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The degradation of paracetamol (PCT) in an aqueous medium using the Fenton and photo-Fenton reactions was investigated. The aim of this research was the development of a kinetic model based on a reaction mechanism, which includes two main intermediates of PCT degradation and the local volumetric rate of photon absorption (LVRPA). Ferrioxalate was used as a catalyst and the working pH was adjusted to 5.5 (natural pH). Experimental work was planned through a D-optimal experimental design and performed in a flat plate reactor irradiated by a solar simulator. Hydrogen peroxide (HP) concentration, reaction temperature, and radiation level were the operating parameters. The photo-Fenton reaction allowed to reach a minimum relative PCT concentration of 2.01% compared to 5.04% achieved with Fenton reaction. Moreover, the photo-Fenton system required a 50% shorter reaction time and lower HP concentration than in dark conditions (90 min and 189 mg L-1 vs. 180 min and 334 mg L-1, respectively). The experimental results were used to estimate the kinetic parameters of the proposed kinetic model employing a nonlinear, multi-parameter regression method. The values obtained from the normalized root-mean-square error (14.52, 1.96, 4.36, 13.16, and 8.72 % for PCT, benzoquinone, hydroquinone, HP, and oxalate, respectively) showed a good agreement between the predicted and experimental data.

Since COVID-19 pandemic, indoor air quality control has become a priority, and the development of air purification devices effective for disinfecting airborne viruses and bacteria is of outmost relevance. In this work, a photocatalytic device for the removal of airborne microorganisms is presented. It is an annular reactor filled with TiO2-coated glass rings and irradiated internally and externally by UV-A lamps. B. subtilis spores and vegetative cells have been employed as model biological pollutants. Three types of assays with aerosolized bacterial suspensions were performed to evaluate distinct purification processes: filtration, photocatalytic inactivation in the air phase, and photocatalytic inactivation over the TiO2-coated rings. The radiation distribution inside the reactor was analysed by performing Monte Carlo simulations of photon absorption in the photocatalytic bed. Complete removal of a high load of microorganisms in the air stream could be achieved in 1 h. Nevertheless, inactivation of retained bacteria in the reactor bed required longer irradiation periods: after 8 h under internal and external irradiation, the initial concentration of retained spores and vegetative cells was reduced by 68% and 99%, respectively. Efficiency parameters were also calculated to evaluate the influence of the irradiation conditions on the photocatalytic inactivation of bacteria attached at the coated rings. Fil: Zacarias, Silvia Mercedes. 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: Manassero, Agustina. 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: Pirola, Silvana 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: 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: 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

Radiation modeling and kinetics in two different packed-bed reactors filled with TiO2-coated glass rings are presented. The first reactor was cylindrical, irradiated from one end by a 150 W mercury lamp. It was employed to obtain the values of the intrinsic kinetic parameters of the degradation of the emerging contaminant clofibric acid (CA). The expression to represent the kinetics of the pollutant was derived from a proposed reaction scheme, and it includes explicitly the effect of photon absorption rate on the reaction rate. The second reactor was annular, irradiated internally and externally by 40 UV-LED lamps. The kinetic parameters calculated in the first reactor were directly employed to simulate the performance of the second one, without using any adjustable parameter. The Monte Carlo method was applied to solve the radiation models in both reactors. Good agreement was obtained between simulation results and experimental data under different operating conditions, with a percentage root-mean-square error of 4.6%. The kinetic parameters proved to be independent of the irradiation source, reactor geometry, and catalyst film thickness, and can be readily applied to design real scale devices.

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.

A regional raw clay was used as the starting material to prepare iron-pillared clays with different iron contents. The catalytic activity of these materials was tested in the heterogeneous photo-Fenton process, applied to the degradation of 2-chlorophenol chosen as the model pollutant. Different catalyst loads between 0.2 and 1.0 g L −1 and pH values between 3.0 and 7.0 were studied. The local volumetric rate of photon absorption (LVRPA) in the reactor was evaluated solving the radiative transfer equation applying the discrete ordinate method and using the optical properties of the catalyst suspensions. The photonic and quantum efficiencies of the 2-chlorophenol degradation depend on both the catalyst load and the iron content of the catalyst. The higher values for these parameters, 0.080 mol Einstein −1 and 0.152 mol Einstein −1 , respectively, were obtained with 1.0 g L −1 of the catalyst with the higher iron content (17.6%). For the mineralization process, photonic and quantum efficiencies depend mainly on the catalyst load. Therefore, it was possible to employ a natural and cheap resource from the region to obtain pillared clay-based catalysts to degrade organic pollutants in water. Fil: de León, María A.. Universidad de la República Facultad de Química; Uruguay Fil: Sergio, Marta. Universidad de la República Facultad de Química; Uruguay Fil: Bussi, Juan. Universidad de la República Facultad de Química; Uruguay Fil: Ortiz de la Plata, Guadalupe Beatriz. 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

This study discusses the degradation of paracetamol (PCT) by Fenton and photo-Fenton reactions at circumneutral pH with the aid of ferrioxalate and a solar simulator as the light source. The influence of three main operating variables: H2O2 concentration (HP), temperature (T) and radiation level (Rad) on PCT conversion was evaluated with a D-optimal design and a response surface methodology (RSM). The analysis of variance (ANOVA) revealed that Rad and T significantly affected the studied response. The model performance was satisfactory, giving low standard deviation (0.74) and good R2 and adjusted R2 values (0.9997 and 0.9993, respectively). The optimal conditions found for each radiation level were tested. The obtained PCT conversions after 90 min of reaction (75.52 %, 96.88 % and 91.50 %, respectively) were in good agreement with the predicted values (71.28 %, 96.75 % and 92.75 %, respectively). It was observed that the maximum and minimum levels of toxicity (bioluminescence inhibition of Vibrio fischeri bacteria) found in the system were closely related to the maximum and minimum concentrations observed for the reaction intermediaries (hydroquinone and 1,4-benzoquinone). In addition, it was only possible to completely reduce the toxicity of the system after 240 min of reaction when high levels of radiation were applied. Fil: Giménez, Bárbara Natalí. 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: Conte, Leandro Oscar. 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: Schenone, Agustina Violeta. 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

