Person:
Sánchez Yepes, Andrés

First Name

Andrés

Last Name

Sánchez Yepes

URI

https://hdl.handle.net/20.500.14352/85779

Affiliation

Universidad Complutense de Madrid

Faculty / Institute

Ciencias Químicas

Department

Ingeniería Química y de Materiales

Identifiers

Full item page

Search Results

Now showing 1 - 8 of 8

Regeneration of Granulated Spent Activated Carbon with 1,2,4-Trichlorobenzene Using Thermally Activated Persulfate
(Industrial & Engineering Chemistry Research, 2022) Sánchez Yepes, Andrés; Santos López, Aurora; Rosas, Juana M.; Rodríguez Mirasol, José; Cordero, Tomás; Lorenzo Fernández, David
Chlorinated organic compounds (COCs) are persistent organic pollutants often found in groundwater near industrial sites or in industrial wastewaters. Adsorption into activated carbon is a common strategy to remediate these waters, but spent activated carbon results in a toxic residue to manage. To avoid the transport of the chlorinated compounds out of the site, the in-situ regeneration of the spent activated carbon can be considered for reuse to implement a circular economy. In this work, the regeneration of a commercial granular activated carbon (GAC) has been carried out using thermally activated sodium persulfate (TAP). GAC was previously saturated in 1,2,4-trichlorobenzene (124-TCB) as the model compound. The initial adsorption value was 350 mg124 TCB·gGAC −1 . First, the nonproductive consumption of sodium persulfate was studied at different temperatures using nonsaturated GAC. Then, the regeneration of the saturated GAC (5 g) was studied by an aqueous solution (166 mM) of TAP (1 L) at a temperature range from 20 to 80 °C. The possible recovery of the adsorption capacity was studied after 3 h of treatment in three successive adsorption−regeneration cycles at the selected temperature (60 °C). The physicochemical changes of the GAC were also investigated before and after the regeneration treatments. The results evidence the significant deposition of sulfate on the GAC after each treatment of regeneration, which avoids the recovery of the initial adsorption capacity. Therefore, each regeneration cycle was necessarily followed by a washing step at 60 °C to remove this sulfate. After that, the regeneration treatment achieved a stable and high recovery of the initial adsorption capacity of about 48.2%.
LED visible light assisted photochemical oxidation of HCHs in aqueous phases polluted with DNAPL
(Process Safety and Environmental Protection, 2022) Conte, Leandro O.; Cotillas Soriano, Salvador; Sánchez Yepes, Andrés; Lorenzo Fernández, David; Santos López, Aurora
This work focuses on removing hexachlorocyclohexanes (HCHs) found in groundwater polluted with dense non-aqueous phase liquids (DNAPLs) by photo-oxidation with hydrogen peroxide or persulfate using LED visible light and ferrioxalate as the catalyst. Single oxidation tests were also performed to evaluate the contribution of LED-vis light on HCHs removal. Results show that it is possible to attain the degradation of HCHs up to 85% in 420 min with persulfate, whereas percentages lower than 40% are obtained when using hydrogen peroxide. Using both oxidants in the presence of ferrioxalate and LED visible light promotes the generation of hydroxyl and sulfate radicals under circumneutral pH values, which are the main responsible species for HCHs removal. Specifically, an oxidant conversion higher than 50% was achieved during the photochemical treatment with both oxidants, whereas conversions below 20% were obtained in the absence of LED visible light irradiation. On the other hand, DNAPL produced as liquid residuum of lindane production contains other chlorinated organic compounds (COCs), which are susceptible to being oxidized by hydroxyl and sulfate radicals, generating competitive oxidation reactions. The final conversion of chlorbenzenes reaches values close to 100% and HCHs are only effectively removed when persulfate is used as the oxidant. This better performance indicates that the photo-oxidation of DNAPL polluted groundwater with LED-vis light should be carried out with persulfate to ensure the removal of more dangerous COCs. This confirms the excellent ability of sulfate radicals for C-Cl bond breakdown.
Sustainable reuse of toxic spent granular activated carbon by heterogeneous fenton reaction intensified by temperature changes
(Chemosphere, 2023) Sánchez Yepes, Andrés; Santos López, Aurora; Rosas, Juana M.; Rodríguez-Mirasol, José; Cordero, Tomás; Lorenzo Fernández, David
A common strategy for removing highly toxic organic compounds, such as chlorinated organic compounds, is their adsorption on granular activated carbon. Spent granular activated carbon results in a toxic residue to manage; therefore, the regeneration and reuse of granular activated carbon on the site would be advisable. This work studies the regeneration of a granular activated carbon saturated in 1,2,4-trichlorobenzene, chosen as the model chlorinated organic compounds, by heterogeneous Fenton, where iron was previously immobilised on the granular activated carbon surface. This methodology avoids the addition of iron to the aqueous phase at concentrations above the allowable limits and the need for acidification. Three successive cycles of adsorption-regeneration were carried out batchwise (5 gGAC·L−1) with a granular activated carbon saturated with 300 mg124-TCB·gGAC−1. The recovery of the adsorption capacity after regeneration was studied with H2O2 (166 mM, 1.5 the stoichiometric dosage), at different concentrations adsorbed with iron adsorbed concentrations (0–12 mgFe·gGAC−1) and temperatures (20–80 °C). Stable recovery of the adsorption capacity values of 65% were obtained at 180 min with 12 mgFe·gGAC−1 and 60 °C. The porosity and surface chemistry of the adsorbent remained very similar after different adsorption-regeneration cycles without iron leaching into the aqueous phase. The oxidant consumption was close to the stoichiometric value for the mineralization of 1,2,4−trichlorobenzene, with a low unproductive consumption of H2O2 with granular activated carbon. In addition, no aromatic or chlorinated by-products were detected in the aqueous solution obtained in the regeneration process. The negligible toxicity of the aqueous phase with the Microtox bioassay confirmed the absence of toxic oxidation by-products. Keywords: Heterogeneous fenton; Adsorption; Regeneration; Activated carbon; Chlorinated organic compounds
