Ciencias Exactas y Ciencias de la Salud
Permanent URI for this collectionhttps://hdl.handle.net/11285/551039
Pertenecen a esta colección Tesis y Trabajos de grado de las Maestrías correspondientes a las Escuelas de Ingeniería y Ciencias así como a Medicina y Ciencias de la Salud.
Browse
Search Results
- Kinetic modeling of the photocatalytic degradation of acetaminophen and its main transformation product using TiO2 nanotubes(Instituto Tecnológico y de Estudios Superiores de Monterrey, 2021-06-15) Delgado Juárez, Jocelin Alí; LOPEZ ZAVALA, MIGUEL ANGEL; 37056; López Zavala, Miguel Ángel; emipsanchez/puemcuervo; García Orozco, Jorge Humberto; Monarrez Cordero, Blanca Elizabeth; School of Engineering and Sciences; Campus MonterreyIn this study, a kinetic model of the heterogeneous photocatalytic degradation of acetaminophen (APAP) and its main transformation product is presented. The mechanistically kinetic model incorporated the modeling of the radiation field in the reactor with a Monte Carlo simulation. Experiments were carried out in a reactor operated in batch mode, with the use of TiO2 nanotubes as photocatalyst and an irradiation at 254 nm (UVC). Kinetic parameters were estimated from the experiments by applying a non-linear regression procedure. Later, the intrinsic expressions to represent the kinetics of APAP and its main transformation product were derived. The predicted results of the kinetic model show a concordance with the experimental data, however, experimental results showed that most of the APAP degradation was due to a photolytic process and not due to a photocatalytic process. Since the photolytic process was not incorporated into the model, it is necessary to adjust the proposed kinetic model for incorporating photolytic radiation; or the proposed model could be adjusted for the evaluation of the photocatalytic degradation of another drug that does not have photolysis under UVC.
- Evaluation of the external resistance, graphite and modified graphene as electrodes in microbial fuel cells for the improvement of wastewater treatment and power generation(Instituto Tecnológico y de Estudios Superiores de Monterrey, 2021-06-15) Cámara Gutiérrez, Iris Cassandra; LOPEZ ZAVALA, MIGUEL ANGEL; 37056; López Zavala, Miguel Ángel; emipsanchez/puemcuervo; Montesinos Castellanos, Alejandro; Monárrez Cordero, Blanca Elizabeth; García Orozco, Jorge Humberto; School of Engineering and Sciences; Campus MonterreyCurrently, the constant increase of population and its not sustainable consumption has caused the depletion of water and actual sources of energy are not bast enough to meet the growing necessities. A proposed solution that tackles these problems resides in the application of renewable energy processes, such as the production of bioenergy through the treatment of wastewater by electrogenic bacteria in microbial fuel cells. This document presents the results of the thesis research, to obtain the degree of Master of Science in Engineering with a specialty on clean energy and sustainable water use. The objective of this work was to evaluate the external resistant and electrode materials (graphite and modified graphene) in a dual chamber microbial fuel cell for improving the wastewater treatment and electricity generation. Through this investigation, different external resistances and two electrode materials were evaluated. The results obtained allow to identify the combination of operating conditions that give the best performance. A 10-fold increase in power output and a 20-fold increase in coulombic efficiency were obtained. This study shows a cost-effective way to improve power generation in microbial fuel cells, contributing to offering new clean renewable energy sources.
- Paraquat degradation by electrochemical oxidation in surface water: mathematical modeling(Instituto Tecnológico y de Estudios Superiores de Monterrey, 2021-06) Valle Verduzco, Jorge Luis; López Zavala, Miguel Ángel; dnbsrp; García Orozco, Jorge Humberto; Monárrez Cordero, Blanca Elizabeth; School of Engineering and Sciences; Campus MonterreyToday’s society must face a series of challenges to ensure continuous survival. In addition, agriculture is one of the main activities in rural areas. In some cases, this is the only possible activity in the economy of these regions and, therefore, the only engine of growth. Pesticides are agents that protect crops from pests and diseases. Paraquat (1,1’-dimethyl-4,4’-bipyridinium dichloride) is a non-selective, contact broad- spectrum herbicide that has been widely used as an herbicide for decades. Paraquat poisoning has a high mortality rate. Several methods have been investigated to remove paraquat from aquatic environments. Currently, adsorption and degradation are the two main methods to remove/reduce paraquat. Solutions of paraquat dichloride tetrahydrate (100%, AccuStandard) were prepared with surface water (“Rodrigo Gomez” dam) with a concentration of 13 mg/L, 14 mg/L and 15 mg/L. Initial pH (8.2) of the solutions was adjusted to 3, 7 and 9. Then, electrochemical oxidation of samples of each solution was conducted at DC densities of 16.29 mA/cm2 (6.5 V), 30 mA/cm2 (12 V) and 60 mA/cm2 (24 V). The reaction times were 1, 2.5, 5, 7.5, 10, 15, 20, 25, 30, 35, 40, 50 and 60 minutes. Paraquat and their transformation products (TP) were analyzed by HPLC using an Agilent 1260 HPLC-DAD equipment (Agilent Technologies, Santa Clara, CA, USA) with a reverse phase Zorbax Eclipse XDB C-18 column with dimensions of 150 x 4.6 mm and 5 µm diameter spherical particles (Agilent Technologies, Santa Clara, CA, USA). All samples were filtered using 0.45µm polytetrafluoroethylene syringe filters before analysis. For the mathematical modeling of paraquat degradation, four scenarios were proposed. The first scenario was anodic oxidation with active electrodes with active hydroxyl radicals, the second scenario was with active chlorine species at pH < 3 with Cl2 (gas), the third scenario was with active chlorine species at 3 < pH < 8 with HClO as oxidant, and the fourth scenario was with active chlorine species at pH > 8 with ClO-. At pH 3 was the only treatment that completely degraded paraquat within 60 minutes since pH 7 and pH 9 did not show complete degradation of the herbicide. From the experiments carried out, the current density of 30 mA/cm2 at pH < 3 was the one that showed the best degradation. The validation of the mathematical model, at a current density of 30 mA/cm2, resulted in a correlation of 94% of paraquat degradation and 95% of Cl2 production (pH < 3). The formulation of ordinary differential equations facilitated the modeling.