Photocatalytic building materials containing TiO2 were extensively studied for outdoor applications using solar radiation. Nowadays, the market offers a wide variety of these materials with self-cleaning and air purification functionalities. However, heterogeneous photocatalysis applied in indoor construction materials was less developed. The objective of this work is to investigate the photocatalytic performance of carbon doped TiO2 in replacement of the normal pigments in indoor wall paint formulations. To achieve this goal, the photocatalytic oxidation of acetaldehyde in gas phase was carried out. The air decontamination process was conducted us-ing regular indoor light in a bench scale chamber photoreactor simulating a room. The main environmental conditions that affect the photocatalytic process were varied: air flow rate, irradiance, relative humidity and acetaldehyde concentration. The results were analyzed through the response surface methodology and revealed the air purifying power of photocatalytic paints under indoor conditions. 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: 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: 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

A kinetic model describing Fenton and photo-Fenton degradation of paracetamol (PCT) and consumption of hydrogen peroxide (H 2 O 2 ) was proposed. A set of Fenton and photo-Fenton experiments (18 runs in total) was performed by fixing the initial concentration of PCT to 40 mg L −1 and varying the initial concentrations of H 2 O 2 and ferrous ion, Fe 2+ . The experimental set-up was a well-stirred annular photoreactor equipped with an actinic BL TL-DK 36 W/10 1SL lamp. Experimental results highlighted that PCT is no more detected by HPLC analysis within a minimum reaction time of 2.5 and a maximum reaction time of 15.0 min. Besides, a maximum conversion of total organic carbon (TOC) of 68.5% was observed after 75 min of reaction in case of using UV radiation and the highest concentrations of the Fenton reagents. The experimental data were used to fit the kinetic model. The radiation field inside the reactor was taken into account through the local volumetric rate of photon absorption, evaluated by assuming a line source model with spherical and isotropic emission. The kinetic parameters were estimated by using a non-linear least-squares regression procedure and root mean square errors (RMSE) were calculated in order to validate the feasibility of the proposed model. A good agreement between experimental and predicted data was observed and the lowest values of RMSE resulted in 5.84 and 9.59% for PCT and H 2 O 2 normalized concentrations, respectively. Fil: Audino, Francesca. Universitat Politècnica de Catalunya; España Fil: Conte, Leandro Oscar. 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: Schenone, Agustina Violeta. 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: Pérez-Moya, Montserrat. Universitat Politècnica de Catalunya; España Fil: Graells, Moisès. Universitat Politècnica de Catalunya; España 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

The fungicide effect employing Aspergillus niger as a representative microorganism was tested applying a Photocatalytic paint formulated with an anatase carbon doped TiO2 and compared with a homemade non-active paint (rutile TiO2), a commercial normal indoor latex paint and a commercial “antifungal” latex paint. For this purpose Aspergillus niger conidia inactivation on the paints coatings was performed under visible and UV radiation applying different experimental conditions (relative humidity, radiation flux and absence of light). Under visible light no significant difference in conidia inactivation was found for all studied paints. Nevertheless, the Photocatalytic paint under UV radiation presented around 1.4 times higher fungus inactivation than the blank control paints. In order to evaluate the damage produced by visible or UV radiation over the conidia and to analyze the ability of repairing it, incubation at optimal germination conditions of Photocatalytic and normal paints after irradiation treatment was performed. For conidia irradiated on Photocatalytic paint, not only conidia could not germinate but also the inactivation continued even after the end of the irradiation assay. Finally, A. niger conidia was exposed over a culture medium with or without the paints pigments (Carbon doped TiO2 or Rutile) under different types of radiation (visible and UV). Much greater growth control of vegetative forms was obtained by applying photocatalytic TiO2 under both types of light. It can be concluded that the developed Photocatalytic paint presents a higher ability to control fungal growth compared to the other paints studied and could be applied for indoor air decontamination. Also, it was possible to control the dissemination agent that can generate more mold growth on surfaces and affect the people health. Fil: Zacarias, Silvia Mercedes. 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: Marchetti, Sofía. 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: 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

In this work, MCM-41 materials have been synthesized and modified with different metal loadings of iron by the wet impregnation method. The different meso-structures obtained were characterized by XRD, UVVIS-RD, ICP and TEM and their behaviors as heterogeneous catalysts in the photo-Fenton reaction were studied. Thus, ironcontaining mesostructured materials have been successfully tested for the heterogeneous photo-Fenton degradation of atrazine aqueous solutions using UV?vis irradiation at room temperature and close to neutral pH. In order to assess the effectiveness of the herbicide degradation in the heterogeneous photo-Fenton process, and to compare experimental results obtained, a study of the photonic efficiency is presented. The photonic efficiency of Atrazine degradation was evaluated considering different experimental conditions employed two factorial designs. The results showed that the iron modified MCM-41 with a nominal metal loading of 2.5 wt.% exhibited the highest activity. Consequently, the high performance of this material indicates that the heterogeneous via of the photo-Fenton process can also be efficiently employed for the treatment of simulated wastewater containing atrazine, thus presenting advantages unlike the homogeneous process. Fil: Benzaquén, Tamara Belén. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigación y Tecnología Química. Universidad Tecnológica Nacional. Facultad Regional Córdoba. Centro de Investigación y Tecnología Química; Argentina Fil: Cuello, Natalia Inés. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigación y Tecnología Química. Universidad Tecnológica Nacional. Facultad Regional Córdoba. Centro de Investigación y Tecnología 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: Eimer, Griselda Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigación y Tecnología Química. Universidad Tecnológica Nacional. Facultad Regional Córdoba. Centro de Investigación y Tecnología Química; Argentina

