An In Situ Evaluation of Different CAM Plants as Plant Microbial Fuel Cells for Energy Recovery in the Atacama Desert.

Excess energy derived from photosynthesis can be used in plant microbial fuel cell (PMFC) systems as a sustainable alternative for the generation of electricity. In this study, the in situ performance of CAM (Crassulacean acid metabolism) plants in Calama, in the Atacama Desert, was evaluated for energy recovery using PMFCs with stainless steel AISI 316L and Cu as electrodes. The plant species evaluated included Aloe perfoliata, Cereus jamacaru, Austrocylindropuntia subulata, Agave potatorum, Aloe arborescens, Malephora crocea, and Kalanchoe daigremontiana. Among the plant species, Kalanchoe daigremontiana demonstrated significant potential as an in situ PMFC, showing a maximum cell potential of 0.248 V and a minimum of 0.139 V. In addition, the cumulative energy for recovery was about 9.4 mWh m-2 of the electrode. The use of CAM plants in PMFCs presents a novel approach for green energy generation, as these plants possess an inherent ability to adapt to arid environments and water-scarce areas such as the Atacama Desert climate.

Corrosion of Reinforced A630-420H Steel in Direct Contact with NaCl Solution.

The deterioration of reinforced concrete structures in marine environments presents multiple problems due to the premature degradation of reinforced steel. This work aimed to study the corrosion of reinforced A630-420H steel when exposed to a 0.5 M NaCl solution. Although this carbon steel is the most widely used material for reinforced concrete structures in Chile, there is limited research on its resistance to corrosion when in contact with saline solutions. The electrochemical reactions and their roles in the corrosion rate were studied using linear sweep voltammetry, weight loss, scanning electron microscopy, and X-ray diffraction techniques. This analysis is unique as it used the superposition model based on mixed potential theory to determine the electrochemical and corrosion parameters. The outcomes of this study show that A630-420H steel has a higher corrosion rate than those of the other commercial carbon steels studied. This fact can be attributed to the competition between the cathodic oxygen reduction reaction and hydrogen evolution reaction, which also depends on the environmental conditions, exposure time, stabilization of the corrosion products layer, and presence of chloride ions. Additionally, the results under mechanical stress conditions show a brittle fracture of the corrosion product oriented longitudinally in the direction of the bend section, where the presence of pores and cracks were also observed. The corrosion products after corrosion were mainly composed of magnetite and lepidocrocite oxide phases, which is in concordance with the electrochemical results.

Cellular Automata Modeling as a Tool in Corrosion Management.

Cellular automata models have emerged as a valuable tool in corrosion management. This manuscript provides an overview of the application of cellular automata models in corrosion research, highlighting their benefits and contributions to understanding the complex nature of corrosion processes. Cellular automata models offer a computational approach to simulating corrosion behavior at the microscale, capturing the intricate interactions between electrochemical reactions, material properties, and environmental factors and generating a new vision of predictive maintenance. It reviews the key features of cellular automata, such as the grid-based representation of the material surface, the definition of state variables, and the rules governing cell-state transitions. The ability to model local interactions and emergent global behavior makes cellular automata particularly suitable for simulating corrosion processes. Finally, cellular automata models offer a powerful and versatile approach to studying corrosion processes, expanding models that can continue to enhance our understanding of corrosion and contribute to the development of effective corrosion prevention and control strategies.

Metal Recovery from Natural Saline Brines with an Electrochemical Ion Pumping Method Using Hexacyanoferrate Materials as Electrodes.

