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.