DigitalUM :: Browsing by browse.metadata.contributordepartment "Ingeniería Química"

Browsing by browse.metadata.contributordepartment "Ingeniería Química"

Now showing 1 - 20 of 92

Open Access
A KrCl exciplex flow-through photoreactor for degrading 4-chlorophenol:Experimental and modelling
(Elsevier, 2012) M. Gomez; M.D. Murcia; J.L. Gomez; E. Gomez; M.F. Maximo; A. Garcia; Ingeniería Química
A KrCl exciplex flow-through photoreactor has been used for the removal of 4- chlorophenol. UV/H2O2 and photo-Fenton processes were tested. Considering the degradation of the different compounds, the molar ratio H2O2:4-chlorophenol did not show a significant influence on 4-chlorophenol while an optimum ratio of 25:1 was established for the photoproducts. The presence of the Fenton reagent led to a considerable improvement in the photodegradation of both the substrate and by- products, and an optimum Fe2+ concentration of 5 mg L-1 was determined. Under these conditions, total degradation was attained for a range of substrate concentrations between 50 and 150 mg L-1 and for reaction volumes of 500 mL. A photodegradation mechanism was also proposed, based on the formation of two intermediate compounds that quickly degrade to the primary photoproducts previously identified. A kinetic model was developed and theoretical conversion values of the 4-chlorophenol and the photoproducts were compared with the experimental ones, reaching a high degree of agreement (xcalc = 0.9964 xexp, R2 = 0.9986) and validating the proposed model. This system simulation using relatively high reaction volumes and including the by-products in the kinetic equations represents a first approach with a view to operating in continuous or semi-continuous systems that allow the scaling up of the process.
Embargo
A multi-pollutant methodology to locate a single air quality monitoring station in small and medium-size urban areas
(Elsevier, 2020-08-11) Baeza Caracena, Antonia; Doval Miñarro, Marta; Bañón Gómez, Daniel; Costa Gómez, Isabel; Egea, José A.; Ingeniería Química
Air quality management is underpinned by continuous measurements of concentrations of target air pollutants in monitoring stations. Although many approaches for optimizing the number and location of air quality monitoring stations are described in the literature, these are usually focused on dense networks. However, there are small and medium-size urban areas that only require one monitoring station but also suffer from severe air pollution. Given that target pollutants are usually measured at the same sampling points; it is necessary to develop a methodology to determine the optimal location of the single station. In this paper, such a methodology is proposed based on maximizing an objective function, that balances between different pollutants measured in the network. The methodology is applied to a set of data available for the city of Cartagena, in southeast Spain. A sensitivity analysis reveals that 2 small areas of the studied city account for 80% of the optimal potential locations, which makes them ideal candidates for setting up the monitoring station. The methodology is easy to implement, robust and supports the decision-making process regarding the siting of fixed sampling sites.
Open Access
A new substrate and by-product kinetic model for the photodegradation of 4-chlorophenol with KrCl exciplex UV lamp and hydrogen peroxide
(Elsevier, 2012-04-01) Murcia Almagro, María Dolores; Gómez, María; Gómez, Elisa; Gómez, José Luis; Hidalgo Montesinos, Asunción María; Christofi, Nick; Ingeniería Química
Embargo
A simple fractionation method and GPC analysis of organosolv extracts obtained from lignocellulosic materials
(Springer-Verlag, 2020-01-16) Andreo-Martínez, Pedro; Ortiz-Martínez, Víctor Manuel; García-Martínez, Nuria; Hernández-Fernández, Francisco José; Pérez de los Ríos, Antonia; Quesada-Medina, Joaquín; Ingeniería Química
The elucidation of lignin structural features is necessary for the efficient application of this polymer. Fractionation is an effective technique to achieve homogeneous lignin fractions, helping to better understand its composition and structure, and improving its use as source of phenolic compounds. This work develops a new and simple fractionation method of organosolv extracts obtained from lignocellulosic materials that enables the selective separation of lignin (from complex macromolecules to low molecular weight aromatic compounds originated from their degradation) from saccharides derived from hemicelluloses and cellulose. For this purpose, the non-catalytic organosolv extraction of lignin from almond shells was performed with dioxane/water mixtures and then the successful fractionation of the organosolv extracts with anhydrous tetrahydrofuran was achieved, resulting in the selective separation of lignin (lignin fraction) from saccharides (saccharide fraction). Gel permeation chromatography (GPC), thioacidolysis, and GC-MS were used as analytical methods to qualitatively determine the purity of both fractions. In addition, GPC was also used to quantify the content of lignin monomers and furfural in the organosolv extracts, thus allowing valuable information on the state of degradation of the lignin and hemicelluloses extracted to be obtained, respectively. The application of the GPC method also enabled the determination of the molecular weight distribution of the extracted lignin in the same analysis.