Project number: PIMCD328/23-24
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
Project number: 334
Aprendizaje bidireccional a través de cuestionarios online
(2022) Domínguez Torre, Carmen María; Santos López, Aurora; Rodríguez Vega, Sergio; Lorenzo Fernández, David; Cotillas Soriano, Salvador; Conte, Leandro Oscar; Sáez González, Patricia; García Cervilla, Raúl; Checa Fernández, Alicia; Sánchez Yepes, Andrés
El presente proyecto de innovación docente utiliza la herramienta online del Campus Virtual “entorno de cuestionarios” para mejorar la docencia impartida por los profesores, ayudar a los estudiantes a detectar sus puntos débiles (con suficiente antelación a la realización de los exámenes de la asignatura) e incentivar el estudio, autonomía y aprendizaje en Ingeniería de la Reacción Química, asignatura anual y de carácter obligatorio, de tercer curo del Grado de Ingeniería Química.
Selective removal of chlorinated organic compounds from soil flushing emulsions: Adsorbent regeneration with thermal-activated persulfate and surfactant recovery
(Journal of Water Process Engineering, 0202) Sánchez Yepes, Andrés; Santos López, Aurora; Romero Salvador, Arturo; Lorenzo Fernández, David
Hydrophobic organic compounds (HOCs) released into the environment can form nonaqueous phase liquids, contaminating soil and groundwater. Surfactant-enhanced aquifer remediation, followed by extracting a highly contaminated emulsion comprising surfactants and contaminants, is a promising technology for remediating polluted sites. However, the sustainable treatment of the emulsion is crucial. This study presents a two-step method for treating emulsions containing HOCs and surfactants. Firstly, pollutants are selectively adsorbed onto granular activated carbon (GAC) in a column. Secondly, spent GAC is regenerated by oxidizing adsorbed pollutants using persulfate activated at 60 ◦C. The emulsion was obtained from surfactant-enhanced aquifer remediation at a polluted site with lindane production waste, consisting of E-Mulse® 3 surfactant (12 g L− 1 ) and 28 chlorinated organic compounds (COCs) at a concentration of 9.1 gCOCs L− 1 . Selective adsorption of COCs was observed since the adsorption kinetic constant was much higher than the E3, being 31.60 and 1.76 gGAC− W⋅mg− 1 j ⋅ h− 1 respectively. The adsorption-regeneration cycle was repeated three times. It was found that the GAC adsorbed 90 mgCOCs⋅gGAC − 1 were constant after four cycles (70 % of the COCs adsorption capacity in the first step). The surfactant adsorption decreased by approximately 80 % from 108 to 26 mgE3 gGAC − 1 after the third cycle, enabling surfactant recovery from the emulsion. In addition, the remaining amount of persulfate increased from 24 to 39 %, reducing oxidant consumption. Finally, the water effluent obtained after regeneration showed reduced toxicity due to the generation of nontoxic by-products, such as short-chain acids and sulphates. The results obtained proved the GAC-based adsorption/regeneration process was effective and stable over multiple cycles.
Project number: 444
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 María
El 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.
Abatement of Naphthalene by Persulfate Activated by Goethite and Visible LED Light at Neutral pH: Effect of Common Ions and Organic Matter.
(Catalysts, 2022) Sánchez Yepes, Andrés; Lorenzo Fernández, David; Sáez González, Patricia; Romero, Arturo; Santos López, Aurora
Naphthalene (NAP) has received particular attention due to its impact on the environment and human health, mandating its removal from water systems. In this work, the abatement of NAP in the aqueous phase was achieved using persulfate (PS) activated by Fe (III) and monochromatic LED light at a natural pH. The reaction was carried out in a slurry batch reactor using goethite as the Fe (III) source. The influence of the PS concentration, goethite concentration, irradiance, temperature and presence of organic matter, chloride, and bicarbonate on the abatement of NAP was studied. These variables were shown to have a different effect on NAP removal. The irradiance showed a maximum at 0.18 W⋅cm−2W·cm−2 where the photonic efficiency was the highest. As for the concentration of goethite and PS, the influence of the first one was negligible, whereas for PS, the best results were reached at 1.2 mM due to a self-inhibitory effect at higher concentrations. The temperature effect was also negative in the PS consumption. Regarding the effect of ions, chloride had no influence on NAP conversion but carbonates and humic acids were affected. Lastly, this treatment to remove NAP has proved to be an effective technique since minimum conversions of 0.92 at 180 min of reaction time were reached. Additionally, the toxicity of the final samples was decreased.