Browsing by Author "Bennett Valverde, Christian Jairo"

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    Influencia del pH en la adsorción del cromo hexavalente en distintos materiales
    (Universidad de Cuenca, 2024-03-17) Bennett Valverde, Christian Jairo; Peñafiel Tenorio, María Eulalia
    This study focuses on the influence of pH on the adsorption of hexavalent chromium on different materials. The adsorption of hexavalent chromium was investigated on a variety of materials such as zeolite, bentonite, untreated coffee bagasse, coffee bagasse treated with citric acid, coffee bagasse treated with hydrochloric acid, cocoa pod, cane waste bagasse, corn gopher, commercial activated carbon, coconut activated carbon and Green Harmony brand activated carbon. The results revealed that pH plays a fundamental role in the effectiveness of the adsorption process, demonstrating a greater adsorbent capacity in specific pH ranges between 2 and 10. The characterization of them through point of zero charge (PCC), Brunauer, Emmett and Teller (BET) and Fourier Transform Infrared Spectroscopy (FTIR) tests, allowed the identification of the structural and chemical properties of the adsorbents and their contribution to the process adsorption. The adsorbent that presented the highest adsorption capacity was the Green Harmony active carbon at pH 2, while among the agricultural waste, the coffee bagasse treated with citric acid showed better results at pH 2, with adsorption yields of 94.11% and 98.56% respectively. The clays did not show good adsorption capacity. The kinetic and equilibrium study was carried out on these two materials. The experimentally obtained data fitted well to pseudo-second-order kinetics, while the equilibrium of the processes was described by the Freundlich model and BET.