Mercedes Regadío

Mercedes Regadío
Universidad Autónoma de Madrid | UAM · Geology and Geochemistry

ENVIRONMETAL SCIENCES

About

80
Publications
22,226
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508
Citations
Introduction
I study the attenuation of landfill pollutants by compacted liners made of mixtures of clays with industrial process residues. For that, geotechnical diffusion tests are performed with settings that mimick the real conditions, to model long time and distance of the landfill leachate impact. After experimental modelling of reactive transport with a geotechnical centrifuge, a software will be applied for numerical modelling. Focus on (1) real landfill leachate effects on the different liners, (2) evaluation of the liners to retain leachate pollutants in the long-term, (3) physico-chemical processes which control pollutant-soil interactions, (4) fate, transport and biogeochemistry of pollutants. Past: Recovery of metals by ion exchange, solvent extraction and solvometallurgical leaching.
Additional affiliations
March 2020 - present
The University of Sheffield
Position
  • Research Associate
March 2018 - March 2020
The University of Sheffield
Position
  • Fellow
Description
  • Marie Curie Individual Fellow working on High Attenuation Recycling Materials as sustainable barriers for waste disposal sites
June 2014 - February 2018
KU Leuven
Position
  • PostDoc Position
Description
  • Selective recovery of critical metals from industrial process residues and low-grade ores. Extraction of valuable metals via solvoleaching. Recovery of rare earth elements by solvent extraction with ionic liquids.
Education
October 2009 - July 2011
Complutense University of Madrid
Field of study
  • Environmental Geology and Geological Resources, specialization in Hydrology and Soils
November 2008 - March 2012
Universidad Autónoma de Madrid
Field of study
  • Earth Sciences and the Environment (MENTION OF EUROPEAN DOCTOR)
October 2005 - September 2007
Universidad Politécnica de Madrid
Field of study
  • Environmental Sciences

Publications

Publications (80)
Chapter
In a world where circular economy and zero waste have increasing importance, exploring the potential to transform low value waste residues into a marketable product is essential. Each year industries produce hundreds of thousands of tonnes of process residues that accumulate on site until their eventual disposal. However, some waste residues can be...
Conference Paper
Full-text available
Globalmente, el 70% de los residuos (≈1,4×10 9 toneladas) son depositados en alguna forma de vertedero (Kaza, et al., 2018). Los vertederos son una gran fuente de contaminación y enfermedad, directamente relacionados con la degradación de la tierra y la contaminación del agua. Para evitar estos problemas, se instalan barreras alrededor de los resid...
Article
Full-text available
Correction for ‘Split-anion solvent extraction of light rare earths from concentrated chloride aqueous solutions to nitrate organic ionic liquids’ by Mercedes Regadío et al. , RSC Adv. , 2018, 8 , 34754–34763, DOI: 10.1039/c8ra06055j.
Article
Full-text available
Ethylenediaminetetraacetic acid (EDTA) has been widely used as an effective reagent for removal of lead from soil because of its high lead extraction efficiency caused by the high thermodynamic stability of the Pb(II)–EDTA complex. In this study, EDTA was used as a lixiviant for recovery of lead from residues (matte and slag) of secondary lead smel...
Article
The selection of a proper diluent should be based on several criteria such as the distribution ratio, phase disengagement time, cost, safety and environmental impact of the process. The effect of different diluents on the solvent extraction of Nd(III) by the neutral extractant tri-n-butylphosphate (TBP) from nitrate feed solutions was studied. The...
Article
Full-text available
Engineered synthetic liners on their own cannot protect the environment and human health against landfill leachate pollution. Despite their initial impermeability, they are susceptible to failure during and after installation and have no attenuation properties. Conversely, natural clay liners can attenuate leachate pollutants by sorption, redox tra...
Preprint
Full-text available
A new approach in landfill liner design which combines hydraulic containment of leachate with contaminant attenuation to improve the performance of these environmental control systems at landfills is described. The idea is to re-use readily available industrial waste residues (construction and biomass waste) as additives for natural clay liners, wh...
Article
A new approach in landfill liner design which combines hydraulic containment of leachate with contaminant attenuation to improve the performance of these environmental control systems at landfills is described. The idea is to re-use readily available industrial waste residues (construction and biomass waste) as additives for natural clay liners, wh...
Preprint
Full-text available
Engineered synthetic liners on their own are not the ideal solution to protect land, water and living beings against landfill leachate pollution. Despite their impermeability, engineered liners are susceptible to fail during installation and after a few years of landfill operation, and have no attenuation properties. Conversely, natural clay liners...
Preprint
p>Diluent plays an important role in the solvent extraction of metals. The selection of a proper diluent is important since it affects the economics of the process. The effect of different diluents (aliphatic, mixed aliphatic-aromatic and aromatic) on the solvent extraction of Nd(III) by the neutral extractant tri- n -butylphosphate (TBP) from nitr...
