Adsorption and Desorption of Cd by Soil Amendment: Mechanisms and Environmental Implications in Field-Soil Remediation

Shanshan Li, Meng Wang, Zhongqiu Zhao, Changbao Ma and Shibao Chen
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Shanshan Li: School of Land Science and Technology, China University of Geosciences, Beijing 100083, China
Meng Wang: Key Laboratory of Plant Nutrition and Fertilizer, Ministry of Agriculture/Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100081, China
Zhongqiu Zhao: School of Land Science and Technology, China University of Geosciences, Beijing 100083, China
Changbao Ma: Cultivated Land Quality Monitoring and Protection Center, Ministry of Agriculture, Beijing 100125, China
Shibao Chen: Key Laboratory of Plant Nutrition and Fertilizer, Ministry of Agriculture/Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100081, China

Sustainability, 2018, vol. 10, issue 7, 1-14

Abstract: In China, 1/5 of the total farmland area is Cd-enriched; the wide occurrence of Cd-contaminated soil in China has already posed significant public health risk and deserves immediate action. In situ immobilization has been regarded as one of the most promising agricultural extension-technologies for remediating low-to-medium levels of heavy metal contaminated land in China. Although extensive research has been conducted to examine the effectiveness of different amendments on remediation of Cd-contaminated soils, the influence of changed soil properties on secondary release of Cd from Cd-amendment to soil is rarely known. The objective of this study was to evaluate the effectiveness of four soil amendments (denoted as Ad1, Ad2, Ad3 and Ad4, their main components being clay mineral, base mineral, humus and biochar, respectively) on reducing Cd availability and increasing Cd stability in soil. The maximum adsorption capacity of test amendments on Cd ranged from 7.47 to 17.67 mg g −1 . The characterizations of test amendments before and after Cd loading provided the evidence that surface precipitation and ion exchange were the main reasons for Ad1 and Ad2 to adsorb Cd, and complexation was for Ad3 and Ad4. In addition, there was significant increase in the desorption percentages of Cd from amendments as pH decreased (from 7 to 1) or ion strength increased (from 0 to 0.2 M). Comparatively, Ad3 and Ad4 could be more effective for in situ immobilization of Cd in contaminated soils, due to their high adsorption capacities (12.82 and 17.67 mg g −1 , respectively) and low desorption percentages (4.46–6.23%) at pH from 5 to 7 and ion strengths from 0.01 to 0.1 mol L −1 . The results obtained in this study could provide a guideline for in-situ remediation of Cd polluted field-soil in China.

Keywords: soil amendments; Cd(II); adsorption; desorption; environmental implications (search for similar items in EconPapers)
JEL-codes: O13 Q Q0 Q2 Q3 Q5 Q56 (search for similar items in EconPapers)
Date: 2018
References: View complete reference list from CitEc
Citations: View citations in EconPapers (4)

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