[Effect and mechanism of heavy metal stabilization treatment of sediment in Jinshan Lake].
The heavy metal stabilization treatment (by mixture of CaO, CaO2, CaO and CaO2) of sediment in Jinshan Lake were investigated through soil column experiment, including the transport and transformation of heavy metal in sediment after stabilization, and the mechanism of heavy metal stabilization treatment technology. In the simulated acid rain experiment under a pH of 2.9, Zn in the sediment stabilized by CaO, CaO+ CaO2, CaO2, respectively, transferred to the third layer with the first layer's migrating quantities of 96, 97 and 93 mg/kg, while in another experiment under a pH of 5.0, Zn transferred to the third layer with the first layer's migrating quantities of 87, 90 and 89 mg/kg, respectively. In the blank experiments under pH 2.9 and 5.0, Zn transferred to the sixth and fifth layer with the first layer migrating quantities of 128 and 112 mg/kg, respectively. The above results were concluded to be: 1) both migrating velocity and first layer's migrating quantity of Zn decreased in stabilized sediment; 2) the three tested ways could reduce it migrating capability in soil; 3) pH of leached solution could affect the migrating capability of Zn and high Ph would lead to the decrease of Zn in soil. For Ni and Cd, the similar conclusion could also be gained. The results of metal transporting mechanism experiments with CaO, CaO + CaO2, CaO2 showed that: 1) pH of the sediment increased from 6.76 to 8.33, 8.15 and 8.21; 2) TOC content decreased with a range of 5%, 10.9% and 13.1%; 3) fixedness part contents of Zn, Ni and Cd increased 10.6%, 1.7% and 4.5%, respectively, which is the important reason leading to the decrease of metal transporting capability. The transformation proportion of heavy metal from labilization to stabilization showed that the stabilization capability of heavy metal followed the sequence: Zn > Cd > Ni.
Zhou
Xue-fei
XF
Key Laboratory of Yangtze Water Environment of Ministry of Education, Tongji University, Shanghai 200092, China. zhouxuefei@mail.tongji.edu.cn
Zhang
Ya-lei
YL
Zhang
Ming
M
Zhu
Hong-guang
HG
Li
Jian-hua
JH
Zhao
Jian-fu
JF