Influence of operating temperature on the activation efficiency of Li-ion cells with xLi2MnO3-(1-x)LiMn0.5Ni0.5O2 electrodes

In this study, the effect of operating temperature at 55 °C on xLi2MnO3-(1-x)LiMn0.5Ni0.5O2 electrodes during the charge/discharge process at different current densities was investigated. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used for structural and morphological analysis of the fabricated cathode materials, while charge-discharge curves and differential capacity were used to study the electrochemical behavior. Results confirm the formation of the structures with two phases associated with the components of the layered material. It was found that at 55 °C, a capacity higher than 357 mAh g-1 could be achieved at a voltage of 2.5-4.8 V vs. Li/Li+, which was larger than the capacity achieved at room temperature. At 55 °C, a change in valence could be observed during charging and discharging due to the change in the position of the peaks associated with Mn and Ni, highlighting cathodic material with x = 0.5 as the material that retains the layered structure at this temperature. This work confirms the good performance of electrodes made with this material at elevated temperatures and gives a better understanding of its electrochemical behavior

Effect of x on the Electrochemical Performance of Two-Layered Cathode Materials xLi2MnO3–(1−x)LiNi0.5Mn0.5O2

In our study, the cathodic material xLi2MnO3–(1−x)LiNi0.5Mn0.5O2 was synthesized by means of the co-precipitation technique. The effect of x (proportion of components Li2MnO3 and LiNi0.5Mn0.5O2) on the structural, morphological, and electrochemical performance of the material was evaluated. Materials were structurally characterized using X-ray diffraction (XRD), and the morphological analysis was performed using the scanning electron microscopy (SEM) technique, while charge–discharge curves and differential capacity and impedance spectroscopy (EIS) were used to study the electrochemical behavior. The results confirm the formation of the structures with two phases corresponding to the rhombohedral space group R3m and the monoclinic space group C2/m, which was associated to the components of the layered material. Very dense agglomerations of particles between 10 and 20 µm were also observed. In addition, the increase in the proportion of the LiNi0.5Mn0.5O2 component affected the initial irreversible capacity and the Li2MnO3 layer’s activation and cycling performance, suggesting an optimal chemical ratio of the material’s component layers to ensure high energy density and long-term durability

Microbial biosensors for wastewater monitoring: mini-review

Research on the use of microbial biosensors for monitoring wastewater contaminants is a topic that covers few publications compared to their applicability in other fields, such as biomedical research. For this reason, a systematic analysis of the topic was carried out, for which research-type articles were reviewed during the period 2012 to September 2022. For this, different search platforms were used, including PubMed, ScienceDirect, Springer Link, and Scopus, and through the use of search equations a relevant bibliography was located. After that, the research articles were selected based on exclusion criteria. As a result, it was found that, of the 126 articles, only 16 articles were strictly related to the topic, since there was a duplication of articles among the different databases. It was possible to demonstrate the usefulness of microorganisms as components of biosensors to monitor BOD, heavy metals, and inorganic contaminants in wastewater that also had a high sensitivity. Additionally, recombinant DNA techniques were shown to improve the performance of this type of biosensor and can finally be coupled to other emerging technologies, such as microbial fuel cells (MFCs). In conclusion, it was established that microbial biosensors have high acceptability and monitoring characteristics that make them a useful tool to detect low concentrations of pollutants in wastewater that can also provide results in real-time, thus generating forms of ecological safety and social responsibility in companies where wastewater is generated.Campus Trujill

Generation of bioelectricity from organic fruit waste

This research proposes an alternative for companies and farmers through the production of electricity using microbial fuel cells (MFCs) using waste from export products. Nine MFCs were manufactured with zinc and copper electrodes; and as substrates, pineapple, potato and tomato pulp wastes were used in the anode chamber, and residual sludge in the cathode chamber. It was observed that the MFCs with pineapple substrate generated higher values of the electrical parameters, resulting in voltage and current values of 0.3484 ± 0.003 V and 27.88 ± 0.23 mA, respectively. It was also observed that the maximum power density was 0.967 ± 0.059 W/cm2 at a current density of 0.04777 A/cm2 for the same substrate. Acid pH values were observed in the three samples, while the conductivity reached its maximum value on day 23 (69.47 ± 0.91 mS/cm) which declined until the last day of monitoring; the turbidity values increased abruptly after day 22 until the last day where a value of 200.3 ± 2.52 UNT was observed for the pineapple substrate. The scanning electron microscopy for the pineapple substrate MFC electrodes shows the formation of a porous biofilm on the zinc and copper electrodes. These results show that a new form of electricity production has been achieved by generating high voltage and current values, using low-cost materials

Electric current generation by increasing sucrose in papaya waste in microbial fuel cells

