Browsing by Author "Morales Morales, Jimmy Alexander (Director)"
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Item Aplicación de la técnica Espectroscopía Raman para la determinación de microplásticos en el agua potable(Universidad Santiago de Cali, 2025) Collazos Reina, Jhon Jairo; Morales Morales, Jimmy Alexander (Director)The presence of microplastics in the environment represents a chemical, environmental, and social issue that has been increasing over the past few decades. This monograph addresses this situation, focusing particularly on the detection of microplastics in tap and drinking water across various cities and countries, thus evidencing their presence in urban water systems worldwide. Special attention is given to the Raman spectroscopy technique and its variants (μRaman). This analytical method is selective and non-destructive, allowing for the efficient identification and quantification of various types of microplastics at microscopic and even nanometric scales. Due to its high sensitivity and specificity, this technique has become a key tool in the analysis of emerging pollutants, surpassing some limitations of other methodologies such as Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM/EDX). Several recent studies have reported varying concentrations of microplastics in drinking water samples using Raman spectroscopy as the method of identification. These results not only validate the effectiveness of the technique but also highlight the need to implement monitoring and control systems to prevent microplastics from entering water distribution networks. Although the presence of microplastics in drinking water has been widely documented, their specific effects on human health remain inconclusive. However, their persistence, bioaccumulation potential, and toxicity make their study a continued priority for the scientific community from a preventive perspective.Item Calificación de un dispositivo de inmersión para así realizar recubrimientos de TiO2/Hidroxiapatita sobre superficies metálicas(Universidad Santiago de Cali, 2019) Martínez Bellaiza, Daniela; Morales Morales, Jimmy Alexander (Director); Castillo Ayala, Jorge Enrique (Director)The Dip-Coating method is used to obtain thin films on different surfaces and with a wide range of application; This consists in the immersion and subsequent extraction of a substrate inside a precursor solution for the formation of the film. In this work, the qualification of a low cost immersion device developed at the Santiago de Cali University was carried out and coatings were executed on stainless steel substrates with TiO2 / Hydroxyapatite by the wet chemistry technique. For the qualification, parameters of speed and time of immersion were evaluated, addressing the operational installation, performance and design (IQ, PQ and QD respectively); the synthesis of Hydroxyapatite was carried out by controlled precipitation and the dry samples were analyzed by IR / ATR and TGA-DSC, obtaining characteristic peaks of the compound and a good thermal behavior. In addition, the coatings made using spectroscopic techniques were analyzed, obtaining the expected deposits in the samples. substrates and obtaining a Ca / P ratio of 1,57.Item Coprecipitación de hidrotalcitas y aplicación de sus óxidos en la síntesis de bases de Schiff derivadas de 2-aminotiazol y aldehídos aromáticos(Universidad Santiago de Cali, 2021) Granja Banguera, Claudia Patricia; Morales Morales, Jimmy Alexander (Director); Mora Vargas, Jorge Andrés (Director)Recently, the development of new methodologies for the synthesis of products with value-added has increased, especially, the obtaining of compounds that present in their structure sulfur and nitrogen atoms mainly in heterocyclic rings, and that also contain other types of functional groups. For example, imine group (-C=N-), because they are of great importance for their applications as anticancer, antibacterial, antifungal, antiinflammatory agents, among others. Herein, we the synthesis of 1-phenyl-N-(thiazol-2-yl)methanimine (Schiff's base, SB) derived from 2-aminothiazole and benzaldehyde using mixed metal oxides (MMOs) derived from hydrotalcites (LDHs) modified with Ni2+ and Cu2+. The LDHs were synthesized by coprecipitation method, and their subsequent thermal treatment provided the corresponding