7 research outputs found
Producción de bioelectricidad utilizando nanofibras duales de TiO2/carbón como electrodo de una celda de combustible microbiana
RESUMEN
En este trabajo se presenta el desarrollo de un novedoso material compuesto por redes de nanofibras duales de TiO2(rutilo)-C(semigrafito)/C(semigrafito), con interesantes características morfológicas y propiedades eléctricas. Los resultados obtenidos de voltamperometría cíclica (CV), espectroscopía de impedancia electroquímica (IES) y conductividad eléctrica demuestran que este material cuenta con las características necesarias para aplicarse como ánodo en una celda de combustible microbiana. La morfología de este material fue comprobada por microscopía electrónica de barrido (SEM), microscopía electrónica de transmisión (TEM), mientras que la composición química de las nanofibras fue claramente observada por espectroscopía de energía dispersiva de rayos X (EDXS), y su análisis cristalográfico se llevó a cabo por difracción de rayos X (DRX) y difracción de electrones de área selecta (SAED). Este material nanoestructurado con alta área superficial es biocompatible y puede hospedar una densa biopelícula de E. coli K12 electroactivadas. El desempeño del electrodo anódcio se evaluó por amperometría, y se generó biocatalíticamente una densidad de corriente de 800 mA/cm2.
ABSTRACT
In summary, we present a novel material composed of dual nanofibers of TiO2(rutile)-C(semi-graphitic)/C(semi-graphitic) with interesting morphological and electrical properties. Based on the results obtained by cyclic voltammetry (CV), Electrochemical Impedance Spectroscopy (EIS) analyses and electrical conductivity, it was shown that the material is suitable for application as the anodic material in a microbial fuel cell. Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) confirmed the morphology of these materials; while the difference in composition between the fibers forming the dual fibers was clearly observed by Energy Dispersive X-Ray Spectroscopy (EDXS), and the crystallinity of nanofibers was evident in the results obtained from the X-Ray Diffraction (XRD) and Selected Area Electron Diffraction (SAED) studies.
This nanostructured material with high superficial area is biocompatible and can host a dense biofilm of electroactivated E. coli. The anodic electrode performance was evaluated by cronoamperometry. The maximum current density obtained in these conditions was 800 mA/cm2
Metal-Induced Production of a Novel Bioadsorbent Exopolysaccharide in a Native Rhodotorula mucilaginosa from the Mexican Northeastern Region
There is a current need to develop low-cost strategies to degrade and eliminate industrially
used colorants discharged into the environment. Colorants discharged into natural water
streams pose various threats, including: toxicity, degradation of aesthetics and inhibiting
sunlight penetration into aquatic ecosystems. Dyes and colorants usually have complex aromatic
molecular structures, which make them very stable and difficult to degrade and eliminate
by conventional water treatment systems. The results in this work demonstrated that
heavy metal-resistant Rhodotorula mucilaginosa strain UANL-001L isolated from the northeast
region of Mexico produce an exopolysaccharide (EPS), during growth, which has colorant
adsorption potential. The EPS produced was purified by precipitation and dialysis and
was then physically and chemically characterized by Scanning Electron Microscopy, Fourier
Transform Infrared Spectroscopy, and chemical elemental analysis. Here, the ability of the
purified EPS produced to adsorb methylene blue (MB), which served as a model colorant, is
studied. MB adsorption by the EPS is found to follow Langmuir Adsorption Isotherm kinetics
at 25°C. Further, by calculating the Langmuir constant the adsorption capabilities of the EPS
produced by the Rhodotorula mucilaginosa strain UANL-001L is compared to that of other
adsorbents, both, microbially produced and from agroindustrial waste. The total adsorption
capacity of the EPS, from the Rhodotorula mucilaginosa strain UANL-001L, was found to be
two-fold greater than the best bioadsorbents reported in the literature. Finally, apart from
determining which heavy metals stimulated EPS production in the strain, the optimal conditions
of pH, heavy metal concentration, and rate of agitation of the growing culture for EPS production, was determined. The EPS reported here has the potential of aiding in the efficient
removal of colorants both in water treatment plants and in situ in natural water streams
Aplicaciones de la nanotecnología en fuentes alternas de energía
La nanotecnología ha recibido mucha atención en los últimos años, y en consecuencia ha generado expectativas que van más allá del ámbito académico. Su capacidad única de fabricar estructuras novedosas ha derivado en la creación de materiales y dispositivos con un gran potencial de aplicaciones en diferentes áreas del conocimiento. Entre éstas destaca el sector energético, en virtud de la necesidad de nuevas tecnologías que permitan sostener el creciente consumo de energía eléctrica a nivel mundial, y al mismo tiempo sean amigables con el medio ambiente. En este sentido, las celdas solares surgen como un dispositivo prometedor para la generación de energía limpia a través del uso de recursos alternos. El presente artículo tiene como finalidad el mostrar un panorama general de la aplicación de las nanoestructuras en el desarrollo de celdas solare
Nuevos materiales anódicos para la generación de bioelectricidad en celdas de combustible microbianas
Con la intención de contribuir al desarrollo de nuevas tecnologías para la energía alternativa, en este trabajo se expone un estudio sobre el desarrollo de redes de nanofibras duales, cuya composición y metodología de formación son estrategias fundamentales para el desarrollo de biopelículas exoelectrogénicas sobre su superficie, lo que favorece el proceso de bioconversión de un sustrato químico a electricidad
A Comparative and Critical Analysis for In Vitro Cytotoxic Evaluation of Magneto-Crystalline Zinc Ferrite Nanoparticles Using MTT, Crystal Violet, LDH, and Apoptosis Assay
Zinc ferrite nanoparticles (ZFO NPs) are a promising magneto-crystalline platform for nanomedicine-based cancer theranostics. ZFO NPs synthesized using co-precipitation method are characterized using different techniques. UV-visible spectroscopy exhibits absorption peaks specific for ZFO. Raman spectroscopy identifies Raman active, infrared active, and silent vibrational modes while Fourier transforms infrared spectroscopic (FTIR) spectra display IR active modes that confirm the presence of ZFO. X-ray diffraction pattern (XRD) exhibits the crystalline planes of single-phase ZFO with a face-centered cubic structure that coincides with the selected area electron diffraction pattern (SAED). The average particle size according to high-resolution transmission electron microscopy (HR-TEM) is 5.6 nm. X-ray photoelectron spectroscopy (XPS) signals confirm the chemical states of Fe, Zn, and O. A superconducting quantum interference device (SQUID) displays the magnetic response of ZFO NPs, showing a magnetic moment of 45.5 emu/gm at 70 kOe. These ZFO NPs were then employed for comparative cytotoxicity evaluation using MTT, crystal violet, and LDH assays on breast adenocarcinoma epithelial cell (MCF-7), triple-negative breast cancer lines (MDA-MB 231), and human embryonic kidney cell lines (HEK-293). Flow cytometric analysis of all the three cell lines were performed in various concentrations of ZFO NPs for automated cell counting and sorting based on live cells, cells entering in early or late apoptotic phase, as well as in the necrotic phase. This analysis confirmed that ZFO NPs are more cytotoxic towards triple-negative breast cancer cells (MDA-MB-231) as compared to breast adenocarcinoma cells (MCF-7) and normal cell lines (HEK-293), thus corroborating that ZFO can be exploited for cancer therapeutics