Open Access
A simplified kinetic model to describe the solvent-free enzymatic synthesis of wax esters
(2021-04-17) Serrano-Arnaldos, M.; Murcia, M.D.; Ortega-Requena, S.; Montiel, M.C.; Máximo, F.; Gómez, E.; Bastida, J.; Ingeniería Química
BACKGROUND: The use of biotechnological processes at industrial scale is a promising tool to replace conventional synthesis as an efficient and eco-friendly technology. For that purpose, the kinetic modelling of an in-lab optimized enzymatic process prior to scaling-up is of great utility. RESULTS: In this work, a kinetic model for the solvent-free synthesis of cetyl laurate, myristate, palmitate and stearate using different commercial immobilized lipases has been developed. In order to describe the esterification process of the cetyl esters separately and as a mixture similar to natural spermaceti, a pseudo-first-order kinetic has been proposed and tested. A relation between the inverse values of the kinetic constant and the amount of biocatalyst has been observed. The effect of temperature on the reaction rate can be accurately described by the Arrhenius equation except for immobilized Thermomyces lanuginosus, which appears to be less resistant to temperatures above 70 °C. CONCLUSION: Low deviations between experimental and predicted values (R2 ≥ 0.99) indicate that this pseudo-first-order kinetic model can be considered valid for the data range studied. In addition, the reaction rate of spermaceti can be successfully predicted through a weighted average of the kinetic constants obtained during the synthesis of each cetyl ester. This simple but accurate kinetic model for describing the solvent-free enzymatic biosynthesis of wax esters from spermaceti may contribute to extending the application of lipases as industrial catalysts.
Open Access
Accelerated Simple Preparation of Curcumin-Loaded Silk Fibroin/Hyaluronic Acid Hydrogels for Biomedical Applications
(MDPI, 2023-01-18) Chaala, M.; Seeba, F. Z.; Fuster, M. G.; Moulefera, I.; Montalbán, M. G.; Carissimi, G.; Víllora, G.; Ingeniería Química; Facultad de Química
The development of new biomaterials from natural fibres in the field of biomedicine have attracted great interest in recent years. One of the most studied fibres has been silk fibroin produced by the Bombyx mori worm, due to its excellent mechanical properties and its biodegradability and bioavailability. Among the different biomaterials that can be prepared from silk fibroin, hydrogels have attracted considerable attention due to their potential use in different fields, such as scaffolding, cell therapy and biomedical application. Hydrogels are essentially a three-dimensional network of flexible polymer chains that absorb considerable amounts of water and can be loaded with drugs and/or cells inside to be used in a wide variety of applications. Here we present a simple sonication process for the preparation of curcumin-hyaluronic acid-silk fibroin hydrogels. Different grades of hydrogels were prepared by controlling the relative amounts of their components. The hydrogels were physically and morphologically characterised by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA) and field emission scanning electron microscopy (FESEM) and their biological activity was tested in terms of cell viability in a fibroblast cell line.
Open Access
Advances on kinetics and thermodynamics of non-catalytic supercritical methanol transesterification of some vegetable oils to biodiesel
(Elsevier, 2018-07-29) Andreo Martínez, Pedro; García Martínez, Nuria; Durán del Amor, María del Mar; Quesada Medina, Joaquín; Ingeniería Química
Kinetic and thermodynamic parameters of the non-catalytic supercritical methanol transesterification reaction of castor, jatropha, pongamia, tobacco, soybean and jojoba oils to biodiesel production were evaluated in the present study. The experiments were conducted in an 83 ml closed batch reactor at different temperatures (250–350 °C) and reaction times (15–90 min), and at optimal methanol-to-oil molar ratios (15:1 in the case of jojoba wax-oil and 43:1 for the rest of the oils). The pressure reached in the reactor ranged from 10 to 43 MPa. Integral method was used to determine appropriated reaction orders by an adjustment of experimental data to pseudo-zero, pseudo-first and pseudo-second order kinetic equations using Levenberg-Marquardt algorithm. Pseudo-first-order kinetic equation was found to be the most appropriate to describe the supercritical transesterification reaction of the vegetable oils studied. Rate constants and Arrhenius parameters were calculated, the activation energy followed the sequence: castor oil < jatropha oil < tobacco oil < pongamia oil < soybean oil < jojoba wax-oil. It is difficult to explain the behavior of jojoba and castor oils in relation to that of the rest of vegetable oils because they have a very different structure and fatty acid composition, respectively. However, the aforementioned sequence observed for the rest of vegetable oils (jatropha, tobacco, pongamia and soybean oils), which have a similar structure and fatty acid composition, can be attributed to the content of linolenic acid in the oil: the higher the content of linolenic acid, the higher the activation energy and the lower the reaction rate. Finally, thermodynamic study showed that the non-catalytic supercritical methanol transesterification reaction is non-spontaneous (endergonic) and endothermic in nature.