The efficiency of three photocatalytic reactor configurations for the degradation of the micropollutant clofibric acid in water was assessed. The following reaction systems were tested: (i) a slurry reactor with suspended TiO2 particles; (ii) a fixed-film reactor with TiO2 immobilized onto the reactor window; and (iii) a fixed-bed reactor filled with TiO2-coated glass rings. The influence of the catalyst concentration in the suspended system and the number of the catalyst coatings in the immobilized systems were evaluated. The performances of the reactors, under the experimental condition of highest reaction rate for each configuration, were compared with the aid of two parameters: (i) the photonic efficiency (g), which is the ratio of the reaction rate to the rate of incident photons; and (ii) the quantum efficiency (gRxn), which is the ratio of the reaction rate to the photon absorption rate. The obtained values of gRxn were 4.59, 2.96 and 2.02% for the slurry reactor, the fixed-bed reactor and the fixed-film reactor, respectively. Although the slurry reactor was the most efficient configuration, the fixed-bed reactor rendered a value of quantum efficiency only one third lower than the suspended system, making this configuration very convenient for photocatalytic reactions. The analysis of the reaction rate, the photon absorption rate and the quantum efficiency are essential to rationally improve the design, configuration and experimental conditions of photocatalytic reactors. Fil: Manassero, Agustina. 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: 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: 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 theoretical and experimental study of bisphenol A (BPA) degradation by the UV/H2O2 process in water is presented. The effects of the H2O2 concentration and the specific rate of photon emission (EP,0) on BPA degradation were investigated. A kinetic model derived from a reaction sequence was employed to predict BPA and hydrogen peroxide concentrations over time using an annular photochemical reactor in batch recirculation mode. The local volumetric rate of photon absorption (LVRPA) inside the photoreactor was computed using a Line Source with Parallel Plane emission model (LSPP). From the proposed kinetic model and the experimental data, the second order rate constants of the reactions between hydroxyl radicals and the main reacting species (H2O2 and BPA) were estimated applying a nonlinear regression method. A good agreement between the kinetic model and experimental data, for a wide range of operating conditions, was obtained. For BPA, H2O2, and TOC concentrations, the calculated root means square errors (RMSE) were 2.3 × 10− 2, 9.8 × 10− 1, and 9.0 × 10− 2 mmol L− 1, respectively. The simplified kinetic model presented in this work can be directly applied to scaling-up and reactor design, since the estimated kinetic constants are independent of the reactor size, shape, and configuration. Further experiments were made by employing low BPA initial concentration (100 μg L− 1) in water and real wastewater. A lower degradation rate of BPA was observed in the real wastewater, although the UV/H2O2 process has also been able to completely degrade the target pollutant in less than 1 h. Fil: Goulart de Araujo, Leandro. Universidade de Sao Paulo; Brasil Fil: Conte, Leandro Oscar. 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: Schenone, Agustina Violeta. 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: Silva Costa Teixeira, Antonio Carlos. Universidade de Sao Paulo; Brasil

This Accepted Manuscript will be available for reuse under a CC BY-NC-ND licence after 24 months of embargo period, An intrinsic kinetic model, derived from a suggested reaction photo-mechanism and with an explicit dependence on the local volumetric rate of photon absorption (LVRPA), was developed to simulate the photocatalytic degradation of clofibric acid and the main reaction intermediates, with a new titania-reduced graphene oxide nanocomposite (TiO2-rGO), The proposed reaction mechanism takes into account that graphene behaves as an electron acceptor and, therefore, this effect was included in the derivation of the reaction rate expressions and in the parameters estimation of the kinetic model. The photodegradation of clofibric acid was performed in a slurry photoreactor under different irradiation levels and using several loadings of a TiO2-rGO nanocomposite, prepared by hydrothermal method with a 0.5»wt. % of GO. Absorbed radiation profiles inside the photoreactor were obtained by solving the radiation model with the Monte Carlo method. A photocatalyst loading of 100»mg»L-1 gave place to the best photodegradation results. Mass balances were proposed for the main pollutant and their main detected intermediates: p-benzoquinone and 4-chlorophenol. The intrinsic kinetic parameters were obtained for the complete (6-parameters) and simplified (5-parameters) models by comparing the experimental and the theoretical concentration values of all the organic compounds detected. The model proved to be able to predict with good accuracy the concentration evolution of clofibric acid, 4-chlorophenol and p-benzoquinone under several photocatalyst concentrations and irradiation levels. Finally, a very good correlation between calculated and experimental values of clofibric acid concentration was obtained with root-mean-square errors below 11%., Thanks are due to the Spanish Plan Nacional I+D+i (projects CTM2015-64895-R and CTM2016-76454-R) and Universidad Nacional del Litoral (UNL), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), and Agencia Nacional de Promoción Científica y Tecnológica (ANPCyT)for financial support. We would also like to thank Antonio C. Negro for his valuable help during the experimental work. Alvaro Tolosana-Moranchel acknowledges to Ministerio de Educación, Cultura y Deporte for his FPU grant (FPU14/01605) and (EST17/00110)

A methodology for photocatalytic reactor modeling applied to advanced oxidation processes for chemical pollution abatement is presented herein. Three distinct reactor configurations typically employed in the field of air and water purification?wall reactors, slurry reactors, and fixed-bed reactors?are considered to illustrate the suggested approach. Initially, different mechanistically derived kinetic expressions to represent the photocatalytic rate of pollutant degradation are reviewed, indicating the main assumptions made by the authors in the published contributions. These kinetic expressions are needed to solve the mass balances of the reactant species in the photocatalytic reactors. As is well known, at least one of the steps of the reaction mechanism requires evaluation of the rate of electron?hole generation, which depends on the photon absorption rate: a volumetric property for reactions with the catalyst particles in aqueous suspension or a surface property for systems with a fixed catalyst deposited on an inert support. Subsequently, the different techniques for evaluating the optical properties of slurry and immobilized systems, and the numerical methods applied to calculate the photon absorption rate, are described. The experimental and theoretical results of pollutant degradation in each reactor type are then presented and analyzed. Finally, the definition, calculation, and relevance of different efficiency parameters are briefly reviewed. Using these illustrative examples, we emphasize the need for a systematic and rigorous approach for photocatalytic reactor modeling in order to overcome the inherent drawbacks of photocatalysis and to improve the overall efficiency of the process. 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: 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: 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

