Adsorption of Heavy Metals on Soil Collected from Lixisol of Typical Karst Areas in the Presence of CaCO 3 and Soil Clay and Their Competition Behavior

Guandi He, Zhenming Zhang, Xianliang Wu, Mingyang Cui, Jiachun Zhang and Xianfei Huang
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Guandi He: The Key Laboratory of Plant Resources Conservation and Germplasm Innovation in Mountainous Region (Ministry of Education), Institute of Agro-Bioengineering and College of Life Sciences, Guizhou University, Guiyang 550025, China
Zhenming Zhang: Guizhou Institute of Biology, Guizhou Academy of Sciences, Guiyang 550009, China
Xianliang Wu: Guizhou Institute of Biology, Guizhou Academy of Sciences, Guiyang 550009, China
Mingyang Cui: College of Life Science, Guizhou University, Guiyang 550025, China
Jiachun Zhang: Guizhou Botanical Garden, Guizhou Academy of Sciences, Guiyang 550004, China
Xianfei Huang: Guizhou Provincial Key Laboratory for Information Systems of Mountainous Areas and Protection of Ecological Environment, Guizhou Normal University, Guiyang 550001, China

Sustainability, 2020, vol. 12, issue 18, 1-19

Abstract: The content of heavy metals in the soil in Guizhou Province, which is a high-risk area for heavy metal exposure, is significantly higher than that in other areas in China. Therefore, the objective of this study was to evaluate the ability of CaCO 3 and clay to accumulate heavy metals in topsoil sample collected from Lixisol using the method of indoor simulation. The results showed that the contents of Cu, Zn, Cd, Cr, Pb, Hg and As in the soil sample were 10.8 mg/kg, 125 mg/kg, 0.489 mg/kg, 23.5 mg/kg, 22.7 mg/kg, 58.3 mg/kg and 45.4 mg/kg, respectively. The soil pH values increased with the CaCO 3 concentration in the soil, and the fluctuation of the soil pH values was weak after the CaCO 3 concentrations reached 100 g/kg. The adsorption capacity of lime soil increased by approximately 10 mg/kg on average, and the desorption capacity decreased by approximately 300 mg/kg on average. The desorption of all heavy metals in this study did not change with increasing clay content. Pseudo-second-order kinetics were more suitable for describing the adsorption kinetics of heavy metals on the soil material, as evidenced by the higher R 2 value. The Freundlich model can better describe the adsorption process of As on lime soil. The process of As, Cr, Cd and Hg adsorption on the soil sample was spontaneous and entropy-driven. Additionally, the process of Cu and Pb adsorption on the soil materials was spontaneous and enthalpy-driven. Generally, the adsorption and desorption of heavy metals in polluted soil increased and decreased, respectively, with increasing CaCO 3 content. The effect of calcium carbonate on the accumulation of heavy metals in soil was greater than that of clay. In summary, CaCO 3 and pH values in soil can be appropriately added in several areas polluted by heavy metals to enhance the crop yield and reduce the adsorption of heavy metals in soils.

Keywords: heavy metals; Guizhou Province; CaCO 3; clay; pseudo-second-order kinetic; Freundlich model (search for similar items in EconPapers)
JEL-codes: O13 Q Q0 Q2 Q3 Q5 Q56 (search for similar items in EconPapers)
Date: 2020
References: View complete reference list from CitEc
Citations: View citations in EconPapers (2)

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