Open Access
Aggregation behaviour of gold nanoparticles in presence of chitosan
(Springer, 0013-06-15) Mar Collado-González; Vanesa Fernández Espín; Mercedes G Montalbán; Ramón Pamies; José Ginés Hernández Cifre; F Guillermo Díaz Baños; Gloria Víllora; José García de la Torre; Ingeniería Química; Facultades de la UMU
Chitosan (CS) is a biocompatible polysaccharide with positive charge that is widely used as a coating agent for negatively charged nanoparticles. However, the types of structures that emerge by combining CS and anoparticles as well as their behaviour are still poorly understood. In this work, we characterize the nanocomposites formed by gold nanoparticles (AuNPs) and CS and study the influence of CS in the expected aggregation process that should experience those nanoparticles under the favourable conditions of low pH and high ionic strength. Thus, at the working CS concentration, we observe the existence of CS structures that quickly trap the AuNPs and avoid the formation of nanoparticle aggregates in environmental conditions that, otherwise, would lead to such an aggregation.
Open Access
An Approach for the Evaluation of Exposure Patterns of Urban Populations to Air Pollution
(Elsevier, ) Pérez Ballesta, Pascual; Baeza Caracena, Antonia; Field, Robert A.; Fernández Patier, Rosalía; Galán Madruga, David; Connolly, Richard; De Saeger, Emile; Ingeniería Química; Centro Común de Investigación de la Unión Europea. Instituto de Medioambiente
Open Access
An Interactive Tool for Simulation of Biological Models Into the Wastewater Treatment With Microalgae
(Frontiers Media, 2021-07-28) Sánchez Zurano, Ana; Guzmán Sánchez, José Luis; Fernández Sevilla, José María; Acién Fernández, Francisco Gabriel; Ingeniería Química
Este trabajo presenta una novedosa herramienta de simulación para comprender y analizar modelos biológicos para procesos de tratamiento de aguas residuales utilizando microalgas. Los modelos para este tipo de procesos son muy complejos de analizar debido a los muy diferentes fenómenos, variables y parámetros involucrados. El modelo ya incluido en la herramienta ha sido validado en condiciones controladas que simulan las condiciones exteriores, resultando útil para simular cultivos reales al aire libre. La principal contribución de la herramienta propuesta es que estos modelos pueden simularse y compararse de manera fácil e interactiva. La herramienta permite simular modelos biológicos considerando solo microalgas o incluyendo el consorcio microalgas-bacterias. Además, las simulaciones se pueden realizar utilizando únicamente la contribución de la radiación solar o agregando los efectos ambientales y bacterianos como términos cardinales. Asimismo, se pueden evaluar los efectos de las propiedades de las aguas residuales o de diferentes cepas de microalgas. Las simulaciones interactivas se pueden realizar para días seleccionados como representativos de las diferentes estaciones del año que ya están precargadas en la herramienta. Sin embargo, el usuario también puede cargar datos de otras ubicaciones para simular los modelos en condiciones particulares.
Open Access
Antitumor Activity of Rosmarinic Acid-Loaded Silk Fibroin Nanoparticles on HeLa and MCF-7 Cells
(MDPI, 2021-09-18) Fuster, M. G.; Carissimi, G.; Montalbán, M. G.; Víllora, G.; Ingeniería Química; Facultad de Química
Rosmarinic acid (RA), one of the most important polyphenol-based antioxidants, has drawn increasing attention because of its remarkable bioactive properties, including anti-inflammatory, anticancer and antibacterial activities. The aim of this study was to synthesize and characterize RA-loaded silk fibroin nanoparticles (RA-SFNs) in terms of their physical–chemical features and composition, and to investigate their antitumor activity against human cervical carcinoma and breast cancer cell lines (HeLa and MCF-7). Compared with the free form, RA bioavailability was enhanced when the drug was adsorbed onto the surface of the silk fibroin nanoparticles (SFNs). The resulting particle diameter was 255 nm, with a polydispersity index of 0.187, and the Z-potential was 􀀀17 mV. The drug loading content of the RA-SFNs was 9.4 wt.%. Evaluation of the in vitro drug release of RA from RA-SFNs pointed to a rapid release in physiological conditions (50% of the total drug content was released in 0.5 h). Unloaded SFNs exhibited good biocompatibility, with no significant cytotoxicity observed during the first 48 h against HeLa and MCF-7 cancer cells. In contrast, cell death increased in a concentration-dependent manner after treatment with RA-SFNs, reaching an IC50 value of 1.568 and 1.377 mg/mL on HeLa and MCF-7, respectively. For both cell lines, the IC50 of free RA was higher. The cellular uptake of the nanoparticles studied was increased when RA was loaded on them. The cell cycle and apoptosis studies revealed that RA-SFNs inhibit cell proliferation and induce apoptosis on HeLa and MCF-7 cell lines. It is concluded, therefore, that the RA delivery platform based on SFNs improves the antitumor potential of RA in the case of the above cancers.
