos; España Fil: Satuf, María Lucila. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Santa Fe. Instituto de Desarrollo Tecnológico Para la Industria Química (i); Argentina. Universidad Nacional del Litoral; Argentina Fil: Cassano, Alberto Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Santa Fe. Instituto de Desarrollo Tecnológico Para la Industria Química (i); Argentina. Universidad Nacional del Litoral; Argentina Fil: Alfano, Orlando Mario. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Santa Fe. Instituto de Desarrollo Tecnológico Para la Industria Química (i); Argentina. Universidad Nacional del Litoral; Argentina

A scaling-up methodology for the design of large-scale slurry reactors for the photocatalytic oxidation of cyanide is proposed. The only experimental information required to be determined at laboratory-scale is the intrinsic kinetics that describes the explicit dependence of the reaction rate with the local volumetric rate of photon absorption (LVRPA). Based on the kinetic model and the information about the geometry, irradiation source and the cyanide and catalyst concentrations as operation conditions, the performance of a larger scale reactor has been simulated following a predictive procedure with no adjustable parameters. The validation of the method has been carried out in a bench-scale reactor with ten times higher irradiated volume and a different geometry and irradiation source, in order to ensure that the conclusions about the applicability of the scaling-up model are independent of these parameters. The proposed scaling-up methodology and their correspondent procedures for the evaluation of the LVRPA distribution on the photoreactors has been successfully validated both with commercial TiO2 and a silica-supported TiO2 synthesized in our laboratory. The normalized root mean square error in the verification of the conversions predicted by the model for the larger scale reactor when compared with the experimental data are 7.7% and 6.2% for TiO2 and TiO2/SiO2, respectively. Fil: Marugán, Javier. Universidad Rey Juan Carlos; España Fil: Van Grieken, Rafael. Universidad Rey Juan Carlos; España Fil: Cassano, Alberto Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; Argentina Fil: Alfano, Orlando Mario. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; Argentina

Fil: Alfano, Orlando Mario. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Santa Fe. Instituto de Desarrollo Tecnologico para la Industria Quimica. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnologico para la Industria Quimica; Argentina

A proposal for scaling-up photocatalytic reactors is described and applied to catalytic walls coated with a thin layer of titanium dioxide and irradiated with near UV radiation. The method is exclusively based on the fundamentals of chemical reaction engineering and radiative 11 transfer theory, without the use of adjustable parameters in going from the laboratory information to a pilot scale apparatus. Mathematical modeling has been utilized. From kinetic information obtained in experiments performed in a flat plate of 81 cm2, operating at steady state in 13 a continuous, well-mixed reactor with recycle, predictions for a continuous flow, multi-annular reactor having a catalytic surface of 5209 cm2 agree very well with the validation tests. Thus, the achieved scale-up implies a change in size, shape, configuration and operating conditions of 15 both employed reactors. Requirements to apply satisfactorily the proposed methodology are reported in detail. The root mean square error in the verification of conversion predictions for the larger scale photocatalytic reactor when compared with experimental data is less than 5.6%. Fil: Imoberdorf, Gustavo Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; Argentina Fil: Irazoqui, Horacio Antonio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; Argentina Fil: Alfano, Orlando Mario. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; Argentina Fil: Cassano, Alberto Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; Argentina