New Perspectives for Electrodialytic Remediation

Electrodialytic remediation has been widely used for the recovery of different contaminants from numerous matrices, such as, for example, polluted soils, wastewater sludge, fly ash, mine tailing or harbour sediments. The electrodialytic remediation is an enhancement of the electrokinetic remediation technique, and it consists of the use of ion-exchange membranes for the control of the acid and the alkaline fronts generated in the electrochemical processes. While the standard electrodialytic cell is usually built with three-compartment configuration, it has been shown that for the remediation of matrices that require acid environment, a two-compartment cell has given satisfactory removal efficiencies with reduced energy costs. Recycling secondary batteries, with growing demand, has an increasing economic and environmental interest. This work focusses on the proposal of the electrodialytic remediation technique as a possible application for the recycling of lithium-ion cells and other secondary batteries. The recovery of valuable components, such as lithium, manganese, cobalt of phosphorous, based on current recycling processes and the characterization of solid waste is addressed.This work has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No. 778045. Paz-Garcia acknowledges the financial support from the University of Malaga, project: PPIT.UMA.B5.2018/17. Villen-Guzman acknowledges the funding from the University of Malaga for the postdoctoral fellowship PPIT.UMA.A.3.2.2018. Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

Electrodialytic Recovery of Cobalt from Spent Lithium-Ion Batteries

Contribución en congreso científicoRecycling lithium-ion batteries has an increasing interest for economic and environmental reasons. Disposal of lithium-ion batteries imposes high risk to the environment due to the toxicity of some of their essential components. In addition to this, some of these components, such as cobalt, natural graphite and phosphorus, are included in the list of critical raw materials for the European Union due to their strategic importance in the manufacturing industry. Therefore, in the recent years, numerous research studies have been focused on the development of efficient processes for battery recycling and the selective recuperation of these key components. LiCoO2 is the most common material use in current lithium-ion batteries cathodes. In the current work, an electrodialytic method is proposed for the recovery of cobalt from this kind of electrode. In a standard electrodialytic cell, the treated matrix is separated from the anode and the cathode compartments by means of ion-exchange membranes. A cation-exchange membrane (CEM) allows the passage of cations and hinders the passage of anions, while the behaviour of anion-exchange membrane (AEM) does the opposite. A three-compartment electrodialytic cell has been designed and assembled, as depicted in the figure. In the central compartment, a suspension of LiCoO2 is added. Different extracting agents, such as EDTA, HCl and HNO3, are tested to enhanced the dissolution and the selective extraction of the target metal. Dissolved cobalt-containing complexes migrate towards the cathode or the anode compartments depending on the ionic charge of the complexes. While cobalt extraction via extracting agents is an expensive treatment, as it requires the constant addition of chemicals, an efficient electrodialytic cell could allow the recirculation of the extracting agents and the economical optimization of the process.This work has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No. 778045. Paz-Garcia acknowledges the financial support from the University of Malaga, project: PPIT.UMA.B5.2018/17. Villen-Guzman acknowledges the funding from the University of Malaga for the postdoctoral fellowship PPIT.UMA.A.3.2.2018. Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