The electrochemical ion pumping device is a promising alternative for the development of the industry of recovering metals from natural sources-such as seawater, geothermal water, well brine, or reverse osmosis brine-using electrochemical systems, which is considered a non-evaporative process. This technology is potentially used for metals like Li, Cu, Ca, Mg, Na, K, Sr, and others that are mostly obtained from natural brine sources through a combination of pumping, solar evaporation, and solvent extraction steps. As the future demand for metals for the electronic industry increases, new forms of marine mining processing alternatives are being implemented. Unfortunately, both land and marine mining, such as off-shore and deep sea types, have great potential for severe environmental disruption. In this context, a green alternative is the mixing entropy battery, which is a promising technique whereby the ions are captured from a saline natural source and released into a recovery solution with low ionic force using intercalation materials such as Prussian Blue Analogue (PBA) to store cations inside its crystal structure. This new technique, called "electrochemical ion pumping", has been proposed for water desalination, lithium concentration, and blue energy recovery using the difference in salt concentration. The raw material for this technology is a saline solution containing ions of interest, such as seawater, natural brines, or industrial waste. In particular, six main ions of interest-Na+, K+, Mg2+, Ca2+, Cl-, and SO42--are found in seawater, and they constitute 99.5% of the world's total dissolved salts. This manuscript provides relevant information about this new non-evaporative process for recovering metals from aqueous salty solutions using hexacianometals such as CuHCF, NiHCF, and CoHCF as electrodes, among others, for selective ion removal.

Ultrafine Kaolinite Removal in Recycled Water from the Overflow of Thickener Using Electroflotation: A Novel Application of Saline Water Splitting in Mineral Processing.

The presence of ultrafine clay particles that are difficult to remove by conventional filtration creates many operational problems in mining processing systems. In this work, the removal of clay suspensions has been investigated using an electroflotation (EF) process with titanium electrodes. The results show that EF is a viable and novel alternative for removing ultrafine particles of kaolinite-type clay present in sedimentation tank overflows with low salt concentrations (<0.1 mol/L) in copper mining facilities based on the saline water splitting concept. Maximum suspended solid removal values of 91.4 and 83.2% in NaCl and KCl solutions, respectively, were obtained under the experimental conditions of the constant applied potential of 20 V/SHE, salinity concentration of 0.1 mol/L, and electroflotation time of 10 and 20 min in NaCl and KCl solutions, respectively. Furthermore, the visual evidence of particle aggregation by flocculation during the experiments indicates a synergy between EF and electrocoagulation (EC) that enhances the removal of ultrafine particles of kaolinite.

Corrosion of Titanium Electrode Used for Solar Saline Electroflotation.

The solar electroflotation (EF) processes using saline electrolytes are today one of the great challenges for the development of electrochemical devices, due to the corrosion problems that are generated during the operation by being in permanent contact with Cl- ions. This manuscript discloses the corrosion behavior of titanium electrodes using a superposition model based on mixed potential theory and the evaluation of the superficial performance of the Ti electrodes operated to 4 V/SHE solar electroflotation in contact with a solution of 0.5 M NaCl. Additionally provided is an electrochemical analysis of Ti electrodes regarding HER, ORR, OER, and CER that occur during the solar saline EF process. The non-linear superposition model by mixed potential theory gives electrochemical and corrosion parameters that complement the information published in scientific journals, the corrosion current density and corrosion potential in these conditions is 0.069 A/m2 and -7.27 mV, respectively. The formation of TiO2 and TiOCl on the anode electrode was visualized, resulting in a reduction of its weight loss of the anode electrode.

Bioleaching Modeling-A Review.

The leaching of minerals is one of the main unit operations in the metal dissolution process, and in turn it is a process that generates fewer environmental liabilities compared to pyrometallurgical processes. As an alternative to conventional leaching methods, the use of microorganisms in mineral treatment processes has become widespread in recent decades, due to advantages such as the non-production of emissions or pollution, energy savings, low process costs, products compatible with the environment, and increases in the benefit of low-grade mining deposits. The purpose of this work is to introduce the theoretical foundations associated with modeling the process of bioleaching, mainly the modeling of mineral recovery rates. The different models are collected from models based on conventional leaching dynamics modeling, based on the shrinking core model, where the oxidation process is controlled by diffusion, chemically, or by film diffusion until bioleaching models based on statistical analysis are presented, such as the surface response methodology or the application of machine learning algorithms. Although bioleaching modeling (independent of modeling techniques) of industrial (or large-scale mined) minerals is a fairly developed area, bioleaching modeling applied to rare earth elements is a field with great growth potential in the coming years, as in general bioleaching has the potential to be a more sustainable and environmentally friendly mining method than traditional mining methods.

