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Strength, leaching characteristics and microstructure of CGF+P all-solid-waste binder solidification/stabilization Cu(Ⅱ) contaminated soil
Abstract Utilizing solid waste-based binder to solidify/stabilize (S/S) heavy metal contaminated soils is a sustainable approach. This paper implemented microscopic tests on Cu(II)-doped paste and macro-microscopic tests on S/S Cu(II) contaminated pure clay-particles soil (P-CS), pure silt-particles soil (P-ST), pure sand-particles soil (P-SD), and their mixed soil (CSSM), respectively, with CGF+P all-solid-waste binders (abbreviated as CGF+P binders) composed of calcium carbide residue (CCR), ground granulated blast furnace slag (GGBS), fly ash (FA), and phosphogypsum (PG). The results showed that the clay-minerals in soil determine the S/S efficiency, and Cu(II) threshold content exist in the presence of clay-minerals and absent without clay-minerals. The strength of P-CS and CSSM containing clay-minerals first increased and then decreased with the increase of Cu(II) content, while the leached Cu(Ⅱ) were lower than 2 mg/kg. The strength of P-ST and P-SD without clay-minerals decreased gradually, and the leached Cu(Ⅱ) concentration far higher than 2 mg/kg. Cu(II) ions are immobilized by CGF+P paste and clay-minerals in soil. The S/S mechanism of Cu(II) by CGF+P binders rely on precipitation, adsorption, encapsulation, chemical compound, and ion exchange, and the immobilized mechanism of Cu(II) by clay-minerals through electrostatic attraction, ion exchange, and physical adsorption. However, the binder paste and clay-minerals have the immobilization capacity on Cu(II) ions, is related to the component of the binder and the type of clay-minerals, respectively. The findings provided useful reference for the design and development of solid waste-based binders suitable for S/S heavy metal contaminated soils.
Graphical Abstract Display Omitted
Highlights The S/S mechanism of Cu(II) was revealed by using microscopic tests of Cu(II)-doped CGF+P all-solid-waste paste. The S/S mechanism of Cu(II) by CGF+P all-solid-waste binders rely on precipitation, adsorption, encapsulation, chemical compound, and ion exchange. The efficiency of the CGF+P S/S Cu(II) contaminated soils were better than cement. The strength and leaching characteristics of CGF+P S/S Cu(II) contaminated P-CS, P-ST), P-SD, and CSSM were revealed, S/S is the coupling of S/S binder and the clay-minerals in soil. The addition of PG significantly increased the strength of solidified soils but led to a reduction in S/S Cu(II) contaminated soils, which attributed to the retarding effect of Cu(II) and acidic nature of PG.
Strength, leaching characteristics and microstructure of CGF+P all-solid-waste binder solidification/stabilization Cu(Ⅱ) contaminated soil
Abstract Utilizing solid waste-based binder to solidify/stabilize (S/S) heavy metal contaminated soils is a sustainable approach. This paper implemented microscopic tests on Cu(II)-doped paste and macro-microscopic tests on S/S Cu(II) contaminated pure clay-particles soil (P-CS), pure silt-particles soil (P-ST), pure sand-particles soil (P-SD), and their mixed soil (CSSM), respectively, with CGF+P all-solid-waste binders (abbreviated as CGF+P binders) composed of calcium carbide residue (CCR), ground granulated blast furnace slag (GGBS), fly ash (FA), and phosphogypsum (PG). The results showed that the clay-minerals in soil determine the S/S efficiency, and Cu(II) threshold content exist in the presence of clay-minerals and absent without clay-minerals. The strength of P-CS and CSSM containing clay-minerals first increased and then decreased with the increase of Cu(II) content, while the leached Cu(Ⅱ) were lower than 2 mg/kg. The strength of P-ST and P-SD without clay-minerals decreased gradually, and the leached Cu(Ⅱ) concentration far higher than 2 mg/kg. Cu(II) ions are immobilized by CGF+P paste and clay-minerals in soil. The S/S mechanism of Cu(II) by CGF+P binders rely on precipitation, adsorption, encapsulation, chemical compound, and ion exchange, and the immobilized mechanism of Cu(II) by clay-minerals through electrostatic attraction, ion exchange, and physical adsorption. However, the binder paste and clay-minerals have the immobilization capacity on Cu(II) ions, is related to the component of the binder and the type of clay-minerals, respectively. The findings provided useful reference for the design and development of solid waste-based binders suitable for S/S heavy metal contaminated soils.
Graphical Abstract Display Omitted
Highlights The S/S mechanism of Cu(II) was revealed by using microscopic tests of Cu(II)-doped CGF+P all-solid-waste paste. The S/S mechanism of Cu(II) by CGF+P all-solid-waste binders rely on precipitation, adsorption, encapsulation, chemical compound, and ion exchange. The efficiency of the CGF+P S/S Cu(II) contaminated soils were better than cement. The strength and leaching characteristics of CGF+P S/S Cu(II) contaminated P-CS, P-ST), P-SD, and CSSM were revealed, S/S is the coupling of S/S binder and the clay-minerals in soil. The addition of PG significantly increased the strength of solidified soils but led to a reduction in S/S Cu(II) contaminated soils, which attributed to the retarding effect of Cu(II) and acidic nature of PG.
Strength, leaching characteristics and microstructure of CGF+P all-solid-waste binder solidification/stabilization Cu(Ⅱ) contaminated soil
Wu, Yalei (author) / Yang, Junjie (author) / Chang, Ruiqing (author) / Li, Sichen (author) / Kou, Hailei (author)
2023-12-01
Article (Journal)
Electronic Resource
English
Solidification and Stabilization of Heavy Metal—Contaminated Industrial Site Soil Using KMP Binder
British Library Online Contents | 2018
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