Chapter
Full-text available
The determination of concentrations of rare earth elements (REEs) continues to be important today in metallurgical, biological, medical, and environmental fields [1-4]. At a time when the greatest advances in analytical methods are available, REEs’ researchers and industries are looking for methods that will enable them to obtain reliable results i...
Presentation
Full-text available
In a world where circular economy and zero waste are taking over, exploring the potentialities to transform a residue into a marketable product is essential. Industrial process residues are very abundant in part due to the fourth industrial revolution currently evolving. The reuse of industrial residues would save natural resources, avoid the cost...
Article
Methanesulfonic acid (MSA) is a green acid with a remarkably high solubility for several speciality and base metals including lead, making it an interesting leaching agent for metals. MSA is safer and less toxic than the mineral acids (HCl, H2SO4, HNO3) currently employed for leaching metals from primary and secondary sources. In this study, MSA wa...
Poster
Full-text available
Landfills produce a toxic, dark and smelly liquid that can pollute the surrounding areas; representing a groundwater risk. For that reason, landfill barriers that stop the migration of leachate pollutants are required. Compacted clays are normally used for the attenuation of landfill leachates. However, clays suffer from volume changes due to hydra...
Article
Recovery of valuable metals from industrial process residues is complex because those metals are often present in very low concentrations and often locked in complex matrices. Hence it is important to develop a process that selectively recovers the metal(s) of interest, while the undesired metals remain in the solid residue. Conventional pyrometall...
Article
A continuous worldwide increase in scandium (Sc) criticality leads to a quest for secondary scandium resources. Among them, bauxite residue (BR) – a waste product from alumina refineries – often contains substantial amounts of scandium. However, the complexity in BR composition drives the need for developing a selective, efficient and cost-effectiv...
Article
Full-text available
Selective recovery of valuable metals from secondary (waste) sources is essential for better resource efficiency. However, low-grade waste streams typically have complex and variable compositions and low concentrations of valuable metals. Therefore, development of novel technologies, able to deal with these complex and variable waste streams, is ne...
Presentation
Full-text available
Characterisation of industrial wastes for their valorisation as additives in clays for high-attenuation containment barriers. 86-87 pp.
Article
Full-text available
Despite its benefits, the extraction of rare earths (REEs) from chloride solutions with neutral or basic extractants is not efficient, so that separation is currently carried out by using acidic extractants. This work aims to improve this process by replacing the conventional molecular diluents in the organic phase by ionic liquids (ILs) which cont...
Article
Rare-earth elements (REEs) were efficiently recovered by a supported ionic liquid phase (SILP) after iron(III) precipitation from simulated bauxite residue (BR) leachates in sulfuric acid media, since leaching of BR with sulfuric acid is more feasible than leaching with other mineral acids. The SILP betainium sulfonyl(trifluoromethanesulfonylimide)...
Conference Paper
Full-text available
Scandium (Sc) has attracted a lot of attention in the last decades because of the unique technological applications of this element. It is a key component in solid oxide fuel cells and aluminium alloys, which are especially produced for the aerospace industry. Unfortunately, there exist very few scandium deposits. Thus, scandium is generally recove...
Conference Paper
Full-text available
Liquid-solid extraction is often required in hydrometallurgy for the recovery of trace amounts of valuable metals from leaching solutions. Supported ionic liquid phases (SILPs) are a new class of adsorbents which involve covalently attached ionic liquid fragments on the surface of a solid material. In this work, we examined the recovery and separat...
Article
Full-text available
Bauxite residue (BR) contains substantial concentrations of rare-earth elements (REEs), but their recovery is a challenge. Acidic BR leachates typically comprise much higher concentrations of base elements (g L À1) than those of the REEs (ppm). Thus, adsorbents that are highly selective for the REEs over the base elements are required for the separ...
Article
The separation of rare-earth elements (REEs) is usually carried out by a multi-stage solvent extraction process utilising organophosphorus extractants. Inspired by the structure of the solvating extractant tri-n-butyl phosphate (TBP), new sorbents were designed by covalently attaching short n-alkyl chains (ethyl, n-propyl and n-butyl) to titanium(I...
Article
Full-text available
The adsorption of scandium from diluted, acidic solutions by a supported ionic liquid phase (SILP) was investigated, as part of a process for recovery of scandium from bauxite residue (red mud). Both dry impregnation and covalent linking were studied for the SILP preparation. The SILP betainium sulfonyl(trifluoromethanesulfonylimide) poly(styrene-c...
Presentation
Full-text available
The European Union defined the rare‐earth elements (REEs) as critical metals due to their high economic value (increasing demand in motors, electronics, renewal energy and catalysts) and high supply risks (>95% sourced from China).1 The most important process for separating mixtures of REEs is the solvent extraction (SX). In SX, a pregnant leach so...
