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首页> 外文期刊>Environmental Science & Technology: ES&T >(Pu(V)O{sub}2){sup}+ Adsorption and Reduction by Synthetic Magnetite (Fe{sub}3O{sub}4)
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(Pu(V)O{sub}2){sup}+ Adsorption and Reduction by Synthetic Magnetite (Fe{sub}3O{sub}4)

机译：（Pu（V）O{子}2）{sup}+ 合成磁铁矿的吸附和还原 （Fe{sub}3O{sub}4）

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摘要

Changes in aqueous- and solid-phase Pu oxidation state were monitored overtime in magnetite (Fe{sub}3O{sub}4) suspensions containing 239{sup left}Pu(V)-amended 0.01 M NaCI. Oxidation state distribution was determined by leaching of Pu into an aqueous phase followed by an ultrafiltration/solvent extraction technique. The capability of the technique to measure Pu oxidation state distribution was verified using 230{sup left}Th(IV), 237{sup left}Np(V), and 233{sup left}U(VI) as oxidation state analogues. Reduction of Pu(V) was observed at all pH values (pH 3 to 8) and magnetite concentrations (10 to 100 m{sup}2 L{sup}(-1)). In the pH range 5 to 8, adsorption was a rate-limiting step, and reduction was mediated by the solid phase; at pH 3 reduction occurred in the aqueous phase. The overall reaction (describing both adsorption and reduction of Pu(V)) was found to be approximately first order with respect to the magnetite concentration and of order -0.34 ± 0.02 with respect to the hydrogen ion concentration. Assuming first order dependence with respect to Pu, the overall reaction rate constant was calculated as k{sub}(rxn) = 4,79 ± 0.62 × 10{sup}(-8) (m{sup}(-2) L){sup}0.99(mol{sup}(-1) L)-0.34(s{sup}(-1)). The Pu(IV) solid-phase species became more stable over time.
机译：在含有 239{sup left}Pu（V） 修正的 0.01 M NaCI 的磁铁矿 （Fe{sub}3O{sub}4） 悬浮液中监测水相和固相 Pu 氧化态的变化。氧化态分布是通过将Pu浸出到水相中，然后进行超滤/溶剂萃取技术来确定的。使用230{sup left}Th（IV）、237{sup left}Np（V）和233{sup left}U（VI）作为氧化态类似物，验证了该技术测量Pu氧化态分布的能力。在所有pH值（pH 3至8）和磁铁矿浓度（10至100 m{sup}2 L{sup}（-1））下均观察到Pu（V）的降低。在pH值为5至8的范围内，吸附是限速步骤，还原由固相介导;在pH 3时，水相发生还原。发现整个反应（描述Pu（V）的吸附和还原）相对于磁铁矿浓度约为一级反应，相对于氢离子浓度约为-0.34±0.02级。假设与Pu的一阶依赖性，总反应速率常数计算为k{sub}（rxn） = 4,79 ± 0.62 × 10{sup}（-8） （m{sup}（-2） L）{sup}0.99（mol{sup}（-1） L）-0.34（s{sup}（-1））。随着时间的推移，Pu（IV）固相物质变得更加稳定。

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