Browsing by Author "Jara Cobos, Lourdes Elizabeth"

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Ciprofloxacin Removal Using Pillared Clays
(2023) Montero, Carolina; Pinos Vélez, Verónica Patricia; Menendez, Miguel; Jara Cobos, Lourdes Elizabeth; Peñafiel Tenorio, María Eulalia
In this work, Ti-pillared bentonites were evaluated to remove ciprofloxacin (CIP) from the aqueous solution. Pillared sodium bentonite (BSP) and pillared calcium bentonite (BCP) were prepared by means of the sol–gel method using titanium tetraisopropoxide with calcination for 3 h at 500 ◦C. They were characterized using the BET method for N2 adsorption, and subjected to X-ray diffraction and Fourier transform infrared spectroscopy. The results show that the surface area of the pillared bentonites increased after the process, more than the natural ones. Pillared sodium bentonite has a more porous structure, larger surface areas, and higher adsorption capacity than pillared calcium bentonite. The kinetic adsorption of ciprofloxacin (CIP) onto pillared bentonites is well described by the pseudo second-order kinetic model. The BSP isotherm well fitted the Freundlich model, while the BCP isotherm fits the BET model better, suggesting multilayer adsorption. DR model shows mostly physical adsorption for CIP on the two adsorbents. The pH influence study indicated that CIP is adsorbed at pH between 6 and 8, which facilitates the use of BCP and BSP in wastewater treatment, whose pH generally oscillates between these ranges.
Design and development of a catalytic fixed-bed reactor for gasification of banana biomass in hydrogen production
(2022) Tacuri Sarmiento, Diego Mauricio; Andrade Herrera, Christian Javier; Álvarez Lloret, Edgar Paúl; Abril González, Mónica Fernanda; Salamea Piedra, Teresita Silvana; Pinos Vélez, Verónica Patricia; Jara Cobos, Lourdes Elizabeth; Montero Izquierdo, Iván Andrés
Hydrogen produced from biomass is an alternative energy source to fossil fuels. In this study, hydrogen production by gasification of the banana plant is proposed. A fixed-bed catalytic reactor was designed considering fluidization conditions and a height/diameter ratio of 3/1. Experimentation was carried out under the following conditions: 368 °C, atmospheric pressure, 11.75 g of residual mass of the banana (pseudo-stem), an average particle diameter of 1.84 mm, and superheated water vapor as a gasifying agent. Gasification reactions were performed using a catalyzed and uncatalyzed medium to compare the effectiveness of each case. The catalyst was Ni/Al2O3, synthesized by coprecipitation. The gas mixture produced from the reaction was continuously condensed to form a two-phase liquid–gas system. The synthesis gas was passed through a silica gel filter and analyzed online by gas chromatography. To conclude, the results of this study show production of 178 mg of synthesis gas for every 1 g of biomass and the selectivity of hydrogen to be 51.8 mol% when a Ni 2.5% w/w catalyst was used. The amount of CO2 was halved, and CO was reduced from 3.87% to 0% in molar percentage. Lastly, a simulation of the distribution of temperatures inside the furnace was developed; the modeled behavior is in agreement with experimental observations.
Diseño de un biodigestor y construcción de un prototipo
(2003-11-11) Jara Cobos, Lourdes Elizabeth; Moscoso Vanegas, Diana Lucía; Parra Alvarracín, Juan
Enhancing adsorptive removal of diclofenac from aqueous solution: Evaluating organic and inorganic acid treatment of zeolite
(2024) Jara Cobos, Lourdes Elizabeth; Jerves Vázquez, Fanny Carola; Peñafiel Tenorio, María Eulalia; Flores Zamora, Damián Vicente
This study examined the adsorption capacity of natural zeolite (ZN) and zeolite treated with citric acid (ZCA) and nitric acid (ZNA) to evaluate their effectiveness in removing the pharmaceutical compound diclofenac (DCF) from water in batch experiments. Fourier Transform Infrared Spectroscopy (FTIR) and textural properties (BET) were used to investigate the changes in zeolite resulting from chemical modifications. The findings demonstrate a significant enhancement in surface area, pore volume, and the presence of acidic sites, resulting in an improved adsorption capacity for DCF. The observed increase in the Si/Al ratio following acid treatment suggests the de-alumination of the zeolite. Results have shown an increase in the percentage of DCF adsorbed to 76.8 % from 11.2 % using nitric acid-treated and untreated zeolites, respectively. In comparison, citric acid zeolite achieves 48.9 %. The adsorption kinetic was assessed using pseudo-first and pseudo-second-order models, and it was observed that the pseudo-second-order provided the best fit for all adsorbents. Furthermore, the BET model exhibited the best fit for the adsorption isotherm data. The maximum adsorption capacities were found to follow the order: ZNA (85.9 mg/g) > ZCA (33.6 mg/g) > ZN (14.4 mg/g). These results indicate that the acidic treatment enhances the adsorption capacity of the zeolite, and nitric acid treatment shows the most significant improvement.