Article
Total Reflection X-ray Fluorescence (TXRF) is becoming more and more popular for elemental analysis in academia and industry. However, simplification of the procedures for analyzing samples with complex compositions and residual matrix effects is still needed. In this work, the effect of an inorganic (CaCl2) and an organic (tetraalkylphosphonium ch...
Article
Full-text available
Despite the fact that Total Reflection X-ray Fluorescence (TXRF) is becoming more and more popular as a quantification technique in analytical chemistry due to its simplicity and robustness, there are still some key aspects related to the sample preparation that need to be improved. In this work, the effect of different parameters is investigated:...
Poster
Full-text available
Bauxite residue (BR) or red mud is a by-product in the production of alumina by the Bayer process. About 1–1.5 tonnes is generated for each tonne of alumina produced (1). Still, BR contains relatively large concentrations of not only elements like aluminium, iron and titanium but also of scandium, yttrium and other rare-earth elements (REEs), which...
Poster
Full-text available
The European Union defined the rare‐earth elements (REEs) as critical metals due to their high economic value (increasing demand in motors, electronics, renewal energy and catalysts) and high supply risks (>95% sourced from China).1 The most important process for separating mixtures of REEs is the solvent extraction (SX). In SX, a pregnant leach so...
Data
4th International Conference on Methods and Materials for Separation Processes Brunów, Poland
Presentation
Full-text available
The increasing demand for rare earth elements (REE) in automotive sector, electronics, renewal energy and catalysts, has led to a growing interest in their production process. Solvent extraction (SX) in hydrometallurgy is the most important process for separating and obtaining the REE. First, a leaching solution of dissolved elements (aqueous phase...
Article
The performance of a widely distributed natural clay to attenuate contaminants released from an old landfill was investigated. The objective is to evaluate its potential use as a barrier for waste containment systems. Core samples of the natural clay were collected below the landfill and their parameters distribution with depth was determined. Part...
Presentation
Full-text available
El denominado Almacén Geológico Profundo (AGP) es, la solución internacionalmente aceptada como más segura y viable para la disposición final de los residuos radioactivos de alta actividad. Consiste en alojar los residuos a gran profundidad en formaciones geológicas estables y rodearlos de una serie de barreras de ingeniería que los aísla de la bio...
Presentation
Full-text available
The aim of this study was to obtain evidences on the physical and geochemical processes occurring by the combined effects of cementitious materials from the concrete degradation and magnetite from steel corrosion on the bentonite barrier during disposal of radioactive waste. The experiments try to reproduce the repository conditions prevailing from...
Book
Full-text available
El auge de los Sistemas de Información Geográfica (SIG) ha hecho que estas herramientas se apliquen en casi todas las disciplinas, desde Ciencias Ambientales hasta Geografía o Economía. Su éxito reside en que facilitan considerablemente el abordaje y resolución de los problemas de localización óptima (i.e.; situación más adecuada) de actividades hu...
Poster
Full-text available
Landfills suppose an old problem still unsolved which has persisting implications that remain for long periods due to the continuous flow of contaminated leachate from the waste. In the case of unlined landfills or landfills with barriers that fail, the leachate percolates through the underlying unsaturated soil vertically downward. The infiltratin...
Poster
Full-text available
Los sistemas que se diseñan actualmente para la contención de residuos, y en general de efluentes contaminados, se fundamentan en la utilización de barreras de ingeniería compuestas a base de capas minerales (suelos, arcillas) y geosintéticas (materiales poliméricos y mixtos). En ocasiones, como alternativa, también se ha empleado el propio suelo m...
Poster
Full-text available
The aim of this experimental study was to obtain evidences on the physical and geochemical processes occurring by the combine effects of cementitious materials from the concrete degradation and magnetite from steel corrosion on the bentonite barrier during storage and disposal of radioactive wastes. The tests try to reproduce the repository conditi...
Poster
Full-text available
El conocimiento de cómo se forma la sepiolita es relevante tanto por motivos paleo-ambientales como tecnológicos. Existen evidencias acerca de su origen bio-inducido (Leguey et al., 2010; Cuevas et al., 2011), lo que ha llevado a diseñar y ensayar procesos geo-inspirados dirigidos hacia la síntesis de sepiolita. La hipótesis de trabajo se basa en l...
Poster
Full-text available
El sustrato natural bajo un vertedero constituye una de las barreras principales integradas en el concepto multibarrera para conservar el medio ambiente y la salud humana. Cuando dicha capa mineral posee una conductividad hidráulica ≤10─9 m s─1 y un espesor ≥1 m se considera que proporciona una protección suficiente y se denomina ”barrera geológica...