This Accepted Manuscript will be available for reuse under a CC BY-NC-ND licence after 24 months of embargo period, Corrigendum to this paper available at: https://doi.org/10.1016/j.apcatb.2019.03.031 It includes the co-author responsible for the TEM study whose name is L. Pascual and who belongs to the following affiliation: Instituto de Catálisis y Petroleoquímica, ICP-CSIC, C/Marie, Madrid (Spain). It also contains an apology for the mistake, TiO2-reduced graphene oxide (TiO2-rGO) photocatalysts with different mass ratios (GO:TiO2 0.1-0.5-1%) were synthesized via a hydrothermal method and compared through their physico-chemical properties and photocatalytic activity in the degradation of an emerging contaminant, clofibric acid. The optical properties of the TiO2-rGO nanocomposites were first estimated in order to calculate the local volumetric rate of photon absorption inside a photocatalytic reactor. Radiation models were solved using the Monte Carlo method. The effect of rGO as well as the photocatalyst loadings on the radiation absorption was evaluated. The lowest photodegradation rate found in P25-rGO 1% was ascribed to an excess of rGO that could well favor charge carriers recombination leading to detrimental photoactivity. A GO/TiO2 mass ratio of 0.5% provided the fastest initial photodegradation rate under the operating conditions studied here. Finally, the photo-efficiency of all these photocatalysts was also analyzed by calculating the quantum efficiency parameter. The highest value of quantum efficiency was achieved with P25-rGO 0.5% at 100 mg L−1, with an increase of 11% compared to the value obtained for P25-rGO 0%., This work has been supported by the Spanish Plan Nacional de I+D+i through the project CTM2015-64895-R and CTM2016-76454-R. Alvaro Tolosana-Moranchel thanks Ministerio de Educación, Cultura y Deporte for his FPU grant (FPU14/01605) and (EST17/00110). The authors are also grateful to Universidad Nacional del Litoral (UNL), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), and Agencia Nacional de Promoción Científica y Tecnológica (ANPCyT) for financial support

The effects of four inorganic anions (Cl-, SO42-, HCO3-, NO3−) usually present in groundwater were investigated on the photo-Fenton degradation of 2,4-dichlorophenoxyacetic acid (2,4-D). A kinetic model derived from a reaction sequence is proposed using the ferrioxalate complex as iron source at pH close to natural conditions (pH = 5). It was demonstrated that oxalate not only maintained iron in solution for the natural groundwater system, but also increased the photochemical activation of the process. Results showed that the minimum conversion of 2,4-D for the simulated groundwater after 180 min was 63.80%. This value was only 14.1% lower than the conversion achieved without anions. However, with all anions together, the consumption of hydrogen peroxide (HP) per mole of herbicide showed an increase with respect to the test without anions. Only one kinetic parameter was estimated for each anion applying a nonlinear regression method. Subsequently, these optimized kinetic constants were used to simulate the system behaviour, considering the influence of all the studied anions together. A good agreement between kinetic model predictions and experimental data was observed, with the following errors: RMSE2,4-D = 3.98 × 10-3 mM, RMSEHP = 1.83 × 10-1 mM, RMSEOX = 1.39 × 10-2 mM, and RMSE2,4-DCP = 5.59 × 10-3 mM. Fil: Conte, Leandro Oscar. 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: Schenone, Agustina Violeta. 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: Giménez, Bárbara Natalí. 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

This work presents the photocatalytic degradation of the pharmaceutical drug clofibric acid in a fixed-bed reactor filled with TiO2-coated glass rings. Experiments were carried out under UV radiation. A kinetic model that takes into account radiation absorption by means of the local surface rate of photon absorption (LSRPA) has been developed. The LSRPA was obtained from the results of a radiation model. The Monte Carlo method was employed to solve the radiation model, where the interaction between photons and TiO2-coated rings was considered. Data from experiments carried out with rings with different number of catalyst coatings and different irradiation levels were used to estimate the parameters of the kinetic model. A satisfactory agreement was obtained between model simulations and experimental results. Fil: Manassero, Agustina. 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: 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: 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

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 aim of this work was to investigate the photocatalytic inactivation efficiencies of eight phages infective to lactic acid bacteria (LAB) contained in bioaerosols. Studies were performed in a semi-pilot scale equipment, which consists of a stainless steel camera, in which air containing the phage particles circulates, and an acrylic reactor with twenty UV-A lamps and six borosilicate plates covered with the catalytic film (TiO2). Phages (ALQ13.2, ATCC 15807-B1, ATCC 8014-B1, BYM, CHD, LDG, Ln-9 and MLC-A) were nebulized into the camera using the 6-jet Collison nebulizer, being assays performed for a total time of 100 min. Sampling by impact of air on a glass slide was carried out. Some conditions of equipment operation (phage suspension concentration, nebulization method, influence of relative humidity) using phage ATCC 8014-B1 were previously adjusted. Phages ALQ13.2, ATCC 15807-B1, BYM and CHD were not detected in the air because of loss of their infectivity after nebulization when assays in absence of catalyst and UV radiation were conducted. On the other hand, it was possible to achieve a complete inactivation (

Photocatalytic building materials constitute a promising technology to control air pollution, although intrinsic kinetics is needed for prediction of decontamination processes. Herein, the kinetic study of acetaldehyde oxidation was carried out applying photocatalytic paints under normal indoor illumination source and different ambient conditions. An intrinsic kinetic model for the main contaminant and reaction intermediates was proposed as a function of the Local Superficial Rate of Photon Absorption, which was evaluated for paints containing different amounts of carbon doped TiO2. A novel parameter to account for the relationship between photocatalytic active area, TiO2 amount and particles agglomeration in the paints was proposed. Also, based on the model predictions and the photocatalyst bandgap energy a spectral radiation analysis was performed determining the maximum wavelength at which the photocatalyst is active. Finally, the quantum and photonic efficiencies were calculated and the effect of operating conditions on these efficiencies was analyzed. 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: 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: 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

A theoretical and experimental study of bisphenol A (BPA) degradation by the UV/H

