Influence of the anodizing process variables on the acidic properties of anodic alumina films

In the present work, the effect of the different variables involved in the process of aluminum anodizing on the total surface acidity of the samples obtained was studied. Aluminum foils were treated by the electro-chemical process of anodic anodizing within the following variable ranges: concentration=1.5-2.5 M; temperature=303-323 K; voltage=10-20 V; time=30-90 min. The total acidity of the samples was characterized by two different methods: acid-base titration using Hammet indicators and potentiometric titration. The results showed that anodizing time, temperature and concentration were the main variables that determined the surface acid properties of the samples, and to a lesser extent voltage. Acidity increased with increasing concentration of the electrolytic bath, whereas the rest of the variables had the opposite effect. Theresults obtained provide a novel tool for variable selection in order to use synthetized materials as catalytic supports, adding to previous research based on the morphology of alumina layers.Fil: Boldrini, Diego Emmanuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; ArgentinaFil: Yañez, Maria Julia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca; ArgentinaFil: Tonetto, Gabriela Marta. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; Argentin

Study of Cu-Zn and Au/TiO2 Catalysts on Anodized Aluminum Monoliths for Hydrogen Generation and Purification

This work reports the preparation of Cu-Zn and Au/TiO2 catalysts on anodized aluminum monoliths(AAM). The structured catalysts were studied for the generation of H2 by methanol steam reforming (MSR) and its purification by preferential oxidation of CO (CO-PrOx). Initially, it was possible to generate a surface with whiskers and larger surface area by hydrothermal treatment of the AAM. Subsequently, the structured catalysts were synthesized by incipient wetness impregnation (IWI) and ydrothermal synthesis (HS). IWI synthesis allowed for the deposition of a larger amount of catalytic material than HS, with very good adhesion. The TiO2-IWI structured catalyst presented a homogeneous catalytic coating, with the presence of agglomerated particles. On theother hand, Cu-Zn-IWI showed good dispersion of the deposited particles with a homogeneous surface coating. EDX analysis corroborated the presence of Ti, Cu and Zn in all the catalytic surfaces. The incorporation of Au over TiO2-IWI structured catalysts was successfully performed by IWI using a colloidal solution of gold nanoparticles.MSR was studied over the developed metallic monoliths functionalized with Cu-Zn by the IWI method. The samples showed promising results in terms of activity, selectivity, and stability. Both diluted and concentrated methanol + water feeds were assayed. Complete methanol conversion was achieved for the diluted feed. Maximum methanol conversions of 55% with 60% H2 yield were measured when the concentrated feed was selected. Promising results were also achieved for the Au-based structured catalysts in the CO-PrOx in an H2- rich atmosphere. Although CO conversions of approximately 60% were achieved, operating with higher catalyst loadings would be recommended to reach the high CO conversions required for PrOx catalysts.Fil: Adrover, María Esperanza. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; ArgentinaFil: Boldrini, Diego Emmanuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; ArgentinaFil: Jiménez Divins, Nuria. Universidad Politecnica de Catalunya; EspañaFil: Casanovas Hoste, Adria. Universidad Politecnica de Catalunya; EspañaFil: Tonetto, Gabriela Marta. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; ArgentinaFil: Lopez, Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; ArgentinaFil: Llorca Piqué, Jordi. Universidad Politecnica de Catalunya; Españ

Search for new particles in events with energetic jets and large missing transverse momentum in proton-proton collisions at root s=13 TeV

A search is presented for new particles produced at the LHC in proton-proton collisions at root s = 13 TeV, using events with energetic jets and large missing transverse momentum. The analysis is based on a data sample corresponding to an integrated luminosity of 101 fb(-1), collected in 2017-2018 with the CMS detector. Machine learning techniques are used to define separate categories for events with narrow jets from initial-state radiation and events with large-radius jets consistent with a hadronic decay of a W or Z boson. A statistical combination is made with an earlier search based on a data sample of 36 fb(-1), collected in 2016. No significant excess of events is observed with respect to the standard model background expectation determined from control samples in data. The results are interpreted in terms of limits on the branching fraction of an invisible decay of the Higgs boson, as well as constraints on simplified models of dark matter, on first-generation scalar leptoquarks decaying to quarks and neutrinos, and on models with large extra dimensions. Several of the new limits, specifically for spin-1 dark matter mediators, pseudoscalar mediators, colored mediators, and leptoquarks, are the most restrictive to date.Peer reviewe

