氧化铁矿物对重金属离子的吸附及其表面特征

SURFACE CHARACTERS OF IRON-(HYDRO) OXIDES AND THEIR ADSORPTION OF HEAVY METAL IONS

杂质和复杂的微形貌导致铁（氢）氧化矿物表面的能量和结构高度不均一。能量高、配位数低的位置吸附力强。电荷和离子半径决定了重金属离子的吸附能力。由于表生地球化学过程中的吸附过程几乎都与流体有关，流体的pH值主要通过对铁氧化物的影响来影响吸附过程，pH值的变化改变了铁氧化物表面羟基的分布，即改变表面吸附位置的结构，进而影响铁氧化物的吸附能力。铁（氢）氧化物的表面结构极其复杂，现有的吸附理论从不同的角度出发，在一定程度上解释了铁（氢）氧化物的吸附行为，但也存在许多问题。

This paper reviews the current theories about the adsorption o f heavy metal ions on the surfaces of iron-(hydro) oxides and discusses the che mical reactivities of different sites based on surface characters of iron-(hydr o) oxide minerals. Impurities and complicated micro-morphisms of minerals lead to heterogeneities of energy and surface structures. Usually the adsorbing abili ties of heavy metal ions depend on their charges and radius. The sites with high energy and low coordinations have strong adsorbing abilities. In most geochemic al processes, fluids would affect the adsorbing abilities via pH. Variation in p H value will change the surface structures of iron-(hydro) oxides.