La cáscara de naranja (Citrus sinensis L.) se ha considerado como un residuo debido al elevado costo y la compleja gestión de su procesamiento, convirtiéndose en un problema de contaminación ambiental. Por esta razón, se ha prestado gran atención a la valorización de este residuo agroindustrial para obtener beneficios monetarios con una reducción del volumen de residuos orgánicos y la posibilidad del desarrollo de tecnologías eficientes para generar y almacenar energía eléctrica. Este trabajo presenta un proceso térmico ambientalmente amigable para producir un carbón conductivo. Primero las cáscaras de naranja se lavaron por baño ultrasónico y se secaron al sol y en mufla. Posteriormente pedazos de cáscara de naranja deshidratada se cubrieron completamente con arena de mar de grano fino y se carbonizaron a 1000 °C durante 1 hora. Después, el biocarbón fue estudiado por voltametría cíclica. La capacitancia eléctrica de doble capa de la muestra fue estimada para conocer el comportamiento electroquímico del carbono en el electrolito. El material de carbón sintetizado mostró una capacitancia específica de 272 F/g a 20 mV/s. Los resultados observados demostraron que el nuevo proceso térmico propuesto produce carbono grafitizado con buenas propiedades electroquímicas a bajo costo. Además, esta propuesta contribuye con el desarrollo de nuevos materiales conductores de carbón usando un tratamiento térmico simple, económico y respetuoso con el medio ambiente a partir de biomasa residual de bajo valor.

This study evaluates naproxen (NP) degradation efficiency by ozonation using nickel oxide films (NiO(F)NiO(F)) as a catalyst. The NiO films were synthesized by chemical vapor deposition and characterized by X-ray diffraction, scanning electron microscopy, atomic force microscopy and X-ray photoelectron spectroscopy. NP degradation was conducted for 5 min using 10 films of NiO(F) comparing against ozonation using 100 mg/L NiO powder in suspension (NiO(s)NiO(S)) and conventional ozonation (O3-conv). Total organic carbon analysis demonstrated a mineralization degree of 12% with O3O3-conv, 35% with NiONiO as powder and 22% with NiO(F)NiO(F) after 60 min of reaction. The films of NiO(F)NiO(F) were sequentially used 4 times in ozonation demonstrating the stability of the synthesized material, as well as its properties as a catalyst for ozonation. A proposed modeling strategy using robust parametric identification techniques allows the comparison of NP decomposition pseudo-monomolecular reaction rates.

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Transparent conducting antimony doped tin oxide (ATO) films were sputtered on quartz glass substrates by RF magnetron sputtering at an oxygen flow rate ranging from 0 to 15 sccm. The films were prepared at room temperature and annealed for 15 min in air atmospheres at a temperature of 450 °C. The effect of oxygen flow rate has been investigated by comparing eletrical and optical properties of ATO films. The results suggest that, oxygen flow rate has a great impact on Sb5+/Sb3+ ratio and lattice structure integrity, which finally affects the transmittance and electrical resistivity. With the increase of oxygen flow rate, the grain size is enlarged, which leads to a higher average optical transmittance. On the other hand, with oxygen flow rate increasing, the Sb5+/Sb3+ ratio first increases and then decreases sharply when the oxygen flow rate exceeds 5 sccm. The increase of Sb5+/Sb3+ ratio results in the increase of carrier concentration and finally contributes to a decrease of electrical resistivity. The optimal resistivity is 8.9×10-2 Ω·cm and the average transmittance is about 95% at an oxygen flow rate of 5 sccm.