Embargo
Aplicación de modelos de red neuronal para la exposición personal a contaminantes atmosféricos.
(EAE Editorial Academia Espanola, 2011) Baeza Caracena, Antonia; Pérez Valera, Ana; Ingeniería Química
Uno de los retos a los que se enfrenta nuestra generación es el de la construcción de inteligencia artificial. Dentro de esta se pueden distinguir dos grandes áreas, la Inteligencia Artificial Simbiótica y la Subsimbiótica. Las redes neurales se encuadran dentro de las subsimbióticas. Por otro lado, hoy día un problema de gran importancia es la Contaminación Atmosférica, dicho problema es complejo, ya que está afectado por un gran número de factores así como de las características atmosféricas. Este problema llevó a finales de 1996 al proyecto LIFE-MACBETH, para evaluar los escenarios, establecer la causa-efecto, y aportar soluciones; de este proyecto se han recogido los datos para este estudio. El objetivo de este trabajo ha sido, estudiar las aplicaciones de las neuronas en el campo de la exposición personal y comparar los resultados obtenidos con el método tradicional.
Open Access
Application of a diffusion-reaction kinetic model for the removal of 4-chlorophenol in continuous tank reactors
(Taylor & Francis, 2014-08-03) Murcia Almagro, María Dolores; Gómez M.; Bastida Rodríguez, Josefa; Hidalgo A.M.; Montiel Morte, María Claudia; Ortega S.; Ingeniería Química
Open Access
Application of reverse osmosis to remove aniline from wastewater
(Elsevier B.V., 2009) Gómez, J.L.; León, G.; Hidalgo Montesinos, Asunción María; Gómez, M.; Murcia Almagro, María Dolores; Griñán, G.; Ingeniería Química
The presence of organic toxic solutes in industrial wastewater is a common environmental problem. Aniline is known to be a harmful and persistent pollutant and its presence in wastewater requires treatment before disposal. The performance of reverse osmosis to remove aniline from aqueous solutions is studied in this paper. The study has been carried out in a flat membrane test module using three thin layer composite membranes, two of polyamide, HR98PP and SEPA-MS05, and one of polyether sulphone, DESAL-3B. Recycling of both concentrate and permeate has been carried out in order to keep the feed concentration practically constant and so simulate a continuous process in a quasi-stationary state. The influence of different operational variables (pressure, feed volumetric flow rate, feed concentration and pH) on the performance of the aniline removal process is analyzed.
Open Access
Application of the Spiegler-Kedem-Kachalsky model to the removal of 4-chlorophenol by different nanofiltration membranes
(Elsevier B.V., 2012-10-31) Hidalgo Montesinos, Asunción María; León, G.; Gómez, M.; Murcia Almagro, María Dolores; Gómez, E.; Gómez, J.L.; Ingeniería Química
Chlorophenols, commonly found in the wastewaters of numerous industries, are widely considered as priority pollutants and their persistence may cause severe environmental problems. Among the methods described for their removal, pressure-driven membrane processes are considered as a reliable alternative. In this paper we study the influence of different operational variables (applied pressure, feed concentration and pH) on the removal of 4-chlorophenol from synthetic aqueous solutions by nanofiltration using three different polyamide membranes (NF-97, NF-99 and RO98pHt). The Spiegler-Kedem-Kachalsky model was applied to predict the nanofiltration removal process. Model constants for the three membranes were obtained and there was good agreement between the experimental and model rejection data.
