Influence of chemical reaction kinetics on electrokinetic remediation modelling results

A numerical model describing transport of multiple species and chemical reactions during electrokinetic treatment is presented. The transport mechanisms included in the model were electromigration and electroosmosis. The chemical reactions taken into account were water electrolysis at the electrodes, aqueous species complexation, precipitation, and dissolution. The model was applied to simulate experimental data from an acid-enhanced electrokinetic treatment of a Pb-contaminated calcareous soil. The kinetics of the main pH buffering process (i.e., calcite dissolution) was taken into account and its time-dependent behavior was described by a rate law. The influence of kinetics was evaluated by comparing the results from a set of simulations in which calcite dissolution was implemented considering thermodynamic equilibrium and another set in which the same reaction was described by the rate law. The results show that the prediction capability of the model significantly improves when the kinetic rate is taken into account.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Effectiveness of conventional drinking water treatment in the removal of polycyclic aromatic hydrocarbons

The presence of recalcitrant organic pollutants, such as polycyclic aromatic hydrocarbons (PAHs) in aquatic environments poses a threat to the human health. According to recent studies, PAHs, such as benz[a]anthracene and phenanthrene, has been found in untreated drinking water. Hence, the removal of these contaminants through conventional treatment processes should be carefully evaluated. In this work, levels of selected PAHs in drinking water have been monitored during conventional treatment processes. The simulation of a full-scale Potable Water Treatment Plant (PWTP) located in the south of Spain was carried out using jar tests, a widely accepted tool in water treatment. The quantification of PAH concentration in drinking waterwas carried out using gas chromatography coupled with mass spectrometry.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Removal of polycyclic aromatic hydrocarbons (PAHs) in conventional drinking water treatment processes

Authors acknowledge the Central Laboratory of EMASA for the facilities provided to carry out the research. M. Villen-Guzman acknowledges the postdoctoral fellowship obtained from Universidad de Malaga, Spain. Funding for open access charge: Universidad de Malaga / CBUA, Spain.The presence of polycyclic aromatic hydrocarbons (PAHs) in water poses a serious threat to the human health due to their toxic effects. Therefore, the removal of these compounds from drinking water in Potable Water Treatment Plants (PWTPs) should be evaluated and optimized to assure the quality of water intended for human consumption. In this work, changes in PAHs levels during drinking water treatment processes have been monitored to evaluate the effectiveness of conventional processes in the removal of these recalcitrant pollutants. Several chemical treatment methods based on the addition of KMnO4, FeCl3 and NaClO were evaluated through jar tests. The analysis of PAH content of aqueous samples was carried out by gas chromatography coupled with mass spectrometry. The highest removal efficiency, over 90%, was obtained for benzo(a)anthracene, benzo(a) pyrene and dibenzo(a,h)anthracene. The most recalcitrant compounds to degradation were fluorene, anthracene, phenanthrene and flouranthene with reduction rates between 45 and 57%. The conventional treatment processes assessed have been proved to be effective reducing the PAH below the legal limits of drinking water quality. The definition of a parameter based on chemical properties of PAHs, i.e., sorption capacity and energy required to remove an electron, enabled the prediction of removal rate of pollutants which represents a valuable information for the plant operation.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Life cycle assessment of aluminium cans and glass bottles

In this work, we present a simplified LCA on two commom products: an aluminum can and a glass bottle, both containing the same amoung of beverage (1/3 L of beer). The work presented here seeks to find out which option would be less harmful to the environment by studying the CO2 emissions produced by each container using a combined the cradle-to-cradle and cradle-to-grave approach, based on the current recycling rates in Spain. The functional unit is set to 1 m3 of beer, and the target consumer is someone purchasing beer at a supermarket. Therefore, according to the current waste management system in Spain, glass bottles are considered not reusable: This means that they are either disposed to landfill or deposited to the glass container for recycling. Recycling of glass would involve using the glass as raw material to produced new bottles. The free to use database IDEMAT has been used in the work presented here to obtain the data necessary for the Life Cycle Inventory. The results indicate that purchasing beer in aluminiun cans have a lower environmental impact than non-reusable glass bottles. The main reason related to this results are the lower transport emissions related to the cans due to the lower weight. This means that, for the same amount of beer, the energy required to transport the bottles is higher than the cans, and therefore the CO2 emissions are also higher. Additionally, aluminium is 100% and infinitely recyclable, while glass bottles made of recycled glass still need a certain intake of new raw material (of around 40%). The results presented here do not contemplate the posiblity to clean and reuse the bottles, which is expected to have a lower environmental footprint that the two scenarios discussed here.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Technical analysis of CO2 capture pathways and technologies

