Kumpiene Jurate, Lagerkvist Anders, Maurice Christian
Division of Waste Science and Technology, Luleå University of Technology, SE-97187 Luleå, Sweden.
Waste Manag. 2008;28(1):215-25. doi: 10.1016/j.wasman.2006.12.012. Epub 2007 Feb 22.
The spread of contaminants in soil can be hindered by the soil stabilization technique. Contaminant immobilizing amendments decrease trace element leaching and their bioavailability by inducing various sorption processes: adsorption to mineral surfaces, formation of stable complexes with organic ligands, surface precipitation and ion exchange. Precipitation as salts and co-precipitation can also contribute to reducing contaminant mobility. The technique can be used in in situ and ex situ applications to reclaim and re-vegetate industrially devastated areas and mine-spoils, improve soil quality and reduce contaminant mobility by stabilizing agents and a beneficial use of industrial by-products. This study is an overview of data published during the last five years on the immobilization of one metalloid, As, and four heavy metals, Cr, Cu, Pb and Zn, in soils. The most extensively studied amendments for As immobilization are Fe containing materials. The immobilization of As occurs through adsorption on Fe oxides by replacing the surface hydroxyl groups with the As ions, as well as by the formation of amorphous Fe(III) arsenates and/or insoluble secondary oxidation minerals. Cr stabilization mainly deals with Cr reduction from its toxic and mobile hexavalent form Cr(VI) to stable in natural environments Cr(III). The reduction is accelerated in soil by the presence of organic matter and divalent iron. Clays, carbonates, phosphates and Fe oxides were the common amendments tested for Cu immobilization. The suggested mechanisms of Cu retention were precipitation of Cu carbonates and oxy-hydroxides, ion exchange and formation of ternary cation-anion complexes on the surface of Fe and Al oxy-hydroxides. Most of the studies on Pb stabilization were performed using various phosphorus-containing amendments, which reduce the Pb mobility by ionic exchange and precipitation of pyromorphite-type minerals. Zn can be successfully immobilized in soil by phosphorus amendments and clays.
土壤稳定化技术可以抑制污染物在土壤中的扩散。污染物固定化改良剂通过引发各种吸附过程来减少微量元素的淋溶及其生物有效性：吸附到矿物表面、与有机配体形成稳定络合物、表面沉淀和离子交换。以盐的形式沉淀和共沉淀也有助于降低污染物的迁移性。该技术可用于原位和异位应用，以对工业破坏地区和矿渣进行修复和重新植被，通过稳定剂和工业副产品的有益利用来改善土壤质量并降低污染物迁移性。本研究概述了过去五年中发表的关于一种类金属（砷）和四种重金属（铬、铜、铅和锌）在土壤中固定化的数据。用于固定砷的研究最广泛的改良剂是含铁材料。砷的固定化通过砷离子取代表面羟基吸附在铁氧化物上，以及通过形成无定形铁（III）砷酸盐和/或不溶性次生氧化矿物来实现。铬的稳定化主要涉及将其有毒且易迁移的六价形式Cr(VI)还原为在自然环境中稳定的Cr(III)。土壤中有机物和二价铁的存在会加速这种还原。粘土、碳酸盐、磷酸盐和铁氧化物是测试用于固定铜的常见改良剂。建议的铜保留机制是碳酸铜和羟基氧化铜的沉淀、离子交换以及在铁和铝羟基氧化物表面形成三元阳离子 - 阴离子络合物。大多数关于铅稳定化的研究使用了各种含磷改良剂，这些改良剂通过离子交换和磷氯铅矿型矿物的沉淀来降低铅的迁移性。锌可以通过磷改良剂和粘土成功固定在土壤中。