Poster
Full-text available
The natural substratum around a municipal landfill constitutes one of the main barriers integrated in the multibarrier concept to preserve the environment and human health. When the substratum itself provides sufficient protection, it is called “geological barrier” according to the Council Directive 1999/31/EC (1999) and is defined as any mineral l...
Poster
Full-text available
To know how sepiolite can be formed is relevant for both technological and paleo-environmental interests. There exist are some evidences about its bio-induced origin in ancient shallow lacustrine environments in the Miocene Madrid basin (Leguey et al., 2010; Cuevas et al., 2011). This fact has aimed us to design and try geo-inspired processes focus...
Poster
Full-text available
Landfills are often lined to minimize the migration of harmful contaminants into the surrounding soil and groundwater. The most important engineering specification for geomaterials, used as landfill liners, is a low hydraulic conductivity (less than 10-9 m/s) but also is necessary to assess their chemical stability and performance during the operat...
Technical Report
Full-text available
Como paso previo a la realización del informe, se ruega lean detenidamente las instrucciones de elaboración de los informes de seguimiento científico-técnico de proyectos disponible en la página web del ministerio. A. Datos del proyecto Relacione los datos del proyecto. En caso de que haya algún cambio, indíquelo cambiando de color el texto Referen...
Conference Paper
Full-text available
The study analyzes solid samples from two substrata (kaolinitic clay acid environment (1) and illite-smectite carbonated clay environment (2) under old municipal landfills that were in direct contact with the waste. The main soluble constituents of the leachates (Na+sol, NH4+sol, alkalinity, Clsol) and the composition of the exchangeable complex in...
Article
The diffusion of a synthetic urban landfill leachate through compacted natural illitic clays and the role of reactive accessory minerals (carbonates and gypsum) in the geochemical behavior of major soluble ions are evaluated. The leachate is composed of NH4 + and Na+ (0.25 M) balanced by Cl- (0.25 M), acetate (0.1 M) and HCO3 - (0.15 M). The pH is...
Article
Full-text available
Changes in the way the lectures are done in college are expected to become more and more frequent and important over the next few years. This follows from the priorities defined in the framework of the EHEA (European Higher Education Area) and in the assessment of the teaching capacity of professors. This work compares two didactical methods and th...
Thesis
Full-text available
An appropriate disposal of waste in landfills is a key issue for protecting, preserving and improving the environment and the human health. The most applied policy for landfilling is the containment strategy (complete isolation of the deposited waste by means of bottom and top liner systems and collection of gas and leachate emissions combined with...
Article
Enhanced sand-clay mixtures have been prepared by using a sandstone arkosic material and have been evaluated for consideration as landfill liners. A lab-scale test was carried out under controlled conditions with different amended natural sandstones whereby leachate was passed through the compacted mixtures. The compacted samples consisted of silic...
Data
Full-text available
Physicochemical, geochemical and mineralogy data measured in soil samples under three unlined Municipal Waste landfills. Tables of: - Depths from the surface, thicknesses and depths from the landfill base of the samples from the three landfills, - pH, redox potential, electrical conductivity, water soluble organic/inorganic carbon, moisture of th...
Data
Full-text available
PRINCIPAL COMPONENT ANALYSIS FOLLOWED BY A VARIMAX ROTATION Table B.1. Correlation matrix of the 28 variables (correlations)... 2 Table B.2. Correlation matrix of the 28 variables (sig. unilateral). When correlation coefficient is < 0.05, then it is significant.... 3 Table B.3. Eigenvalues (total variance explained)... 4 Fig. B.1. Finding the...
Article
The long-term effectiveness of the geological barrier beneath municipal-waste landfills is a critical issue for soil and groundwater protection. This study examines natural clayey soils directly in contact with the waste deposited in three landfills over 12 years old in Spain. Several physicochemical and geological parameters were measured as a fun...
Conference Paper
Full-text available
Nowadays, two changes in the university system worth noting are: the EHEA (European Higher Education Area) and the assessment of teaching capacity of professors. Consequently, in the last decades, a lot of variations and new ideas were introduced in the way the lectures were done. This paper compares two of these didactical methods in the first-yea...
Conference Paper
Full-text available
Municipal solid waste (MSW) landfills are usually built on obsolete clay quarries. This study presents the results of seven boreholes drilled into natural clay materials, placed under the waste of three old Spanish landfills. Electrical conductivity (EC), water soluble organic carbon, Cl-, NH4+ and Na+ (WSOC, Cl-sol, NH4+sol and Na+sol); as well as...
Presentation
Full-text available
INTRODUCCIÓN. Los vertederos de residuos urbanos son instalaciones de almacenamiento de residuos muy sofisticadas, cuya función es el aislamiento de los residuos, la prevención del flujo de contaminantes y la reducción de su peligrosidad mediante procesos de atenuación natural (Committee to Assess the Performance of Engineered Barriers, 2007). Con...