Instrumentación de un refrigerador doméstico para el análisis del comportamiento de las variables de presión y temperatura de operación
(2017) Reinoso, Fran
Abstract: Due to the high consumption of electric energy that represent the use of a domestic refrigerator in homes, due mainly to one of its main parts such as the compressor, it was established the need to analyze the thermodynamic behavior in order to know its operating conditions, so in this article presents mainly the results of the temperature behavior of the freezing compartment and the pressure at the compressor outlet of a domestic refrigeration system, obtained on the basis of the minutal measurement of said variables during a period of operation of 6 hours. This has been achieved through the instrumentation of a 234 liter total volume refrigerator / freezer that works with R134a refrigerant. In addition, the influence of the on / off condition of the compressor on the measured temperature and pressure variables has been analyzed. It has been verified that once the compressor is switched on, the freezer temperature drops to -20.7 ° C in 90 minutes, at which temperature the compressor switches off. The average time for restarting the compressor is 7 min. As for the pressure values at the output of the compressor, a variation between 0.9 and 14.67 bar is observed, which are influenced by the on / off state of the compressor. Concluding that the energy consumption of the refrigerator is a direct function of the operating temperature ranges, thermal load and the frequency of opening and closing refrigerator doors.
Modificación de arcilla ecuatoriana mediante pilarización con especies metálicas de zinc y evaluación de su capacidad como fotocatalizador para la eliminación de fármacos en solución acuosa
(Universidad de Cuenca, 2025-02-11) Curay Flores, Juan Diego; Espejo Carchipulla, David Santiago; Jara Cobos, Lourdes Elizabeth
For decades, the environmental impact assessment of chemical substances has primarily focused on the so-called priority pollutants, collectively known as persistent, bioaccumulative and toxic pollutants (PBTs) or persistent organic pollutants (POPs). However recent advancements in more sensitive analytical methods have revealed the presence of other potentially hazardous pollutants that fall outside current regulatory frameworks, often referred to as emerging pollutants. This research aims to evaluate the photocatalytic treatment of an emerging contaminant (diclofenac sodium), using a locally sourced bentonite clay modified with zinc metal species, where ZnCl2.2(H2O) serves as the pilarizing agent. The study involves the pillarization of clay, followed by the synthesis and physicochemical characterization of the catalyst. An experimental design will be implemented to vary the adsorbent dosage, contact time, and initial adsorbate concentration. The adsorption kinetics will be analyzed using pseudo-first order PFO and pseudo-second order PSO models, alongside the adsorption isotherms which will be modeled using the Langmuir and Freudnlich equations. The effect of adsorbate pH will also be assessed. These parameters will be evaluated under two different conditions: in the absence and presence of UV light.
Production of hydrogen from lignocellulosic biomass: a review of technologies.
(2023) Jara Cobos, Lourdes Elizabeth; Abril González, Mónica Fernanda; Pinos Vélez, Verónica Patricia
Hydrogen is considered one of the most important forms of energy for the future, as it can be generated from renewable sources and reduce CO2 emissions. In this review, the different thermochemical techniques that are currently used for the production of hydrogen from biomass from plantations or crops, as well as those from industrial or agro-industrial processes, were analyzed, such as gasification, liquefaction, and pyrolysis. In addition, the yields obtained and the reactors, reaction conditions, and catalysts used in each process are presented. Furthermore, a brief comparison between the methods is made to identify the pros and cons of current technologies
Programa de enriquecimiento instrumental para desarrollar las funciones cognitivas en el octavo año de educación básica de la Unidad Educativa Salesiana María Auxiliadora
(2014) Jara Cobos, Lourdes Elizabeth; Montesinos Jaramillo, José Vinicio
The following study focuses on the application of an instrumental enrichment program aimed at helping the teaching learning process of eight grade basic education students. The developed Project is a program which intend to improve the cognitive performance of students with academic deficiencies, so that it generates a positive change in their study behavior. This change is fundamentally based on the adoption of affective modalities that direct, and guide a person’s behavior; it additionally involves the use of logic and reasoning in the academic formation of mathematics. This Project uses the FIE (Reuven Feuerstein’s instrumental enrichment program), from which it is proposed a guide to reinforce the teacher’s job as a mediator and the student as the main actor in his / her learning; the developed tools will help students enhance cognitive skills. This research intends to support the educational process, since it enables students to improve their level of logic reasoning, providing basis for higher intellectual and personal development.