Probing effective field theory operators in the associated production of top quarks with a Z boson in multilepton final states at root s=13 TeV

Peer reviewe

Three-phase mass transfer: theoretical development of the overall effectiveness factor for cylindrical geometries

This work presents a theoretical analysis for predicting the overall effectiveness factor (η) for cylindrical geometries in a three-phase catalytic reaction system. Implicit expressions for η, taking into account all the transport effects, gas–liquid mass transfer, liquid-solid mass transfer and intraparticle diffusion as well the chemical reaction were obtained. Various types of kinetics were considered; namely, Langmuir–Hinshelwood, power-law and zeroth order. The obtained results are presented as a useful tool to be used in field of reactors design and laboratory kinetics data interpretation.Fil: Boldrini, Diego Emmanuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; Argentina. Universidad Nacional del Sur. Departamento de Ingeniería Química; Argentin

Monolithic stirrer reactor for vegetable oil hydrogenation: A technical and economic assessment

The monolithic stirrer reactor (MSR) which consists on monolithic structures mounted on reactor axis as agitator blades is a novel design with the potential to intensify different production processes. Its most outstanding advantages are the absence of a filtering stage after the reaction and the high-speed mass transfer. In this paper, the technical and economic feasibility of sunflower oil hydrogenation process under MSR (Pd/Al2O3/Al) configuration was studied considering a 100 ton day-1 productive plant, a 20 ton capacity reactor and a final product with 75 iodine index. Moreover, several reaction conditions were taken into account, such as catalyst loading and initial and final reaction temperatures, in order to determine the operating costs. The proposed alternative process could be profitable, displaying a higher Net Present Value (NPV) than the conventional technology one. However, slight variations in the monolithic catalyst cost performed through a sensitivity analysis generate a considerable decrease in NPV, thus determining that the implementation of the proposed alternative technology presents a high economic risk. The achieved results in this study indicate that further research is necessary in order to develop a regenerating procedure to extend the catalyst useful life, thus favouring the monolithic technology economy.Fil: Boldrini, Diego Emmanuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; Argentina. Universidad Nacional del Sur. Departamento de Ingeniería Química; Argentin

Corrigendum to “Monolithic stirrer reactor for vegetable oil hydrogenation: A technical and economic assessment” [Chem. Eng. Process. – Process Intensif. 132 (2018) (October) 229–240]

The monolithic stirrer reactor (MSR) which consists on monolithic structures mounted on reactor axis as agitator blades is a novel design with the potential to intensify different production processes. Its most outstanding advantages are the absence of a filtering stage after the reaction and the high-speed mass transfer. In this paper, the technical and economic feasibility of sunflower oil hydrogenation process under MSR (Pd/Al2O3/Al) configuration was studied considering a 100 ton day−1 productive plant, a 20 ton capacity reactor and a final product with 75 iodine index. Moreover, several reaction conditions were taken into account, such as catalyst loading and initial and final reaction temperatures, in order to determine the operating costs. The proposed alternative process could be profitable, displaying a higher Net Present Value (NPV) than the conventional technology one. However, slight variations in the monolithic catalyst cost performed through a sensitivity analysis generate a considerable decrease in NPV, thus determining that the implementation of the proposed alternative technology presents a high economic risk. The achieved results in this study indicate that further research is necessary in order to develop a regenerating procedure to extend the catalyst useful life, thus favouring the monolithic technology economy.Fil: Boldrini, Diego Emmanuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; Argentina. Universidad Nacional del Sur. Departamento de Ingeniería Química; ArgentinaFil: Tonetto, Gabriela Marta. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; Argentin