Open Access
Assessing combination treatment, enzymatic oxidation and ultrafiltration in a membrane bioreactor, for 4-chlorophenol removal: experimental and modeling
(Elsevier, 2009-10-15) Murcia Almagro, María Dolores; Gómez, M.; Gómez, E.; Bódalo, A.; Gómez, J.L.; Hidalgo, A.H.; Ingeniería Química
Open Access
Assessing the impact of petrol stations on their immediate surroundings
(Elsevier, 2010-08-09) Baeza Caracena, Antonia; Morales Terrés, Isabel M.; Doval Miñarro, Marta; González Ferradás, Enrique; Barberá Rico, Jonathan; Ingeniería Química
Embargo
Biocatalytic intensified process for the synthesis of neopentyl glycol dicaprylate/dicaprate
(Elsevier, 2022-11-07) Máximo, F.; Asensi, M.; Serrano-Arnaldos, M.; Ortega-Requena, S.; Montiel, M.; Bastida, J.; Ingeniería Química
Emollient esters are widely used ingredients in the cosmetics industry. Their chemical synthesis requires the use of high temperatures and polluting acid catalysts, resulting in environmentally unfriendly processes. This paper describes, for the first time, the biocatalytic synthesis process of the cosmetic ingredient neopentyl glycol dicaprylate/dicaprate (INCI name), a mixture of branched diesters with excellent emollient properties. The co-esterification of the acids with the alcohol is carried out in a solvent-free system, using the biocatalyst Lipozyme®435, a commercial immobilized derivative of Candida antarctica lipase B marketed by Novozymes. Process intensification has been approached by acting on three different aspects. Firstly, the use of solvent-free systems provides higher yields by operating with smaller reactor volumes. Secondly, the inhibition of the enzymatic activity caused by caprylic and capric acids has determined the need to implement a new reaction strategy consisting in the use of a fed-batch reactor, in which the acid is added to the reactor using a peristaltic pump in order to maintain an optimal acid concentration that minimizes the inhibition effects. Finally, the reusability of the biocatalyst used has been verified, allowing it to be used in at least five consecutive reaction cycles without noticeable loss of activity. All this results in an efficient synthesis process with a process productivity of 0.15 kg product/L reactor·h and a biocatalyst productivity of 167.09 kg product/kg biocatalyst. Only 6 h are needed, operating in a fed-batch reactor at 80 °C, to obtain a product with 92.5% purity. In addition, the most commonly used sustainability indicators have been calculated, reflecting that the biocatalytic process developed for the synthesis of neopentyl glycol dicaprylate/dicaprate complies with many of the principles of “green chemistry” and is suitable for future implementation on an industrial scale.
Open Access
Biocatalytic solutions to cyclomethicones problem in cosmetics
(Wiley, 2019-03-16) Montiel Morte, María Claudia; Máximo Martín, María Fuensanta; Serrano-Arnaldos, M.; Ortega Requena, Salvadora; Murcia Almagro, María Dolores; Bastida Rodríguez, Josefa; Ingeniería Química
Open Access
Biocatalytic Synthesis of Polyglycerol Polyricinoleate: A Comparison of Different Commercial Lipases
(Assoc. of Chemists and Chemical Engineers of Croatia, 2013-10) Ortega Requena, Salvadora; Gómez, José Luis; Bastida Rodríguez, Josefa; Máximo Martín, María Fuensanta; Montiel Morte, María Claudia; Gómez, María; Ingeniería Química
In this work, the studies were carried out to select the most suitable lipase as catalyst for the esterification of polyglycerol with polyricinoleic acid to yield polyglicerol polyricinoleate (PGPR), a valued-added, biobased food emulsifier are described. The enzymes assayed were lipases from Rhizopus arrhizus, Rhizopus oryzae and Mucor javanicus, previously selected because of their suitable activity and moderate cost. First, reaction was catalyzed by free lipases in a batch reactor and the influence of different operating conditions (initial water content, amount of enzyme and temperature) on the progress of the reaction was studied. Next, the three lipases were immobilized by physical adsorption on the anion exchange resin, Lewatit MonoPlus MP 64, providing derivatives with a high activity and stability. Recovery of the immobilized derivative from the reaction medium was conducted with very good yields (up 99%) and no loss of activity of the derivative with successive uses was proved. Finally, a high performance reactor, which operates at low pressure and with a dry atmosphere, was used to synthesise PGPR using the immobilized enzymes. Both Rhizopus arrhizus and Rhizopus oryzae lipases allowed the production of a PGPR which fulfils the “specific purity criteria on food additives other than colours and sweeteners” established by the Commission of the European Communities, with an acid value of 4.91 and 5.31 mg KOH/g respectively.

Browsing by browse.metadata.contributordepartment "Ingeniería Química"

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