科研之友
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摘要
Thermal treatments commonly used to remedy organic-contaminated soils can inadvertently impact the behavior of non-targeted pollutants, notably heavy metal(loid)s in soil. This study introduces an integrated calcination-stabilization remediation strategy employing steel slag as a stabilizing agent, with a focus on elucidating the transformations and remobilization tendencies of As, Cr, and Cd. Thermal treatment alters the mobility of these elements by modifying soil properties, with pH and redox conditions playing pivotal roles. After anaerobic calcination, the leaching concentrations of As reached 163 mu g L-1, far surpassed 7.57 mu g L-1 after the aerobic calcination. Although Cr and As share oxygen-containing anion forms, they display opposing leaching tendencies after thermal treatment. At 400 degrees C, Cr leaching from aerobically treated soil reaches 64.5 mg L-1, dropping to 6.63 mg L-1 after anaerobic heating due to pH-induced Cr(OH)3 formation. Thermal treatment significantly amplifies the leaching of Cd cations. In contrast to the leaching concentration of 122 mu g L-1 in the untreated soil, aerobic and anaerobic heating (400 degrees C) resulted in leaching concentrations of 896 mu g L-1 and 132 mu g L-1, respectively. Noteworthy, the integrated treatment (400 degrees C anaerobically) decreases leached As and Cd con-centrations to 68.3 mu g L-1 and 15.4 mu g L-1, attributed to stabilizer alkalinity and porosity. Column leaching shows initial rapid release followed by continuous behavior for As and Cd, with the average leaching concen-trations of the remediated soil decreasing to 60.5 mu g L-1 and 1.32 mu g L-1, ensuring safe backfilling. In conclusion, this study contributes to the understanding of the mobility and stabilization of heavy metal(loid)s subsequent to the integrated calcination-stabilization process.
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单位中山大学; 华南农业大学; 中国科学院
