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Heavy metal pollution in landfill soil poses a dual challenge of environmental toxicity and resource depletion. Enzyme-induced carbonate precipitation (EICP) was systematically evaluated as a sustainable stabilization method for cadmium (Cd), lead (Pb), and chromium (Cr) under both solution- and soil-phase conditions. Laboratory-scale experiments demonstrated that EICP achieved over 80% removal efficiency for Cd, Pb, and copper (Cu) in solution-phase systems, while soil-phase trials focused on Cd, Pb, and Cr to simulate realistic field conditions. Optimal performance was achieved using a 1:1 molar ratio of soybean-derived urease (1.0 U/mL) to CaCl2 (0.5 M), with Cd stabilization reaching 91.5%. Vacuum-assisted filtration improved treatment uniformity by 29.2% in clay soils. X-ray diffraction identified crystalline otavite in Cd systems, while Pb and Cu were stabilized via surface adsorption. Sequential extraction confirmed that over 70% of Cd was transformed into carbonate-bound phases. Treated soils met TCLP leaching standards and reuse criteria, maintaining neutral pH (7.2-8.1) and low salinity. Compared to cement-based methods, EICP avoids CO2 release from calcination and fossil fuel use. Carbon in urea is retained as solid CaCO3, reducing emissions by 0.3-0.5 t CO2-eq per ton of soil. These findings support EICP as a scalable, low-carbon alternative for landfill soil remediation.
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SUSTAINABILITY
Year: 2025
Issue: 10
Volume: 17
3 . 3 0 0
JCR@2023
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ESI Highly Cited Papers on the List: 0 Unfold All
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30 Days PV: 1