Review on stabilization/solidification methods and mechanism of heavy metals based on OPC-based binders

Chen, Liyuan; Nakamura, Kimihito; Hama, Takehide

doi:10.1016/j.jenvman.2023.117362

Cited by 44 publications

(5 citation statements)

References 95 publications

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“…As a whole, LF-RMS reduced more than 60% of the heavy metal leaching concentration. Because heavy metal ions were solidified by precipitation, adsorption, encapsulation, and replacement during the generation of gelling substances, the metal leaching concentration of LF-RMS could be reduced [37]. LF-RMS underwent hydration to form Ca(OH) 2 and C-S-H, and a large amount of free Ca 2+ , OH − , and hydroxides were produced in the soil during this process.…”

Section: Environmental Impact Analysismentioning

confidence: 99%

Experimental Study on the Strength and Microstructure of Red Mud-Based Silty Sand Modified with Lime–Fly Ash

Yin,

Yan,

et al. 2024

Buildings

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This study aimed to assess the viability of utilizing lime–fly ash (LF) and red mud (RM) in the modification of silty soil (LF-RMS) for subgrade filling. The primary objective of this research was to analyze the mechanical characteristics and examine the curing mechanisms associated with said modified materials. Different curing times were utilized in the analysis of mechanical properties (e.g., via unconfined compression testing), microstructure (via scanning electron microscopy, X-ray diffraction, and thermogravimetric-differential thermal analysis), and environmental indices (via assessment of corrosivity, heavy metal concentration, and radioactivity) with various dosages of red mud (DRM) and Lime–fly ash (DLF). Analyses of the curing mechanisms, failure modes, microstructures, and degrees of environmental impact associated with LF-RMS were also undertaken. The tests indicated that the unconfined compressive strength (UCS) exhibited an initial increase followed by a decrease as the DRM and DLF levels increased. Additionally, the strength of LF-RMS increased with an increase in curing time. It is worth noting that the specimen composed of 20% LF and 23% RM (D20%LF+23%RM) demonstrated a maximum UCS value of 4.72 MPa after 90 days of curing, which indicates that it has the strongest ability to resist deformation. The strength of the specimen cured for 90 days was 1.4 times higher than that of the specimen cured for 7 days (1.97 MPa). Furthermore, the toxic concentration and radionuclide index of LF-RMS were significantly reduced compared to those of pure RM. The overall concentration of heavy metals in the D20%LF+23%RM specimen decreased by more than 60% after curing for 28 days. The internal irradiation index and the external irradiation index decreased by 1.63 and 1.69, respectively. The hydration products in LF-RMS play a key role in the solidification of heavy metals, and the alkaline environment provided by RM also contributes to the precipitation and replacement of heavy metals. In this study, red mud, fly ash and lime were used to modify silty soil. The central tenets of sustainable development may be achieved through the reuse of RM as a road filler.

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Section: Environmental Impact Analysismentioning

confidence: 99%

Experimental Study on the Strength and Microstructure of Red Mud-Based Silty Sand Modified with Lime–Fly Ash

Yin,

Yan,

et al. 2024

Buildings

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“…It showed that when the dosage of fly ash was 15% or less, the prepared cement did not have the risk of excessive heavy metal leaching. This was because after 28 days of cement hydration, the entire cement body was alkaline, which would promote the precipitation of heavy metals, and the hydrated calcium silicate gel and AFt crystals in the hydration products would also adsorb and encapsulate heavy metals [33], thereby reducing the leaching concentration of heavy metals.…”

Section: Leaching Characteristics Of Heavy Metals In Cementsmentioning

confidence: 99%

Low Temperature Thermal Treatment of Incineration Fly Ash under Different Atmospheres and Its Recovery as Cement Admixture

et al. 2023

Materials

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Municipal solid waste incineration fly ash is classified as hazardous waste because it contains dioxins and a variety of heavy metals. It is not allowed to be directly landfilled without curing pretreatment, but the increasing production of fly ash and scarce land resources has triggered consideration of the rational disposal of fly ash. In this study, solidification treatment and resource utilization were combined, and the detoxified fly ash was used as cement admixture. The effects of thermal treatment in different atmospheres on the physical and chemical properties of fly ash and the effects of fly ash as admixture on cement properties were investigated. The results indicated that the mass of fly ash increased due to the capture of CO2 after thermal treatment in CO2 atmosphere. When the temperature was 500 °C, the weight gain reached the maximum. After thermal treatment (500 °C + 1 h) in air, CO2, and N2 atmospheres, the toxic equivalent quantities of dioxins in fly ash decreased to 17.12 ng TEQ/kg, 0.25 ng TEQ/kg, and 0.14 ng TEQ/kg, and the degradation rates were 69.95%, 99.56%, and 99.75%, respectively. The direct use of fly ash as admixture would increase the water consumption of standard consistency of cement and reduce the fluidity and 28 d strength of mortar. Thermal treatment in three atmospheres could inhibit the negative effect of fly ash, and the inhibition effect of thermal treatment in CO2 atmosphere was the best. The fly ash after thermal treatment in CO2 atmosphere had the possibility of being used as admixture for resource utilization. Because the dioxins in the fly ash were effectively degraded, the prepared cement did not have the risk of heavy metal leaching, and the performance of the cement also met the requirements.

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“…[93]. So, the remediation and detection of pollutant is very essential [94]. In the contemporary era, there has been significant progress in the field of environmental restoration.…”

Section: Impact On Humans and Plantsmentioning

confidence: 99%

Analytical Approaches for the Detection of Heavy Metals and Agrochemicals in the Environment Samples and their Recent Technologies

BHARDWAJ,

PATLE,

JHA

et al. 2023

ajc

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At part per billion (ppb) concentrations, heavy metals and pesticides both pose a significant health risk. Over-ingestion of pesticides and heavy metals in the environment may cause various diseases and effects on human life. So, a systematic analysis for detecting and removing pesticides and heavy metals from the environment is required. This review provides a comprehensive study of the several analytical methodologies employed in the quantification of heavy metal ions and agrochemicals in environmental samples. Furthermore, the detrimental impacts of these substances on both human health and plant life are also discussed. Moreover, a concise overview of the latest developments in the design of nanomaterial-based sensors, specifically focusing on colorimetric and electroanalytical approaches. These sensors are utilized for the detection and analysis of heavy metals and pesticides. In addition, the information garnered from the study will improved the capability to detect and remove contaminants from environmental samples.

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Review on stabilization/solidification methods and mechanism of heavy metals based on OPC-based binders

Cited by 44 publications

References 95 publications

Experimental Study on the Strength and Microstructure of Red Mud-Based Silty Sand Modified with Lime–Fly Ash

Experimental Study on the Strength and Microstructure of Red Mud-Based Silty Sand Modified with Lime–Fly Ash

Low Temperature Thermal Treatment of Incineration Fly Ash under Different Atmospheres and Its Recovery as Cement Admixture

Analytical Approaches for the Detection of Heavy Metals and Agrochemicals in the Environment Samples and their Recent Technologies

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