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Adsorption of Arsenic on Polyaluminum Granulate

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journal contribution
posted on 03.07.2012, 00:00 by Jasmin Mertens, Jérôme Rose, Ralf Kägi, Perrine Chaurand, Michael Plötze, Bernhard Wehrli, Gerhard Furrer
The kinetics and efficiencies of arsenite and arsenate removal from water were evaluated using polyaluminum granulates (PAG) with high content of aluminum nanoclusters. PAG was characterized to be meso- and macroporous, with a specific surface area of 35 ± 1 m2 g–1. Adsorption experiments were conducted at pH 7.5 in deionized water and synthetic water with composition of As-contaminated groundwater in the Pannonian Basin. As­(III) and As­(V) sorption was best described by the Freundlich and Langmuir isotherm, respectively, with a maximum As­(V) uptake capacity of ∼200 μmol g–1 in synthetic water. While As­(III) removal reached equilibrium within 40 h, As­(V) was removed almost entirely within 20 h. Micro X-ray fluorescence and electron microscopy revealed that As­(III) was distributed uniformly within the grain, whereas As­(V) diffused up to 81 μm into PAG. The results imply that As­(V) is adsorbed 3 times faster while being transported 105 times slower than As­(III) in Al hydroxide materials.