Adsorption of Arsenic on Polyaluminum Granulate
Résumé
The kinetics and efficiencies of arsenite and arsenate removal from water were evaluated using poly-aluminum granulates (PAG) with high content of aluminum nanoclusters. PAG was characterized to be meso- and macroporous, with a specific surface area of 35 +/- 1 m(2) 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 similar to 200 mu mol 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 pm 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.