Person:
Vanegas Peña, María Eulalia

Birth Date

1980-01-26

ORCID

0000-0003-1976-8346

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Scopus ID:

Afiliación

Universidad de Cuenca, Facultad de Ciencias Químicas, Cuenca, Ecuador

País

Ecuador

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Organizational Unit

Facultad de Ciencias Químicas

Fundada en 1955 como la Escuela de Química Industrial, la facultad ha sido un pilar fundamental en la formación de profesionales altamente capacitados, comprometidos con el desarrollo de la ciencia, la educación y el bienestar social. La Facultad de Ciencias Químicas pone a consideración su trabajo académico, investigativo y de vinculación con la sociedad, desarrollado a través de la práctica de una docencia de calidad, investigación e innovación en su área de estudio. Desde su oficio de conocimiento se permite contribuir a la sociedad con cuatro carreras: Bioquímica y Farmacia, Ingeniería Química, Ingeniería Ambiental e Ingeniería Industrial. Su carta de presentación en la Academia, la coloca como una dependencia dinámica, donde confluye la solidez de una trayectoria de más de sesenta años. Aquí se trabaja en una continua formación de pregrado y posgrado de la más alta calidad, mediante la mejora continua con la innovación y a la vanguardia de las ciencias químicas.

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Profesor (T)

