Sorption of anionic metsulfuron-methyl and cationic difenzoquat on peat and soil as affected by copper.
The effect of cationic copper (Cu2+) on the sorption of anionic metsulfuron-methyl (Me) and cationic difenzoquat (DZ) to peat and soil was studied using a batch equilibration method. The results showed that Cu2+ increased the sorption of Me but diminished the sorption of DZ. The adsorption of Cu2+ on the surface of peat and soil neutralizes the negative charge, making the zeta potential (zeta) of peat and soil less negative, consequently decreasing the repulsion between the surface of peat or soil and Me and increasing the sorption of Me. Cu2+ may additionally form Cu-Me complexes in aqueous solution, which was preferentially sorbed to peat and soil over the anionic Me. In contrast, the decreased negative surface charge of soil and peat does not favor the sorption of cationic DZ. Fourier transform infrared showed that DZ may be sorbed through interaction with -OH or -COOH groups of peat and soil and that surface complexes of Cu2+ may form through these groups. A competitive sorption between Cu2t and DZ for the same sorption sites is indicated, leading to mutual sorption inhibition of both cations.
State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, Beijing 100085, China.
Zhiguo
Z
Pei
Xiao-quan
XQ
Shan
Bei
B
Wen
Bo
B
He
Tao
T
Liu
Yaning
Y
Xie
Gary
G
Owens
D000327:Adsorption; D000838:Anions; D001190:Arylsulfonates / Q000302:isolation & purification*; D002412:Cations; D003300:Copper / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D011720:Pyrazoles / Q000302:isolation & purification*; D012987:Soil; D017550:Spectroscopy, Fourier Transform Infrared; D013696:Temperature
D000838:Anions; D001190:Arylsulfonates; D002412:Cations; D011720:Pyrazoles; D012987:Soil; C050296:metsulfuron methyl; C031394:difenzoquat; D003300:Copper