Person: Checa Fernández, Cristina Alicia
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First Name
Cristina Alicia
Last Name
Checa Fernández
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Ciencias Químicas
Department
Ingeniería Química y de Materiales
Area
Identifiers
5 results
Search Results
Now showing 1 - 5 of 5
- Project number: PIMCD328/23-24
Item Elaboración de una metodología basada en el aprendizaje autónomo de herramientas informáticas para fomentar las competencias digitales de los estudiantes de Ingeniería Química(2024) Lorenzo Fernández, David; Checa Fernández, Cristina Alicia; Cotillas Soriano, Salvador; Domínguez Torre, Carmen María; Herraíz Carboné, Miguel; García Cervilla, Raúl; Martínez Rodríguez, Mercedes; Rodríguez Vega, Sergio; Sánchez Yepes, Andrés; Santos López, Aurora Item Remediation of real soils polluted with pesticides by activated persulfate and surfactant addition(Journal of Water Process Engineering, 2023) Checa Fernández, Cristina Alicia; Santos López, Aurora; Romero Salvador, Arturo; Domínguez Torre, Carmen MaríaThe existence of soils contaminated with organochlorine pesticides represents a serious environmental problem. In this work, a real soil contaminated with hexachlorocyclohexanes (ΣHCH = 373 mg kg−1), persistent organic pollutants included in the Stockholm Convention, was remediated. Surfactants were used to enhance the pollutants solubilization and activated persulfate (PS) oxidation to degrade the pollutants. Solubilization experiments were performed to evaluate the effect of surfactant (sodium dodecyl sulfate (SDS), Emulse-3® (E3) and Tween-80® (T80)), pH, reagents addition order and concentration (Csurfactant = 0–10 g L−1, CNaOH = 0–13.5 g L−1). Surfactants selection was performed attending to their ability to solubilize chlorinated organic compounds (COCs). The use of surfactants improved COCs solubilization, especially at pH > 12; conditions at which HCHs hydrolyze to trichlorobenzenes (TCBs), with higher solubility. The higher the surfactant concentration, the higher the COCs concentration in the emulsion. COCs solubilization of 83 % and 89 % were achieved in three surfactant consecutive cycles at highly alkaline conditions using SDS and E3, respectively (T80 was unstable). The resulting emulsions were treated by PS activated by alkali and intensified by temperature. COCs conversion of 30 % and 96 % were achieved when treating E3 and SDS-emulsions (72 h), respectively, highlighting the suitability of SDS for the integrated process.Item Comprehensive study of acute toxicity using Microtox® bioassay in soils contaminated by lindane wastes(Science of the Total Environment, 2023) Domínguez Torre, Carmen María; Ventura, Paula; Checa Fernández, Cristina Alicia; Santos López, AuroraThis research studies the acute toxicity of real contaminated soils (topsoil and subsoil) with hazardous chlorinated organic compounds (COCs) from lindane manufacturing wastes. The Microtox® bioassay was used to determine the toxicity of soils (modified Basic Solid Phase Test), soil elutriates (Basic Test), and organic extracts (adapted Organic Solvent Sample Solubilization Test), in which hydrophobic organic compounds are soluble. The acute toxicity of these persistent contaminants (hexachlorocyclohexanes, HCH isomers, as particulate matter in topsoil, and COCs, from dense nonaqueous phase liquid, DNAPL, in subsoil) and the commercial compounds were also measured. Soils tested showed different contaminant levels (topsoil: 0.9–1149 mg/kg and subsoil: 20–9528 mg/kg). Soil contaminants distribution, concentration and acute toxicity were highly related to the contamination source (HCHs or DNAPL). Soils, organic extracts, and subsoil elutriates presented high toxicity, highlighting the need for remediation of these sites. EC50 was calculated in the three-test applied for the soils tested. EC50 vs. COCs concentration in soils and soil elutriates showed an asymptotic trend, explained by the low pollutants solubility in the aqueous phase. Contrarily, EC50 vs. soil COCs concentration was more linear in the case of the organic extracts. This test was the most reliable from statistical analysis. The three methods reveal interesting and complementary information and are necessary for a complete overview of the acute toxicity of contaminated soils.- Project number: 444