SBA-15 and KIT-6 materials have been synthesized and modified with iron salts by the wet impregnation method with different metal loadings. The different mesostructures obtained were characterized by N 2 adsorption–desorption at 77 K, X-ray diffraction, temperature-programmed reduction, and ultraviolet–visible spectroscopy. These iron-containing mesostructured materials have been successfully tested for the heterogeneous photo-Fenton degradation of aqueous solutions of dangerous herbicides, such as atrazine, using UV–visible light irradiation, at room temperature and close to neutral pH. The results showed that the Fe/SBA-15 (10%) and Fe/KIT-6 (5%) catalysts exhibited the highest activities. However, the Fe/KIT-6 (5%) catalyst with minor Fe loading than Fe/SBA-15 (10%) presented a higher degradation of atrazine (above 98% in a reaction time of 240 min). Therefore, the interconnectivity of the cage-like mesopores had an important influence on the catalytic activity, favoring probably mass-transfer effects. Thus, the high performance of these materials indicates that the heterogeneous via of photo-Fenton process can also be efficiently employed to treat wastewaters containing pollutants such as herbicides, in order to reduce them to simplest and less toxic molecules. Fil: Benzaquén, Tamara Belén. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigación y Tecnología Química. Universidad Tecnológica Nacional. Facultad Regional Córdoba. Centro de Investigación y Tecnología Química; Argentina Fil: Barrera Diaz, Deicy Amparo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich". Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich"; Argentina Fil: Carraro, Paola María. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigación y Tecnología Química. Universidad Tecnológica Nacional. Facultad Regional Córdoba. Centro de Investigación y Tecnología Química; Argentina Fil: Sapag, Manuel Karim. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich". Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich"; 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: Eimer, Griselda Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigación y Tecnología Química. Universidad Tecnológica Nacional. Facultad Regional Córdoba. Centro de Investigación y Tecnología Química; Argentina

The photocatalytic inactivation of Bacillus subtilis spores in air was evaluated employing a fixed-bed reactor with TiO 2 -coated glass rings, under artificial UV-A radiation. Calculations of the radiation effectively absorbed inside the reactor were carried out by Monte Carlo simulations. The photocatalytic inactivation was assessed by analyzing the viability of the microorganisms retained by the coated glass rings inside the reactor at different irradiation periods. The initial concentration of the spores was reduced by almost 55% at the end of the experiment (12 h). Complementary assays were carried out employing Bacillus subtilis vegetative cells, obtaining a reduction of more than 96% under the same conditions. Two efficiency parameters were computed to assess the reactor performance: the photonic efficiency and the quantum efficiency of inactivation. Results of the efficiency parameters allow an objective comparison of the reactor performance under different experimental conditions and configurations. Fil: Zacarias, Silvia Mercedes. 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: Pirola, Silvana 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: Manassero, Agustina. 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: Visuara, María Eugenia. 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: 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

[EN] The combination of kinetic and spectroscopic tools has become a key scientific methodology for the understanding of catalytic behavior but its application in photocatalysis has inherent difficulties due to the nature of the energy source of the reaction. This review article provides an overview of its use by, first, presenting mechanistically derived kinetic formulations and spectroscopic data handling methods including intrinsic expressions for light and, second, highlighting representative examples of application. To do it we consider universal catalytic systems, particularly (although not exclusively) titania-based materials, and the most frequent hole and/or electron triggered reaction schemes. This review also provides a general framework to pave the way for the future progress of the spectro-kinetic approach in the photocatalysis area., A. K., M. J. M.-B. and M. F.-G. thank MINECO (Spain) project ENE2016-77798-C4-1-R for financial support. M. J. M.-B. thanks MINECO for the award of postdoctoral JdC contract (Ref. FJCI- 2016-29014). O. M. A. and M. M. B. thank Universidad Nacional del Litoral (UNL, PIC50420150100009LI), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET, PIP-2015 0100093), and Agencia Nacional de Promoción Científica yTecnológica (ANPCyT, PICT-2015-2651) of Argentina for financial support.

This paper presents, for first time, a mechanistic model of the solar photo-Fenton process at neutral pH with the Fe 3+ -EDDS complex for micropollutant removal, taking into account irradiance and reactor geometry. Due to its high photon absorptivity, this biodegradable complex allows high percentages of micropollutant removal to be achieved for short reaction times. Nonetheless, no model of the process with the Fe 3+ -EDDS has yet been developed, meaning the proposed mechanism relies on photochemical reactions with the complex previously reported, and hypotheses deduced from experimental observation. The data for acetamiprid (ACTM) removal (100 μg L −1 ) in stirred tank reactors with different liquid depths, under controlled conditions of irradiance and temperature, was used to obtain the model parameters. The model successfully fitted the experimental results obtained outdoors in a raceway pond reactor (RPR), with a change of scale from 0.85 to 19 L. For the calculation of the average volumetric rate of photon absorption (VRPA), the effect of the two components of solar UV radiation (direct and diffuse) as a function of the environmental conditions and the reactor layout was considered. The results showed an important contribution by diffuse radiation, even at noon under spring conditions (≈40% of the total VRPA). In addition, the applicability of the model has been demonstrated in water matrices containing organic matter and HCO 3 −/CO 3 2− ions, usually found in secondary wastewater treatment plant (WWTP) effluents. This approach allows for the development of control and optimization tools for the photo-Fenton process at neutral pH in low-cost photoreactors. Fil: Soriano Molina, P.. Solar Energy Research Centre (ciesol); . Universidad de Almeria; Fil: García Sánchez, J.L.. Solar Energy Research Centre (ciesol); . Universidad de Almeria; 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: Conte, Leandro Oscar. 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: Malato, S.. Ciemat-plataforma Solar de Almería; Fil: Sánchez Pérez, J.A.. Solar Energy Research Centre (ciesol); . Universidad de Almeria

