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Characteristics and Mechanisms for Metsulfuron-methyl Sorption by Sediments, Biochars and Activated Carbon
Received:July 15, 2014  
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KeyWord:sediment;biochar;activated carbon;metsulfuron-methyl;sorption
Author NameAffiliationE-mail
ZHANG Gui-xiang School of Environment and Safety, Taiyuan University of Science and Technology, Taiyuan 030024, China  
HE Qiu-sheng School of Environment and Safety, Taiyuan University of Science and Technology, Taiyuan 030024, China  
YAN Yu-long School of Environment and Safety, Taiyuan University of Science and Technology, Taiyuan 030024, China  
SUN Ke State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China  
LIU Xi-tao State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China liuxt@bnu.edu.cn 
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Abstract:
      Metsulfuron-methyl has high mobility in the environment compartments and ecological risks. Sorption is a key process influencing the environmental behaviors of contaminants. In this study, the characteristics and mechanisms of metsulfuron-methyl sorption by sediments and carbonaceous sorbents(biochars and activated carbon). The properties of sorbents significantly affected their sorption of metsulfuron-methyl. The sediments with higher organic matter contents and lower pH adsorbed more metsulfuron-methyl. For carbonaceous sorbents, H/C was found to be negatively correlated with nonlinearity index n and positively with sorption affinity lgKoc, indicating that carbonaceous sorbents with higher carbonization degree had stronger sorption nonlinearity and sorption affinity. This might be attributed to increased micropores and aromatic carbon, which were favorable to pore-filling and π-π electron donor-acceptor(π-π EDA) interaction, respectively. Positive correlation between lgKoc and specific surface area(SA) further verified the important role of pore-filling mechanism. Negative correlation between lgKoc and O/C indicated that carbonaceous sorbents with stronger hydrophobicity more facilitated metsulfuron-methyl sorption. Sorption affinities of biochars and activated carbon for metsulfuron-methyl were about 1 and 3 order of magnitude higher than those of sediments, suggesting that adding carbonaceous sorbents to sediments might reduce metsulfuron-methyl leaching into the surface and ground water. Although sorption affinities of biochars for metsulfuron-methyl were lower than that of activated carbon, biochars might also have promising applications because of much lower cost than activated carbon.