The accelerated increase in energy consumption by human activity has generated an increase in the search for new energies that do not pollute the environment, due to this, microbial fuel cells are shown as a promising technology. The objective of this research was to observe the influence on the generation of bioelectricity of sucrose, with different percentages (0%, 5%, 10% and 20%), in papaya waste using microbial fuel cells (MFCs). It was possible to generate voltage and current peaks of 0.955 V and 5.079 mA for the cell with 20% sucrose, which operated at an optimal pH of 4.98 on day fifteen. In the same way, the internal resistance values of all the cells were influenced by the increase in sucrose, showing that the cell without sucrose was 0.1952 ± 0.00214 KΩ and with 20% it was 0.044306 ± 0.0014 KΩ. The maximum power density was 583.09 mW/cm2 at a current density of 407.13 A/cm2 and with a peak voltage of 910.94 mV, while phenolic compounds are the ones with the greatest presence in the FTIR (Fourier transform infrared spectroscopy) absorbance spectrum. We were able to molecularly identify the species Achromobacter xylosoxidans (99.32%), Acinetobacter bereziniae (99.93%) and Stenotrophomonas maltophilia (100%) present in the anode electrode of the MFCs. This research gives a novel use for sucrose to increase the energy values in a microbial fuel cell, improving the existing ones and generating a novel way of generating electricity that is friendly to the environment.Campus Trujill

Impact of Dragon Fruit Waste in Microbial Fuel Cells to Generate Friendly Electric Energy

Pollution generated by the misuse of large amounts of fruit and vegetable waste has become a major environmental and social problem for developing countries due to the absence of specialized collection centers for this type of waste. This research aims to generate electricity in an eco-friendly way using red dragon fruit (pitahaya) waste as the fuel in single-chamber microbial fuel cells on a laboratory scale using zinc and copper electrodes. It was possible to generate voltage and current peaks of 0.46 ± 0.03 V and 2.86 ± 0.07 mA, respectively, with an optimum operating pH of 4.22 ± 0.09 and an electrical conductivity of 175.86 ± 4.72 mS/cm at 8 °Brix until the tenth day of monitoring. An internal resistance of 75.58 ± 5.89 Ω was also calculated with a maximum power density of 304.33 ± 16.51 mW/cm2 at a current density of 5.06 A/cm2, while the FTIR spectra showed a decrease in the initial compounds and endings, especially at the 3331 cm−1 peaks of the O–H bonds. Finally, the yeast-like fungus Geotrichum candidum was molecularly identified (99.59%). This research will provide great opportunities for the generation of renewable energy using biomass as fuel through electronic devices with great potential to generate electricity

Electric power generation through dairy waste in microbial fuel cells

El aumento de la población humana a generado que el consumo de diferentes tipos de lácteos aumente también, debido a que es uno de los principales alimentos en la dieta en la vida temprana de cada ser humano. Esto a generado que los desechos de este tipo de alimento aumenten de la misma forma, motivo por el cual se ha buscado una forma de utilizarlo ecoamigalemente, encontrado en las celdas de combustible microbiana una forma de generar energía eléctrica de manera sostenible. En esta investigación se utilizó desechos de leche como combustible en celdas de combustible microbiana a escala de laboratorio, logrando generar picos de corriente eléctrica y voltaje de 4.125 ± 0.347 mA y 1.104 ± 0.101 V con pH óptimo de operación de 7.46 ± 0.35 cuya conductividad eléctrica del sustrato fue de 119.373 ± 4.59 mS/cm, todo esto en el día 21. Así mismo se calculó la densidad de potencia máxima en 443.765 ± 26.738 mW/cm2 con una densidad de corriente de 5.257 A/cm2 y mostrando un voltaje de 1005.78 ± 13.54 mV, todo esto operando con una resistencia interna de61.795 ± 8.691 Ω . Por ultimo las tres celdas de combustible microbiana se conectaron en serie, logrando generar 2.66 V lo suficiente para encender un foco LED de color rojo. De esta forma se da una novedosa forma de generar corriente eléctrica a pequeña escala, dando grandes esperanzas a las empresas ganaderas para reutilizar sus residuos en forma beneficiosas para ellas mismas

Biodegradable potato starch films reinforced with aqueous extract of mango skin for use as active packaging [Películas biodegradables de almidón de papa reforzadas con extracto acuoso de piel de mango para su uso como envase activo]