Mesoporous silica material type MCM-41 was modified with different amounts of Zn (1-15 wt.%) by the wet impregnation method. Support and catalysts were characterized by means of powder X-ray diffraction (XRD), N2 nitrogen adsorptiondesorption, transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and ICP-OES techniques. The Zn-modified mesoporous silicates have been successfully tested for the degradation in aqueous solutions of different endocrinedisrupting (EDs), such as herbicides (atrazine), compounds derived from the plastic industry (bisphenol A) and from the pharmaceutical industry (clofibric acid). The results showed that the Zn/M(5) catalyst exhibited the highest activity. The high performance of this material indicates that the heterogeneous photo-Fenton-like reaction appears as a very promising pretreatment capable of enhancing the biodegradability of water contaminated with biorecalcitrant chemicals, as the most endocrine disruptors. Materiales mesoporosos del tipo MCM-41 fueron modificados por el método de impregnación húmeda con diferentes cargas de Zn (1 - 15 % p/p). El soporte y los catalizadores fueron caracterizados por difracción de rayos X (DRX), adsorcióndesorción de N2, microscopia electrónica de transmisión (TEM), espectroscopia de fotoelectrones emitidos por rayos X (XPS) y técnica de ICP-OES. Los silicatos mesoporosos modificados con Zn se evaluados exitosamente en la reacción de degradación en solución acuosa de diferentes disruptores endocrinos (EDs), tales como herbicidas (atrazina), compuestos derivados de la industria plástica (bisfenol A) y de la industria farmacéutica (ácido clofíbrico). Los resultados mostraron que el catalizador Zn/M(5) exhibió la mayor actividad. La mejor performance de este material indica que la reacción heterogénea foto-Fenton aparece como un pretratamiento muy prometedor, capaz de mejorar la biodegradabilidad de aguas contaminadas con productos químicos biorecalcitrantes, como la mayoría de los disruptores endocrinos. Palabras clave: MCM-41, Zn, procesos avanzados de oxidación, disruptores endocrinos. Fil: Carraro, Paola María. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigación y Tecnología Química. Universidad Tecnológica Nacional. Facultad Regional Córdoba. Centro de Investigación y Tecnología Química; Argentina Fil: Benzaquén, Tamara Belén. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigación y Tecnología Química. Universidad Tecnológica Nacional. Facultad Regional Córdoba. Centro de Investigación y Tecnología 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: Oliva, Marcos Iván. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; Argentina Fil: Eimer, Griselda Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigación y Tecnología Química. Universidad Tecnológica Nacional. Facultad Regional Córdoba. Centro de Investigación y Tecnología Química; Argentina

Fil: Benzaquen, Tamara Belen. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Santa Fe. Instituto de Desarrollo Tecnologico para la Industria Quimica (i); Argentina

Optical properties of iron pillared clays (Fe-PILCs) were determined by using spectrophotometer measurements coupled with the solution of the radiative transfer equation (RTE). The specific absorption and scattering coefficients, as well as the phase function for scattering, were obtained as a function of the wavelength in the range from 300 to 500 nm. Optical properties of the Fe-PILCs are greatly affected by their iron contents which are ascribed to changes in their textural properties and are significantly different from those of two other iron containing materials, goethite and zerovalent iron. To show an application of the optical properties, the quantum efficiency of the heterogeneous photo-Fenton process with a Fe-PILC was determined. The results indicate that Fe-PILCs could be used as catalysts in large-scale photoreactors whose dimensions could be adjusted in a wide range according to the catalyst load and iron content to be used. Fil: de Leon, María A.. Universidad de la Republica. Facultad de Quimica; Uruguay Fil: Sergio, Marta. Universidad de la Republica. Facultad de Quimica; Uruguay Fil: Bussi, Juan. Universidad de la Republica. Facultad de Quimica; Uruguay Fil: Ortiz de la Plata, Guadalupe Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico 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 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 Santa Fe. Instituto de Desarrollo Tecnológico Para la Industria Química (i); Argentina

The photocatalytic activity of different TiO2 films for the degradation of 17-α-ethinylestradiol (EE2) in aqueous solution was studied using a continuous flow, planar microreactor. Pure and cerium-doped TiO2 films, prepared by the sol-gel method, were tested under simulated sunlight. The influence of the cerium content on the radiation absorption properties of the films and on the photocatalytic oxidation of EE2 was investigated. The performances of the catalytic films were objectively assessed by means of the absorption efficiency parameter and the quantum efficiency parameter. Spectral diffuse transmittance and reflectance measurements of the films were carried out to evaluate the fraction of radiation absorbed by the coatings. Although the film with 0.8 nominal atomic % of cerium (Ce at.%) showed the highest absorption efficiency, it was the less efficient in terms of pollutant degradation, even less than the undoped catalyst. The most efficient photocatalytic film to degrade EE2 was the sample with 0.3 Ce at.%. The benefits of employing a microreactor for catalyst screening are demonstrated, allowing the study of different operating conditions in a simple and fast way, and with minimum consumption of reagents. Fil: Martin, Marcela Vanessa. 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: 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

BACKGROUND This study is focused on the kinetic modelling of the Fenton and photo-Fenton degradation of a model pollutant (atrazine) in aqueous solution. The effects of hydrogen peroxide and ferric ion concentrations as well as those of radiation level on the atrazine degradation processes have been investigated. RESULTS The experimental work was performed in a well-stirred tank laboratory reactor irradiated from both sides with two tubular UV-lamps. The reaction rate expressions were derived from an accepted reaction mechanism, explicitly taking into account the local volumetric rate of photon absorption inside the photoreactor. The proposed kinetic model was able to reproduce the combined effects of changing the ferric iron concentrations, hydrogen peroxide to atrazine molar ratios and radiation level on the pollutant degradation rate. Model predictions were compared with experimental data and good agreement was obtained. The maximum root mean square error (RMSE) for all the estimations was

The photocatalytic activity under UV, visible and UV-visible radiation of two commercial catalysts for water remediation are evaluated and compared in a slurry reactor. Bisphenol A (BPA) was employed as the model pollutant. The activities of the carbon-doped, TiO2 catalyst Kronos vlp 7000 and, as a reference, the undoped catalyst Aeroxide P25 are compared by means of efficiency parameters: the overall photonic efficiency and the quantum efficiency. For the evaluation of the radiation absorbed by the catalyst suspensions, the optical properties of TiO2 Kronos vlp 7000 between 300 and 550 nm were measured and reported, as well as the properties of TiO2 Aeroxide P25 in the range 400?550 nm. Kronos catalyst exhibits absorption in the visible range and was almost three times more efficient than Aeroxide for BPA degradation under this condition. However, under UV radiation, Aeroxide P25 quantum efficiency was about 1.5 times the corresponding value of Kronos. Similar BPA photonic and quantum efficiencies were obtained under UV-visible radiation with both commercial catalysts. Fil: Manassero, Agustina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - CONICET- 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 - 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

