Síntesis sonoquímica de Ni(OH)₂-Ag₂O para la fotodecoloración del Rojo-Congo

El presente estudio muestra resultados preliminares de la síntesis sonoquímica del sistema Ni(OH)₂‐Ag₂O para la fotodecoloración del colorante Rojo-Congo con luz dentro del rango del visible. Análisis morfológico, estructural y de superficie muestran una estructura tipo laminar con tamaños promedio de cristal de 5 nm y una distribución homogénea del Ag₂O en la superficie del Ni(OH)₂. La actividad fotocatalítica fue evaluada a una concentración de 50 ppm a temperatura ambiente usando radiación visible. La correlación de los resultados estructurales y de superficie son analizados y reportados.The present study shows preliminary results of the sonochemical synthesis of the Ni(OH)₂‐Ag₂O system for the photodecolorazation of the Congo-Red dye with light within the visible range. Morphological, structural and surface analyzes show a lamellar type structure with average crystal sizes of 5 nm and a homogeneous distribution of Ag₂O on the Ni(OH)₂ surface. Ni(OH)₂‐Ag₂O were subjected to catalytic activity for dye decolorization of Congo-Red (CR, 50 mg/L) at room temperature using visible radiation. Correlation of structural and surface results are analyzed and reported herein

Depósito, caracterización y desempeño de películas delgadas de óxido de cromo en la protección de aleaciones ferrosas en atmósferas carburizantes

Tesis (Doctorado en Ciencias en Metalurgia y Materiales), Instituto Politécnico Nacional, SEPI, ESIQIE, 2014, 1 archivo PDF, (70 páginas). tesis.ipn.m

Development of AlN thin films for breast cancer acoustic biosensors

Although the development of biosensors has become popular in the recent past, there are still many opportunities to develop specific designs that address public health problems of third world countries. This paper presents the initial efforts toward the development of an affordable acoustic biosensor for breast cancer detection. The core of the sensor consists of a piezoelectric AlN thin film that requires specific crystallographic and morphological features. In this study, the processing–structure relationship of our radio-frequency magnetron sputtering (r.f. MS) system was established. Al/AlN films were produced via r.f. MS varying the applied power and atmosphere composition. The films were analyzed by glancing angle X-ray diffraction, scanning electron microscopy + energy dispersive analysis, X-ray photoelectron spectroscopy, and transmission electron microscopy. The results indicate that applied power had a much stronger influence on the phase selection, orientation and morphology of the films and was attributed to the effect of power on ad-atom mobility on the substrate. Higher power values resulted in films better suited for biosensor applications. The presence of the Al adhesion layer favored the formation of undesirable metastable c-AlN. Preliminary results on the biofunctionalization of the films were encouraging, but require further work both in the protocol and on the effect of the film surface on this process. Keywords: AlN thin films, Breast cancer, Acoustic biosensors, Biofunctionalization, Reactive magnetron sputtering, Piezoelectric thin film

Sonochemical Synthesis of Nanostructured Ni-Fe-C System and Its Catalytic Activity Based on Decolorization of Reactive Black 5 Dye

This study investigates the thermal decomposition of acetyl acetonates of Ni(II) and Fe(III) via a sonochemical process at 20 kHz for 50 min. In the absence of magnetic fields the reactions of Ni(II) and Fe(III) acetyl acetonates under ultrasonic treatment produce Ni(OH)2 and FeO(OH) nanoparticles coated with carbon. The synthesized materials with different Ni-Fe stoichiometries, Ni90-Fe10, Ni80-Fe20, and Ni50-Fe50 wt%, were subjected to catalytic activity for dye decolorization of Reactive Black 5 (RB5, 100 mg/L) at room temperature using visible radiation. The correlation between the structural and optoelectronic properties and the catalytic performance of the Ni-Fe system with different stoichiometries is reported