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利用软件CHEMSPEC模拟计算了Np和Pu在北山地下水中的种态分布以及两者在水合氧化铁上的吸附,并考察了氧化还原电位、酸碱度、溶液中不同离子及其浓度对种态分布的影响.结果表明:Np对环境的氧化还原条件十分敏感,随着pH在3~11范围内不断增加,在还原性以及弱氧化性的环境中主要以正四价形式存在,Np F_2~(2+)、Np(CO_3)_2(OH)_2~(2-)和Np(OH)_4为主要种态,在氧化性较强的环境中以正五价形式存在的种态NpO_2~+、NpO_2CO_3~-和NpO_2(OH)含量会显著上升,Np(V)在水合氧化铁上的总吸附量先快速后缓慢增加,表面吸附种态分别是≡FeOHNpO_2~+与≡FeOHNpO_3~-;Pu主要以正四价形式存在,在pH3~11的范围内,主要种态为PuSO_4~+和Pu(OH)_4,Pu(IV)在水合氧化铁上的总吸附量先增加后减小,pH8.1时达到最大,表面吸附种态为≡FeOHPuO~(2+)与≡FeOHPuO_2.溶液中的其他离子对Np和Pu的种态分布影响顺序分别为HCO_3~->F~->SO_4~(2-)>Cl~-和HCO_3~->SO_4~(2-)>Cl~->F~-.
The software CHEMSPEC was used to simulate the species distribution of Np and Pu in Beishan groundwater and their adsorption on hydrous iron oxide. The effects of redox potential, pH value, different ions in solution and their concentrations on species distribution The results showed that Np was very sensitive to the redox conditions of the environment, with increasing pH in the range of 3-11, mainly in the form of normal tetravalent in the environment of reducing and weak oxidizing. Np F 2 2+ , Np (CO_3) _2 (OH) _2 ~ (2-) and Np (OH) _4 were the main species. The NpO_2 ~ +, NpO_2CO_3 ~ And NpO 2 (OH) increased significantly. The total adsorption capacity of Np (V) on the hydrated iron oxide increased rapidly at first and then slowly. The surface adsorption species were ≡FeOHNpO_2 ~ + and ≡FeOHNpO_3 ~ , The total adsorption capacity of PuSO 4+ and Pu (OH) 4, Pu (IV) on the hydrous iron oxide first increased and then decreased at pH 3- 11, reaching the maximum at pH 8.1 , The surface adsorption species ≡ FeOHPuO ~ (2+) and ≡ FeOHPuO_2. The order of the influence of other ions in solution on the species distribution of Np and Pu were HCO 3 ~ -> F ~ -> SO_4 ~ (2 -)> Cl ~ - and HCO_3 ~ -> SO_4 ~ (2 -)> Cl ~ -> F ~ -.