The optimization of a corrugated wall photocatalytic reactor for air treatment was addressed using the concept of efficiencies in series. A new concept has been introduced: the inner incidence efficiency, associated with the internal configuration of the reactor (for instance, the folding angle in the considered case). The goal of the study was to obtain an optimum for the folding angle, subjected to certain constraints: fixed reactor volume, radiation flux, and gas flow rate. Previous experimentally determined degradation kinetics of a gaseous pollutant was used in the reactor modeling. The simulations of the reactor were performed computationally by using a computational fluid dynamics (CFD) package. The results showed opposed behaviors for the relative catalytic area per unit window area and the relative incident flux with the folding angle. Given that the inner incidence efficiency comprises the product of the two mentioned variables, an optimal folding angle was identified. Fil: Passalia, Claudio. 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. Facultad de Ingeniería y Ciencias Hídricas; 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. Facultad de Ingeniería y Ciencias Hídricas; Argentina Fil: Brandi, Rodolfo Juan. 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. Facultad de Ingeniería y Ciencias Hídricas; Argentina

An experimental comparative study of different meshes as support materials for photocatalytic applications in gas phase is presented. The photocatalytic oxidation of dichloromethane in air was addressed employing different coated meshes in a laboratory-scale, continuous reactor. Two fiberglass meshes and a stainless steel mesh were studied regarding the catalyst load, adherence, and catalytic activity. Titanium dioxide photocatalyst was immobilized on the meshes by dip-coating cycles. Results indicate the feasibility of the dichloromethane elimination in the three cases. When the number of coating cycles was doubled, the achieved conversion levels were increased twofold for stainless steel and threefold for the fiberglass meshes. One of the fiberglass meshes (FG2) showed the highest reactivity per mass of catalyst and per catalytic surface area. Fil: Passalia, Claudio. Universidad Nacional del Litoral. Facultad de Ingeniería y Ciencias Hídricas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; Argentina Fil: Nocetti, Emanuel. Universidad Nacional del Litoral. Facultad de Ingeniería y Ciencias Hídricas; 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: Brandi, Rodolfo Juan. 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 aims of this work were to design and build a photocatalytic reactor (UV-A/TiO2) to study the inactivation of phages contained in bioaerosols, which constitute the main dissemination via phages in industrial environments. The reactor is a close system with recirculation that consists of a stainless steel camera (cubic form, side of 60 cm) in which air containing the phage particles circulates and an acrylic compartment with six borosilicate plates covered with TiO2. The reactor is externally illuminated by 20 UV-A lamps. Both compartments are connected by a fan to facilitate the sample circulation. Samples are injected into the camera using two piston nebulizers working in series whereas several methodologies for sampling (impinger/syringe, sampling on photocatalytic plates, and impact of air on slide) were assayed. The reactor setup was carried out using phage B1 (Lactobacillus plantarum), and assays demonstrated a decrease of phage counts of 2.7 log orders after 1 h of photocatalytic treatment. Photonic efficiencies of inactivation were assessed by phage sampling on the photocatalytic plates or by impact of air on a glass slide at the photocatalytic reactor exit. Efficiencies of the same order of magnitude were observed using both sampling methods. This study demonstrated that the designed photocatalytic reactor is effective to inactivate phage B1 (Lb. plantarum) contained in bioaerosols.

The performance of different TiO 2 coatings is compared for the photocatalytic inactivation of dry Bacillus subtilis spores dispersed on TiO 2 films under UV-A radiation. Three different TiO 2 coatings were assayed: Degussa P-25, sol-gel, and composite sol-gel/Degussa P-25. The influence of the increase in the number of TiO 2 layers was also studied. Furthermore, the amount of TiO 2 deposited on the borosilicate glass plates and the fraction of energy effectively absorbed by the catalytic films were determined. Spectral diffuse transmittance and reflectance measurements were performed using a spectroradiometer with an integrating-sphere attachment. The net-radiation method was then applied to evaluate the fraction of energy absorbed by the coatings. To objectively compare the performance of the catalytic films, two types of efficiencies were calculated: the photonic efficiency and the quantum efficiency of inactivation. The highest quantum efficiency was obtained with the TiO 2 Degussa P-25 coating with two layers. © 2012 American Chemical Society. Fil: Zacarias, Silvia Mercedes. 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: 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: Vaccari, Maria Celia. Universidad Nacional del Litoral; 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

In this paper, the photocatalytic inactivation efficiency of phages infecting lactic acid bacteria (LAB) was evaluated. Ten bacteriophages (ATCC 15807-B1, 832-B1, 0241, 204, 342, MLC-A, J-1, OBJ, CHD and QF9) dispersed on TiO 2 -coated plates were exposed to UV-A radiation during different periods of time. Two kinds of efficiencies were defined and assessed: (i) the apparent photonic yield and (ii) the quantum yield of inactivation. Considering all phages studied in this work, dissimilar values of inactivation efficiencies were found; the results differ in more than one order of magnitude. The highest inactivation efficiency was found for the bacteriophage J-1, whereas the lowest one was obtained for the phage 342. The data presented in this work can provide useful information to design innovative and effective treatments to be applied in laboratories and industrial plants which handle LAB strains.

Heterogeneous photocatalysis is a suitable technology for eliminating indoor pollutants at low concentration ranges. In this work we deal with the modeling and experimental evaluation of a continuo...

In the present work the existente of mass transfer limitations in slurry, photocatalytic reactors is studied. Experimental validation is made in a flat plate reactor that is part of a recycling system. The reactor is described with a mathematical model previously developed [Ballari et al., 2008a. Chemical Engineering Journal 136, 50], considering a transient, two-dimensional mass balance (TDM). The complete reactor model was developed to show the existence of these effects, which result from the occurrence of concentration gradients in reaction space. They develop when these reactors are operated under some operating conditions whose effects should be always analyzed before assuming the validity of existence of perfect mixing in reaction space. Dichloroacetic acid (DCA) was the adopted model compound. To solve TDM, a kinetic expression for DCA acid was determined before under well mixed conditions [Ballari et al., 2009. Industrial and Engineering Chemistry Research 48(4), 1847]. The studied variables are flow rate, catalyst loading, and irradiation rates. The experimental data agree quite well when they are interpreted in terms of the two-dimensional model (TDM) regardless of the operating mode. The perfect mixing model (PMM), normally employed to describe this and other types of slurry photoreactors, does not have the same level of universal application; i.e. it is restricted to perfect mixing, but in many cases far simpler to use. However, it can be concluded that when the photocatalytic reaction is not fast, employing catalyst loadings below 1gL–1, irradiation rates at the reactor wall below 1x10x-6 Einstein cm-2 s-1 and good mixing operation (Re41700) it will be always safe to assume that mass transport limitations in the bulk of the fluid are non existent. In a typical batch reactor the above flow conditions are equivalent to very intense mixing. If the catalyst concentration is in creased, the mixing conditions should be improved in the same proportion. Within limits, higher solid loadings can be compensated with lower irradiation rates[Ballarietal.,2008a. Chemical Engineering Journal 136, 50]. In addition, with the validated model, additional simulations are shown, operating the reactor under different virtual reactor thicknesses to widen amplitude of the reached conclusions. These findings Hill be useful in kinetic studies to prevent incursion in certain ranges of experimental conditions that could lead to erroneous interpretation of the obtained kinetic data. Fil: Ballari, Maria de Los Milagros. 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 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

