Xie Wei-qiang, Li Xiao-mingi, Chen Can, Chen Xun-feng, Zhong Yu, Zhong Zhen-yu, Wan Yong, Wang Yan
Huan Jing Ke Xue. 2015 Dec;36(12):4609-14.
In the present work, the combined application of potassium dihydrogen phosphate, quick lime and potassium chloride was used to immobilize the Pb and Zn in contaminated soils. The efficiency of the process was evaluated through leaching tests and Tessier sequential extraction procedure. The mechanism of stabilization was analyzed by X-ray diffraction (XRD) and scanning electron microscope (SEM) to reveal the mechanism of stabilization. The results showed that the stabilizing efficiency of Pb contaminated soils was above 80% and the leaching concentrations of Pb, Zn were far below the threshold when the ratio of exogenous P and soil (mol · mol⁻¹) was 2:1-4: 1, the dosing ratio of CaO was 0.1%-0.5% ( mass fraction) and the dosage of potassium chloride was 0.02-0. 04 mol. Meanwhile, Pb and Zn in soil were transformed from the exchangeable fraction into residual fraction, which implied that the migration of Pb, Zn in soil could be confined by the stabilization treatment. XRD and SEM analysis revealed that Ca-P-Pb precipitation, lead orthophosphate [PbHP0₄, Pb₃ (PO₄)₂], pyromorphite (Pb-PO₄-Cl/OH) and mixed heavy metal deposits (Fe-PO₄- Ca-Pb-Zn-OH) could be formed after solidification/stabilization in which Pb and Zn could be wrapped up to form a solidified composition and to prevent leaching.
在本研究中，采用磷酸二氢钾、生石灰和氯化钾联合应用来固定污染土壤中的铅和锌。通过浸出试验和Tessier连续提取程序评估该过程的效率。利用X射线衍射（XRD）和扫描电子显微镜（SEM）分析稳定化机制，以揭示稳定化机理。结果表明，当外源磷与土壤的摩尔比为2:1 - 4:1、氧化钙投加比例为0.1% - 0.5%（质量分数）、氯化钾用量为0.02 - 0.04 mol时，铅污染土壤的稳定化效率高于80%，铅、锌的浸出浓度远低于阈值。同时，土壤中的铅和锌从可交换态转化为残渣态，这意味着稳定化处理可限制铅、锌在土壤中的迁移。XRD和SEM分析表明，固化/稳定化后可形成钙磷铅沉淀、磷酸铅[PbHPO₄、Pb₃(PO₄)₂]、磷氯铅矿（Pb - PO₄ - Cl/OH）和混合重金属沉积物（Fe - PO₄ - Ca - Pb - Zn - OH），其中铅和锌可被包裹形成固化组分，防止浸出。