MMOs. MMOs were investigated for imines synthesis in solvent free and microwave-assisted conditions. The physicochemical characterization of the LDHs demonstrated the insertion of Ni2+ and Cu2+ ions in the lamellar structure and no secondary phase formation was observed. XRD of the MMOs obtained showed the decrease in the crystallinity of the precursor and the formation of three characteristic peaks of this type of oxides, proving they are obtaining. SB was obtained with 51.3% yield when the MMO modified with 15% Cu2+ as catalyst and 1.0 equivalent of each of the starting reagents was used in 10 min of reaction at 300 W and 125 ° C.Item Crecimiento de una barrera electroquímica por la electrolisis oxidativa de 2-aminotiazoles y derivados 4-x-fenil(Universidad Santiago de Cali, 2019) Patiño Izquierdo, José Luis; Morales Morales, Jimmy Alexander (Director); Flórez López, Edwin (Director)Se realizó el seguimiento electroquímico de los compuestos 4-(4-X-fenil)-2-aminotiazol [ X = 1a -CH3, 1b -NO2 , 1c 2-amino-5-metil-4-feniltiazol y 1d 5-(4-Bromofenil)-oxazol-2- ylamina] a través de voltamperométrica cíclica utilizando como electrodo de trabajo carbón vítreo, electrodo de referencia Ag/Ag+ y como contra electrodo espiral de platino; se estudió el efecto que producen variables como el electrolito soporte, concentración, velocidad de barrido, sustituyente y temperatura durante la electro-oxidación de cada compuesto. Se evidenció que el tamaño del electrolito soporte influye en los valores de potencial y corriente pico. La velocidad de barrido como la concentración modifican proporcionalmente los valores de corriente pico. Por otra parte, el cambio de temperatura afecta los procesos de transferencia electrónica modificando las señales de oxidación. Se evidenció que un sustituyente electro-donador facilita la oxidación del compuesto y uno electro-atractor la dificulta. Por último, se evidencio durante la electrolisis oxidativa el crecimiento de una barrera electroquímica influenciada por cambios estructurales.Item Determinación simultánea de acetaminofén y levofloxacina usando un electrodo modificado con carbón vegetal y nanopartículas ecológicas de óxido de hierro y lantano(Universidad Santiago de Cali, 2025) Montilla Martinez, Sebastian; Morales Morales, Jimmy Alexander (Director)In this study, an electrochemical sensor was designed and evaluated, modified with environmentally low-impact materials and aimed at the simultaneous detection of two highly relevant pharmaceutical contaminants: acetaminophen (AC) and levofloxacin (LE). For this purpose, a glassy carbon electrode (GCE) was doped with a combined suspension of lanthanum ferrite (LaFeO₃) nanoparticles and activated vegetal carbon, both synthesized through a green synthesis process using molasses as an organic fuel, promoting an eco-friendly and cost-effective production pathway. The modification was performed using the drop-casting technique, applying 8 µL of the activated suspension (1:1 ratio), previously dispersed via ultrasonication. The electroanalytical performance of the system was characterized using cyclic voltammetry (CV), differential pulse voltammetry (DPV), and electrochemical impedance spectroscopy (EIS). The modified electrode exhibited a well-defined voltammetric response, with two distinct, non-overlapping anodic peaks, confirming the feasibility of simultaneous and selective detection of both analytes under optimal conditions at pH 5. A linear response was achieved in the 20–60 µM range (R² = 0.966), with limits of detection and quantification of 9.20 µM and 27.88 µM, respectively. The analysis of peak current (Ip) versus the square root of the scan rate (√v) revealed a diffusion-controlled mass transport mechanism. Furthermore, the system showed a significant reduction in charge transfer resistance (Rct ≈ 27.7 kΩ) and an improvement in interfacial capacitance, attributed to the electrocatalytic synergy between the metal oxide and the carbonaceous support. The sensor demonstrated good repeatability (RSD < 10%) and operational stability up to 12 hours, with a signal loss of less than 14%, establishing it as a technically robust, reproducible, and environmentally sustainable alternative. These findings highlight the feasibility of employing eco-friendly materials and accessible fabrication techniques