摘要
研究了ＨＮＯ３介质中羟胺还原微量Ｐｕ（Ⅳ）（ｃ（Ｐｕ（Ⅳ））≤１０－５ｍｏｌ／Ｌ）的动力学。测定了酸度、羟胺、Ｐｕ（Ⅳ）、Ｐｕ（Ⅲ）和ＮＯ－３浓度对微量Ｐｕ（Ⅳ）还原速率的影响，得到羟胺还原微量Ｐｕ（Ⅳ）的速率方程：－ｄｃ（Ｐｕ（Ⅳ））ｄｔ＝ｋ′０ｃ２（Ｐｕ（Ⅳ））ｃ１．８（ＮＨ３ＯＨ＋）ｃ２（Ｐｕ（Ⅲ））ｃ３．６（Ｈ＋）（Ｋｄ＋ｃ（ＮＯ－３））２２０℃时，速率常数ｋ′０＝（０．０１８８±０．００２８）ｍｏｌ４．８·Ｌ－４．８·ｍｉｎ－１。Ｐｕ（Ⅳ）的还原速率随温度提高而显著加快，其表观活化能为１４７ｋＪ／ｍｏｌ。同时讨论了羟胺还原微量Ｐｕ（Ⅳ）的反应机理。
eaction kinetics of trace Pu(Ⅳ)(c(Pu(Ⅳ))≤10-5 mol/L) with hydroxylamine in nitric acid solution is investigated.The effects of concentrations of Pu(Ⅳ),Pu(Ⅲ),NO_3^- ,H^+ and hydroxylamine on the reduction rate of trace Pu(Ⅳ) are examined.The rate law of reaction of trace Pu(Ⅳ) with hydroxylamine is as follows:-dc(Pu(Ⅳ))dt=k′0c2(Pu(Ⅳ))·c18(NH3OH+)c2(Pu(Ⅲ))·c3.6(H+)·(Kd+c(NO-3))2The value of k′0 at 20℃ is (0.0188±0.0028) mol4.8· L-4.8·min-1.The reduction rate of Pu(Ⅳ) increases obviously with increasing temperature and the apparent activation energy with k′0 is equal to 147 kJ/mol.The reaction mechanism of trace Pu(Ⅳ) with hydroxylamine is discussed.
出处
《核化学与放射化学》
CAS
CSCD
北大核心
1998年第2期65-74,共10页
Journal of Nuclear and Radiochemistry
关键词
还原动力学
羟胺
钚
PUREX流程
硝酸
Kinetics of reduction Trace Pu(Ⅳ) Hydroxylamine Nitric acid
