Remediation of Cd- and Pb- contaminated clay soils through combined freeze-thaw and soil washing

Rui, Dahu; Wu, Zhipeng; Ji, Mingchng; Liu, Jianfei; Wang, Shuren; Ito, Yuzuru

doi:10.1016/j.jhazmat.2019.02.038

Cited by 79 publications

(25 citation statements)

References 34 publications

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“…It is mainly derived from anthropogenic activities, including mining, electroplating, metallurgy and other industries. 1,2 Multiple heavy metals (including Cd, Cr, Pb, Zn and Hg) 3,4 represent a threat to the environment and human health due to their persistence in soil and potential uptake by crops. 5 Therefore, the remediation of soil contaminated by heavy metals, particularly in combination with different pollutants, is of practical signicance.…”

Section: Introductionmentioning

confidence: 99%

Simultaneous removal of multiple heavy metals from soil by washing with citric acid and ferric chloride

et al. 2020

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Section: Introductionmentioning

confidence: 99%

Simultaneous removal of multiple heavy metals from soil by washing with citric acid and ferric chloride

et al. 2020

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“…The third pattern is where the value of k. decreased during early the freeze-thaw cycle, and then increased as the duration of the freeze-thaw cycle increased, as seen in C2.5S2.5Pb1, C5S2.5F2.5Pb1, and C2.5Pb1. The reason for the decline is as seen in the second trend with the reason for the subsequent increase being that the freeze-thaw cycle relieved the excessive cementation of the soil before continuing to destroy the original structure of the soil particles, causing the formation of polygonal shrinkage cracks and a reduction in the volume of fine powder in the pores of the coarse fraction, which eventually appeared as an increase in k [74,75]. The reason why the k values of C5S5Pb1 and C5F5Pb1 did not appear to rise was that their binder contents were higher, and thus, their degrees of cementation were higher.…”

Section: Discussionmentioning

confidence: 95%

“…As mentioned earlier, an excessive binder dosage can result in too many hydration products occurring, which leads to excessive cementation and compaction of solidified contaminated soil, widening the seepage channels and thus eventually increasing k [62,73]. The freezing and thawing cycle then destroys the big aggregates, though the frozen and thawed soil particles might not completely return to their original positions, causing excessive cementation and making the compact soil become loose and split into small aggregates, causing seepage channels to be blocked and making k decrease [61,63,74].…”

Section: Discussionmentioning

confidence: 99%

Influence of Freeze–Thaw Cycles and Binder Dosage on the Engineering Properties of Compound Solidified/Stabilized Lead-Contaminated Soils

Zhong

Wang

et al. 2020

IJERPH

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The solidification/stabilization (S/S) method is the usual technique for the remediation of soils polluted by heavy metal in recent years. However, freeze-thaw cycles, an important physical process producing weathering of materials, will affect the long-term stability of engineering characteristics in solidified contaminated soil. In addition, it is still questionable whether using large dosages of binders can enhance the engineering properties of solidified/stabilized contaminated soils. In this study, the three most commonly used binders (i.e., cement, quicklime, and fly ash), alone and mixed in different ratios, were thus added to lead-contaminated soil in various dosages, making a series of cured lead-contaminated soils with different dosages of binders. Afterward, unconfined compression strength tests, direct shear tests, and permeability tests were employed on the resulting samples to find the unconfined compressive strength (UCS), secant modulus (E 50 ), internal friction angle (ϕ), cohesion (c), and permeability coefficient (k) of each solidified/stabilized lead-contaminated soil after 0, 3, 7, and 14 days of freeze-thaw cycles. This procedure was aimed at evaluating the influence of freeze-thaw cycle and binder dosage on engineering properties of solidified/stabilized lead-contaminated soils. Results of our experiments showed that cement/quicklime/fly ash could remediate lead-contaminated soils. However, it did not mean that the more the dosage of binder, the better the curing effect. There was a critical dosage. Excessive cementation of contaminated soils caused by too much binder would result in loss of strength and an increase in permeability. Furthermore, it was found that UCS, E 50 , ϕ, c, and k values generally decreased with the increase in freeze-thaw cycle time-a deterioration effect on the engineering characteristics of solidified lead-contaminated soils. Avoiding excessive cementation, 2.5% cement or quicklime was favorable for the value of E 50 while a 2.5% fly ash additive was beneficial for the k value. It is also suggested that if the freeze-thaw cycle continues beyond the period supported by excessive cementation, such a cycle will rapidly destroy the original structure of the soil and create large cracks, leading to an increase in permeability. The results also showed that the contaminated soils with a larger dosage of binders exhibited more significant deterioration during freeze-thaw cycles.

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“…To remediate PTE-contaminated soils and reduce the exposure possibility, several approaches are developed and applied, including solidification (Tantawy et al, 2012), elution (Rui et al, 2019), phytoremediation (Jiang et al, 2018;Jin et al, 2019). Stabilization aims to adsorb or reduce PTEs, transferring unstable PTEs into stable phases with less availability, e.g., hydroxides and minerals (Wang and Vipulanandan, 2001;Yuan et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

Interrogating cadmium and lead biosorption mechanisms by Simplicillium chinense via infrared spectroscopy

Jin

Xie

Zhang

et al. 2020

Environmental Pollution

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show abstract

Remediation of Cd- and Pb- contaminated clay soils through combined freeze-thaw and soil washing

Cited by 79 publications

References 34 publications

Simultaneous removal of multiple heavy metals from soil by washing with citric acid and ferric chloride

Simultaneous removal of multiple heavy metals from soil by washing with citric acid and ferric chloride

Influence of Freeze–Thaw Cycles and Binder Dosage on the Engineering Properties of Compound Solidified/Stabilized Lead-Contaminated Soils

Interrogating cadmium and lead biosorption mechanisms by Simplicillium chinense via infrared spectroscopy

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