Combined Remediation towards Cadmium–Arsenic-Contaminated Soil via Phytoremediation and Stabilization

Chenxu Zhang, Jiamei Wu and Jian Cao ()
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Chenxu Zhang: School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, China
Jiamei Wu: School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, China
Jian Cao: School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, China

Resources, 2023, vol. 12, issue 9, 1-17

Abstract: Using a phytoremediation technique for soil remediation usually takes many years, which increases the risk that heavy metals spread into the environment during the project period. Currently, the combined remediation technique (phytoremediation and stabilization) is known as the solution to reduce this risk. In this study, the combined remediation of cadmium–arsenic-contaminated soil via phytoremediation and stabilization was studied. The pot experiment was carried out using modified fly ash (MFA) and solid waste material (steel slag (SS): pyrolusite (PY): ferrous sulfide (FS) = 1:2:8) as stabilization materials and Bidens pilosa as the accumulative plant. The characteristics of B. pilosa , including its water content, biomass, root length, plant height, and heavy metal content, were obtained after harvesting, and the reduction rate of the bioavailability of Cd and As and their physico-chemical properties, including the pH, Eh, and Ec values of the soil, were also measured. The remediation effect was evaluated according to the above indexes, and the mechanism of combined remediation was studied through the FTIR, XRD, and XPS analyses. These experiments have shown that adding an appropriate amount of MFA can enhance the absorption of heavy metals by plants in the soil and reduce the bioavailability of heavy metals in contaminated soil. In addition, the mechanism study revealed that Cd 2+ /Cd(OH) + was easily adsorbed on Si-OH and MnOOH, while AsO 4 3− was more easily adsorbed on Fe-OH and Al-OH.

Keywords: heavy metal; modified fly ash; phyto-extraction; soil remediation; solidification (search for similar items in EconPapers)
JEL-codes: Q1 Q2 Q3 Q4 Q5 (search for similar items in EconPapers)
Date: 2023
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