Modeling of Electrodialytic Treatment of Lithium-Ion Batteries

Lithium-ion batteries are currently present in most portable electronic devices and their use is rapidly growing in the field of electric vehicles and renewable energy storage. Many components in lithium-ion batteries are toxic and/or environmentally hazardous. Furthermore, some of them are expensive and listed as critical materials in terms of supply-chain risk. Therefore, the need to improve the recycling techniques for lithium-ion batteries is becoming a priority. Herein, we describe and present a model for the electrodialytic treatment of disposed lithium-ion batteries. Electrodialysis is a separation process based on the use of electric fields and ion-selective membranes. The electrodialytic cell can be designed in different configurations, to enhance the selective extraction of the target products. In a standard electrodialytic cell, the treated matrix is separated from the anode and the cathode compartments by means of anion- and cation-exchange membranes respectively. However, depending on the ionic charge and the specific chemistry of the matrix, different cell designs can be used. In the present work, different possible configurations are explored for the optimization of the extraction of key valuable components from spent lithium-ion batteries, taking into account the chemical properties of the system depending on the chosen extracting agent and cell configuration. The model presented here is based on a set of differential and algebraic equations consisting of a Nernst-Planck based continuity equations for each of the chemical species involved in the process, coupled with the electroneutrality and the local chemical equilibrium conditions. The numerical solution is performed using COMSOL Multiphysics, and the simulation results are compared with experimental data for model validation.This work has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No. 778045. Paz-Garcia acknowledges the financial support from the University of Malaga, project: PPIT.UMA.B5.2018/17. Villen-Guzman acknowledges the funding from the University of Malaga for the postdoctoral fellowship PPIT.UMA.A.3.2.2018. Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

A Model for Electrodialytic Treatment of Lithium-Ion Batteries

New recycling processes for secondary batteries are needed to achieve sustainable use of natural resources. Indeed, many components in lithium ion batteries, such as cobalt and graphite, are in the European Union’s “Critical Raw Materials” list. Electrodialytic treatment of disposed lithium-ion batteries is a pioneer proposal for the selective recovery of some of these relevant elements. In this work, a model for the electrochemical technology of disposed batteries implemented using COMSOL Multiphysics is presented. The main aim of this model is the optimization of the extraction of valuable components from spent batteries and the prediction of experimental results, which entails a better understanding of the different process involved. The model is based on the Nernst-Planck- Poisson system of equations coupled with the local chemical equilibrium conditions. The model uses multi-scale discretization of the different components; including the assumed well-stirred compartments, the ion-exchange membranes and the diffuse double-layer at the surface of the membranes. Different cell configuration has been tested, and results were compared to experimental data for model validation.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. The authors acknowledge the financial support from the "Plan Propio de Investigación de la Universidad de Málaga" with project numbers PPIT.UMA.D1, PPIT.UMA.B1.2017/20 and PPIT.UMA.B5.2018/17. This work has also received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No. 778045

Electrodialytic Treatment of Secondary Batteries Cathodes

The interest for reusing and recycling secondary batteries is increasing, driven by both economic and environmental reasons. Lithium-ion batteries are among the main energy storage devices more popular in portable electronic and there are being used more every year in the field of electric transportation. The growing demand for rechargeable batteries entails an increase in the attention paid to the recycling of spent batteries due to the toxicity of some of their essential components. Furthermore, some of these components, such as cobalt, natural graphite and phosphorus, are included in the list of critical raw materials for the European Union due to their strategic importance in the manufacturing industry. Therefore, the development of new technologies to selectively recover these key components should be addressed. In this work, an electrodialytic method is applied to real battery wastes previously submitted to a pre-treatment process (Figure 1). We focused on the extraction of Co and Li from spent cathodes, in combination with acid-extraction and different oxidation/reduction environments. The optimization of some of the most relevant operating parameters, such as cell design, selection of enhancing agent and current density has been carried out according to the lithium-ion batteries waste characteristic. Results indicate that the electrodialytic method could be a useful technique for the selective extraction of Li and Co from spent batteries. Furthermore, the deposition of Co at the cathode surface may be optimized to separate the cations at the catholyte, for a direct reincorporation in the manufacturing chain.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. The authors acknowledge the financial support from the "Plan Propio de Investigación de la Universidad de Málaga" with project numbers, PPIT.UMA.D1, PPIT.UMA.B1.2017/20 and PPIT.UMA.B5.2018/17. This work has also received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No. 778045