The reduction of CO2 emissions to minimize the impact of the climate change has become a global priority. The continuous implementation of renewable energy sources increases energy efficiency, while the reduction of CO2 emissions opens new options for carbon capture technologies to reduce greenhouse gases emissions. The combination of carbon capture with renewable energy balancing production offers excellent potential for fuels and chemical products and can play an essential role in the future energy system. This paper includes a critical review of the state of the art of different CO2 capture engineering pathways and technologies including a techno-economics analysis and focusing on comparing these technologies depending on the final CO2 application. The current cost for CO2 capture is in the range of 60–110 USD/t, likely to halve by 2030. This review offers technical information to select the most appropriate technology to be used in specific processes and for the different carbon capture pathways, i.e., Pre-combustion, Post-Combustion and Direct Air Capture. This comparison includes the CO2 capture approach for biomethane production by biogas upgrading to substitute fossil natural gas and other alternatives fuels production routes which will be introduces in future works performed by this review authors.Funding for open access charge: Universidad de Málaga / CBUA

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

Alternative reducing agents for Lithium-Ion batteries recycling via hydrometallurgical process

Lithium-ion batteries (LIB) are a key factor in the transition to a decarbonised and clean energy system due to their application in the power sector and electric transport. However, a growing demand of these batteries involves two direct problems: an increase in the generation of spent LIBs as well as in the demand of raw materials. Hence, the development of efficient recycling treatment of LIBs is crucial to make them a true enabler of the green transition. Currently, the LIBs recycling process can be divided into pyrometallurgical and hydrometallurgical. The first one is based on the treatment of LIBs at high temperatures to produces metal pyrolysis and metal reduction, while the second method consists in the recovery of metals via acidic leaching. Although pyrometallurgical method is the most used in the industry, hydrometallurgical process presents a series of advantages, such as low energy consumption, high metal recovery and high product purity, that make it more promising in the search of more effective recycling method. In the hydrometallurgical process, the addition of acids and reducing agents is required to dissolve the solid particles and extract the valuable metals. The purpose of this work was to evaluate the effect of alternative reducing agent in the leaching process to maximize the amount of metal (Mn, Li, Ni, Co) recovered from a real LIBs waste. With this aim, the leaching processes were carried out using as reducing agent H2O2, Fe and NH4Cl. According to the experimental results, Fe and NH4Cl enhance the extraction yield as well as the reaction time comparing with the results obtain using H2O2.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Hydrometallurgical extraction of Li and Co from LiCoO2 particles–Experimental and Modeling

The use of lithium-ion batteries as energy storage in portable electronics and electric vehicles is increasing rapidly, which involves the consequent increase of battery waste. Hence, the development of reusing and recycling techniques is important to minimize the environmental impact of these residues and favor the circular economy goal. This paper presents experimental and modeling results for the hydrometallurgical treatment for recycling LiCoO2 cathodes from lithium-ion batteries. Previous experimental results for hydrometallurgical extraction showed that acidic leaching of LiCoO2 particles produced a non-stoichiometric extraction of lithium and cobalt. Furthermore, the maximum lithium extraction obtained experimentally seemed to be limited, reaching values of approximately 65–70%. In this paper, a physicochemical model is presented aiming to increase the understanding of the leaching process and the aforementioned limitations. The model describes the heterogeneous solid–liquid extraction mechanism and kinetics of LiCoO2 particles under a weakly reducing environment. The model presented here sets the basis for a more general theoretical framework that would describe the process under different acidic and reducing conditions. The model is validated with two sets of experiments at different conditions of acid concentration (0.1 and 2.5 M HCl) and solid to liquid ratio (5 and 50 g L−1). The COMSOL Multiphysics program was used to adjust the parameters in the kinetic model with the experimental results.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 financial support from the program “Proyectos I+D+i en el marco del Programa Operativo FEDER Andalucía 2014–2020”, No. UMA18-FEDERJA-279. Cerrillo-Gonzalez acknowledges the FPU grant obtained from the Spanish Ministry of Education. The University of Malaga is acknowledged for the financial support in the postdoctoral fellowship of Villen-Guzman

Acid leaching of LiCoO2 enhanced by reducing agent. Model formulation and validation.

In this work, a model has been formulated to describe the complex process of LiCoO2 leaching through the participation of competing reactions in acid media including the effect of H2O2 as reducing agent. The model presented here describes the extraction of Li and Co in the presence and absence of H2O2, and it takes into account the different phenomena affecting the controlling mechanisms. In this context, the model predicts the swift from kinetic control to diffusion control. The model has been implemented and solved to simulate the leaching process. To validate the model and to estimate the model parameters, a set of 12 (in triplicate) extraction experiments were carried out varying the concentration of hydrochloric acid (within the range of 0.5–2.5 M) and hydrogen peroxide (range 0–0.6%v/v). The simulation results match fairly well with the experimental data for a wide range of conditions. Furthermore, the model can be used to predict results with different solid-liquid ratios as well as different acid and oxygen peroxide concentrations. This model could be used to design or optimize a LiCoO2 extraction process facilitating the corresponding economical balance of the treatment.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 and the “Proyectos I+D+i en el marco del Programa Operativo FEDER Andalucía 2014–2020”, Project no. UMA18-FEDERJA-279. Cerrillo-Gonzalez acknowledges the FPU grant (FPU18/04295) obtained from the Spanish Ministry of Education. Funding for open access charge: Universidad de Málaga / CBUA