【摘要】 研究了腐殖酸浓度、溶液pH、温度以及无机离子等对Pu（Ⅵ）还原的影响,测定了Pu（Ⅵ）在模拟地下水中的还原速率。实验结果表明,随着腐殖酸浓度的增加、溶液pH的增大和温度的升高,Pu（Ⅵ）的还原速率明显加快。Fe²⁺、F^-和SO₄^2-等离子对Pu（Ⅵ）还原速率也有很大影响。更多还原

【Abstract】 The composition of groundwater is very complicated. It contains inorganic ions and dissolved organic compounds (DOC).As one aspect of the environmental chemistry of the actinide elements,the influences of inorganic ions,concentration of humic acid,pH value of the solution and temperature, etc. on reduction rate of Pu (Ⅵ) are studied. The results indicate that the reduction rate of Pu (Ⅵ) is proportional to the concentration of Pu (Ⅵ). With the increasing humic acid concentration and the pH value, the reduction of Pu (Ⅵ) accelerates obviously. The rate equation of reduction reaction of Pu (Ⅵ) is; - d[Pu(Ⅵ)]/dt= k[Pu(Ⅵ)][HA]0.52[H+]-0.069The reduction rate of Pu(Ⅵ) increases with the increase of temperature. Because the temperature of deep groundwater is so high, it can be estimated that the reduction of Pu (Ⅵ) would be very fast in deep underground condition.The influences of Na+ ,K+ ,Ca2+ ,Mg2+ ,NO3- ,HCO3- and HPO42- etc. on the reduction of Pu (Ⅵ) are not significant, but the existence of Fe2+ ,F- and SO42- accelerates the reduction of Pu( Ⅵ) obviously.The reduction behaviour of Pu (Ⅵ) in simulated groundwater is plotted. It can be seen that the curves of the Pu (Ⅵ) content against reaction time can be devided into two straight lines. The possible reason of decreasing slope of Pu (Ⅵ) reduction could be explained by the fact that under the open experimental condition,Fe2- could not exist for a long period,thus causing the gradual lowering of the reduction power.更多还原