钼在自然界主要以四价与六价存在，在氧化条件下主要以含氧阴离子MoO42-存在，因此，在空气氧化与选冶作用下，矿体中MoS2被氧化为MoO42-进入水体，并伴有酸化与SO42-升高的特点。沉积物中铁氧化矿物对Mo的吸附作用，是影响钼在环境中迁移转化的重要机制，目前制约铁氧化矿物表面Mo吸附机理研究的主要问题是：MoO42-在铁氧化矿物表面的吸附层位与构型存在显著争议，导致现有模型无法预测水体中存在SO42-等竞争性离子时矿物对Mo的吸附性，原因在于单独依靠XAFS表征所得矿物表面Mo-O、Mo-Fe键长等信息，在确定吸附层位与构型时存在多解性，因此，本课题采用铁氧化矿物表面Mo分子形态XAFS表征与分子动力学计算相结合的方法，查明水铁矿、针铁矿、赤铁矿表面钼的吸附层位与构型，建立能准确预测矿区水系不同SO42-浓度背景下铁氧化矿物对Mo的吸附模型，研究成果对矿区水系中钼污染防治具有重要意义。

Molybdenum mainly exists as the valence of Mo(Ⅳ) and Mo(Ⅵ). At the oxidative condition, molybdenum predominantly exists as MoO42-, therefore, MoS2 in the ore body will be oxidized into MoO42- which will enter into the water, in accompany with acidification and SO42-. Adsorption of molybdenum by ferric minerals has been proved to be the major component controlling the fate of molybdenum in the migration. The major problem inhibiting the understanding the molybdenum adsorption mechanism on the ferric minerals is there is strong controversy about whether the molybdenum adsorption exists as the outer-sphere or inner-sphere. Moreover, the specific molybdenum adsorption structure on ferric mineral is still not determined yet. The reason is that we can’t identify the specific molybdenum adsorption structure only based on the bond length of Mo-O, Mo-Fe from the XAFS characterization. To resolve this problem, this proposal combined the application of XAFS result with molecular dynamics simulation to identify the molybdenum sorption sphere and structure on the goethite, ferrihydrite and hematite. We will construct a new surface complexation model to accurately predict the molybdenum adsorption on ferric minerals, even in the presence of competitive anions like SO42-. Result of our study will have an important significance for the pollution remediation of molybdenum in the mining environment.