Repository logo

Browsing by Author "Hormaza, Angelina"

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Adsorción de azul de metileno sobre cascarilla de arroz
    (Corporación Universitaria Lasallista, 2012) Moreno, Anderson; Figueroa, Danilo; Hormaza, Angelina
    Introduction. The contamination produced by the download of industrial effluents, especially from textile, food and paint industries, not only affects ecosystems due to its aesthetic degradation, but, above all, to the reduction of photosynthetic processes. Dyes, due to their aromatic structure, are characterized by their difficult and slow degradation, thus generating accumulations and becoming a contamination source that can even be carcinogenic for some molecules. Adsorption on agricultural wastes appears as an innovative alternative, environmentally favorable and very efficient to treat those dyed effluents. Objective. To find the conditions which allow an efficient removal of the methylene blue dye on rice hulls by the use of the statistical design of experiments and compositionally and structurally analyze the adsorbent material. Materials and methods. The best conditions of the adsorption process were determined under a discontinuous system, evaluating an interval of the variables pH value, dosage of the adsorbent, dye concentration and contact time. The temperature, the agitation and the size of the particles were constant. The dye content was quantified by the use of Ultraviolet-Visible spectrophotometry. Results. A maximum removal of 99% was obtained at pH 9.0, 3.5 mgL-1dosage, 10 mgL-1of concentration and 163 minutes of contact time, with a good adjustment to the statistical models (R2 = 0.92) and with no bias in the measuring. Conclusions. The statistical design was useful to establish the conditions necessary to achieve a high efficiency to remove the methylene blue dye on rice hulls. It also proved that this agricultural waste is a remarkable material to scale the process in a later phase.
  • Thumbnail Image
    Item
    Diseño estadístico para la remoción eficiente del colorante rojo 40 sobre tusa de maíz
    (Corporación Universitaria Lasallista, 2012) Moreno, Anderson; Figueroa, Danilo; Hormaza, Angelina
    Introduction. Industrial colored effluents are an evident indicator of water pollution. Small quantities of dye affect, negatively, the appearance of water bodies and dramatically affect water regeneration, affecting the aquatic life. Several physical-chemical and biological methods have been usted to treat colored effluents, with considerable efficiency degrees, but they are expensive and produce more toxic by-products, so there are problems for their use. Adsorption with alternative adsorbents has proved its efficiency to eliminate colorants in solutions. Objetive. Achieving the maximum removal of the red 40 dye on corn cob by the use of a statistical experimental design and characterize the adsorbent material. Materials and methods. The most important variables of the adsorption process were evaluated under a discontinuous system through a factorial design, with the support of the Statgraphics software for its execution and analysis. The remaining concentration of the colorant was determined with the absorbance, by the use of an UV-vis Perkin Elmer Lamba spectrophotometer. Results. A maximum removal of 99% was achieved with the statistical model used, and a good adjustment (R2 equals 98.97%). The pH was the most significant variable in the adsorption of the red 40 dye. Conclusions. Corn cob proved to be an excellent adsorption material and the high removal degree achieved was due to the statistical experimental design, which is more economic and facilitates the analysis of the most important variables involved in the process.