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Browsing by Author "Mera Benavides, Adriana Consuelo"

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    Acople fotocatalítico - biológico para el tratamiento de desechos complejométricos generados en laboratorios de análisis químico y ambiental
    (Corporación Universitaria Lasallista, 2010) Baquero Dulcey, Martha Isabel; Sterling López, Adriana María; Mera Benavides, Adriana Consuelo
    Introducción. La fotocatálisis heterogénea es útil como pretratamiento antes de un tratamiento biológico para contaminantes resistentes a la biodegradación. La fitorremediación se utiliza para degradar y extraer contaminantes del ambiente. El acople de estas dos técnicas podría ser una buena alternativa para el tratamiento de desechos complejométricos con presencia de indicadores metalocrómicos. Objetivo. Aplicar fotocatálisis y fitorremediación a desechos complejométricos generados en el laboratorio de Ingeniería Ambiental y Sanitaria de la Universidad del Cauca. Materiales y métodos. Para el proceso de fotocatálisis se utilizó un foto-reactor y se analizaron las condiciones bajo las cuales se obtuvieron los mayores porcentajes de degradación y mineralización del indicador Negro de Ericromo T (NET). En el proceso de fitorremediación se utilizaron reactores con plantas acuáticas y el control se realizó por medio del conteo de frondas y análisis químico. Resultados. Las condiciones óptimas para el tratamiento del desecho con presencia del indicador complejométrico NET son: 0,3 g/L de catalizador TiO2, 80 ppm de H2O2 y un tiempo de exposición de luz UV de tres horas, obteniéndose un porcentaje de degradación del NET de 86,85%. En el proceso de fitorremediación no se alcanzó la remoción de sales esperada para este experimento. Conclusión. La utilización de concentraciones adecuadas de TiO2 y H2O2 permite obtener buenos porcentajes de degradación del indicador NET presente en desechos químicos. Se recomienda realizar un estudio más detallado que permita la elección de otro tipo de tratamiento biológico complementario al fotocatalítico, que logre la remoción de las sales presentes.
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    Alternativa para la segregación de residuos químicos generados en el Laboratorio de Ingeniería Ambiental y Sanitaria de la Universidad del Cauca
    (2007) Mera Benavides, Adriana Consuelo; Andrade Vivas, Bárbara; Ortiz Sarria, Mauricio Fernando
    Introduction. Universities with chemical analysis laboratories manage, of course, chemical substances and make diverse operations that generate residues which are, in most of the cases, dangerous for human health and the environment. Objective. To achieve an adequate segregation of the residues generated in the Environmental and Sanitary Engineering laboratory of the University of the Cauca. Materials and methods. In order to establish this new classification alternative, several activities were done, among them a wide bibliographical research and an analysis of experiences, activities developed in the laboratory, clarity in the moment of the segregation, easiness of recovering and reuse of waste, among others. Results. the outlined alternative classifies and gathers the chemical waste inside the laboratory in groups and subgroups according to each practice or laboratory activity to be developed during the semester. Conclusion. the outlined alternative allows gathering, in an appropriate way, the residuals generated in laboratory practices, allowing its easy recovery and potential reuse. It also facilitates to identify dangerous and not dangerous residues and, with the application of this alternative, several useful assets have been recovered such as: copper sulphate, potassium chromate, ethanol, disinfectant solutions, saline solutions, acid- base solutions, silicon dioxide, manganese, dioxide and sulphur.
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    Fertilización biológica: técnicas de vanguardia para el desarrollo agrícola sostenible
    (Corporación Universitaria Lasallista, 2010) Carvajal Muñoz, Juan Sebastián; Mera Benavides, Adriana Consuelo
    The use of biological fertilizers has grown significantly during the last two decades. Their massive use is a result of the high demand of raw material for food production and supply, worldwide. They act as traditional chemical fertilizers´ substitutes, have a good performance in harvests, help to the growth of sane fruits that resist plagues and are easy to apply. Besides, essential nutrients contained in biological fertilizers have physical-chemical properties that are beneficial to the soil, helping to increase productivity in the global agricultural sector. In this article a revision to the main current techniques for the biological fertilization is made, and an outlook to its future potential for sustainable agricultural development is shown.
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    Fotocatálisis heterogénea con TiO2 y H2O2 para el tratamiento de desechos líquidos con presencia de Fenolftaleína generados en los laboratorios de análisis químico de la Universidad del Cauca
    (Corporación Universitaria Lasallista, 2008) Castro Guerrero, Brenda Astrid; Huetio Vergara, Viviana Andrea; Mera Benavides, Adriana Consuelo
    Introduction. The heterogeneous photocatalysis using titanium dioxide in suspension is an efficient technology that at the moment is applied for the degradation of recalcitrant contaminants. The use of this technique is a good alternative for the degradation of the acid-base phenolphthalein indicator, present on the liquid wastes generated by the laboratories of chemical analysis in the University of Cauca. Objective. To apply the heterogeneous photocatalysis using TiO2 suspended and H2O2, in the treatment of liquid wastes with the phenolphthalein indicator. Materials and equipment. For the photocatalysis process, a system composed of three parts was used: A photo-reactor with a lamp of ultraviolet light that has a tube of low pressure of mercury (wavelength 254 nm), a zone of homogenization and a pump for the recirculation of the sample. The conditions from which the highest percentage of degradation of the indicator was obtained, were analyzed. The specific variables analyzed in this treatment were: catalyst concentration (TiO2 Degussa P25), oxidinsing agent concentration (H2O2), and the time of exhibition to the light Uv. Results.The degradation and mineralization of the indicator in the process were evaluated by using colorimetric methods. Results. the highest percentage of degradation was 86,54% using 500 ppm of TiO2, 2600 ppm of H2O2, and 8 hours of light Uv time exposition. These standardized conditions were applied for the liquid wastes. Conclusion. the use of optimum concentrations of TiO2 and H2O2 allows to obtain good degradation percentages of the acid-base phenolphthalein indicator present in chemical wastes.
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    Tratamiento fotocatalítico de aguas residuales generadas en laboratorios con presencia del indicador verde de bromocresol
    (Corporación Universitaria Lasallista, 2011) Mera Benavides, David Alejandro; Mera Benavides, Adriana Consuelo
    Introduction. The advance of heterogeneous photocatalysis as an advanced oxidation process has been used in the treatment of water contaminated with recalcitrant substances, which bring negative impacts to the environment and, in consequence, to human health.Given the urgent necessity of preserving water as a natural resource, heterogeneous photocatalysis was used in this research work to treat effluents generated in chemical and environmental research laboratories. Objetive. To apply heterogeneous photocatalysis by the use of TiO2 to treat waste water with bromocresol green. Materials and methods. Batch type reactors were used in this process. Titanium dioxide (TiO2 ) Degussa P-25 was used as a catalyst and natural UV radiation was taken as the source to activate the photocatalytic method to generate the discoloration and mineralization of the bromocresol green indicator in the liquid effluents.The process was followed up by pH tests;Absorbance by the use of a spectrophotometer (418 nm wave length) and COD by the technique suggested by Standard Methods, every day during a five days period. Results. The comparison of the data obtained shows the feasibility of the technique, especially by the use of a 300 ppm concentration of catalyst, obtaining a 93,94% of degradation and a 72.22% of mineralization. Conclusion. With the results of degradationand mineralization percentages obtained, it is evident that heterogeneous photocatalysis, using sunlight, is an advanced oxidation process useful to treat waste water with bromocresol green indicator.