Low-carbon and low-alkalinity stabilization/solidification of high-Pb contaminated soil
Low-carbon and low-alkalinity stabilization/solidification of high-Pb contaminated soil
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DOI：
10.1016/j.cej.2018.06.118
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发表时间：
2018-11
影响因子：
15.1
通讯作者：
Lei Wang;Kequan Yu;Jiang-shan Li;Daniel C W Tsang;C. Poon;Jongchan Yoo;K. Baek;S. Ding;D. Ho
中科院分区：
文献类型：
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作者：
Lei Wang;Kequan Yu;Jiang-shan Li;Daniel C W Tsang;C. Poon;Jongchan Yoo;K. Baek;S. Ding;D. Ho
稳定化/固化（S/S）是一种低成本、高效率的土壤修复方法，但其水化反应延迟和高碳足迹是高铅污染土壤处理的主要限制因素。本研究开发了一种新的低碳方法，将磨细的粒化高炉矿渣（GGBS）和普通波特兰水泥（PC）与富含磷酸盐/硫酸盐的副产物相结合，制备低碱度、高相容性、高强度的S/S工艺用二元水泥（BC）。结果表明，含有大量可交换态和可溶态铅的污染土壤（如，在常规的S/S处理中，Pb（Pb）的析出和吸附（如元素分布图所示）严重干扰了水化产物的形成，而BC体系可以通过沉淀和吸附均匀地分布在BC水合物上来减轻Pb的干扰。因此，BC的毒性特征浸出程序（TCLP）和半动态浸出试验，这是由定量X射线衍射和热重分析证实了上级的环境性能。磷酸二氢钾的加入使Pb的TCLP可溶解性降低了86.9%，Pb的扩散系数降低了69.4%，这是由于形成了不溶性的Pb 3（PO 4）2。同样，焚烧污水污泥灰增强铅稳定，而废磷石膏通过沉淀PbSO 4增加早期强度，虽然物理封装的有效性受到损害，由于减少水合产物。因此，建议的二元粘合剂与选定的添加剂提出了一种新的和低碳的S/S处理高铅靶场土壤修复。
Stabilization/solidification (S/S) is a low-cost and time-efficient method for soil remediation, however, delayed hydration reactions and high carbon footprint are major limitations for the treatment of high-Pb contaminated soil. This study develops a novel and low-carbon approach that combines ground granulated blast furnace slag (GGBS) and ordinary Portland cement (PC) with phosphate-/sulphate-rich byproducts to produce low-alkalinity, high-compatibility, high-strength binary cement (BC) for S/S process. Results show that contaminated soil with a large fraction of exchangeable and soluble Pb (e.g., shooting range sites) severely disturbed the formation of hydration products in conventional S/S treatment, whereas BC system could mitigate the Pb interference via precipitation and sorption evenly distributed on the BC hydrates as shown by elemental mapping. Thus, BC presented superior environmental performance in terms of toxicity characteristic leaching procedure (TCLP) and semi-dynamic leaching tests, which were substantiated by quantitative X-ray diffraction and thermogravimetric analyses. The addition of potassium dihydrogen phosphate reduced TCLP leachability of Pb by 86.9% and Pb diffusion coefficients by 69.4% due to the formation of insoluble Pb3(PO4)2. Similarly, incinerated sewage sludge ash enhanced Pb stabilization, whereas waste phosphogypsum increased early strength via precipitation of PbSO4, although the effectiveness of physical encapsulation was compromised due to reduction in hydration products. Therefore, the proposed binary binders with selected additives present a new and low-carbon S/S treatment for high-Pb shooting range soil remediation.