Abiotic oxidation of Mn(II) and its effect on the oxidation of As(III) in the presence of nano-hematite

TY - JOUR

T1 - Abiotic oxidation of Mn(II) and its effect on the oxidation of As(III) in the presence of nano-hematite

AU - Han, Xu

AU - Li, Yi Liang

AU - Gu, Ji Dong

N1 - Funding Information: Acknowledgments This work is partially supported by the Strategic Research Theme on Sustainable Environment (Sustainable Water) and the Faculty of Science, both of The University of Hong Kong (J-DG and Y-LL), and the National Natural Science Foundation of China (No. 41003040) and the Natural Science Foundation of Tianjin (No. 10JCYBJC06000) (XH). We thank experiment assistance of Ms. Jessie Lai and XPS analysis of Mr. Rayman Chan (HKSTP), and additional support of Ms. Ya-Min She and Mr. Yu-Zhu Mao at Tianjin Polytechnic University.

PY - 2012/8

Y1 - 2012/8

N2 - Manganese (hydr)oxides (MnOx) is a powerful oxidant in the oxidation of As(III) in natural environment. Under some circumstances, Mn(II) can be oxidized to MnOx which in turn accelerates the oxidation of As(III). However, to the best of our knowledge, little is known regarding how Mn(II) affects the oxidation of both the dissolved and the adsorbed As(III) in aquatic environments. In this study, effects of abiotic oxidation of Mn(II) on the oxidation of As(III) were investigated. Kinetic results as well as TEM and XRD analyses confirmed the formation of amorphous MnOx after sorption of Mn(II) on hematite nano-particles under oxic conditions. Mn(II) was oxidized to Mn(III) and then to Mn(IV), and this process was dependent upon pH and Mn(II) concentrations. The newly formed MnOx played an important role in the further oxidation of the dissolved and the adsorbed As(III) on hematite, and the oxidation rate of As(III) increased with the rising Mn(II) concentrations. As the adsorbed As(III) was oxidized to As(V), a fraction of As(V) was released into the solution, which increased the mobility of As. The present study reveals that abiotic oxidation of Mn(II) affects the oxidation of As(III) in aquatic environment.

AB - Manganese (hydr)oxides (MnOx) is a powerful oxidant in the oxidation of As(III) in natural environment. Under some circumstances, Mn(II) can be oxidized to MnOx which in turn accelerates the oxidation of As(III). However, to the best of our knowledge, little is known regarding how Mn(II) affects the oxidation of both the dissolved and the adsorbed As(III) in aquatic environments. In this study, effects of abiotic oxidation of Mn(II) on the oxidation of As(III) were investigated. Kinetic results as well as TEM and XRD analyses confirmed the formation of amorphous MnOx after sorption of Mn(II) on hematite nano-particles under oxic conditions. Mn(II) was oxidized to Mn(III) and then to Mn(IV), and this process was dependent upon pH and Mn(II) concentrations. The newly formed MnOx played an important role in the further oxidation of the dissolved and the adsorbed As(III) on hematite, and the oxidation rate of As(III) increased with the rising Mn(II) concentrations. As the adsorbed As(III) was oxidized to As(V), a fraction of As(V) was released into the solution, which increased the mobility of As. The present study reveals that abiotic oxidation of Mn(II) affects the oxidation of As(III) in aquatic environment.

KW - Abiotic oxidation

KW - Arsenate

KW - Arsenite

KW - Mn

KW - Mobility

UR - http://www.scopus.com/inward/record.url?scp=84864886650&partnerID=8YFLogxK

U2 - 10.1007/s10646-012-0950-z

DO - 10.1007/s10646-012-0950-z

M3 - 文章

C2 - 22688359

AN - SCOPUS:84864886650

SN - 0963-9292

VL - 21

SP - 1753

EP - 1760

JO - Ecotoxicology

JF - Ecotoxicology

IS - 6

ER -