Improving Cr (VI) Extraction through Electrodialysis

A laboratory study has been carried out to determine the feasibility of in situ remediation of chromium (VI) contaminated soil using electrodialysis. In a classic setup, this technique implies the application of a low intensity direct current to the soil, which is separated from the electrode compartments by ion-exchange membranes. If the pollutants are ionic compounds, they can be forced to migrate to the oppositely charged electrode by electro-migration. Membranes selectively impede the flow of ions in the electrode compartments back to the soil. If a metal species is naturally present as an anion, mobilization from the soil at alkaline pH can be realized and, at the same time, the mobilization of other metal cations that occur at low pH can be minimized. Experiments have been carried out with clayey soils (kaolinite clay and soil clay mixtures) that have been characterized and then contaminated by mixing with a potassium dichromate solution for several days. Initial Cr (VI) content ranges from 500 to 4000 mg/kg. Treatment tests were carried out in an acrylic laboratory cells consisting of a central soil compartment and two electrode compartments located at both ends of the column. Dimensionally stable titanium electrodes coated with mixed metal oxides were placed in the electrode compartments. 0.01M Na2SO4 electrolytes were recirculated through them from two 1-liter deposits using a peristaltic pump. Two commercial ion exchange membranes separated the anolyte and catholyte compartments from the soil in the standard configuration. A programmable DC: power supply was connected to the electrodes and a computer for data acquisition.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. The authors acknowledge the financial support from the "Plan Propio de Investigación de la Universidad de Málaga" with project numbers PPIT.UMA.D1; PPIT.UMA.B1.2017/20 and PPIT.UMA.B5.2018/17. This work has also received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No. 778045

The dependence of oxygen and nitrogen abundances on stellar mass from the CALIFA survey

Context. The study of the integrated properties of star-forming galaxies is central to understand their formation and evolution. Some of these properties are extensive and therefore their analysis require totally covering and spatially resolved observations. Among these properties, metallicity can be defined in spiral discs by means of integral field spectroscopy (IFS) of individual H ii regions. The simultaneous analysis of the abundances of primary elements, as oxygen, and secondary, as nitrogen, also provides clues about the star formation history and the processes that shape the build-up of spiral discs. Aims. Our main aim is to analyse simultaneously O/H and N/O abundance ratios in H ii regions in different radial positions of the discs in a large sample of spiral galaxies to obtain the slopes and the characteristic abundance ratios that can be related to their integrated properties. Methods. We analysed the optical spectra of individual selected H ii regions extracted from a sample of 350 spiral galaxies of the CALIFA survey. We calculated total O/H abundances and, for the first time, N/O ratios using the semi-empirical routine Hii-Chi-mistry, which, according to Pérez-Montero (2014, MNRAS, 441, 2663), is consistent with the direct method and reduces the uncertainty in the O/H derivation using [N ii] lines owing to the dispersion in the O/H-N/O relation. Then we performed linear fittings to the abundances as a function of the de-projected galactocentric distances. Results. The analysis of the radial distribution both for O/H and N/O in the non-interacting galaxies reveals that both average slopes are negative, but a non-negligible fraction of objects have a flat or even a positive gradient (at least 10% for O/H and 4% for N/O). The slopes normalised to the effective radius appear to have a slight dependence on the total stellar mass and the morphological type, as late low-mass objects tend to have flatter slopes. No clear relation is found, however, to explain the presence of inverted gradients in this sample, and there is no dependence between the average slopes and the presence of a bar. The relation between the resulting O/H and N/O linear fittings at the effective radius is much tighter (correlation coefficient ρ = 0.80) than between O/H and N/O slopes (ρ = 0.39) or for O/H and N/O in the individual H ii regions (ρ = 0.37). These O/H and N/O values at the effective radius also correlate very tightly (less than 0.03 dex of dispersion) with total luminosity and stellar mass. The relation with other integrated properties, such as star formation rate, colour, or morphology, can be understood only in light of the found relation with mass.E.P.M., J.M.V., C.K., S.P., and J.I.P. acknowledge support from the Spanish MICINN through grants AYA2010-21887-C04-01 and AYA2013-47742-C4-1-P and the Junta de Andalucia for grant EXC/2011 FQM-7058. R.G.B., R.G.D., and E.P. acknowledge support from grants AYA2014-57490-P and JA-FQM-2828. Support for L.G. is provided by the Ministry of Economy, Development, and Tourism's Millennium Science Initiative through grant IC120009, awarded to The Millennium Institute of Astrophysics, MAS. L.G. acknowledges support by CONICYT through FONDECYT grant 3140566Peer Reviewe

