Remoción de arsénico en agua mediante materiales de bajo costo y segura disposición final
Date
2015-10-01
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Abstract
Se estudió la capacidad de remoción de arsénico mediante adsorción y/o co-precipitación
empleando materiales económicos como arcilla natural y hierro cerovalente (Fe(0)) comercial, microparticulado y como viruta. Se realizaron experimentos de remoción de As(III) y
As(V) presente en soluciones acuosas ([As]0 = 5 mg L
-1
, pH 7), empleando concentraciones
variables de arcilla y Fe(0); para el caso de la arcilla, se estudió la cinética de remoción y el
efecto del pH (5,5 ≤ pH ≤ 8,5). También se estudió la lixiviación del As retenido en los residuos generados, los cuales fueron sometidos previamente a distintos tratamientos térmicos.
Se determinó que son necesarias concentraciones de 2,5% m/v de arcilla o 0,05% m/v de
Fe(0) para lograr una remoción ≥ 95% para ambas especies de As. Los estudios de remoción
con arcilla indicaron que la cinética de adsorción de As(III) y As(V) respondió a un comportamiento bi-exponencial y que la remoción de As(V) por arcilla es mayor a valores ácidos,
mientras que la presencia de materia orgánica (ácido cítrico) disminuye la remoción. En todos
los casos, se observó una lixiviación despreciable para As(V), mientras que para As(III) es
inferior al 3% del As total removido.
The objective of this work was to study the arsenic removal capacity of low cost materials, such as natural clay or zerovalent iron (Fe(0)), both as microparticulated material or as iron wool. Re- moval experiments for As(III) and As(V) ([As]0 = 5 mg L -1 , pH 7) with varying concentrations of clay and Fe(0) were performed. For clay, the kinetics of removal and the effect of pH (pH ≤ 5.5 ≤ 8.5) was studied. As leaching of the solid wastes generated and previously subjected to different heat treatments was also studied. The results obtained indicate that concentrations of 2.5% m/v for clay or 0.05% m/v for both Fe(0) materials are required for As removals higher than 95% for both As(V) and As(III). The studies of arsenic removal with clay indicated that the adsorption kinetic fitted a bi-exponential model and that As(V) removal was higher at low pH values, while it was inhibited in the presence of organic matter (citric acid). In all cases, a negligible As(V) leaching was observed, whereas for As(III) it was less than 3% of total As removed.
The objective of this work was to study the arsenic removal capacity of low cost materials, such as natural clay or zerovalent iron (Fe(0)), both as microparticulated material or as iron wool. Re- moval experiments for As(III) and As(V) ([As]0 = 5 mg L -1 , pH 7) with varying concentrations of clay and Fe(0) were performed. For clay, the kinetics of removal and the effect of pH (pH ≤ 5.5 ≤ 8.5) was studied. As leaching of the solid wastes generated and previously subjected to different heat treatments was also studied. The results obtained indicate that concentrations of 2.5% m/v for clay or 0.05% m/v for both Fe(0) materials are required for As removals higher than 95% for both As(V) and As(III). The studies of arsenic removal with clay indicated that the adsorption kinetic fitted a bi-exponential model and that As(V) removal was higher at low pH values, while it was inhibited in the presence of organic matter (citric acid). In all cases, a negligible As(V) leaching was observed, whereas for As(III) it was less than 3% of total As removed.
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Keywords
arsénico, remoción, arcillas naturales, hierro cerovalente, lixiviación de arsénico, arsenic, removal, natural clays, zero valent iron, arsenic leaching
Citation
Proyecciones, Vol.13 No. 2
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