Na2SO4 modified low-carbon cementitious binder containing commercial low-reactivity metakaolin for heavy metal immobilization: Mechanism of physical encapsulation and chemical binding

Liu, Minghao; Xia, Yan; Zhao, Yading; Chi, Xiaofeng; Du, Jianxin; Du, Donghang; Guo, Junzhen; Cao, Zhenggang

doi:10.1016/j.jobe.2022.105194

Cited by 6 publications

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“…After adding the Fe-Mn material, the mineral facies of the soil were added mica (KAl 2 (AlSi 3 O 10 )(OH) 2 ), gypsum (CaSO 4 •2H 2 O), and feldspar (Or x Ab y An z (x + y + z = 100), with Or, Ab, and An representing KAlSi 3 O 8 , NaAlSi 3 O 8 , and CaAl 2 Si 2 O 8 , respectively). This was due to the hydration reaction between the oxide in the solid waste material and calcium hydroxide, with the reaction equation being as follows [41]: The resulting calcium aluminate hydrate (C-A-H), calcium silicate hydrate (C-S-H and ettringite (AFt) can enhance the fixation of cadmium ions through physical encapsu lation or isotropy between Ca 2+ and Cd 2+ [42,43].…”

Section: Study On the Combined Remediation Mechanismmentioning

confidence: 99%

“…The results showed that the peaks of N KLL, Fe 2s, Cd 3p1, Cd 3p3, Ca 2s, MN-3 and MN-3p in the soil after remediation disappeared. After analysis, it was found that th peak strengths of Si2p at C1s, O1s, and 102 eV and Al2p at 74 eV were weakened, indica The resulting calcium aluminate hydrate (C-A-H), calcium silicate hydrate (C-S-H), and ettringite (AFt) can enhance the fixation of cadmium ions through physical encapsulation or isotropy between Ca 2+ and Cd 2+ [42,43].…”

Section: Study On the Combined Remediation Mechanismmentioning

confidence: 99%

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

Zhang,

Wu,

Cao

2023

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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 Cd2+/Cd(OH)+ was easily adsorbed on Si-OH and MnOOH, while AsO43− was more easily adsorbed on Fe-OH and Al-OH.

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Section: Study On the Combined Remediation Mechanismmentioning

confidence: 99%

Section: Study On the Combined Remediation Mechanismmentioning

confidence: 99%