Photo-induced oxidation of Sb(III) on goethite.
Goethite widely exists in soils and sediments, and plays a very important role in the environmental fate of toxic metal(loid)s. In the present study, photo-induced oxidation of antimonite [Sb(III)] on goethite was investigated with kinetic measurements and X-ray photoelectron spectroscopy (XPS) techniques. Effects of environmental factors including solution pH, the content of goethite as well as humic acid on the photo-induced oxidation of antimonite were tested. The results indicated that no oxidation of antimonite occurred in goethite suspension in the dark, but significant amounts of antimonite were transformed to antimonate when the suspension was exposed to light. Ferrous ions were found in the solution during the antimonite oxidation process, and its concentration decreased with increasing solution pH, which strongly affected the oxidation rate of antimonite. The initial solution pH has great impact on Sb oxidation. After 2h illumination, the highest oxidation rate was found at pH 3, while the initial oxidation rate was even higher at pH 9. In conclusion, the antimonite can be adsorbed and oxidized on goethite irradiated with light, which will greatly reduce its environmental risk.
Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; University of Chinese Academy of Sciences, Beijing 100049, China.
Jian-Xin
JX
Fan
Yu-Jun
YJ
Wang
Ting-Ting
TT
Fan
Xiao-Dan
XD
Cui
Dong-Mei
DM
Zhou
D000327:Adsorption; D000965:Antimony / Q000737:chemistry*; D006812:Humic Substances; D006863:Hydrogen-Ion Concentration; D007477:Ions; D058085:Iron Compounds / Q000737:chemistry*; D007700:Kinetics; D008903:Minerals / Q000737:chemistry*; D010084:Oxidation-Reduction; D055668:Photochemical Processes; D012989:Soil Pollutants / Q000737:chemistry*
D006812:Humic Substances; D007477:Ions; D058085:Iron Compounds; D008903:Minerals; D012989:Soil Pollutants; C094886:goethite; C061374:antimonite; D000965:Antimony
Antimonate; Antimonite; Goethite; Photo-oxidation; XPS