Evaluating the use of activated carbon felts to remove Co2+, Ni2+ and Sr2+ from wastewater

As a result of numerous advantages such as high surface areas, rapid sorption rates and low hydrodynamic resistances, activated carbon felts (ACF) are interesting materials for applications in wastewater treatment. This paper studies the use of a polyacrylic acid grafted and a non grafted ACF in the sorption of Co2+, Ni2+ and Sr2+ from a synthetic solution (high NaNO3 concentration) representing a nuclear wastewater. Scanning electron microscopy and surface area analysis were employed to physically characterize bothmaterials. Experimental results for the sorption of ternary mixtures allowed us to uncover a selectivity among the three cations that could not be deducted directly from the sorption isotherms of individual cations. In all cases, differences in the sorption capacity could be related to the electronegativity of the metal cations. Complementarily, removal of Co2+, Ni2+ and Sr2+ by a fixed bed column containing non grafted ACF was studied by means of monoelement and ternary sorption experiments. Only breakthrough curves of individual metals could be fitted by the Thomas model. Overshot of Sr2+ and Co2+ was observed on ternary sorption experiments. The set of results obtained indicate that ACF can potentially be employed in the treatment of nuclear effluents where a selective separation of Sr2+ from Ni2+ and Co2+ is required. (C) 2014 Elsevier Ltd. All rights reserved.