MS title: Catalytic oxidation and removal of arsenite in the presence of Fe ions and zero-valent Al metals.
Arsenic immobilization in acid mine drainage (AMD) is required prior to its discharge to safeguard aquatic organisms. Zero-valent aluminum (ZVAl) such as aluminum beverage cans (AlBC) was used to induce the oxidation of As(III) to As(V) and enhance the subsequent As removal from an artificially prepared AMD. While indiscernible As(III) oxidation was found in aerated ZVAl systems, the addition of 0.10-0.55mM Fe(II) or Fe(III) into the AMD significantly promoted the As(V) production. Reactions between Fe(II) and H2O2, which was produced through an oxidative reaction of ZVAl with dissolved oxygen, generated OH radicals. Such OH radicals subsequently induced the As(III) oxidation. Over the course of the Fenton like reaction, ZVAl not only directly generated the H2O2, but indirectly enhanced the OH radical production by replenishing Fe(II). Arsenite oxidation in the aerated ZVAl/Fe and AlBC/Fe systems followed zero- and first-order kinetics. Differences in the kinetic reactions of ZVAl and AlBC with respect to As(III) oxidation were attributed to higher productive efficiency of the oxidant in the AlBC systems. After the completion of As(III) oxidation, As(V) could be removed simultaneously with Al(III) and Fe(III) by increasing solution's pH to 6 to produce Al/Fe hydroxides as As(V) scavengers or to form Al/Fe/As co-precipitates.
Scientific Research Division, National Synchrotron Radiation Research Center, Hsinchu, Taiwan; Department of Soil and Environmental Sciences, National Chung Hsing University, Taichung, Taiwan.
Liang-Ching
LC
Hsu
Department of Soil and Environmental Sciences, National Chung Hsing University, Taichung, Taiwan.
Kai-Yue
KY
Chen
Department of Soil and Environmental Sciences, National Chung Hsing University, Taichung, Taiwan.
Ya-Ting
YT
Chan
Department of Soil and Crop Sciences, Texas A&M University, College Station, TX, 77843, USA.
Youjun
Y
Deng
Department of Soil and Environmental Sciences, National Chung Hsing University, Taichung, Taiwan.
Che-En
CE
Hwang
Department of Soil and Environmental Sciences, National Chung Hsing University, Taichung, Taiwan. Electronic address: yliu@nchu.edu.tw.
Yu-Ting
YT
Liu
Department of Agricultural Chemistry, National Taiwan University, Taipei, Taiwan.
Shan-Li
SL
Wang
Department of Safety, Health, and Environmental Engineering, Ming Chi University, Taishan, Taipei 24301, Taiwan.
Wen-Hui
WH
Kuan
Department of Soil and Environmental Sciences, National Chung Hsing University, Taichung, Taiwan. Electronic address: ymtzou@dragon.nchu.edu.tw.
Yu-Min
YM
Tzou
Acid mine drainage; Arsenic; Hydrogen peroxide; Waste Al beverage can