Last Name

Vanegas Peña

First Name

María Eulalia

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Now showing 1 - 10 of 20

Syndiotactic polypropylene copolymer membranes and their performance for oxygen separation
(2010) Quijada, Raúl; Vanegas Peña, María Eulalia
Syndiotactic poly(propylene- -olefin) copolymers with controlled microstructure and desired properties for oxygen enrichment have been synthesized via metallocene catalysts. The controlled incorporation of comonomers as pendant branch mainly improved the oxygen permeability, but the oxygen/nitrogen selectivity dropped around 20%. By controlling the amount and length of the branches in the syndiotactic polypropylene, the permeability of the membrane was enhanced up to 12-fold and it is comparable to typical commercial polymers used for this application. In contrast with conventional commercial polypropylene, copolymers with a large amount of comonomer were soluble in cyclohexane, allowing the manufacture of composite membranes with high permeance.
Adsorption properties of sugarcane bagasse and corn cob for the sulfamethoxazole removal in a fixed-bed column
(2021) Juela Quintuña, Diego Marcelo; Vera Cabezas, Luisa Mayra; Cruzat Contreras, Christian Américo; Álvarez Palomeque, Lourdes Ximena; Vanegas Peña, María Eulalia
Natural adsorbents are a good alternative to remove antibiotic residues from wastewater. In this study, the adsorption capacity of sulfamethoxazole (SMX) onto sugarcane bagasse (SB) and corn cob (CC) in a continuous fixed-bed was compared. Brunauer Emmett Teller, Fourier transform infrared (FTIR), Boehm titration, and point of zero charge (pHpzc) were used to characterize both adsorbents. The adsorption capacity (qe) and the removal percentage of SMX (% R) were investigated at different different flow rates (2, 5, and 7 mL min− 1 ) and adsorbent masses (4 and 6.4 g), and a constant initial concentration of 5 mg L− 1 . The results of the characterization showed that SB has a morphology with more dispersed particles and a specific surface higher than CC (2.6 > 1.2 m2 g− 1 Boehm titration indicates that both the surface of SB and CC have a greater amount of acid groups, which is in agreement with FTIR and pHpzc results. The continuous fixed-bed experiments showed that % R and qe of SMX are higher with SB in all the tests. The highest qe and maximum % R was 0.24 mg g− 1 and 74% with SB, and 0.15 mg g− 1 and 65% using CC. In most cases, the qe of both adsorbents decreased with the increase of flow rate and bed height. An analysis suggests that hydrogen bonds could be the main factor favoring the SMX adsorption with SB. Finally, the intraparticle diffusion was the rate-controlling step, predominating the pore-volume diffusion resistance
Fitorremediación de cinco productos farmaceúticos registrados como contaminantes emergentes en medio acuoso empleando la especie Jacinto de Agua (Eichhornia crassipes)
(2023) Vanegas Peña, María Eulalia
Contamination of freshwater aquatic systems is a recurring environmental problem worldwide, which is becoming increasingly acute with the frequent presence of new chemical compounds, such as emerging pollutants, including pharmaceutical products. The objective of this research was to estimate the ability of the water hyacinth species (Eichhornia crassipes) to remove from the aqueous environment five highly prescribed and over-the-counter drugs such as ciprofloxacin, ibuprofen, sulfamethoxazole, diclofenac, and acetaminophen. The work was carried out under greenhouse conditions at a temperature of 25 0C and a pH of 6.5; with a sampling every 24 h at different concentrations (3, 6, 9.12) mg/L. For the analysis of the samples, UV-VIS Spectrophotometry was used with direct reading of the absorbances of each one of the drugs. The response surface methodology was used for the statistical analysis of the data, which allowed determining the models to establish optimal times and concentrations maximizing the absorption of each pharmaceutical product, as well as obtaining the growth slopes to define where it can be projected the optimum. The main results in this work indicate that E. crassipes removed 95% of diclofenac in aqueous solutions with a concentration of 3 mg/L in 24 h, followed by ciprofloxacin and acetaminophen with a maximum removal of 91.18% and 71% at 96 h, respectively. At the same time, the lowest removal percentages were obtained for ibuprofen and sulfamethoxazole at 57.56% and 36%, respectively. In the present study, the high Eichchornia crassipes removal capacity of the five pharmaceutical products under controlled conditions was verified, evidencing a great possibility of application in the phytoremediation of emerging contaminants in an aqueous medium.
Syndiotactic poly (propene-co-norbornene): synthesis and properties at low norbornene incorporation
(2010) Vanegas Peña, María Eulalia; Quijada, Raúl; Galland, Griselda B.
Copolymerizations of propene with norbornene were carried out using a syndiotactic metallocene catalyst at low initial comonomer concentrations for different polymerization times. The influence of the norbornene concentration on the catalytic activity and on the resulting material properties has been analyzed. The copolymer molecular weight decreased drastically when small amounts of norbornene were added in reactions which lasted 30 min. When longer reaction times were used the molecular weight increased with time, however living polymerizationwas ruled out because the polydispersity was ca. 2. The DSC measurements showed copolymers with low crystallinity or which were completely amorphous.
A new approach for scaling up fixed-bed adsorption columns for aqueous systems: a case of antibiotic removal on natural adsorbent
(2022) Juela Quintuña, Diego Marcelo; Vera Cabezas, Luisa Mayra; Cruzat Contreras, Christian Américo; Astudillo Alemán, Ana Lucía; Vanegas Peña, María Eulalia