Removal of ciprofloxacin from an aqueous medium by adsorption on natural and hydrolyzed bentonites
(2023) Menéndez, Miguel; Abad Delgado, Alex David; Jara Cobos, Lourdes Elizabeth; Peñafiel Tenorio, María Eulalia; Ponce Montalvo, Jonathan Daniel
Two bentonites (sodic bentonite, BSN, and calcic bentonite, BCN) were treated with nitric acid to improve the adsorption capacities using ciprofloxacin (CIP) as an adsorbate. The results demonstrated that nitric acid treatment enhances the specific area and increases the pore volume of both bentonites. The mechanism of adsorption of CIP was investigated using a kinetic model, isotherms, and pH influence. The adsorption capacity for BSN increased from 294.1 mg.g−1 to 416.6 mg.g−1 after acid treatment, while the increase in the adsorption capacity of BCN was minor. The increase in CIP removal may be due to an increase in the specific area and the presence of acidic surface functional groups. The adsorption mechanism of CIP on all adsorbents was governed by external diffusion, internal diffusion, and adsorption to reach equilibrium. The adjustment of strong adsorbents to the BET model indicated multilayer adsorption. The best adsorbent is sodic bentonite with nitric acid treatment. The study of the pH effect showed that the mechanism of CIP adsorption is hydrogen bonds and electrostatic interaction. Therefore, the acid treatment was found promising to improve the adsorbent characteristic of clays for removing CIP from water.
Simulación de la gasificación catalítica de biomasa de banano en la producción de hidrógeno; a partir de un reactor de lecho fijo, mediante ANSYS estudiantil
(Universidad de Cuenca, 2022-11-22) Gaona Cumbicos, Jessica Mayli; Naula Duchi, Kelly Dayanna; Jara Cobos, Lourdes Elizabeth
Biomass gasification technology is of constant interest in the field of sustainable energy, being used as an alternative to traditional combustion technology, especially due to the reduction in the emission of dust and toxic gases. In gasification, hermochemical conversion of organic material, biomass, is carried out, obtaining a gaseous product of great interest known as synthesis gas. The current focus on sustainable energies is aimed at obtaining bioethanol from organic compounds that generally come from waste; however, there is a wide field of study in redirecting the course of the saccharified product to gasification to increase energy efficiencies, as well as the use of catalysts to favor the reaction rate and obtain the gas of interest. Therefore, this research’s objective was to simulate a banana biomass gasification process and system operating conditions during the process. Using Ansys students, the operating conditions of temperatures and fluid velocities were established, whose values were adopted in the simulation of the gasification reaction. In this way, an operating temperature of 604.05 °C was obtained inside the reactor at atmospheric pressure; the temperature of the gasifying agent was 226.85 °C. The mathematical model of the reaction was developed through the reaction kinetics taking as reference the kinetic study based on glucose using the Langmuir-Hinshelwood mechanism, which involves the adsorption of the reactants, catalytic surface reaction. desorption of the products of the dominant reactions: the water-gas shift reaction (WGS), the reverse dry methane reforming reaction (RDRM) and the steam methane reforming reactions (SRM), with which the model describing the evolution of the molar flux with respect to time and Zcoordinate of the main products, i.e. hydrogen (H2), methane (CH4), carbon monoxide (CO), carbon dioxide (CO2) and water (H2O), was obtained. The results of the molar flux concernig time considering 25 s of reaction were 0.16 mol/s of H2, 0.08 mol/s of CO, 0.16 mol/s of CO2, 0.12 mol/ of CH4 and 0.10 mol/s of H2O, the molar fluxes cocnerning concerning the longitudinal axis Z with a varying pressure of 2 bars, did not vary in comparison with the previous ones. The H2/CO ratio was also analyzed and showed a value of 2.2 for both cases
Simulation of the Catalytic Gasification of Banana Biomass in the Production of Hydrogen, Using Glucose as a Model Compound
(2023) Bernal Pesantez, Edison Bolivar; Gaona Cumbicos, Jessica; Jara Cobos, Lourdes Elizabeth; Naula Duchi, Kelly Dayanna; Álvarez Lloret, Edgar Paúl; Mejia Galarza, William Andres
Abstract: In the face of the climate change problem caused by fossil fuels, it is essential to seek efficient alternative energies with a lower environmental impact that are derived from renewable resources. Biomass gasification technology continues to generate significant interest in sustainable energy research as an alternative to traditional combustion technology. Gasification involves the thermochemical conversion of raw materials, resulting in a highly valuable gaseous product known as synthesis gas, commonly used as a fuel. Its numerous advantages include the availability of raw materials, the reduction in harmful emission streams, performance, and costs. As this topic gains momentum in the global energy framework, it is imperative to advance the maturity of this technology by addressing its weaknesses, primarily in terms of efficiency. The objective of this project was to investigate the hydrogen production process through the simulation of glucose gasification as a representative compound for biomass. This was achieved by conducting an integrated simulation of glucose gasification, encompassing both the heat transfer in the external system and the conversion of glucose into hydrogen gas, using the results obtained in the external system as initial conditions. Interrelated aspects of this complex process, including heat transfer and the kinetics of the gasification process, were modeled. Glucose was selected as the model compound due to its availability, simplicity, fundamental understanding, reproducibility, comparability, knowledge of reaction pathways, and simplification of mathematical models. The simulation resulted in a H2:CO ratio of 2.2, and molar fluxes were obtained for H2, CO, CO2, CH4, and H2O consistent with those typically observed in the gasification process of organic ma􀀻er. These models were constructed, laying the foundation for the adaptability of subsequent optimization studies.