摘要
铬含量超标威胁生态环境安全,探究多种粘土矿物作用下铬的迁移转化机理,可以为铬污染土壤修复提供理论依据。主要从粘土矿物对铬的氧化-还原、吸附-解吸、催化作用等几个方面归纳分析了粘土矿物作用下铬迁移转化机理的研究现状,探讨了氧化物及微生物作用、pH、温度、有机质、矿物类型等因素对铬迁移转化的影响。首先,锰氧化物是氧化Cr(Ⅲ)的唯一天然矿物,其结构中Mn(Ⅱ)或Mn(Ⅲ)含量越高,氧化能力越强;低温、碱性条件下,Cr(Ⅲ)稳定性较高。锰氧化细菌会加速Cr(Ⅲ)的氧化,矿物表面吸附的Mn(Ⅱ)会抑制Cr(Ⅲ)的氧化。其次,黄铁矿、黑云母、绿泥石、柯绿泥石、磁铁矿等矿物常用于Cr(Ⅵ)还原,黄铁矿组成中的Fe(Ⅱ)和S22-能有效地还原Cr(Ⅵ),而黑云母、绿泥石只有经生物作用产生Fe(Ⅱ)才能还原Cr(Ⅵ),蒙脱石、伊利石、高岭石、黄铁矿对Cr(Ⅵ)的还原速率在pH<4.5时较大。最后,高岭石、伊利石、蛭石、蒙脱石可吸附固持Cr(Ⅵ),且酸性、有机质含量低的条件下吸附效果明显,吸附顺序为:高岭石>伊利石>蛭石≈蒙脱石;粘土矿物层间结合比表面结合更强,可对粘粒矿物进行改性以提高吸附效果。在吸附机理方面,研究者广泛采用Langumiur、Freundlich等方程来描述矿物对铬的吸附。粘土矿物作用下铬的迁移转化机理探究,可以使我们更加深入的了解沉积物、土壤对铬的解毒原理以及矿物在其中所起的作用,这对于矿物材料吸附性能的提高、铬污染土壤的治理具有深远的意义。
Excessive chromium content threatens the ecological environment.It could provide theoretical basis for the restoration of chromium contaminated soil to explore the mechanism of migration and transformation of chromium under the action of clay minerals.In this paper,the research status of the migration and transformation mechanism of chromium under the action of clay minerals is summarized and analyzed from the aspects of oxidation-reduction,adsorption-desorption and catalysis of clay minerals.The effects of oxides and microorganisms,pH,temperature,organic matter and mineral types on the migration and transformation of chromium were discussed.Firstly,manganese oxide was the only natural mineral that oxidizes Cr(Ⅲ).The higher the content of Mn(Ⅱ)or Mn(Ⅲ),the stronger the oxidizing ability of manganese oxide.The stability of Cr(Ⅲ)was high under low temperature and alkaline conditions.Manganese oxidizing bacteria could accelerate the oxidation of Cr(Ⅲ), however,Mn(Ⅱ)adsorbed on the mineral surface would inhibit the oxidation of Cr(Ⅲ).Secondly,minerals such as pyrite,biotite,chlorite,chlorite,magnetite were often used for Cr(Ⅵ)reduction,and Fe(Ⅱ)and S22-in pyrite composition could effectively reduce Cr(Ⅵ),biotite and chlorite could reduce Cr(Ⅵ)only by Fe(Ⅱ)produced by biological action.The reduction rate of Cr(Ⅵ)by montmorillonite,illite,kaolinite and pyrite was higher at pH<4.5.Finally,Kaolinite,illite,vermiculite and montmorillonite could adsorb and hold Cr(Ⅵ),and the adsorption effect was obvious under the condition of low acidity and organic matter content,and the adsorption order was kaolinite>Illite>vermiculite-montmorillonite.The interlayer bonding of clay minerals was stronger than that of surface bonding,and clay minerals could be modified to improve the adsorption effect.In terms of adsorption mechanism,Langumiur and Freundlich equations were widely used to describe the adsorption of chromium by minerals.The study on the migration and transformation mechanism of chromium under the action of clay minerals can give us a better understanding of the detoxification principle of sediment and soil to chromium and the role of minerals in it.This is of far-reaching significance for the improvement of adsorption properties of mineral materials and the treatment of chromium contaminated soil.
作者
孙亚乔
校康
段磊
王晓冬
SUN Yaqiao;XIAO Kang;DUAN Lei;WANG Xiaodong(School of Environmental Science and Engineering, Chang’an University/Key Laboratory of Subsurface Hydrology and Ecological Effect in Arid Region of Ministry of Education, Xi’an 710054, China)
出处
《生态环境学报》
CSCD
北大核心
2019年第7期1484-1491,共8页
Ecology and Environmental Sciences
基金
国家自然科学基金项目(41877190
41372258)
关键词
铬
粘土矿物
氧化-还原
吸附-解吸
催化
chromium
clay minerals
oxidation-reduction
adsorption-desorption
catalysis