Item Herramientas de gamificación para la evaluación de competencias en ingeniería de la reacción Química(2023) Domínguez Torre, Carmen María; Santos López, Aurora; Martínez Rodríguez, Mercedes; Rodríguez Vega, Sergio; Cotillas Soriano, Salvador; Lorenzo Fernández, David; García Cervilla, Raúl; Checa Fernández, Cristina Alicia; Sánchez Yepes, Andrés; Domínguez Torre, Carmen MaríaEl objetivo del proyecto es la utilización de herramientas de gamificación para motivar la participación del estudiante en clase, identificar los conceptos de la asignatura (Ingeniería de la Reacción Química, del Grado en Ingeniería Química) que presentan mayor dificultad de aprendizaje y evaluar los conocimientos adquiridos en clase por parte de los estudiantes. La herramienta seleccionada en el proyecto ha sido Quizziz (https://quizizz.com/?lng=es-ES). Se trata de una herramienta de gamificación que permite evaluar a los estudiantes mientras se divierten. La información obtenida durante el desarrollo del proyecto permitirá, por un lado, detectar los contenidos de la asignatura más difíciles de asimilar y, por otro, actuar sobre la docencia impartida relativa a dichos aspectos. Durante el curso se propondrán una serie de casos prácticos (problemas relacionados con cada tema/bloque de la asignatura), para que el estudiante los resuelva de forma individual, haciendo uso del material que considere oportuno. De esta forma adquirirá autonomía en el empleo de fuentes bibliográficas. El profesor seleccionará uno de los casos propuestos para resolver en el aula durante una parte de la sesión de seminarios. En la segunda parte de la sesión se emplearán herramientas de gamificación para plantear y resolver cuestiones adicionales en relación con el caso práctico resuelto previamente. De este modo, no solo se evaluarán las destrezas de los estudiantes en cuanto a la resolución de problemas se refiere, sino también, su capacidad para poner en práctica los conocimientos teóricos adquiridos ante problemas abiertos. El estudiante conocerá en tiempo real si su respuesta es correcta y podrá identificar las carencias de aprendizaje y reforzar/profundizar en esos conocimientos. La herramienta de gamificación permite fomentar la participación del estudiante en clase y mejorar su aprendizaje. Los profesores pueden identificar si existen aspectos donde se detectan carencias en el conocimiento en un número mayor de estudiantes para mejorar la transmisión del conocimiento en esos puntos. Así, este proyecto de innovación educativa busca fomentar la participación y el aprendizaje continuo del estudiante durante el curso a través de la resolución de casos prácticos y la aplicación de herramientas de gamificación en el aula. Con esta actividad se pretende aumentar la adquisición de conocimientos y competencias y mejorar la tasa de éxito de la asignatura Ingeniería de la Reacción Química. Item Remediation of HCHs-contaminated sediments by chemical oxidation treatments(Science of The Total Environment, 2021) Domínguez Torre, Carmen María; Romero Salvador, Arturo; Checa Fernández, Cristina Alicia; Santos López, AuroraThe intensive use of organochlorine pesticides, such as lindane (γ-HCH), and the inadequate management of their wastes, is a huge environmental problem. The lindane production during the last century has generated huge volumes of solid wastes of other HCH isomers, causing hot points of soil and groundwater contamination. The soil treated in this work was obtained from a landfill located in the nearby of an old lindane factory, containing α-HCH and β-HCH as main contaminants. This study addresses for the first time the application of different chemical oxidation treatments, viz. Fenton process (H2O2 + Fe), persulfate (PS) activated by temperature (20 and 40 °C), by alkali (NaOH) and by the combination of alkali and temperature (NaOH, 40 °C) for the remediation of HCH-polluted soils (CHCHs = 155 mg kg−1). The intrinsic characteristics of the soil (high carbonate content) led to high consumption of H2O2 (XH2O2 ≈ 100% at 24 h) and complete iron precipitation, making unappropriated the application of the Fenton process. The efficiency of thermal PS was limited by the low solubility of HCH isomers in the aqueous phase, the high refractoriness of these compounds towards oxidation, and the presence of the contaminants in the form of particulate matter. After 25 days of treatment, a conversion of chlorinated organic compounds (COCs) of 50% was achieved (VL/Wsoil = 2, CPS = 40 g L−1, 40 °C), whereas the application of PS activated by alkali and temperature (40 °C) led to promising results. At pH above 12, HCHs were dehydrochlorinated to trichlorobenzenes, which were further oxidized by hydroxyl radicals. The hydrolysis rate of β-HCH was the limiting step of the process, and it was favored by increasing the reaction temperature. At 40 °C, a conversion of COCs above 95% was achieved (VL/Wsoil = 2, CPS = 40 g L−1, CNaOH = 13.5 g L−1, 14 days) with low oxidant consumption (XPS = 30%).