[Kinetic characteristics of Cd2+ desorption in minerals and soils under simulated acid rain].
The kinetic characteristics of Cd2+ desorption in minerals and soils under simulated acid rain were studied by using the flow-stirred method. It showed that Cd2+ desorption could be described by first-order kinetics. Percents of desorption amounts of Cd2+ calculated were 70%-100% in red soil and goethite, and 25%-50% in latosols and kaolinite. Parabolic diffusion could describe Cd2+ desorption kinetics in latosols and not suitable for red soil and goethite and kaolinite. Cd2+ desorption, regarded as a heterogeneous diffusion in minerals and soils, could be fitted by Elovich equation more than Parabolic diffusion and two-constant equation. Cd2+ desorption could be divided into fast reaction and slow reaction. Except for latosols, fast reaction would be over during 60 min and be close to quasi-equilibrium. Adsorption forms of Cd2+ in soil surface could be exchangeable and specific. Fast reaction was relative to easily desorbed Cd2+. The affinity of edge hydroxyl to Cd2+ would lead to the difference of Cd2+ desorption rate and amounts. Increase of pH value in effluent indicated H+ consumption in the processes of Cd2+ desorption.
Wang
Dai-chang
DC
Institute of Soil Science,Chinese Academy of Sciences, Nanjing 210008, China.
Jiang
Xin
X
Bian
Yong-rong
YR
Gao
Hong-jian
HJ
Jiao
Wen-tao
WT
D015258:Acid Rain / Q000009:adverse effects* / Q000032:analysis; D000327:Adsorption; D002104:Cadmium / Q000032:analysis / Q000378:metabolism*; D007700:Kinetics; D012989:Soil Pollutants / Q000032:analysis / Q000378:metabolism*
D015258:Acid Rain; D012989:Soil Pollutants; D002104:Cadmium