for the development of electrochemical sensing platforms, with promising applications in environmental monitoring, pharmaceutical analysis, and contaminated effluent assessment.Item Empleo de melaza industrial en la síntesis de óxidos metálicos mixtos con potencial aplicación industrial(Universidad Santiago de Cali, 2023) Castellanos Bernal, Cindy Vanessa; Morales Morales, Jimmy Alexander (Director)In this work, lanthanum ferrite was prepared by mixing solutions of LaNO3•6H2O and Fe(NO3)3•9H2O with molasse and stirring continuously using a standard stirrer until a porous solid was obtained. It was macerated with agate mortar after being calcined in a muffle at various temperatures between 800 and 900ºC. This substance is placed in a vial for subsequent analysis using analytical methods like thermogravimetry (TGA), infrared vibrational spectroscopy (IR), and X-ray diffractometry (XRD). LaFeO3 nanoparticles measuring 89.2 nm were produced by employing ultrasound to aid in the synthesis and a 9-hour calcination period with a molasses/lanthanum ratio of 1.125. The increase in stated ratio and the shorter calcination time led to a larger crystallite size. The produced mixed metal oxide's electroconductive activity indicated how it might be used to catalyze important reactions, like the electrogeneration of oxygen.Item Enfoque verde para la inhibición de la corrosión por extracto de pimienta en NaCl 3.5% p/v(Universidad Santiago de Cali, 2020) Ospina Lozano, Saray; Morales Morales, Jimmy Alexander (Director); Castillo Ayala, Jorge Enrique (Director)This study presents a corrosion inhibition analysis of pepper oil (Piper nigrum) on carbon steel in 3.5% NaCl solution. Corrosion inhibition efficiency was studied using electrochemical impedance spectroscopy and polarization curves. The results from the polarization curves show that the efficiency of the inhibitor was 95% with a concentration of 200ppm at 27ºC the reductions in the corrosion current being about one order significant. of magnitude. The results of the EIS and analysis of chemical reactivity descriptors, showed that the unsaturation present in the molecular structure of the components of the black pepper extract, or some synergistic effects between different molecules, contributed to its efficiency as an inhibitor, adsorbing on the surface of the metal and blocking the corrosion process.Item Estudio de la degradación fotocatalítica de contaminantes emergentes farmacéuticos por nanopartículas ecológicas de perovskita(Universidad Santiago de Cali, 2025) Bonilla Caicedo, Leidy Johanna; Morales Morales, Jimmy Alexander (Director)This study investigates the ultrasound-assisted synthesis of lanthanum ferrite (LaFeO) nanoparticles using molasses as a carbon matrix, which improves the dispersion of the material and its photocatalytic performance. A visible light lamp with a wavelength between 190 and 1100 nm was used to activate the photocatalytic properties, resulting in a material yield percentage assisted by ultrasound of 52.38% and assisted by mechanical stirring of 56.49%. In aqueous solutions of acetaminophen at a concentration of 70 ppm, 25% was obtained, at 20 ppm 33%, and at 50 ppm 72% degradation. The characterization of the nanoparticles revealed an orthorhombic crystalline phase of LaFeO, thus promoting the effectiveness of the photocatalyst. The use of the carbon matrix not only optimizes the catalyst surface but also improves its stability under different pH and catalyst loading conditions. Ultrasound assistance during synthesis resulted in a more uniform structure and improved photodegradation of the emerging contaminant. This innovative approach, utilizing an industrial waste product for nanoparticle synthesis, not only seeks to offer an effective solution for treating contaminated water but also presents a sustainable alternative for waste management. This work represents a significant advance in the development of more effective technologies to address emerging environmental contamination.Item Evaluación de arsénico total en muestras de aguas y sedimento del río Cauca, por método espectrométrico de generación continua de hidruros / absorción atómica(Universidad Santiago de Cali, 2022) Crespo Arias, Jonathan; Castillo Ayala, Jorge Enrique (Director); Morales Morales, Jimmy Alexander (Director)Studies on arsenic (As) are very important because it has a mutagenic character, therefore, it is necessary to evaluate this metalloid in a tributary as important as the Cauca River, the second most important river in Colombia. Due to this, this study aims to evaluate the concentration of total arsenic present in the Cauca River both in the water matrix and in the sediment matrix. For this, sampling was carried out at four points along the river in the city of Cali, Colombia; The samplings were carried out in duplicate, spread over six days between the dates of October 14, 2021 and February 2, 2022. As a result, a concentration in a range of 0,00393 - 0,0148 mg/L of As in water was obtained. and 0,00602-0,00838 mg/L of As in sediments. The values obtained are associated with natural sources, as well as human activities. The possible human and environmental risks associated with the presence of As in the Cauca River, used to supply drinking water to 80% of the population of Cali, are highlighted.Item Obtención de óxidos metálicos mixtos desde combustión cítrica modificada con extracto natural aloe vera (Aloe barbadensis Miller)(Universidad Santiago de Cali, 2023) Gómez Lara, Kevin Steven; Morales Morales, Jimmy Alexander (Director); Granja Banguera, Claudia Patricia (Codirectora)This work consisted of the preparation of calcium ferrite through the modified citrus combustion route using natural aloe vera extract, from the mixture of solutions of Ca(NO3)2•4H2O and Fe(NO3)3•9H2O, extract of aloe vera, with constant stirring, and assisted in a conventional microwave, until obtaining a porous solid that was subsequently calcined in a muffle at different temperatures between 500 and 900ºC, and then macerated with agate mortar. This material is deposited in a vial to finally be characterized by analytical techniques such as X-ray diffractometry (XRD), vibrational spectroscopy in the infrared region (IR), thermogravimetry (TGA).Item Oxidación electroquímica de 2-tiazolamina y 2-oxazolamina en electrodo modificado con ferritas ternarias mixtas de metales de transición(Universidad Santiago de Cali, 2021) Silgado Cortázar, Daniel Gerardo; Morales Morales, Jimmy Alexander (Director)Item Síntesis verde de nanopartículas de óxidos de hierro a partir de extracto de residuos agroindustriales y caracterización de sus propiedades estructurales y anticorrosivas(Universidad Santiago de Cali, 2024) Avendaño Vargas, Alvaro José; Morales Morales, Jimmy Alexander (Director)This thesis presents green synthesis as a sustainable and environmentally friendly method for obtaining nickelcopper ferrite nanoparticles (Ni(1-x)CuxFe2O4) (x=0, 0.5, 1), using coffee pulp extract, the main agro-industrial waste from coffee processing (Coffea arabica), as a reducing and stabilizing agent. The synthesis employed two drying methods: on a hot plate (method 1) and in a microwave oven (method 2), comparing them to determine the optimal method. The main objective was to characterize the structural properties of the nanoparticles using IR spectroscopy, thermogravimetric analysis, and X-ray diffraction. The structural properties of the nanoparticles were studied using X-ray diffraction (XRD), showing the formation of tetragonal and cubic crystal systems, with crystallite sizes ranging from 25 nm to 114 nm. FT-IR spectra showed characteristic absorption bands of metal-oxygen bonds in tetrahedral positions for Fe-O bonds and octahedral positions for Cu-O and Ni-O bonds, confirming the absence of biomolecules from the coffee pulp extract and demonstrating the quality of the synthesis. TGA analyses revealed that the samples dried on a hot plate showed more significant mass losses compared to those dried in a microwave oven, suggesting that the slower drying method produces a more porous structure with more defects, retaining more moisture or solvents. All samples exhibited a single exothermic peak in DSC, with a maximum between 460°C and 490°C depending on the ferrite, indicating a phase transition or structural reordering. In conclusion, the results demonstrate the viability of this green method, highlighting its potential application in various industrial and environmental areas. Green synthesis ensures nanoparticles with adequate structural and morphological properties, emphasizing its relevance in the development of sustainable materials.