Oxidative removal of arsenite by Fe(II)- and polyoxometalate (POM)-amended zero-valent aluminum (ZVAl) under oxic conditions
Journal
Water Research
Journal Volume
47
Journal Issue
7
Start Page
2583
End Page
2591
ISSN
0043-1354
Date Issued
2013-05-01
Author(s)
Wu, C.C.
Hsu, Liang Ching
Liu, Jen Chyi
Kuan, Wenhui
Chen, Chungchi
Tzou, Yuming Min
Wang, Mingkuang
Hwang, C. E.
Abstract
Abiotic transformation of As(III) to As(V) is possible which would decrease As toxicity. This study investigated the potential applications of zero-valent Al (ZVAl) or Al wastes, such as Al beverage cans, for converting As(III) to As(V) in an acidic solution under aerobic conditions. Results showed that As(III) could not be oxidized by ZVAl within 150 min reaction at pH 1 because of the presence of an oxide layer on ZVAl. However, 85 μM As(III) could be completely oxidized with the addition of Fe(II) or POM due to the generation of a Fenton reaction or the enhancement of H2O2 production, respectively, on the ZVAl surfaces. Because Fe(II) or polyoxometalate (POM) exhibited more stable at low pH and scavenged rapidly the H2O2 produced on the aerated ZVAl surfaces, OH radical productions were more efficient and As(III) was rapidly oxidized in the ZVAl/O2 system with theses two catalysts. The catalytic oxidation kinetics of As(III) in the presence of Fe(II) or POM were best described by zero-order reaction, and the rate constants increased with a decrease of pH from 2 to 1. Following the oxidative conversion of As(III) to As(V) in the ZVAl/Fe/O2 system, As(V) was removed by the newly formed hydrous Al/Fe precipitates by increasing the solution pH to 6. Nonetheless, the As(V) removal was incomplete in the ZVAl/POM/O2 system because the hydrolyzed products of POM, e.g., PO43-, inhibited As(V) removal due to the competitive adsorption of the oxyanion on Al precipitates. Discarded Al-based beverage cans exhibit a higher efficiency for As(III) oxidation and final As removal compared with that of ZVAl, and thus, the potential application of Al beverage cans to scavenge As in solutions is feasible
Subjects
Al beverage can waste
Arsenic
Ferrous ions
Polyoxometalate
Zero-valent aluminum
Publisher
Elsevier BV
Type
journal article