Estructura factorial del Cuestionario de Experiencias Relacionadas con Internet en universitarios chilenos / Factorial structure of the Questionnaire of Experiences Related with Internet on Chilean university students

Resumen El uso de Internet está masificado en casi todo el mundo. Existe evidencia de que su uso excesivo tiene consecuencias negativas, por lo que es necesario contar con instrumentos que evalúen su uso. El Cuestionario de Experiencias Relacionadas con Internet (CERI) es un instrumento de dos factores que evalúan conflictos (intrapersonales e interpersonales) asociados a su uso excesivo. Estudios realizados en distintas partes del mundo han utilizado este instrumento sin analizar sus propiedades psicométricas con la suficiente profundidad y han privilegiado el uso del puntaje total en lugar del puntaje de los dos factores. Por esta razón, en este artículo se evalúan las propiedades psicométricas del instrumento en población chilena. Se realizaron dos estudios en los que participaron un total de 626 estudiantes universitarios (180 en el estudio 1 y 446 en el estudio 2) que respondieron el CERI y un cuestionario de abuso del teléfono móvil. En el estudio 1 se realizó un análisis factorial exploratorio que sugirió seleccionar la estructura unifactorial en lugar de la estructura bifactorial original, aunque ambas presentaban adecuada validez convergente (relaciones directas con el abuso del teléfono móvil). En el estudio 2 se realizó un análisis factorial confirmatorio y ambas estructuras factoriales presentaron buen ajuste, pero la consistencia interna del factor único fue mayor que la de los dos factores originales. Es necesario continuar evaluando la estructura factorial del CERI en orden a determinar cuál es la mejor alternativa factorial, mientras tanto la estructura unifactorial parece entregar mayores garantías psicométricas.

Abstract A large proportion of the world's population has access to the Internet. On the one hand this has brought undeniable benefits to society by facilitating access to information. But on the other hand, the excessive use of the Internet has also brought with it a series of new problems ranging from physical injuries (for example: tendinitis), psychological pathologies (for example: Internet addiction) to new forms of crime (for example: online sexual abuse). For this reason, it is necessary to have reliable and valid instruments that evaluate the use and abuse of the Internet. The Internet Related Experiences Questionnaire (CERI) has two factors that evaluate conflicts (intrapersonal factor, with 6 items and interpersonal factor, with 4 items) associated with excessive use of the Internet. Studies in different parts of the world (Spain, Chile and other Latin American countries) have used this instrument without analyzing its psychometric properties with sufficient depth. These studies have mostly used the total CERI score (10 items) instead of the two-factor structure, but they have not justified this choice. For this reason, this paper intends to analyze the factorial structure of the instrument, its convergent validity and its internal consistency in the Chilean population. We conducted two researches in which participated a total of 626 university students (180 in the study 1, and 446 in the study 2). The participants responded to the CERI and a questionnaire of abuse of the mobile phone (CERM). In the study 1, the results of exploratory factor analyzes suggest to use a unifactorial structure which included the 10 items, instead of the original bifactorial structure. In particular, in the bifactorial structure item 1 was not included in any factor (factorial loads less than .2), two items (items 5 and 10) presented similar factor loads in both factors and other two items (items 8 and 9) were included in the factor that it did not correspond. The single factor was greater internal consistency than that of the original intrapersonal and interpersonal factors (Cronbach´s alpha of .78, .68 and .56, respectively). Although both alternatives have adequate convergent validity (direct relations with mobile phone abuse). In study 2, a confirmatory factorial analysis was carried out in order to compare the unifactorial structure obtained in study 1 with the bifactorial structure of the original study. The results show that both factorial structures presented good fit, but again the internal consistency of the single factor was greater than that of the original intrapersonal factor and interpersonal factor (Cronbach´s alpha of .74, .61 and .51 respectively). The low reliability of interpersonal and intrapersonal factors may be due to the few number of items grouped in them (4 and 6 respectively). It is necessary to continue evaluating the factorial structure of the CERI in order to determine which is the best factorial alternative or if it is necessary to increase the number of items of interpersonal and intrapersonal factors. Although the results are not conclusive, for the moment, it seems advisable to use the one factor structure as it seems to give further psychometric guarantees.