title: [Stabilization Treatment of Pb and Zn in Contaminated Soils and Mechanism Studies].
abstract: 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.
authors.forename: Wei-qiang
authors.initials: WQ
authors.lastname: Xie
authors.forename: Xiao-mingi
authors.initials: XM
authors.lastname: Li
authors.forename: Can
authors.initials: C
authors.lastname: Chen
authors.forename: Xun-feng
authors.initials: XF
authors.lastname: Chen
authors.forename: Yu
authors.initials: Y
authors.lastname: Zhong
authors.forename: Zhen-yu
authors.initials: ZY
authors.lastname: Zhong
authors.forename: Yong
authors.initials: Y
authors.lastname: Wan
authors.forename: Yan
authors.initials: Y
authors.lastname: Wang
mesh_terms: D017610:Calcium Compounds; D007854:Lead / Q000737:chemistry*; D019216:Metals, Heavy; D008855:Microscopy, Electron, Scanning; D008903:Minerals; D010087:Oxides; D010710:Phosphates; D011189:Potassium Chloride; D017680:Potassium Compounds; D012987:Soil; D012989:Soil Pollutants / Q000737:chemistry*; D014961:X-Ray Diffraction; D015032:Zinc / Q000737:chemistry*
chemical_list: D017610:Calcium Compounds; D019216:Metals, Heavy; D008903:Minerals; D010087:Oxides; D010710:Phosphates; D017680:Potassium Compounds; D012987:Soil; D012989:Soil Pollutants; C471364:pyromorphite; D007854:Lead; D011189:Potassium Chloride; C013216:potassium phosphate; C016538:lime; D015032:Zinc