Person:
Vera Cabezas, Luisa Mayra

Birth Date

1970-07-20

ORCID

0000-0002-0240-9147

Scopus Author ID

58812366700

Afiliación

Universidad de Cuenca, Cuenca, Ecuador
Universidad de Cuenca, Facultad de Ciencias Químicas, Cuenca, Ecuador
Universidad de Cuenca, Departamento de Recursos Hídricos y Ciencias Ambientales, Cuenca, Ecuador
Universidad de Cuenca, Centro de Estudios Ambientales, Cuenca, Ecuador
Universidad de Cuenca, Departamento de Química Aplicada y Sistemas de Producción, Cuenca, Ecuador

País

Ecuador

Organizational Units

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.

Job Title

Profesor (T)

Last Name

Vera Cabezas

First Name

Luisa Mayra

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Now showing 1 - 10 of 19

Eliminación de metales pesados de las aguas residuales mineras utilizando el bagazo de caña como biosorbente
(2016) Vera Cabezas, Luisa Mayra; Uguña Rosas, María Fernanda; García Alvear, Nancy Beatriz; Flores Zamora, Marittza Eleanor; Vázquez Freire, Verónica Eulalia
The search for new treatments and technologies for the removal of toxic metals from wastewater have drawn attention to the biosorption. In this work the study of bagasse from sugarcane as biosorbent in removing lead and cadmium from mining wastewater sample. We studied the effect of pH, contact time, concentration of the metal species and kinetic biosorption. Best percent cadmium removal was 77.81% for a working pH equal to 6, and 99.76 to lead to a pH of 5, which is reached after 10 minutes. It is noted for both lead and cadmium to as the metal concentration increases the amount of metal increases adsorbed per gram of adsorbent. The experimental data of biosorption of lead and cadmium favorably reproduce Elovich models and pseudo second order, with correlation coefficients (R2 ) for lead 1 and cadmium from 0.9986.
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.
Efectos de la ultrafiltracion sobre la fitotoxicidad de efluentes primarios y secundarios de la depuración de aguas residuales urbanas
(2016) González, Ea; Pérez Donato, Jorge A; Vera Cabezas, Luisa Mayra; Bravo S., La; Delgado, Sa
The clean / reclaimed waste water has become an important alternative water resources as part of sustainable use and management of water, especially in arid areas with deficits in natural resources. One application of interest is the agricultural irrigation industry that requires large amounts of water. The classic stages of primary and secondary biological treatment supply effluents with limited applications for irrigation, but can be improved significantly if such effluents undergo a process of ultrafiltration membranes. This paper presents the results of a study correlating the physical and chemical quality with phytotoxic properties, parameters in primary and secondary effluents and the effect of the ultrafiltration membrane in such effluents are analyzed. In each sample was measured: conductivity, turbidity, total organic carbon, soluble proteins, polysaccharides, chemical oxygen demand and ions of Na+ , K+ , Ca2+, Mg2+, B3+, Fand Cl- . Criteria phytotoxicity were evaluated by Lactuca sativa L. Biomarker is concluded that phytotoxicity conductivity and are interdependent to evaluate the toxic effect treatment processes for wastewater parameters. Moreover, the Na+ and Clions may play a role in the permeates phytotoxic obtained when subjected to ultrafiltration primary and secondary effluents.
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
Desarrollo de materiales sorbentes para la eliminación de metales pesados de las aguas residuales mineras.
(2016) Vera Cabezas, Luisa Mayra; Aloma, Inés; Vázquez, Verónica; Flores Zamora, Marittza Eleanor; García Alvear, Nancy Beatriz; Uguña Rosas, María Fernanda
Contamination by heavy metals is surely one of the most serious environmental problems. Industries such as mining produce waste containing heavy metals and these end up being transferred to the environment due to improper handling or disposal. Biosorption is one of the most promising technologies in the removal of heavy metals, not only for its low cost, but because it is a quick process that can treat large volumes of water with low concentrations of metal effectively. To study the adsorption mechanism is necessary to have information about the physical and chemical structure of the cell wall of biomass, functional groups present, the type and size of pores, polysaccharide chains, etc. In this paper the characterization of bagazo from sugar cane, corn cob and coconut mesocarp is done, since they are residual advantage for metal biosorption. Different techniques for determining the physical and chemical properties of the biosorbents were applied .The Results gave that the point of zero charge for the bagazo was 6.11 to 3.87 and cob 4.79 coconut. It was verified by the titration method the point of zero charge. BOEHM evidenced method predominant concentration of the acid sites on the surface in all cases. Determination of functional groups in the biosorbent under study was performed by IR spectrophotometer, which was demonstrated that the predominant functional groups include cellulose and lignin
Estudio experimental y simulación dinámica de la adsorción de Cd+2 y Pb+2 utilizando cáscara de cacao en columna de lecho fijo
(2022) Juela Quintuña, Diego Marcelo; Vera Cabezas, Luisa Mayra; Astudillo Ochoa, Sonia Margoth
The use of biomass as an adsorbent constitutes a potential alternative for the removal of heavy metals present in industrial wastewater, which represents a high risk for the environment. In this work, the adsorption of Pb+2 and Cd+2 was performed using the cocoa shell as adsorbent in columns, and the dynamic simulation of the process using the Aspen Adsorption® V10 software, in order to validate the simulation results and those obtained experimentally. The simulator and experimental rupture curves converge in almost the entire trajectory, with slight variations in the final stretch of the curve, with the rupture times coinciding for both metals, giving correlation coefficients (R2) of 0.984 and 0.998 for Pb+2 and Cd+2 respectively, as well as error values (SSE) less than 5%. The effect produced by the variation of the height of the bed and the flow rate in the rupture curves was analyzed, as the bed height increases and the flow rate decreases, the rupture time increases, favoring the adsorption of both metals. The results of this research show the importance of the use of Aspen Adsorption® software in the biosorption process, due to the similarity with experimental results, providing its use saving time and resources.
