Absorción de metales pesados (Hg y Pb) en aguas residuales mediante el uso del exoesqueleto del camarón.
Fecha
2020-12
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Universidad EARTH
Resumen
La contaminación por metales pesados en cuerpos de agua es un problema grave a nivel mundial debido a su persistencia y bio-acumulación. La presente investigación evaluó el efecto de diferentes dosis de quitosano extraído del exoesqueleto de camarón para la remoción de metales pesados (Hg2+ y Pb2+) presentes en una simulación de agua contaminada. Se aplicó un tratamiento químico para la extracción del quitosano, obteniendo un rendimiento del 6.92 %. Se elaboraron soluciones acuosas con concentración de 500 mg/L de mercurio (Hg2+) y 500 mg/L de plomo (Pb2+), éstas se utilizaron en tres tratamientos con sus respectivas repeticiones para evaluar la biosorción en función de diferentes cantidades del quitosano extraído a un tiempo de agitación constante de 120 minutos a 250 rpm, entre un rango de pH de 4 a 6 y a temperatura ambiente; posteriormente se modelaron las isotermas de biosorción con los resultados obtenidos de este experimento. Se obtuvo eficiencias de adsorción tanto para el Hg2+ y el Pb2+ superiores al 90 % en los tres tratamientos. Mediante el análisis estadístico de varianza se determinó que los tratamientos presentaron diferencias significativas, demostrando que la cantidad de quitosano es una variable influyente en el proceso donde se obtuvo la mejor adsorción para el mercurio con 5 g de quitosano y para el plomo, con 10 g. Por otro lado, la biosorción se ajustó al modelo de Langmuir con el cual se determinó que la capacidad máxima de adsorción para el mercurio es de 49.99 mg/g quitosano y del 49.36 mg/g quitosano para el plomo. Se concluye que el quitosano tiene la capacidad de biosorción de los iones de mercurio y plomo presentes en soluciones acuosas, donde el grado de remoción dependerá de la calidad del proceso de desacetilación del quitosano y del tamaño del radio iónico de los metales.
Heavy metal contamination in water bodies is a serious problem worldwide due to its persistence and bio-accumulation. The present research evaluated the effect of different doses of chitosan extracted from the shrimp exoskeleton for the removal of heavy metals (Hg2 + and Pb2 +) present in a simulation of contaminated water. A chemical treatment was applied to extract the chitosan, obtaining a yield of 6.92 %. Aqueous solutions were prepared with a concentration of 500 mg/L of mercury (Hg2 +) and 500 mg/L of lead (Pb2 +), these were used in three treatments with their respective repetitions to evaluate the biosorption based on different amounts of chitosan extracted from a constant stirring time of 120 minutes at 250 rpm, between a pH range of 4 to 6 and at room temperature; subsequently, the biosorption isotherms were modeled with the results obtained from this experiment. Adsorption efficiencies were obtained for both Hg2 + and Pb2 + higher than 90 % in the three treatments. By means of the statistical analysis of variance, it was determined that the treatments presented significant differences, showing that the amount of chitosan is an influential variable in the process where the best adsorption was obtained for mercury with 5 g of chitosan and for lead, with 10 g. On the other hand, the biosorption was adjusted to the Langmuir model with which it was determined that the maximum adsorption capacity for mercury is 49.99 mg/g chitosan and 49.36 mg/g chitosan for lead. It is concluded that chitosan has the biosorption capacity of mercury and lead ions present in aqueous solutions, where the degree of removal will depend on the quality of the chitosan deacetylation process and the size of the ionic radius of the metals.
Heavy metal contamination in water bodies is a serious problem worldwide due to its persistence and bio-accumulation. The present research evaluated the effect of different doses of chitosan extracted from the shrimp exoskeleton for the removal of heavy metals (Hg2 + and Pb2 +) present in a simulation of contaminated water. A chemical treatment was applied to extract the chitosan, obtaining a yield of 6.92 %. Aqueous solutions were prepared with a concentration of 500 mg/L of mercury (Hg2 +) and 500 mg/L of lead (Pb2 +), these were used in three treatments with their respective repetitions to evaluate the biosorption based on different amounts of chitosan extracted from a constant stirring time of 120 minutes at 250 rpm, between a pH range of 4 to 6 and at room temperature; subsequently, the biosorption isotherms were modeled with the results obtained from this experiment. Adsorption efficiencies were obtained for both Hg2 + and Pb2 + higher than 90 % in the three treatments. By means of the statistical analysis of variance, it was determined that the treatments presented significant differences, showing that the amount of chitosan is an influential variable in the process where the best adsorption was obtained for mercury with 5 g of chitosan and for lead, with 10 g. On the other hand, the biosorption was adjusted to the Langmuir model with which it was determined that the maximum adsorption capacity for mercury is 49.99 mg/g chitosan and 49.36 mg/g chitosan for lead. It is concluded that chitosan has the biosorption capacity of mercury and lead ions present in aqueous solutions, where the degree of removal will depend on the quality of the chitosan deacetylation process and the size of the ionic radius of the metals.
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TRATAMIENTO DE AGUAS RESIDUALES, QUITOSANO, METALES PESADOS, ABSORCION