Estudio ¨in vitro¨ de las características de absorción gastro-intestinal de la nicotinamida

Mediante el Simulador de Absorción Sartorius SM 16750 y siguiendo el método de Stricker se ha realizado el estudio de las características de absorción gastrointestinal de la nicotinamída. Se ha comprobado que presenta una manifiesta absorción a partir de pH 3 hasta alcanzar un máximo a pH 6.In the Sartorius Absorption Simulator model SM 16750 and using the Stricker's method, the nicotinamide gastrointestinal absorption characteris ti'cs were studied. Evident absorption at pH 3 value was abserved reaching at pH 6 value the highert absorption level

Kinetic and equilibrium adsorption parameters estimation based on a heterogeneous intraparticle diffusion model

In this work, a commercial resin with a well-developed internal pore structure was chosen to adsorb four parabens used as probe molecules. The main novelty was to propose and validate a phenomenological transient adsorption model based on conservation law in both phases coupled with Langmuir’s equilibrium law and Fick’s mass transfer rate law inside the pores. With such an aim, a heterogeneous three-parameter intraparticle diffusion model, IPDM, was formulated, and its numerical solution was fitted to time-dependent concentration data by minimizing the sum of squared residuals. Equilibrium constants were also predicted by fitting Langmuir isotherm to equilibrium data. A monolayer capacity of 0.81 mmol/g was calculated for the four parabens regardless of the number of carbons in the ester group. With the optimal parameters values from the IPDM fitting process, a system of ODEs comprising local sensitivity coefficients as dependent variables was solved to compute the parameters’ variance-covariance matrix and infer their ranges for a 95% marginal confidence interval. In order to test the validity of the proposed model, an attempt to crosscheck between the parameters obtained by the estimation of the equilibrium related parameter, κ, and the modified capacity parameter, and the ones obtained by fitting the Langmuir’s isotherm to equilibrium data was carried out. As far as equilibrium related parameters concern, there is a relative agreement inside the limits of the confidence range between the estimated values of the amount adsorbed in equilibrium with initial bulk solution concentration, q0, and Langmuir’s equilibrium constant, K, adjusted to kinetic and equilibrium data, independently. Additionally, the order of magnitude of pore diffusivity obtained in this work is in accordance with the one predicted by Wilke-Chang correlation and is inversely proportional to the van der Waals volume raised to the power 0.53 in close agreement with the literature.The authors gratefully acknowledge financial support of this research work through the Comisión Interministerial de Ciencia y Tecnología (CICYT)-CTM2013-41354-R and Fundação para a Ciência e a Tecnologia (FCT)-UIDB/04730/2020 projects.info:eu-repo/semantics/publishedVersio

Obtención de liposomas a partir de arqueas halófilas extremas y aplicaciones en tecnología farmacéutica

Tesis Univ. Granada. Departamento de Microbiología. Leída el 14 de septiembre de 200

Procesos de adsorción para descontaminación ambiental

45 páginas.Capítulo incluido en el libro: Aplicaciones de adsorbentes y catalizadores en procesos medioambientales y energéticos. Miguel Ángel Álvarez Merino, Francisco Carrasco Marín (Editores). Sevilla: Universidad Internacional de Andalucía, 2016. ISBN: 978-84-7993-309-8. Enlace: http://hdl.handle.net/10334/362

Fuel Processing Technology: Preface

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2nd International Conference on Chemical and Biochemical Engineering (ICCBE2) : Abstract book

Organizado por académicos e investigadores pertenecientes a diferentes áreas científicas del C3i/Instituto Politécnico de Portalegre (Portugal), la Universidad de Extremadura (España) y la Universidad de Las Palmas de Gran Canaria (España) con el apoyo técnico de ScienceKNOW Conferences. El evento tuvo el objetivo de crear un foro internacional para académicos, investigadores y científicos de todo el mundo para discutir esultados y propuestas mundiales con respecto a los temas más sólidos relacionados con la Ingeniería Química y Bioquímica

Combating paraben pollution in surface waters with a variety of photocatalyzed systems: Looking for the most efficient technology

The constant presence of parabens in natural surface waters has raised a growing concern of the potential long-term toxic effects that parabens may have in wildlife, mainly as endocrine disruptors. The present report describes the results of a study in which different photocatalyzed systems, such as photo-Fenton, Fenton, UV-H2O2, UV-TiO2 and UV-TiO2-H2O2, were applied to the removal of these recalcitrant pollutants in some surface waters, including natural (e.g. rivers) and man-made (e.g. reservoirs and wastewater treatment plants). Degradation of four widely-used parabens (methyl-paraben, ethyl-paraben, propyl-paraben and butyl-paraben) was analyzed. Experimental results reveal that the most efficient method to combat these emerging pollutants was photo-Fenton. When this process was optimized, optimal removal efficiency was attained using doses of H2O2 and Fe(II) equal to 2.92·10−4 mol dm-3 and 1.85·10−5 mol dm-3, respectively. It is also worth noting that the removal rate of these contaminants is slower in natural waters. The results suggest that the photo-Fenton process is promising and maybe an adequate technology for the treatment of these persistent contaminants

Electrochemical and sonochemical advanced oxidation processes applied to tartrazine removal. Influence of operational conditions and aqueous matrix

Tartrazine degradation was investigated by electrochemical and sonochemical oxidation processes. Anodic oxidation was carried out using boron-doped diamond (BDD) electrodes. The influence of current density and dye initial concentration on the removal of tartrazine from water was analyzed. The experimental results indicate that total removal of tartrazine was obtained, and Chemical Oxygen Demand (COD) and Total Organic Carbon (TOC) removals of up to 94.4% and 72.8% were achieved, respectively. To optimize the process, the pollutant removal percentage, the kinetic rate constant, and the TOC removal efficiency were chosen as target variables. Moreover, sonochemical oxidation experiments at a high-frequency range of cavitation (up to 1 MHz) were performed to establish the influence of three different operating variables, namely ultrasound frequency (0.5–1.1 MHz), ultrasound power (2.0–26.6 W ⋅L¯¹), and pulse-stop ratio (5:1–1:1). The process was also analyzed in terms of kinetics and energy costs. The kinetics resulted to be three times faster for the electrochemical process. However, the calculated energy costs were very similar, at least at long treatment times. Finally, the influence of three aqueous matrices was investigated. According to the experimental results, the natural occurrence of chloride and/or nitrate ions in water strongly conditions the rate of the process, although at least 90% of tartrazine removal was achieved within the first 50 min of treatment.This research work funded through the Comisi´on Interministerial de Ciencia y Tecnología (CICYT)-CTM 2016-75873-R project-as well as through GR15067 and IB16016 projects by the Junta de Extremadura under and the European Regional Development Fund.peerReviewe