Nanofiltración/ósmosis inversa en la separación de fármacos de efluentes
(2021) González, Enrique; Vera Cabezas, Luisa Mayra; Astudillo Alemán, Ana Lucía; Cruzat Contreras, Christian Américo; Solórzano, A.
Membrane separation processes can be an effective barrier against pharmaceuticals and other organic compounds present in water sources. This investigation presents the results of the separation of ciprofloxacin (CIPRO) and sulfamethoxazole (SULFA) in aqueous solution with nanofiltration membranes (NF) and reverse osmosis (OI) at a concentration in the feed of 5 mg / L and the influence of pH on separation mechanisms. With RO membranes, rejection was 100% for CIPRO and greater than 98% for SULFA at the studied pH. For the NF, the pH had influences on the separation of the SULFA, obtaining in the rejection 73.7% at pH 5 and at pH 7 and 9 greater than 94%. In the case of CIPRO, rejection percentages greater than 91% were obtained. The rejection obtained with the solution of the mixture of the two drugs shows no change since the percentages of rejections are very close to the results obtained in the study of the drugs separately. The transmembrane pressure did not influence the rejection of the drugs.
Removal of Mn (II) from aqueous solution via biosorption technology for a drinking water treatment plant: From laboratory-scale tests to semi-industrial scale predictions
(2023) Juela Quintuña, Diego Marcelo; Vera Cabezas, Luisa Mayra; Flores Zamora, Marittza Eleanor; Cruzat Contreras, Christian Américo; Vanegas Peña, María Eulalia
Biosorbents have drawn increasing attention for removing pollutants on lab-scale systems. Although biosorbents are ecofriendly, their potential on large-scale columns has not been assessed yet. This study evaluated the potential of sugarcane bagasse (SB) for the removal of Mn (II) from aqueous media. Firstly, batch experiments were conducted to establish the equilibrium data and predominant adsorption mechanisms. Secondly, a mathematical model was proposed to predict the breakthrough curves in a fixed-bed column. Alternatively, lab- and pilot-scale removal experiments were performed to validate the accuracy of the proposed model. Once the model was validated on both scales, it was employed to predict breakthrough curves for a semi-industrial column under actual conditions of a drinking water treatment plant. Langmuir isotherm (qmax: 2.82 mg/g) and Langmuir kinetic model (R2>0.98 and x2<0.01) reproduced the experimental equilibrium and kinetic behavior. The mathematical model successfully replicated the lab- and pilot-scale breakthrough data (R2>0.95 and x2[removed]
Modelado en columna de lecho fijo para la bioadsorción de Cd2+ y Pb2+ con cáscara de cacao
(2018) Vera Cabezas, Luisa Mayra; Bermejo Campos, Daniel Francisco; Uguña Rosas, María Fernanda; García Alvear, Nancy Beatriz; Flores Zamora, Marittza Eleanor; Brazales Quizhpe, Diana Esperanza
In this work the results of the biosorption of Pb+2 and Cd+2 with cocoa shell in fixed bed columns are presented. A hydrodynamic study was performed varying diameter and height of the column, as well as diameter and mass of biosorbent, to determine the best hydrodynamic conditions, which resulted in a flow through the column of 2.12 mL/min. Experimental data were adjusted to several models depending on the effluent volume, which describe the rupture curve for single component and two component systems. The removal percentages of Pb+2 and Cd+2 in single component systems are 91 and 90 %, respctively. In bicomponent systems (Pb+2-Cd+2) the removal percentages of lead and cadmium were 88 and 90 %, respectively. The dose-response model in bi and mono-component systems best reproduced the experimental rupture curves throughout the measured range.
Determination of the toxic metabolite aflatoxin M1 in raw, pasteurized and ultrapasteurized milks comparing the ELISA Technique and High Performance Liquid Chromatography
(2023) Vera Cabezas, Luisa Mayra; Uguña Rosas, María Fernanda
Aflatoxins are very potent toxic metabolites with car-cinogenic, teratogenic, mutagenic, hepatotoxic and im-munosuppressive effects, which constitute a potential risk to human health, so they should be considered as a latent problem that requires continuous examination in order to ensure food quality.This study was carried out with the objective of quan-titatively determining the content of Aflatoxin M1 in three types of raw, pasteurized and ultrapasteurized milk consumed in the city of Cuenca-Ecuador, through the comparative analysis of the High Performance Liquid Chromatography HPLC Techniques, after an extraction process in immunoaffinity columns and the ELISA Te c h n i q u e .Eighty-four samples were analyzed in three types of milk: raw, pasteurized and ultra-pasteurized, with the ELISA technique, none exceeded the detection limit of Aflatoxin M1(125 ppt or 0.125 ppb), established both by the national INEN: 9-10 in force and the parameters established by the Food and Agriculture Organization of the United Nations, Food and Drug Administration of the United States (0.5ppb) and with the High Performance Liquid Chromatography technique, 16 positive samples were found that were between the limit of detection and quantification (0.09 - 0.18 ppb.), obtaining a prevalence of 19%, so that the High Performance Liquid Chroma-tography technique is more sensitive in the quantitative detection of the toxic metabolite Aflatoxin M1 in milk.