Adsorption of Arsenic on Polyaluminum Granulate

• Published in: Environmental science & technology 2012-07, Vol.46 (13), p.7310-7317
• Main Authors: Mertens, Jasmin, Rose, Jérôme, Kägi, Ralf, Chaurand, Perrine, Plötze, Michael, Wehrli, Bernhard, Furrer, Gerhard
• Format: Article
• Language: English
• Subjects: Adsorption; Aluminum; Aluminum Compounds - chemistry; Applied sciences; Arsenates - isolation & purification; Arsenic; Arsenic content; Arsenites - isolation & purification; Calcium - chemistry; Chemical compounds; Drinking water and swimming-pool water. Desalination; Environmental Engineering; Environmental Sciences; Exact sciences and technology; Groundwater; Groundwater - analysis; Nanostructures - chemistry; Nanostructures - ultrastructure; Pollution; Porosity; Reaction kinetics; Water - analysis; Water Pollutants, Chemical - isolation & purification; Water Purification - methods; Water treatment and pollution
• ISSN: 0013-936X; 1520-5851
• DOI: 10.1021/es204508t

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.