1. Leaching Characteristics of Modified Chitosan on Soil Contaminated by Complex Heavy Metals under Simulated Acid Rain Condition.
- Author
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ZHOU Xueling, ZHOU Kuan, DING Senxu, LI Sijia, CHANG Kaiwei, and YU Jiang
- Subjects
ACID rain ,LEACHING ,CHITOSAN ,SOIL pollution ,HEAVY metals ,ACID soils ,SOILS - Abstract
This paper is intended to probe into the mechanism and environmental effects of modified chitosan, a kind of new materials, on heavy-metal contaminated soil under acid rain condition. Thereby, a leaching experiment of soil-column with simulated acid-rain trickling was conducted, leachate being collected from the soil-column, and ephehydrin modified chitosan-biochar composite (ECS-B) and protochitosan were used as stabilizers. The parameters of pH, conductivity and heavy metals (Cu, Pb, Zn and CD) of the leachate were analyzed in terms of contents and morphological change, and an accumulation-release model of heavy metals under leaching condition were put forward. The results of the experiment showed that compared with the control group, the pH value of leachae increased by 1.32 when ECS-B stabilizer had been added. EC changed significantly, rising up to 1.75 times of that of the control group; compared with the control group, the accumulative contents of Cu, Pb, Zn and Cd were decreased by 82.35%, 71.47%, 61.88% and 90.44%, respectively; and after leaching, the residual state of each heavy metal was 2.59 times higher than that of the control group. As to the study on the release of heavy metals from soil, it was considered involving a complex reaction process controlled by a variety of diffusion mechanisms. Besides, ECS-B stabilizer can inhibit the acid-rain leaching of heavy metals in soil by the increase of soil base ions, and the actions of surface complexation, precipitation and ion exchange, thus effectively reducing the ecological environment risk. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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