The scaling up of adsorption columns is a crucial step toward the removal of emerging pollutants from domestic and industrial wastewaters. In this study, a fixed-bed column to remove sulfamethoxazole packed with sugarcane bagasse was scaled up from laboratory (DL = 2.2 cm) to pilot unit (DP = 4.4 cm) using a scaling factor (K = 2). In addition to the basic similarity rules for scaling, three new criteria were proposed for the mass adsorbent, flow rate, and bed volume. Then, three lab-scale tests at flow rate of 5 mL/min and bed heights of 15, 25, and 35 cm were transferred to the pilot-scale column at flow rate of 20 mL/min and bed heights of 30, 50, and 70 cm, respectively. The breakthrough curves and the fixed-bed parameters (residence time tR, saturation time ts, adsorption capacity qe, volume of solution treated Vef, and removal percentage %R) obtained in both scales were compared to define their effect with the increase of scale. Finally, a mechanistic model was proposed to predict the breakthrough curves in both columns. The results exhibited that the breakthrough curves in the pilot-scale prolonged in time with higher breakthrough and saturation times than the laboratory breakthrough data. Additionally, tR, ts, and Vef changed in function of the K value used: ts and tR doubled their value in the pilot column or ; Vef was eight times higher in the pilot column than the lab-column or ; qe and %R remained constant in both scales; these results were corroborated with the predicted breakthrough curves. Besides, the mechanistic model predicted with great precision the breakthrough data in both scales (R2>0.9), which means that the model can be used confidently for scaling up purposes. This study demonstrated new criteria which can be easily applied to scale up adsorption columns whit results that showed a correlation between both scales.
Potential biopolymer adsorbent functionalized with Fe3O4 nanoparticles for the removal of Cr(VI) from aqueous solution
(2022) Vanegas Peña, María Eulalia; Castro Tamay, Pablo Reinaldo; Novoa, Néstor; Arrué, Ramón; Juela Quintuña, Diego Marcelo; Cruzat Contreras, Christian Américo
In the present study, an adsorbent with a synergistic effect was developed from chitosan (CS) and Fe3O4 nanoparticles (Fe3O4 Nps) to remove Cr(VI) from aqueous solutions. The Fe3O4 Nps were synthesized by co-precipitation and were characterized by TEM. The CS/NPs composites were prepared by electrospinning technique and analyzed by SEM, FT-IR, DSC, and TGA. In the batch system, the influence of Fe3O4 Nps content, pH, contact time, Cr(VI) initial concentration, adsorbent dosage, and the temperature was investigated; the Cr(VI) concentration was determined using a colorimetric method by UV–Vis spectroscopy. The Fe3O4 Nps presented a quasi-spherical shape and an average size of 18 nm, with a low particle distribution. The SEM analysis reveals the presence of highly porous, interconnected micrometric structures. The optimal adsorption conditions were 1% load of Fe3O4 Nps by weight of CS, pH 3, 25 °C, and equilibrium was reached at just 9 min. Besides, the adsorption is favored by increasing Cr(VI) initial concentration and adsorbent dosage. The studies of reaction kinetics and adsorption equilibrium showed that the experimental data were better fitted to the Pseudo-second-order and Langmuir isotherm models, establishing monolayer formation and chemisorption. The maximum adsorption capacity of CS/ Fe3O4 Nps was 440.75 mg/g, which indicates a high affinity of the adsorbent for Cr(VI). Finally, a kinetic diffusion study established that intraparticle diffusion, and in particular surface diffusion, are important resistances in the transport of Cr(VI) from the liquid phase to the active site.
Modeling and computational fluid dynamic simulation of acetaminophen adsorption using sugarcane bagasse
(2021) Vera Cabezas, Luisa Mayra; Juela Quintuña, Diego Marcelo; Cruzat Contreras, Christian Américo; Vanegas Peña, María Eulalia
Evaluación toxicológica de soluciones acuosas de ibuprofeno mediante bioensayos con Artemia salina, Allium schoenoprasum L y Lactuca sativa
(2018) Saetama Guallpa, Maria Veronica; Vera Cabezas, Luisa Mayra; Vanegas Peña, María Eulalia; Cruzat Contreras, Christian Américo; Brazales Quizhpe, Diana Esperanza
Drugs are considered within the so-called emerging pollutants, so it is important to investigate the toxic effects they can produce in the environment. The aim of this study was to determine the toxic effect of aqueous solutions of ibuprofen on an aquatic organism Artemia salina and the seeds of Allium schoenoprasum L and Lactuca sativa. The toxicity tests were carried out by exposing the test organisms to concentrations of aqueous ibuprofen solutions of 20, 10, 5, 2, 1 and 0.5 mgL-1. The percentage of mortality for Artemia salina and the elongation of the radicle and hypocotyl for the seeds were determined. The highest mortality percentage occurred at the concentration of 20 mgL-1, the calculated LC50 was 17.386 mgL-1. A low toxic effect was present in the germination of the seeds of Allium schoenoprasum L. There was inhibition in the elongation of the radicle and hypocotyl in seeds of Allium schoenoprasum L and a stimulation effect in the elongation of the radicle and hypocotyl of the seeds of Lactuca sativa. The highest inhibition effect was presented at 1 and 20mgL-1 and the highest stimulation at 20 mgL-1.
Low-cost crop waste biosorbent technology for removing toxics and pollutants from wastewater
(Springer, 2020) Vera Cabezas, Luisa Mayra; Cruzat Contreras, Christian Américo; Vanegas Peña, María Eulalia
Antibacterial and antifungal properties of electrospun recycled PET polymeric Fibers functionalized with zinc oxide nanoparticles
(2021) Cruzat Contreras, Christian Américo; Vázquez Ordóñez, Katherine Anabel; Vanegas Peña, María Eulalia; Arrué, Ramón Francisco; Novoa, Néstor; Vanegas Peña, Paúl Fernando
Currently, to reduce the environmental problems associated with plastic waste, methods are being sought to use this waste as raw materials in different applications, such as fibers. In addition, to improve these materials and provide different properties, nanoparticles (NPs) are incorporated. In the present work, polymeric fibers made of recycled polyethylene terephthalate (r-PET) from post-consumer water bottles, functionalized with 0%, 1.5%, 3% and 6% zinc oxide nanoparticles (ZnO-NPs) in function of r-PET weight, were elaborated to evaluate their antibacterial and antifungal characteristics. The ZnO-NPs were synthesized by the solvothermal method, obtaining particles with a mean diameter of 38.15 nm, while the fibers were obtained by electrospinning with a diameter range between 200–5000 nm. The functionalized fibers were carried out against Escherichia coli and Bacillus subtilis through the agar diffusion method, obtaining the highest inhibition halo at 6% w/w ZnO-NPs, being 26.5 mm and 34.25 mm, respectively. In addition, the same method was used to evaluate the antifungal activity of Penicillium s.p. and Fusarium graminearum, observing antifungal properties due to the presence of nanoparticles in the fibers.