En este trabajo se presenta el estudio del efecto de la incorporación de extracto acuoso de piel de mango (EPM) sobre las propiedades de películas biodegradables fabricadas a partir de almidón de papa y comprobar su potencial para ser usado como envase activo. El EPM fue añadido en el proceso de gelatinización en concentraciones de 5, 10 y 15% wt. Las propiedades de las películas fabricadas fueron caracterizadas usando Microscopía Electrónica de Barrido (MEB), Espectroscopía FTIR, cinética de absorción de agua y curvas Esfuerzo-Deformación. Las micrografías MEB muestran una formación con una superficie más lisa, sin vacíos ni grietas en las películas con EPM. Los análisis FTIR confirman la formación de bioplástico de almidón por la presencia de los grupos funcionales O-H, C-H, C-O y O=H. Por otro lado, se confirma que al añadir EPM se logra un aumento en la rigidez de las películas, pero una disminución en la elasticidad, sin embargo, no se afecta la capacidad de absorber agua. Este trabajo destaca los beneficios del uso de los residuos agrícolas y su potencial para la fabricación de materiales que podrían ser usados en la industria alimentaria como envase activo.In this work, the study of the effect of the incorporation of aqueous extract of mango skin (EPM) on the properties of biodegradable films made from potato starch is presented and its potential to be used as active packaging is presented. The EPM was added in the gelatinization process in concentrations of 5, 10 and 15% wt. The properties of the manufactured films were characterized using Scanning Electron Microscopy (SEM), FTIR Spectroscopy, water absorption kinetics and Stress-Strain curves. SEM micrographs show a formation with a smoother surface, without voids or cracks in EPM films. The FTIR analyzes confirm the formation of starch bioplastic by the presence of the functional groups O-H, C-H, C-O and O = H. On the other hand, it is confirmed that by adding EPM an increase in the stiffness of the films is achieved, but a decrease in elasticity, however, the ability to absorb water is not affected. This work highlights the benefits of the use of agricultural residues and its potential for the manufacture of materials that could be used in the food industry as active packaging

Effect of Inoculum Concentration on the Degradation of Diesel 2 by a Microbial Consortium

The objective was to determine the effect of inoculum concentration on the degradation of Diesel 2 by a microbial consortium called BIOT.PD001. For this, five systems were designed (in triplicate), which Contained Davis Minimum Medium, 5% Diesel 2 as a carbon source, and a suspension of the microbial consortium BIOT.PD001 (9 × 108 cells/mL) in concentrations of 2, 4, 6, 8, and 10% of the final volume. The monitoring of the degradation of Diesel 2 was carried out indirectly through the bacterial counts by the plate count method, the Biochemical Oxygen Demand (BOD5) by the Winkler Method modified according to Alsterberg, and the concentration of total fats by Gerber’s method. The retention time was 15 days. It was observed that the percentage of efficiency of the process increases as the concentration of inoculum increases, obtaining the highest percentage of efficiency (94.77%) when using 10% of inoculum (v/v), while when using inoculum concentrations of 2 and 4% (v/v), the efficiency percentages are the lowest, (68.4 and 66.6%, respectively). On the other hand, the variance analysis indicated that there is a significant difference between the averages of these values. The regression analysis indicated that the inoculum concentration significantly affects the efficiency of Diesel 2 degradation and that this is 86% explained by a linear regression model. There is a linear relationship between the inoculum concentration of the BIOT.PD001 microbial consortium and the BOD5 tend to decrease as a function of time. It is concluded that the inoculum concentration significantly affects the efficiency of the degradation of Diesel 2 by the BIOT.PD001 consortium

Electric Current Generation by Increasing Sucrose in Papaya Waste in Microbial Fuel Cells

The accelerated increase in energy consumption by human activity has generated an increase in the search for new energies that do not pollute the environment, due to this, microbial fuel cells are shown as a promising technology. The objective of this research was to observe the influence on the generation of bioelectricity of sucrose, with different percentages (0%, 5%, 10% and 20%), in papaya waste using microbial fuel cells (MFCs). It was possible to generate voltage and current peaks of 0.955 V and 5.079 mA for the cell with 20% sucrose, which operated at an optimal pH of 4.98 on day fifteen. In the same way, the internal resistance values of all the cells were influenced by the increase in sucrose, showing that the cell without sucrose was 0.1952 ± 0.00214 KΩ and with 20% it was 0.044306 ± 0.0014 KΩ. The maximum power density was 583.09 mW/cm2 at a current density of 407.13 A/cm2 and with a peak voltage of 910.94 mV, while phenolic compounds are the ones with the greatest presence in the FTIR (Fourier transform infrared spectroscopy) absorbance spectrum. We were able to molecularly identify the species Achromobacter xylosoxidans (99.32%), Acinetobacter bereziniae (99.93%) and Stenotrophomonas maltophilia (100%) present in the anode electrode of the MFCs. This research gives a novel use for sucrose to increase the energy values in a microbial fuel cell, improving the existing ones and generating a novel way of generating electricity that is friendly to the environment