Remoción del colorante azul marino directo sobre borra de café modificada

The presence of dyes in water bodies inhibits the penetration of light, affecting the flora and fauna of these ecosystems, which is why, greater efforts are made to eliminate them before being poured. This study allowed the removal of the direct navy-blue dye (DNB), using activated carbon prepared from coffee beans and H3PO4. The experimental methodology began with the preparation of three types of activated carbon by varying the concentration of H3PO4 (20, 40 and 60% m/v). Texture properties were evaluated by adsorption-desorption isotherms with N2 to 77 K, the identification and quantification of organic functional groups, mainly acids, with FTIR and the Boehm method, respectively. Batch adsorption experiments were performed by varying the initial dye concentration (5, 10, 50, 75, 100 and 200 mg/dm3) to 25 °C and, the adsorption kinetics was determined. Both coffee beans and activated carbons have an acidic nature with surface area development between 519 and 771 m2/g. With respect to the batch study, a monolayer and multilayer growth was observed on a heterogeneous surface. Activated carbon prepared with 20% of H3PO4 recorded the highest removal capacity with a value of 25.8 mg/g. The kinetic model of pseudo second order was the one that best fit to the experimental data (R2 > 0.98). It can be concluded that the coffee bean treated with H3PO4 is an efficient adsorbent to remove DNB from aqueous solutions.La presencia de colorantes en los cuerpos de agua inhibe la penetración de la luz, afectando la flora y la fauna de estos ecosistemas, razón por la cual se hacen cada vez esfuerzos mayores para eliminarlos antes de ser vertidos. Este estudio permitió remover el colorante azul marino directo (AMD), empleando carbón activado preparado a partir de la borra de café y H3PO4. La metodología experimental inició con la preparación de tres tipos de carbón activado, variando la concentración de H3PO4 (20, 40 y 60% m/v). Las propiedades de textura se evaluaron mediante isotermas de adsorción-desorción con N2 a 77 K; la identificación y cuantificación de grupos funcionales orgánicos, en especial ácidos, con FTIR, y el método de Boehm, respectivamente. Se realizaron experimentos de adsorción por lote, variando la concentración inicial del colorante (5, 10, 50, 75, 100 y 200 mg/dm3) a 25 °C y se determinó la cinética de adsorción. Tanto la borra de café como los carbones activados tienen naturaleza ácida con desarrollo de áreas superficiales entre 519 y 771 m2/g. Con respecto al estudio por lote, se observó un crecimiento en monocapa y multicapa sobre una superficie heterogénea. El carbón activado preparado con 20% de H3PO4 registró la mayor capacidad de remoción, con un valor de 25.8 mg/g. El modelo cinético de pseudo segundo orden fue el que mejor se ajustó a los datos experimentales (R2 > 0.98). Se puede concluir que la borra de café tratada con H3PO4 es un adsorbente eficiente para eliminar AMD de soluciones acuosas

Floral odors and the interaction between pollinating Ceratopogonid midges and Cacao

Most plant species depend upon insect pollination services, including many cash and subsistence crops. Plants compete to attract those insects using visual cues and floral odor which pollinators associate with a reward. The cacao tree, Theobroma cacao, has a highly specialized floral morphology permitting pollination primarily by Ceratopogonid midges. However, these insects do not depend upon cacao flowers for their life cycle, and can use other sugar sources. To understand how floral cues mediate pollination in cacao we developed a method for rearing Ceratopogonidae through several complete lifecycles to provide material for bioassays. We carried out collection and analysis of cacao floral volatiles, and identified a bouquet made up exclusively of saturated and unsaturated, straight-chain hydrocarbons, which is unusual among floral odors. The most abundant components were tridecane, pentadecane, (Z)-7-pentadecene and (Z)-8-heptadecene with a heptadecadiene and heptadecatriene as minor components. We presented adult midges, Forcipomyia sp. (subgen. Forcipomyia), Culicoides paraensis and Dasyhelea borgmeieri, with natural and synthetic cacao flower odors in choice assays. Midges showed weak attraction to the complete natural floral odor in the assay, with no significant evidence of interspecific differences. This suggests that cacao floral volatiles play a role in pollinator behavior. Midges were not attracted to a synthetic blend of the above four major components of cacao flower odor, indicating that a more complete blend is required for attraction. Our findings indicate that cacao pollination is likely facilitated by the volatile blend released by flowers, and that the system involves a generalized odor response common to different species of Ceratopogonidae