摘要
土壤中砷(As)的生物可利用性、迁移、转化及归宿在很大程度上依赖于其在土壤中的吸附反应。本文首先概述了土壤中As污染物的主要形态、价态及其与吸附的关系,较为系统地介绍了土壤中As吸附的主要影响因素和土壤中As吸附机理等方面的最新研究进展,并重点对X-射线吸收精细结构光谱(XAFS)、红外光谱(IR)等现代分析技术和方法在As吸附研究中的应用和进展进行了论述。由于土壤组分与结构的复杂性,As在环境介质中的吸附机理研究目前仍集中在单纯矿物上的吸附行为,为As在土壤中的吸附研究提供了理论基础。X-射线吸收精细结构光谱及红外光谱研究结果证明As在土壤中的吸附主要与含Fe、Al等矿物结合,形成以双齿双核结构为主的配位结构:其吸附机理与土壤矿物及As污染物的价态、吸附浓度等有关,主要包括表面络合反应和表面沉淀作用;但是土壤中As吸附机理研究还需要进一步深入研究。文章最后分析了有关土壤中As吸附研究的发展趋势和重要动向。
Bioavailability, mobility, transformation and ultimate fate of arsenic in the environment are strongly dependent on the sorption of arsenic by soil. Main forms and valence states of arsenic in the soil and their relationship with arsenic sorption was firstly summarized, and advances in the research on factors affecting arsenic sorption in the soil and mechanisms of arsenic sorption in soils were introduced systematically, with emphasis on development and application of modern analytical instruments and methods, such as X-ray absorption fine structure spectroscopy （XAFS） and infrared spectroscopy （IR）. Owing to the complexity of soil composition and structure, currently the researches on mechanisms of arsenic sorption in environmental media were still focused mainly on sorption behaviors of pure minerals, which may help lay down a theoretic foundation for research on arsenic sorption by the soil. Arsenic was adsorbed in the soil predominantly by soil minerals, such as aluminum and iron minerals, through formation of inner-sphere complexes with bidentate binuclear configurations in the soil. The reactions of arsenic in the soil, such as surface complex reaction and surface precipitation, depended mainly on forms and concentrations of arsenic and composition of minerals in the soil. Much work still needs to be done on arsenic sorption, especially in the real soil. Finally, trends and orientation of the research in this field were analyzed.
出处
《土壤》
CAS
CSCD
北大核心
2008年第3期351-359,共9页
Soils
基金
北京市重大科技攻关项目(D0706007040291)资助。
关键词
砷
吸附
土壤
X-射线吸收精细结构光谱
Arsenic, Sorption, Soil, X-ray absorption fine structure spectroscopy