Evidence for a mixed mass composition at the `ankle' in the cosmic-ray spectrum

We report a first measurement for ultra-high energy cosmic rays of the correlation between the depth of shower maximum and the signal in the water Cherenkov stations of air-showers registered simultaneously by the fluorescence and the surface detectors of the Pierre Auger Observatory. Such a correlation measurement is a unique feature of a hybrid air-shower observatory with sensitivity to both the electromagnetic and muonic components. It allows an accurate determination of the spread of primary masses in the cosmic-ray flux. Up till now, constraints on the spread of primary masses have been dominated by systematic uncertainties. The present correlation measurement is not affected by systematics in the measurement of the depth of shower maximum or the signal in the water Cherenkov stations. The analysis relies on general characteristics of air showers and is thus robust also with respect to uncertainties in hadronic event generators. The observed correlation in the energy range around the `ankle' at $\lg(E/{\rm eV})=18.5-19.0$ differs significantly from expectations for pure primary cosmic-ray compositions. A light composition made up of proton and helium only is equally inconsistent with observations. The data are explained well by a mixed composition including nuclei with mass $A > 4$. Scenarios such as the proton dip model, with almost pure compositions, are thus disfavoured as the sole explanation of the ultrahigh-energy cosmic-ray flux at Earth.Comment: Published version. Added journal reference and DOI. Added Report Numbe

Implications of early respiratory support strategies on disease progression in critical COVID-19: a matched subanalysis of the prospective RISC-19-ICU cohort.

Uncertainty about the optimal respiratory support strategies in critically ill COVID-19 patients is widespread. While the risks and benefits of noninvasive techniques versus early invasive mechanical ventilation (IMV) are intensely debated, actual evidence is lacking. We sought to assess the risks and benefits of different respiratory support strategies, employed in intensive care units during the first months of the COVID-19 pandemic on intubation and intensive care unit (ICU) mortality rates. Subanalysis of a prospective, multinational registry of critically ill COVID-19 patients. Patients were subclassified into standard oxygen therapy ≥10 L/min (SOT), high-flow oxygen therapy (HFNC), noninvasive positive-pressure ventilation (NIV), and early IMV, according to the respiratory support strategy employed at the day of admission to ICU. Propensity score matching was performed to ensure comparability between groups. Initially, 1421 patients were assessed for possible study inclusion. Of these, 351 patients (85 SOT, 87 HFNC, 87 NIV, and 92 IMV) remained eligible for full analysis after propensity score matching. 55% of patients initially receiving noninvasive respiratory support required IMV. The intubation rate was lower in patients initially ventilated with HFNC and NIV compared to those who received SOT (SOT: 64%, HFNC: 52%, NIV: 49%, p = 0.025). Compared to the other respiratory support strategies, NIV was associated with a higher overall ICU mortality (SOT: 18%, HFNC: 20%, NIV: 37%, IMV: 25%, p = 0.016). In this cohort of critically ill patients with COVID-19, a trial of HFNC appeared to be the most balanced initial respiratory support strategy, given the reduced intubation rate and comparable ICU mortality rate. Nonetheless, considering the uncertainty and stress associated with the COVID-19 pandemic, SOT and early IMV represented safe initial respiratory support strategies. The presented findings, in agreement with classic ARDS literature, suggest that NIV should be avoided whenever possible due to the elevated ICU mortality risk