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a b s t r ac tIn this research, the production of granular activated carbon from coffee waste (CW) by chemical activation with zinc chloride was studied by using a 2 3 factorial design with the three responses (surface area, yield, and hardness) and studying three factors (the activation temperature, activation time, and impregnation ratio). The findings expose that after the experimental design, the highest response values were achieved at an activation temperature of 600°C, an activation time of 40 min, and an impregnation ratio of 1.5 g ZnCl 2 g -1 CW. At these conditions, the experimental tests produced a surface area of 1,279 m 2 g -1 . Batch studies of phenol adsorption onto coffee waste-activated carbon (CW-GAC) were performed at different solution pH, stirring speeds, and initial phenol concentrations. The maximum phenol adsorption capacity onto CW-GAC was 160.52 mg g −1 at pH 7. The adsorption kinetics was affected by stirring speed, the required time to achieve equilibrium decreased from 150 to 120 min when stirring speed varied from 200 to 400 min -1 . Film and intraparticle diffusion mechanisms controlled the adsorption of phenol onto CW-GAC. Finally, the porous material developed in this research is capable of sequestering phenol from aqueous solutions to a higher extent than similar lignocellulosic-based activated carbons.

Gold nanoparticles were synthesized and deposited in situ by ultrasonic spray pyrolysis on glass and indium tin oxide (ITO) substrates. This technique led to the formation of gold nanoparticles with different morphologies without the use of any capping agent. The gold nanoparticles deposited on glass substrate were obtained as nanospheres with an average particle size of 30 nm with some agglomerates; however, the nanoparticles deposited on ITO substrate were obtained with different morphologies, such as triangular nanoprisms, nanorods, nanocubes, and nanorhombus, with particle sizes between 40 and 100 nm. The ITO substrate influenced the morphology of the gold nanoparticles obtained due to changes in the deposition temperature, which also change the crystalline structure of the ITO film on the substrate.

Se depositaron nanopartículas de oro con morfología esferoidal en sustratos de vidriomediante pirólisis en fase aerosol asistido por ultrasonido y usando el ZrO2 como matriz dispersante, la deposición se realizó a tres diferentes velocidades de flujo del gas acarreador. Mediante espectrofotometría UV-Vis se observó el pico de la resonancia de plasmones superficiales,característico de las nanopartículas de oro, con un corrimiento hacia rojo conforme aumenta lavelocidad de flujo; este corrimiento es debido a cambios en el tamaño de partícula. Por difracción derayos-X se confirmó la presencia de oro y de ZrO2, se observó un crecimiento preferencial de lasnanopartículas de oro en el plano {111 }. Mediante microscopia electrónica de barrido y microscopia de fuerza atómica se observó que las nanopartículas presentan morfología esferoidal con una relación aproximada de 2:1, el tamaño de las nanopartículas aumentó con la velocidad de flujo, confirmando los resultados obtenidos por UV-Vis.