Kinetic study of fuel bio-additive synthesis from glycerol esterification with acetic acid over acid polymeric resin as catalyst

The increase of remnant of glycerol from biodiesel production results in the need to develop valorization strategies for this low-cost by-product. In this context, bio-additives synthesis from glycerol such as acetylglycerides has emerged as an economically viable alternative. In this work, a kinetic study of glycerol esterification with acetic acid over Dowex 650C ion exchange resin as catalyst to obtain fuel bio-additives was performed. The experimental study was carried out in a batch reactor at 353–393 K temperature range using acetic acid to glycerol molar ratio from 3:1 to 9:1 and catalyst loading between 4 and 8 wt%. Furthermore, different kinetic models based on the Langmuir-Hinshelwood-Hougen-Watson (LHHW), Eley-Rideal (ER) and Power Law (PL) approaches were proposed in order to correlate the experimental data. In addition, it was determined that the intraparticle and extraparticle mass and heat transfer resistances in the polymeric resin are negligible. The obtained results from kinetics modeling evidence that the best model to describe the studied reaction was the Eley-Rideal. In this model, it was considered that the catalytic surface reaction was the controlling reaction stage, which involves the reaction between adsorbed acetic acid and glycerol as well as mono- and diglycerides from the bulk liquid phase, generating the corresponding acylglycerides and water. Moreover, it was found that glycerol and water adsorption on the catalytic surface is stronger than that for acetic acid and acetylglycerides.Fil: Reinoso, Deborath Mariana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; ArgentinaFil: Boldrini, Diego Emmanuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; Argentin

Overall effectiveness factor for slab geometry in a three-phase reaction system

The overall effectiveness factor for slab geometry applicable to uniform washcoats on a monolith surface for three-phase reaction systems was studied in the present work. Analytical solutions for zero-order reactions and Langmuir–Hinshelwood and power law kinetics were reported. The analysis of the theoretical results showed that not considering the geometry of the monolithic system in a proper way lead to 14% errors in reactions parameters when operating under mixed control (kinetic-internal diffusion) and negligible external mass-transfer resistances.Fil: Boldrini, Diego Emmanuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Planta Piloto de Ingeniería Química (i); Argentina. Universidad Nacional del Sur. Departamento de Ingenieria Quimica; ArgentinaFil: Tonetto, Gabriela Marta. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Planta Piloto de Ingeniería Química (i); Argentina. Universidad Nacional del Sur. Departamento de Ingenieria Quimica; ArgentinaFil: Damiani, Daniel Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Planta Piloto de Ingeniería Química (i); Argentina. Universidad Nacional del Sur. Departamento de Ingenieria Quimica; Argentin

Experimental study of the deactivation of Pd on anodized aluminum monoliths during the partial hydrogenation of vegetable oil

Partial hydrogenation of sunflower oil was studied over Pd/Al2O3/Al catalysts in a monolithic stirred reactor. The catalyst showed similar or even better activity and selectivity than conventional Pd/Al2O3 catalysts. However, in consecutive runs, a continuous decreasing activity was observed. In order to understand the deactivation phenomena, fresh and spent catalysts were characterized using temperature programmed reduction, N2 adsorption isotherms, dynamic H2 chemisorption, transmission electron microscopy (TEM), atomic absorption spectroscopy, inductively coupled plasma spectroscopy, diffuse reflectance infrared Fourier transform spectroscopy, ultrasound adherence tests, and X-ray photoelectron spectroscopy. Furthermore, an extensive number of catalytic tests under different operating conditions were carried out. The loss in activity was proportional to the reduction in metal dispersion. The decrease in Pd dispersion was due to the coverage of the Pd surface. The deactivation occurred due to fouling with reaction residues most probably coming from polymerization and/or cross-linking reactions. The catalysts can be regenerated ex situ using a careful desorption–washing–calcination process, although this requires further research because the temperatures required are too high for Al.Fil: Boldrini, Diego Emmanuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; ArgentinaFil: Tonetto, Gabriela Marta. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; ArgentinaFil: Damiani, Daniel Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; Argentin