A study has been conducted on the decomposition of 2-chlorophenol (2-CP) applying a heterogeneous Fenton reaction using goethite as catalyst at pH 3. The research was aimed at obtaining a workable kinetic expression apt for developing a kinetic model for scaling up purposes. Several aspects of the reaction have been described in the available literature but, for the moment, without a reasonable representation of the entire reaction behavior. In order to provide a more comprehensive and probable explanation of the whole observed performance, a set of experiments was carried out varying systematically all the significant variables. The proposal considers that the reaction is essentially a combination of four heterogeneous processes associated with one typical homogeneous Fenton reaction. Three of the surface reactions explain a very small iron leaching to the medium by a proton induced solubilization, a reductive dissolution reaction and a non-reductive iron release produced by detected 2-CP chemical decomposition byproducts, particularly, chlorohydroquinone (ClHQ) and oxalic acid (OxA). Iron concentration in the solution may be further increased in the final stages of the reaction after most of the 2-CP has been degraded, by the appearance of OxA that takes part in a third surface reaction. The fourth heterogeneous reaction rationalizes the unusual hydrogen peroxide consumption at high catalyst loadings. During the homogeneous reaction, the presence of ClHQ and ClBQ produces a homogeneous autocatalytic beneficial enhancement of the Fe3+ → Fe2+ transformation. Consequently, the existence of phenolic derivatives either in the mixture or as reaction byproducts produces a beneficial enhancement of the reaction rate. Very low iron leaching is required to produce the onset of the homogeneous Fenton reaction, which was shown to be strongly dependent upon the reaction temperature. All the experimental findings were satisfactorily described by a set of 19-step feasible reaction scheme. The process could be useful for the treatment of wastewaters containing pollutants with phenolic derivatives, as long as iron leaching remains within tolerable limits.

The kinetics of the degradation of 2-chlorophenol (2-CP) employing both the heterogeneous Fenton and photo-Fenton reactions using goethite as the solid catalyst is studied. The photoreactor was irradiated with a 350–400 nm wavelength light. The kinetics is based on 19 steps of a combined heterogeneous–homogeneous mechanism derived for the thermal Fenton reaction [see companion article by the authors: Ortiz de la Plata et al. (2009)] [1] . For the photo-Fenton alternative, two more steps are needed. Some of the specific kinetic constants of the reaction scheme are approximately known. However, for the heterogeneous “thermal” Fenton reaction, three new unknown constants were required and were attained from experimental data obtained in this and the previous work. The parameters were (i) the reaction of the HO radical with 2-CP, (ii) the proton induced iron dissolution and (iii) the reductive induced iron dissolution [1] . In the case of the heterogeneous photo-Fenton reaction steps, the radiation field in the reacting system was described by solving the complete radiative transfer equation inside the reactor. With this purpose, the knowledge of the needed goethite optical properties were previously characterized [2] . Combining the dark and the irradiated experiments 21 kinetically consistent parameters were achieved for the proposal of a feasible mechanism. They are valid for both systems; making the two primary quantum yields of the photoreaction equal to zero, the “dark” Fenton reaction performance is properly described by the remaining 19 specific rate constants. These results are independent of the used experimental apparatus and can be safely used for scaling-up purposes within the range of the explored variables.

The photocatalytic degradation of radiation absorbing and nonabsorbing pollutants in slurry reactors is analyzed in terms of two performance parameters: the observed photonic efficiency (OPE) and t...

In a broad sense, photochemical reactions proceed through pathways involving several reaction steps. The initiation step is the absorption of energy both by the reactant or sensitizer molecules and in some cases, by the catalyst, leading to intermediate products that ultimately give rise to stable end products. Preferably, the reaction rate expression is derived from a proposed mechanism together with sound simplifying assumptions; otherwise, it may be adopted on an empirical basis. Under a kinetic control regime, the rate expression thus obtained depends on the local rate of photon absorption according to a power law whose exponent very often ranges from one half to unity. The kinetic expression should be valid at every point of the reactor volume. However, due to radiation attenuation in an absorbing and/or scattering medium, the value of the photon absorption rate is always a function of the spatial position. Therefore, the overall photochemical reaction rate will not be uniform throughout the entire reaction zone, and the distinction between local and volume average photochemical reaction rates becomes mandatory. Experimental values of reaction rates obtained from concentration measurements performed in well-mixed reaction cells are, necessarily, average values. Consequently, for validation purposes, experimental results from these cells must be compared with volume averages of the mechanistically or empirically derived local reaction rate expressions. In this work it is shown that unless the rate is first order with respect to the photon absorption rate or the attenuation in the absorbing and/or scattering medium is kept very low, when the averaging operation is not performed, significant errors may be expected. 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: 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: 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: Farias, Jorgelina. 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

This study is focused on the kineticmodeling of the photocatalytic oxidation of cyanide in slurry reactors. The developed model is based on an accepted reaction mechanism and explicitly takes into account the differences in the local volumetric rate of photon absorption (LVRPA) produced by the unavoidable radiation profiles existing in the photoreactor. The model and its correspondent procedures for the evaluation of the LVRPA distribution, and the estimation of the kinetic parameters have been successfully validated with both powder TiO2 and TiO2/SiO2 photocatalysts with improved recovery properties. In both cases, the model reproduces the influence of the catalyst loading, the initial cyanide concentration, and the inlet radiation flux on the reaction rate, with errors below 5%. The kinetic parameters estimated for the model are independent of the irradiation form, as well as the reactor size and its geometrical configuration, providing the necessary information for scaling-up and designing commercial scale photoreactors. Fil: Marugan, 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